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Hallucinations on Brain Stimulation: Evidence for Revision of the Penfield Hypothesis
Abstract
Visual or auditory hallucinations may accompany epileptic seizures or auras. Penfield reproduced such experiences by electrical stimulation of the temporal lohe cortex. We have found that similar hallucinatory experiences may arise from subcortical stimulation of the temporal lobe. The study of these events yields information pertinent to the processes involved in perception, imagery formation, and memory.
... There is also no evidence that every intrinsic physical property of the human brain ceases to persist when the postmortem tissue is maintained for several years in fixative. The history of direct surgical stimulation of the human brain has produced revealing characteristics of contiguous experiences and how cerebral electrical activity and complex cognition might be correlated [1][2][3][4][5]. Very early in this research, several critical properties about the human brain and the electrical parameters required to elicit experiences or paroxysmal cortical activity became apparent. ...
... Whether or not the results of this experiment require a reevaluation of the explanation of the subjective experiences produced during surgical stimulation over the last decades might only be a philosophical issue. In light of what we hypothesized are conserved intrinsic structural features within the brain which selectively process specific types of signals; the shared experiences of individuals that have historically undergone surgical stimulations [1][2][3][4][5] are now subject to analyses other than only phenomenology. If structure dictates function, then intrinsic organizations in the human brain that are so potent they produce dynamic quantitative effects to appropriate electrical stimulation long after the brain no longer lives may be worthy of further investigation. ...
... Substrate neutrality emerges if we assume that the state-specific character of hallucinations also applies to NDEs. Hallucinations are dependent on states of consciousness (Horowitz and Adams, 1970). The same state of consciousness can produce different phenomena in different individuals. ...
... The same is true for seizures in temporal lobe epilepsy (LaPlante, 1993). If Horowitz and Adams' (1970) hypothesis applies to NDEs as it does to LSD, then the possibility that negative affect is integral to unpleasant NDEs can be reasonably ruled out. The best candidate for the cause of hellish NDEs in our model is resistance, as I shall describe below. ...
Hypothesizes that a near-death experience (NDE) is the subjective experience of having the state of consciousness in which a person experiences the last moment of his or her life being turned, in stages, into the state of consciousness experienced as the “point of no return.” The life review this, as is interpreted as a review of the states of consciousness experienced during our lives. Our responses to reviewing our own behaviors while in specific states reinforces and classifies them into those to repeat in future lives and those to avoid. We examine a modification of the traditional doctrine of reincarnation that takes into account biological and cultural evolution. This allows an understanding of how the attributes of NDEs could have undergone selection even though all opportunities for mating have already passed at the time of death.
... Spontaneous occurrences such as the young woman with temporal lobe epilepsy who reported visualizing a small humanoid that followed her into her automobile [13] could reflect sensitivity to the setting and cognitive state. That context at the time of surgical stimulation affects the details and interpretation of the evoked experiences is well known [14,15] and has been considered a more intense form of ecphory [16]. It is defined as the interaction between the context and the ongoing neurocognitive experiences that eventually determines the details, themes, and attributes of the perception [17]. ...
... Relative low beta(13)(14)(15)(16)(17)(18)(19)(20) Hz) power within the left temporal lobe during the application of a burst-firing magnetic field. Individuals who received treatment exposure over the left temporal lobe showed a decrease in power after 30 min, whereas those who received right hemispheric or sham stimulation showed no significant change. ...
Exotic experiences such as the sensing of another consciousness or the detachment of consciousness from the body are occasionally reported by individuals with partial seizures from a temporal lobe focus. The experiences display the characteristics of Hughlings Jackson's "parasitic consciousness". We have hypothesized that these experiences are encouraged by slight discrepancies in hemispheric activity that can be simulated by application of weak, physiologically-patterned magnetic fields across the cerebral hemispheres. Electroencephalographic and Low Resolution Electromagnetic Tomography (sLORETA) data revealed altered activity bands within specific regions within the cerebral cortices during these experiences. The clear changes in power of brain activity were discerned after consistent durations of exposure to specifically patterned weak magnetic fields. Millisecond range point durations were required. The technology may be useful to explore the subjective components associated with complex partial seizures.
... Penfield and his associates (Penfield & Rasmussen, 1950;Penfield & Jasper, 1954;Penfield & Perot, 1963) have observed that meaningful visual and auditory hallucinations occurred only with electrical stimulation in or near the temporal lobe. Similar results have been obtained by other workers (Mahl et al., 1964;Horowitz & Adams, 1970). Furthermore, a similar response has been observed in one ethically questionable study (Ishibashi et al., 1964) in anatomically healthy brains as opposed to those of patients undergoing surgery for intractable temporal lobe epilepsy. ...
... Nor can hallucinations be reliably produced by repeated stimulation of identical structures in the same patients (e.g. Horowitz & Adams, 1970). This kind of observation is seemingly incompatible with Penfield's thesis that the mechanism is a normal one involving the direct activation of stored records. ...
... From a translational point of view, understanding the causal underpinnings of visual hallucinations induced by local brain stimulation is necessary to develop prosthetic devices that restore vision by direct brain stimulation 8,9 . This knowledge also shapes the building blocks for understanding visual hallucinations in mental disorders and altered states of consciousness [10][11][12] . ...
Neurons in the inferotemporal (IT) cortex respond selectively to complex visual features, implying their role in object perception. However, perception is subjective and cannot be read out from neural responses; thus, bridging the causal gap between neural activity and perception demands independent characterization of perception. Historically, though, the complexity of the perceptual alterations induced by artificial stimulation of IT cortex has rendered them impossible to quantify. To address this old problem, we tasked male macaque monkeys to detect and report optical impulses delivered to their IT cortex. Combining machine learning with high-throughput behavioral optogenetics, we generated complex and highly specific images that were hard for the animal to distinguish from the state of being cortically stimulated. These images, named “perceptograms” for the first time, reveal and depict the contents of the complex hallucinatory percepts induced by local neural perturbation in IT cortex. Furthermore, we found that the nature and magnitude of these hallucinations highly depend on concurrent visual input, stimulation location, and intensity. Objective characterization of stimulation-induced perceptual events opens the door to developing a mechanistic theory of visual perception. Further, it enables us to make better visual prosthetic devices and gain a greater understanding of visual hallucinations in mental disorders.
... Even then, it was known that dopamine is not present uniformly across the brain, and that there are a number of pathways. Meltzer and Stahl (1976) stated that the dopamine hypothesis was supported by the following observations: 1) lesions to the limbic system in animals was found to lead to an impairment of their ability to filter out stimuli and was also associated with disturbances in behaviour (Smythies & Adey, 1966) 2) electrical stimulation of the dorsal hippocampus (which forms part of the outflow of the limbic striatum) has been associated with disruptions to thinking, as well as hallucinations (Horowitz & Adams, 1970) and 3) stimulation or ablation of the limbic system in humans had been shown to induce paranoia, perceptual distortion and impact mood (Torrey & Peterson, 1974). It was also based on amphetamine models, as these pharmacological agents primarily impact dopamine. ...
Psychotic-like experiences (PLEs) include experiences such as hallucinations and delusional thinking that can occur in the absence of a clinical disorder. PLEs peak in middle childhood but appear to spontaneously remit in most children. Nevertheless, their presence, and particularly their persistence, are associated with an increased risk of developing later psychosis and poor psychiatric and social outcomes. However, the mechanisms by which they are generated during childhood are unclear. Existing models of psychosis cite early life experience and childhood neurodevelopment as important but often examine these retrospectively. Furthermore, they suggest mechanisms for how psychotic experiences are generated that are assumed to apply across the lifespan. This assumption has remained untested, however. Consequently, in this thesis, I investigated neurocognitive mechanisms of PLEs in 9-10 year-old-children using data from the Adolescent Brain Cognitive Development (ABCD) study. In Study 1, I examined whether the established mechanistic risk factors in adult psychosis – affective symptoms, traumatic experiences, cognitive function, structural brain changes – are associated with PLEs using network analysis, finding only that depression-related symptoms were associated with PLEs. In Study 2, I tested whether fMRI activation in striatal reward pathways was associated with PLEs in children, as this is an established finding in adults. This study found no strong evidence for alteration to striatal reward pathways with a high likelihood that it was absent, rather than undetectable. Given the prognostic and aetiological important of persistence of PLEs, in Study 3, I tested affective, trauma-related, cognitive and striatal reward activation predictors of 1-year PLE persistence. Only depressive symptoms were substantial predictors. Depressive symptoms emerged as the strongest predictor of PLEs at this developmental stage, both cross-sectionally and longitudinally. The findings indicate that PLEs in childhood are not a ‘mini psychosis syndrome’ and developmental-stage specific models of psychotic experiences in children are required.
... Electrical brain stimulation has never produced accurate perception of anything not visible to the physical eyes, or that persists when the eyes are closed, or that is from an out-of-body perspective-all typical features of spontaneous OBEs (Giesler-Petersen, 2008;Holden et al., 2006). In fact, the vast majority of subjective experiences elicited by external stimulation of the temporal lobes bear no resemblance to NDEs (Horowitz & Adams, 1970), and the vast majority of patients with temporal lobe seizures do not report out-of-body experiences (Devinsky et al., 1989). An epileptologist who himself experienced an NDE noted bluntly: "In spite of having seen hundreds of patients with temporal lobe seizures during three decades of professional life, I have never come across that symptomatology as part of a seizure" (Rodin, 1989, p. 256). ...
... From a translational point of view, understanding the nature of visual hallucinations induced by local brain stimulation is necessary for the development of prosthetic devices that restore vision by direct brain stimulation 9,10 . This knowledge also shapes the building blocks for understanding visual hallucinations in mental disorders and altered states of consciousness [11][12][13] . ...
Neurons in the inferotemporal (IT) cortex respond selectively to complex visual features, implying their role in object perception. However, perception is subjective and cannot be read out from neural responses; thus, bridging the causal gap between neural activity and perception demands independent characterization of perception. Historically though, the complexity of the perceptual alterations induced by artificial stimulation of IT cortex has rendered them impossible to quantify. Here we addressed this old problem by combining machine learning with high-throughput behavioral optogenetics in macaque monkeys. In closed-loop experiments, we generated complex and highly specific images that the animal could not discriminate from the state of being cortically stimulated. These images, named “perceptograms” for the first time, reveal and depict the contents of the complex hallucinatory percepts induced by local neural perturbation in IT cortex. Furthermore, we found that the nature and magnitude of these hallucinations highly depend on concurrent visual input, stimulation location, and intensity. Objective characterization of stimulation-induced perceptual events opens the door to developing a mechanistic theory of visual perception. Further, it enables us to make better visual prosthetic devices and gain a greater understanding of visual hallucinations in mental disorders.
One-Sentence Summary
Combining state-of-the-art AI with high-throughput closed-loop brain stimulation experiments, for the first time, we took “pictures” of the complex and subjective visual hallucinations induced by local stimulation in the inferior temporal cortex, a cortical area associated with object recognition.
... When this duration was specified (for 24.2% of all EBS), it was variable between 2 and 5 s. Some authors only specified a time range for the whole of their study, but do not report accurately the duration of EBS for each reminiscence (3-20 s for 3 EBS, Morris et al., 1984; 5-10 s for 2 EBS, Morris et al., 1984; 0.5-15 s for 8 EBS, Horowitz and Adams, 1970). ...
Electrical Brain Stimulations (EBS) sometimes induce reminiscences, but it is largely unknown what type of memories they can trigger. We reviewed 80 years of literature on reminiscences induced by EBS and added our own database. We classified them according to modern conceptions of memory. We observed a surprisingly large variety of reminiscences covering all aspects of declarative memory. However, most were poorly detailed and only a few were episodic. This result does not support theories of a highly stable and detailed memory, as initially postulated, and still widely believed as true by the general public. Moreover, memory networks could only be activated by some of their nodes: 94.1% of EBS were temporal, although the parietal and frontal lobes, also involved in memory networks, were stimulated. The qualitative nature of memories largely depended on the site of stimulation: EBS to rhinal cortex mostly induced personal semantic reminiscences, while only hippocampal EBS induced episodic memories. This result supports the view that EBS can activate memory in predictable ways in humans.
... The idea that increased excitation of cortical visual areas could lead to the formation of visual hallucinations derived in the nineteenth century from the observations that electrical stimulation of cortical areas in humans can induce several visual phenomena. Specifically, researchers observed that hallucinations of meaningful images were induced in some patients with epilepsies (Penfield and Rasmussen 1950;Penfield and Jasper 1954;Horowitz and Adams 1970) or schizophrenia (Ishibashi et al. 1964) by directly stimulating the temporal lobe. The content of these electrical-induced hallucinations seems to be related to what patients experienced immediate before surgery (Mahl et al. 1964). ...
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT), are famous for their capacity to temporally and profoundly alter an individual’s visual experiences. These visual alterations show consistent attributes despite large inter- and intra-individual variances. Many reports document a common perception of colors as more saturated, with increased brightness and contrast in the environment (“Visual Intensifications”). Environmental objects might be altered in size (“Visual illusions”) or take on a modified and special meaning for the subject (“Altered self-reference”). Subjects may perceive light flashes or geometrical figures containing recurrent patterns (“Elementary imagery and hallucinations”) influenced by auditory stimuli (“Audiovisual synesthesia”), or they may envision images of people, animals, or landscapes (“Complex imagery and hallucinations”) without any physical stimuli supporting their percepts. This wide assortment of visual phenomena suggests that one single neuropsychopharmacological mechanism is unlikely to explain such vast phenomenological diversity. Starting with mechanisms that act at the cellular level, the key role of 5-HT2A receptor activation and the subsequent increased cortical excitation will be considered. Next, it will be shown that area specific anatomical and dynamical features link increased excitation to the specific visual contents of hallucinations. The decrease of alpha oscillations by hallucinogens will then be introduced as a systemic mechanism for amplifying internal-driven excitation that overwhelms stimulus-induced excitations. Finally, the hallucinogen-induced parallel decrease of the N170 visual evoked potential and increased medial P1 potential will be discussed as key mechanisms for inducing a dysbalance between global integration and early visual gain that may explain several hallucinogen-induced visual experiences, including visual hallucinations, illusions, and intensifications.
... Additionally, these " induced out-of-body " illusions are always viewed from the visual perspective of being inside the body, unlike NDEs, and they do not include accurate perceptions of the environment from a spatial perspective distant from the body, as do many NDEs [80,81]. In fact, the vast majority of subjective experiences elicited by stimulation of the temporal lobes are frightening fragments of dreamlike sensations that bear no resemblance to the coherent narratives of NDEs ([82]; [83], pp. 611–55). ...
Near-death experiences (NDEs) are vivid experiences that often occur in life-threatening conditions, usually characterized by a transcendent tone and clear perceptions of leaving the body and being in a different spatiotemporal dimension. Such experiences have been reported throughout history in diverse cultures, and are reported today by 10% to 20% of people who have come close to death. Although cultural expectations and parameters of the brush with death influence the content of some NDEs, near-death phenomenology is invariant across cultures. That invariance may reflect universal psychological defenses, neurophysiological processes, or actual experience of a transcendent or mystical domain. Research into these alternative explanations has been hampered by the unpredictable occurrence of NDEs. Regardless of the causes or interpretations of NDEs, however, they are consistently associated with profound and long-lasting aftereffects on experiencers, and may have important implications for non-experiencers as well.
... NDEs have also been speculatively linked to a number of anatomic locations in the brain, most often the right temporal lobe (Morse et al., 1989;Saavedra-Aguilar and Gómez-Jeria, 1989), based on purported similarity of NDEs to temporal lobe seizure phenomena. However, NDE-like phenomena are almost never seen in temporal lobe seizures (Devinsky et al., 1989;Rodin, 1989), and electrical stimulation of the temporal lobes may elicit fragmented bits of music, isolated and repetitive scenes that seemed familiar, hearing voices, experiencing fear or other negative emotions, or seeing bizarre, dream-like imagery, in addition to a wide range of somatic sensations that are never reported in NDEs (Gloor, 1990;Horowitz and Adams, 1970). Reports of phenomena induced by transcranial magnetic stimulation of the temporal lobes that bear vague resemblance to NDE-like phenomena (Persinger, 1994) have failed attempts at replication and have been attributed to suggestion (Granqvist et al., 2005). ...
CONTEXTO: Quando algumas pessoas vivenciam um estado próximo da morte, elas referem uma experiência profunda de transcender o mundo físico, o que freqüentemente as conduz a uma transformação espiritual. Estas "experiências de quase-morte" (EQMs) são relevantes para os clínicos pois produzem mudanças nas crenças, nas atitudes e nos valores; podem ser confundidas com os estados psicopatológicos, embora tenham conseqüências diferentes necessitando terapêuticas diferentes; e, por fim, porque podem ampliar a nossa compreensão em relação ao fenômeno da consciência. OBJETIVOS: Esta revisão de literatura examina as evidências relacionadas às explicações que têm sido propostas para o fenômeno das EQMs, incluindo expectativa, memórias do nascimento, alterações nos gases sangüíneos, alucinações tóxicas ou metabólicas e modelos neuroquímicos e neuroanatômicos. MÉTODOS: A literatura sobre EQM dos últimos 30 anos foi revisada de modo abrangente, incluindo bases de dados médicas, de enfermagem, psicológicas e sociológicas. RESULTADOS: As EQMs tipicamente produzem mudanças positivas em atitudes, crenças e valores, mas também podem levar a problemas interpessoais e intrapsíquicos. Esses problemas, embora tenham sido comparados a vários transtornos mentais, diferem desses quadros psicopatológicos. Várias estratégias terapêuticas têm sido propostas para ajudar indivíduos que apresentam conseqüências problemáticas de uma EQM, mas tais intervenções ainda não foram testadas. CONCLUSÕES: A consciência mística e o funcionamento mental intensificado durante uma EQM, quando o funcionamento cerebral está gravemente prejudicado, são um desafio para os modelos atuais sobre a interação cérebro/mente e podem, eventualmente, levar a modelos mais completos para o entendimento da consciência.
... This can potentially be explained with reference to the current study. Firstly, it has been found previously that AVHs are inducible by directly electrically stimulating the brain (Horowitz and Adams, 1970;Penfield and Perrot, 1963). Such findings have caused speculation that spontaneous AVHs may be due to the misinterpretation of similar, but spontaneous, neural activity, which is then misinterpreted as being caused by external speech. ...
Discerning a speaker's gender from their voice is a basic and crucial aspect of human communication. Voice pitch height, the perceptual correlate of fundamental frequency, is higher in females and provides a cue for gender discrimination. However, male and female voices are also differentiated by multiple other spectral and temporal characteristics, including mean formant frequency and spectral flux. The robust perceptual segregation of male and female voices is thought to result from processing the combination of discriminating features, which in neural terms may correspond to early sound object analysis occurring in non-primary auditory cortex. However, the specific mechanism for gender perception has been unclear. Here, using functional magnetic resonance imaging, we show that discrete sites in non-primary auditory cortex are differentially activated by male and female voices, with female voices consistently evoking greater activation in the upper bank of the superior temporal sulcus and posterior superior temporal plane. This finding was observed at the individual subject-level in all 24 subjects. The neural response was highly specific: no auditory regions were more activated by male than female voices. Further, the activation associated with female voices was 1) larger than can be accounted for by a sole effect of fundamental frequency, 2) not due to psychological attribution of female gender and 3) unaffected by listener gender. These results demonstrate that male and female voices are represented as distinct auditory objects in the human brain, with the mechanism for gender discrimination being a gender-dependent activation-level cue in non-primary auditory cortex.
... We can offer two reasons for drawing this conclusion. The first is one of the results obtained by a study of hallucinations caused by electrical stimulation deep in the brain (Horowitz & Adams, 1970). In this study, the content of the hallucinations was found to be related to the circumstances in which they occurred, so that the same stimulations could produce different hallucinations. ...
It has been found that there are five million magnetite crystals per gram in the human brain. Interestingly, the meninges, has twenty times that number. These 'biomagnetite' crystals demonstrate two interesting features. The first is that their shapes do not occur in nature, suggesting that they were formed in the tissue, rather than being absorbed from outside. The other is that these crystals appear to be oriented so as to maximize their magnetic moment, which tends to give groups of these crystals the capacity to act as a system. We hypothesize that the entire set of modalities, cognitive and sensory, may be heuristically compared to a sound mixing board. In this metaphor, all the various modalities are represented as vertical rheostats with enhanced functioning increasing towards the top, and suppressed function increas-ing towards the bottom. Further, the act of becoming conscious of phenomena in any given modality involves the ad-justment of that modality's 'rheostat'.
... Os estudos de estimulação cortical de Penfield requerem modificações. O número de experiências alucinatórias eliciadas não é de modo algum grande; o mesmo evento visual se repete raramente HISTÓRIA DA PSICOPATOLOGIA, POR GERMAN E. BERRIOS sob estimulação do mesmo local, a memória para a alucinação é pequena e a alucinação é acompanhada por completa consciência e pouca ou nenhuma resposta emocional (Horowitz & Adams, 1970). A "arteriosclerose cerebral" não pode ser considerada uma explicação suficiente para a presença das alucinações visuais; a distinção entre as alucinações arterioscleróticas dos "pequenas veias" (Giacomo, 1952), ou dos "grandes veias" (Coiffu, 1958) deve ser revista. ...
A literatura, clássica ou recente, sobre os transtornos de percepção nos idosos é revisada. A utilidade do conceito de Síndrome de Charles Bonnet, um epônimo originalmente proposto para descrever as alucinações visuais nos idosos na ausência de prejuízos cognitivos e de oftalmopatia periférica é contestada, principalmente devido à síndrome ter sido progressivamente ampliada. Descrevemos três casos representativos de pacientes idosos que desenvolveram diferentes tipos de transtornos de percepção visual. Propomos a condução de estudos sistemáticos da frequência de tais transtornos nos idosos e de quais outras patologias, particularmente cognitivas e visuais que possam estar associadas a eles.
... Many parapsychological-like experiences (sensed presence of another sentient being, out-of-body experiences, distortions in subjective time, religious reveries) have been reported in association with complex partial seizures with foci within the temporal lobes, particularly the hippocampus and amygdala (Gloor et al., 1982). Direct surgical stimulation of mesiobasal structures within the temporal lobes, particularly in the right hemisphere, evoked comparable experiences (Horowitz & Adams, 1970). Furthermore, individuals who are more prone to parapsychological-like experiences tend to show more prominent alpha rhythms over the temporal lobes (Makarec & Persinger, 1990). ...
Throughout most of the 19th and 20th centuries, trance and mediumistic experiences were regarded as a manifestation of severe mental disorders by most members of the Western scientific community (Almeida, 2007; Moreira-Almeida, Almeida, & Lotufo, 2005) and were usually described as rich in dissociative behavior, hallucinations, feelings of being controlled by an external power, depersonalization, personality shifts, and alleged post-trance amnesia. These phenomena were the subjects of numerous scientific studies around the turn of the 20th century, but scientific interest subsequently declined. However, there has been renewed interest in dissociative and hallucinatory experiences in non-pathological samples, as there is evidence that these experiences often involve people not suffering from mental disorders (Cardeña et al., 1996; Krippner, 1997b; Martinez-Taboas, 1995; Moreira-Almeida, Lotufo, & Greysen, 2007; Moreira-Almeida et al., 2008). These experiences have been widespread in most societies throughout history, and are part of the Greek, Roman, and Judeo-Christian roots of Western society, passed down through oracles, prophets, and shamans (Hastings, 1991). It is often difficult to differentiate the terms "medium" and "channeler" since both claim to refer to receiving information that supposedly does not originate from consensual reality (e.g., from living persons, media, their own memory). Mediums purportedly obtain this information from deceased persons, whereas channelers claim to obtain information from other spiritual entities (e.g., deities, nature spirits, inhabitants of other dimensions; e.g., Hastings, 1991; Klimo, 1998). Although there are several possible definitional approaches to trance and mediumship, for the purposes of the present chapter we define trance as did Wulff (2000): "a state of profound absorption or lack of mental content during which the individual is experientially cut off from the outside world; it is frequently accompanied by vocal and motor automatisms, lack of responsive awareness, and amnesia" (p. 399). Mediumship is defined as an experience in which an individual (the medium) purports to be in communication with, or under the control of, the personality of a deceased person or other nonmaterial being (Moreira-Almeida, Lotufo, & Cardeña, 2008). Frequently, mediumship takes place while the medium is in what Bourguignon (1976) refers to as a "possession trance" in which an alleged incorporeal agency takes possession of a medium's volition, speech, and bodily movements. An interesting fact is that most of the world's population believes in life after death, including the possibility that trance and mediumship can bridge the two, reflecting certain basic assumptions about human nature and cognitive reference points (Peres et al., 2007a, 2007b). The availability of new neurobiological research tools has now opened doors to studying such topics in more sophisticated ways, which may help further understanding of the nature of human consciousness and its relationship with the brain. This chapter reviews neurobiological studies on trance and mediumistic experiences with an emphasis on Brazilian samples, where these continue as a vibrant tradition. We also discuss some crucial methodological issues and the implications of current studies for the mind-brain relationship. Moreover, we report data from two parallel strands of our own investigations conducted in Brazil, namely by the team consisting of Joan H. Hageman, Ian Wickramasekera II, and Stanley Krippner (HWK) and the team of Julio F. P. Peres, Alexander Moreira-Almeida, and Leonardo Caixeta (PAC). The PAC team has studied the neurobiology of mediumship using electroencephalography (EEG) in a group of mediums during their trance state (Caixeta et al., in press), while the HWK team has reported studies on two trance mediums using various neurobiological tools. Krippner was the only member of this team who participated in on-site investigations, and Hageman and her colleagues (Hageman, Krippner, & Wickramasekera II, 2009) also participated in psychophysiological studies of a channeler in the United States.
... Further, there is a higher incidence of the sensed presence among meditators (Persinger, 1992a) than control groups. Because of these observations, the attended breath seemed a good candidate for a means of inducing the positive affective altered state of consciousness upon which the experience of the NDE sensed presence, like any other hallucination, depends (Horowitz, 1970). ...
I describe a guided meditation that, when used by near-death experiencers (NDErs), recreates fragments of their NDEs. The meditation is based on Michael Persinger's neurological theory regarding the “God Experience,” and its success supports that theory. The present study included too few subjects to support quantitative analysis, and must be regarded as a pilot study.
... It has been reported that hallucinatory phenomena are facilitated by altered states of consciousness (Horowitz and Adams, 1970). We might speculate that the altered state of consciousness that occurs in conjunction with OBEs can also facilitate anthropomorphic imagery that conveys the approach of death. ...
Near-death experiences (NDEs) in Thailand do not demonstrate the episodes most noted in those collected in the West, but they do show consistent features. I argue that these features, including harbingers of death, visions of hell, the Lord of the underworld, and the benefits of making donations to Buddhist monks and temples, can be understood within the framework of beliefs and customs unique to Southeast Asia. The simplest explanation is that the phenomenology of NDEs at least in part fulfills the individuals' expectations of what they will experience at death. These expectations are most often derived from the experiencer's culture, subculture, or mix of cultures. Culture-bound expectations are, in turn, most often derived from religion. One case, quoted at length, shows features that suggest that the individual was experiencing stress as a result of living in both Thai and Chinese cultures. Although the phenomenology of Thai NDEs is at variance from those in the West, the typical episodes that appear in each seem to follow a comparable sequencing. This similarity in structure suggests that NDEs in both cultures have a common function.
... Visual phenomena vary from the experience of shadows, entities or colors in the peripheral field to complex animated sequences that are dominated by surrealistic or dream-like features. They contain substantial fantasies that are not always simple reiterations of personal experience (Horowitz & Adams, 1970). ...
The visitor experience, a more intense form of the normal sense of presence, emphasizes the deep belief of personal contact with an extraterrestrial (or religious) entity. Phenomenological details of visitor experiences are expected to reflect the functions of deep temporal lobe structures; common details involve cosmic meaningfulness, vestibular experiences, flickering, complex visual sensations and alimentary references. After intense experiences, interictal-like behaviors similar to religious conversions (widening affect, sense of personal, desire to spread the word, concern about Man's destiny) emerge. Normal people who are prone to these experiences show frequent temporal lobe signs and specific personality characteristics that include enhanced creativity, suggestibility, mild hypomania, anxiety, and emotional lability. Learning histories that encourage the use of right temporal lobe functions for the consolidation of memory, such as compartmentalization of beliefs or repression due to early sexual abuse, predispose to intense visitor experiences. The most frequent precipitants are psychological depression, personal (existential) stress and proximal exposure to the focal tectonic strain fields that accompany luminous phenomena. Possible neuropsychological mechanisms are discussed.
... Mystical, paranormal, and religious experiences are hypothesized (Persinger, 1983) to be associated with some temporal lobe factor in the human brain. This factor is expected to correlate with the neuroelectrical conditions that evoke similar but fragmented experiences during surgical stimulation of particular regions of the temporal lobe (Gloor, 1972;Horowitz & Adams, 1970). The frequency of occurrence and the varieties of these experiences for a person are predicted to reflect the electrical lability of temporal lobe structures and the social-psychological conditions that contribute to this lability (Persinger, 1983). ...
Internal and external validity tests were completed for an inventory that has been uesd to infer signs of temporal lobe lability. Strong, positive correlations were reported for a normal (reference) population between the numbers of responses that referred to paranormal experiences (including feelings of a “presence”) and separately to religious beliefs and the numbers of spikes per minute within electroencephalographic recordings from the temporal lobe. Numbers of spikes were also correlated with the subjects' scores on the hysteria, schizophrenia, and psychasthenia scales from the MMPI. These clusters of items were not correlated with electrical activity from the occipital lobe (the comparison region). Numbers of responses to control clusters of mundane experiences were not correlated with the temporal lobe measures. A group of student poets scored higher on different subclusters of temporal lobe signs and on the schizophrenia and mania scales of the MMPI than the reference group. For both groups, there were positive correlations between the amount of alpha activity in the temporal lobe only and answers to items such as “hearing inner voices” and “feeling as if things were not real.” These results demonstrate that quantitative measures of electrical changes in the temporal lobe are correlated with (or with the report of) specific experiences that are prevalent during surgical or epileptic stimulation of this brain region.
Six adults, who had recently experienced sudden recall of preschool memories of sex abuse or alien abduction/visitation, were given complete neuropsychological assessments. All experiences “emerged” when hypnosis was utilized within a context of sex abuse or New Age religion and were followed by reduction in anxiety. As a group, these subjects displayed significant (T > 70) elevations of childhood imaginings, complex partial epileptic-like signs, and suggestibility. Neuropsychological data indicated right frontotemporal anomalies and reduced access to the right parietal lobe. MMPI profiles were normal. The results support the hypothesis that enhanced imagery due to temporal lobe lability within specific contexts can facilitate the creation of memories; they are strengthened further if there is also reduction in anxiety.
Only humans seem to have the ability to project themselves into their past or future. This mental phenomenon, called autonoetic consciousness, proves the interrelation of memory, imagination, emotion, intelligence and consciousness as a way of creating self-images. The current paper constitutes an integrative study on memory from a theoretical perspective. The first part presents the most known neuroscientific viewpoints on the memory process, along with the pathological case of patient HM, who lost his memory following the removal of his hippocampus. The second part provides a humanistic perspective on recollection to demonstrate its compatibility with the neurological processes of storing information and forming memories. The final part conveys the phenomenon of recollection from the perspective of identity crisis in Kazuo Ishiguro's novels, as a case study in memory literature. According to memory theories to date, identity cannot exist outside the process of recording and recalling past experiences. Despite the fallible nature of recollection, human beings return to their past in order to give a healthy meaning to their present.
The feeling of a presence (FoP) is an illusory vivid feeling that there is another person nearby who is not seen, heard, or felt. In neuropsychiatry, FoP has traditionally been classified among disorders of the body schema but has also been reported from times immemorial by healthy individuals in various conditions. Here the chapter reviews key neurological and psychiatric data on FoP and the involved neural mechanisms. Particular relevance will be given to the distinction between body schema versus body image in the FoP. This is followed by a description of recent efforts in engineering and cognitive neuroscience to apply robotics technology to experimentally induce and study FoP and its phenomenology. The chapter concludes by describing an exciting new research field that integrates consciousness studies, cognitive neuroscience, and engineering—cognetics.
In three separate experiments a total of 85 male and female university students were exposed within a Ganzfeld setting to weak (1 mG, 100 nT), complex magnetic field patterns. They were applied across the temporal lobes and generated by computer software. When the patterns were rotated spatially over the temporal lobes the numbers of subjective experiences that simulate possible temporal lobe signs and symptoms were markedly increased and qualitatively more extreme than those evoked when the fields were not rotated. A 16 Hz pulsed square wave generated more experiences of thought intrusion than a 4 Hz wave. A positive-feedback ringing wave presented at 4 Hz evoked more visual memories and images than the mirror image of the same wave; the effect was only apparent when the subject's quantitative scores for possible temporal lobe signs was covaried. Only those subjects who displayed above average temporal lobe signs and were exposed to a burst-firing wave pattern for one second once every 4 seconds (a condition intended to release endogenous opiates), reported more emotional perturbations when the state was disrupted relative to subjects who were exposed continuously to the same pattern. The results indicate that a person's temporal lobe profile affects the types and intensities of experiences that are reported when very weak magnetic fields are applied through the human brain.
In order to evaluate the construct validity of a subjective experience inventory that has been employed to infer complex partial epileptic-like signs (CPELS), specific tasks such as the Seashore Rhythm. Speech-sounds, Immediate and Delayed Verbal and Figural Memory, Digit Span, Corsi block and Visual Search Tasks, were administered to 50 men and 50 women. The strongest correlation (0.57) occurred between the numbers of CPELS and search times for the upper relative to the lower right visual field for the men but not for the women. The results support the existence of sexual mosaicism and balanced human polymorphism within brain-behavioral correlates. Normative data for the neuropsychological tasks are also presented.
The dopamine hypothesis postulates that at least some schizophrenic symptoms are a reflection of central nervous system hyperdopaminergia. The evidence for this model is briefly reviewed and its shortcomings highlighted. The dysregulation hypothesis of schizophrenia should be a useful reformulation. Rather than conceptualizing a static hyperdopaminergic state, schizophrenia might be better understood as a reflection of a relative failure of dopaminergic regulation. Evidence for such dysregulation is examined and possible mechanisms are presented. Avenues of future drug research are proposed.
Administered a paralogic test, an inventory of childhood memories and imaginings, and a personal philosophy inventory to 100 male and 100 female university students (aged 19–52 yrs). Both sexes displayed moderately strong correlations between content-selected and factor-analyzed clusters of possible temporal lobe signs, exotic beliefs, and number of childhood imaginings. Although there were no sex differences between the accuracy of logical statements that contained paranormal or neutral content, males who displayed more temporal lobe signs were more accurate for logical items that contained paranormal content. Females who displayed more imaginings were more accurate for valid than for invalid items. Accuracy for items with paranormal content increased with exotic beliefs but not with conservative religious beliefs for both sexes. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Volunteers wore opaque goggles while sitting quietly within an acoustic chamber that was weakly illuminated by a red light. During six successive 5-minute periods each subject received 3 pairs (offlon) of either 4 Hz, 9 Hz or 16 Hz, 0.3 mG to 1.0 mG (100 nT), pulsed magnetic fields (both polarities) that were applied externally at the level of the temporal lobes; a fourth group received the sham field. Subjects exposed to the magnetic fields displayed enhanced vestibular, depersonalization and imagining experiences compared to sham-field controls. Pleasantness scores were positively correlated with numbers of temporal lobe spikes; both measures were enhanced within the field conditions. When variance associated with psychometric inferences of temporal lobe sensitivity and cognitive style was accommodated, a significant increase in temporal (but not occipital) lobe alpha activity for the groups exposed to the magnetic fields was revealed. These results suggest that weak, pulsed magnetic fields, focused across the temporal plane, may generate neurostructure-specific behaviors within a context that encourages their occurrence.
In this series of patients the persisting visual or auditory percepts were re-experienced immediately or were “replayed” many hours or even up to a day or more following the original stimulus. The persisting percepts were almost always experienced in the defective visual or auditory space contralateral to the responsible cerebral lesion. These patients usually had clinical evidence of cerebral irritation and seizures. When clinical seizures were controlled medically and stopped, so then did the persistent visual and auditory sensations. These spontaneous phenomena which we observed clinically were similar to the experiences elicited when the cerebrum of conscious man was stimulated through implanted electrodes. It seems that either spontaneous irritation of the brain or electrical excitation of the cerebrum of conscious man may induce “replays” of previous visual or auditory percepts which then appear as reality.
Images, hallucinations, and illusions are moments in the process of object formation displayed prematurely by pathology. Images are incomplete objects, whereas objects are images which are completely unfolded. Images and objects are constructs or representations in cognition which are shaped by — but not derived from — sensory information at successive levels in forebrain evolution. From the pathological material we can reconstruct the microstructure of this process. It leads from a two-dimensional map of the body elaborated at upper midbrain to an egocentric, volumetric space at the limbic-temporal level. From this point, the image is exteriorized to a not fully independent space through parietal mechanisms. Illusory phenomena and deficits in eye-hand and constructional performance reveal the persistent link between body and image. Finally, the terminal featural analysis and exteriorization of the image to an independent object is accomplished through striate and circumstriate mechanisms.
In two separate experiments 61 18- to 35-year-old part-time university students were given the Personal Philosophy Inventory (PPI) that contained items that infer temporal lobe lability. Alpha activity seconds per minute during a 10-min recording (equal intervals of eyes opened or eyes closed) were obtained from the temporal and occipital lobes for each subject. Positive, intermediate strength correlations were obtained between the total numbers of different temporal lobe signs as measured by the questionnaire and both the average amount (eyes closed) of the variability in α activity from the temporal but not the occipital lobes. The results support the construct validity of the temporal lobe signs inventory and suggest that a continuum of temporal lobe lability (as inferred from both experimential and electroencephalographic criteria) exists within the normal population.
This paper compares two sets of scarcely believable reports: those of satanist abuse survivors and those of people with apparent
memories of alien abduction. There are striking parallels between the two phenomena, which are explored in some detail. Whilst
the comparison may be unexpected, and will no doubt provoke scepticism in some readers, the similarities are difficult to
ignore; and I suggest that they give rise to unavoidable questions about the nature of both kinds of experience. The paper
therefore concludes with a sketch of some neurophysiological and psychological research which may help to account for them.
Visual hallucinations were the presenting symptoms in 2 patients with probable infarcts in the territory of a posterior cerebral artery. They occurred in areas of paracentral scotomas, right in Patient 1 and left in Patient 2. In Patient 1 they were formed, prolonged, and not apparently related to past experience. In Patient 2 they were at first paroxysmal and unformed, with more prolonged metamorphopsia; later there appeared to be palinoptic formed images, possibly postictal in nature. Such hallucinations appear to be of a "release" type, and may be more common than is generally appreciated in patients with posterior cerebral artery occlusion.
The purpose of this paper is to present some clinical data which suggests a relationship between abnormal electrical discharges in the depth structures of the temporal lobe and hallucinations. The information has been derived from a series of patients referred to the UCLA Neuropsychiatric Institute who suffered from temporal lobe epilepsy intractable to intensive pharmacologic regimes. The patients were studied with electrodes placed bilaterally in the depth structures of the temporal lobe as well as over the calvarium to monitor the electrical activity of the brain during the ictal and inter-ictal stages. If a unilateral focus for their seizures could be found, it was surgically excised in a second procedure aimed at alleviating their convulsive disorder. One of the patients studied presented initially with a complex hallucination as part of her seizure. In reviewing our series of patients it was of interest to note that hallucinations were produced by electrical stimulation of the depth structures of the temporal lobe in certain patients. The electrical stimulations were carried out in an attempt to induce seizure activity.
We hypothesized that the feeling of a presence, particularly during periods of profound verbal creativity (reading or writing prose or poetry), is an endemic cognitive phenomenon. Factor analyses of 12 clusters of phenomenological experiences from 348 men and 520 women supported the hypothesis. We conclude that periods of intense meaningfulness (a likely correlate of enhanced burst-firing in the left hippocampal-amygdaloid complex and temporal lobe) allow access to nonverbal representations that are the right hemispheric equivalents of the sense of self; they are perceived as "a presence." The relevance of our results to the theories of Jaynes, Bear, Edelman, and MacLean is discussed.
Vivid visual hallucinations without other psychopathology have been reported for several hundred years. However, there is no consensus on whether these hallucinations should be considered a separate syndrome, the Charles Bonnet syndrome, or whether eye disease or brain disease is a necessary or exclusionary criterion for diagnosing this syndrome. In an attempt to resolve these issues, this article reviews the literature on isolated visual hallucinations and presents follow-up data from six cases. Criteria for diagnosing the Charles Bonnet syndrome are suggested.
The authors review the literature on hallucinations; provide theoretical background on these phenomena from physiological, biochemical, and psychological points of view; and discuss the presentations of hallucinations in different diagnostic categories. The longstanding notion that hallucinations are to be equated with schizophrenia, they conclude, is clearly unfounded, and hallucinations are never pathognomonic of any given disorder but can be relatively specific for some conditions. Current knowledge and methods of research have produced no single mechanism to account for the etiology or pathogenesis of hallucinations. The authors present an integrated approach toward viewing the etiology and clinical presentation of hallucinations that involves concepts of biological vulnerability and psychological influences.
This study was designed to test the hypothesis that common bereavement apparitions are hallucinatory experiences evoked by transient electrical instability within the (glucocorticoid) sensitized mesiobasal temporal lobes. All first hand reports of 'postmortem apparition' experiences were collected from a published data base. The days on which the experiences occurred displayed significantly greater (mean increase = 10 gamma) geomagnetic activity compared to the days before or afterwards. These results suggest that bereavement apparitions are situation-specific hallucinations evoked by microseizures within sensitized temporal lobe structures; the occurrence of these microseizures might be facilitated by suppression in melatonin levels that could accompany sudden increases in geomagnetic activity.
With regard to epileptic signs and correlative behaviors, one hypothesis is that the experiences and nonconvulsive behaviors of patients with electrical foci within the temporal lobe are also displayed, but with less intensity, by normal people. If this is correct, then there should be quantitative relationships between the numbers of major complex partial epileptic signs (CPES) and the occurrence of other frequent clinical experiences and behaviors. An inventory to answer this question was developed. Over a 3-year period, 414 (6 groups) university students were administered an inventory that included themes of CPES as well as control and information items. Strong correlations were consistently found between CPES scores and reports of paranormal (mystical, with religious overtones) experiences and "a sense of presence." Results from three personality (CPI, MMPI, and IPAT anxiety) inventories clearly demonstrated similar profiles. In addition to being more anxious, people who displayed higher CPES scores were more suspicious, aloof, stereotyped in their behavior, ruminative (overthinking), intellectually inefficient, and overly judgmental. CPES scores were significantly (p less than .001) correlated with the schizophrenia and mania subscales of the MMPI. The results suggest that functional hyperconnectionism of cortical-limbic systems within the brain may be more prevalent in the normal population than previously suspected.
Transient and very localized geophysical forces are hypothesized to be a major source of phenomena that have been traditionally labelled as haunts and poltergeists. They would be generated by increasing tectonic stresses and would display electromagnetic and gravitational characteristics. Materials would be influenced according to their physical properties. Dielectric materials would respond differently from conductors. Organic semiconductors, of which the human being is an important subcategory, would be affected as well. The conspicuous overlaps between (non-convulsive) complex partial epilepsy and many episodes of poltergeists and haunts are expected in light of the direct stimulation of the observer's brain by the transient, intense magnetic fields and the lability of temporal lobe structures. Implications and some general predictions for the distribution of these phenomena in time and space are discussed.
Mystical and religious experiences are hypothesized to be evoked by transient, electrical microseizures within deep structures of the temporal lobe. Although experiential details are affected by context and reinforcement history, basic themes reflect the inclusion of different amygdaloid-hippocampal structures and adjacent cortices. Whereas the unusual electrical coherence allows access to infantile memories of parents, a source of god expectations, specific stimulation evokes out-of-body experiences, space-time distortions, intense meaningfulness, and dreamy scenes. The species-specific similarities in temporal lobe properties enhance the homogeneity of cross-cultural experiences. They exist along a continuum that ranges from “early morning highs” to recurrent bouts of conversion and dominating religiosity. Predisposing factors include any biochemical or genetic factors that produce temporal lobe lability. A variety of precipitating stimuli provoke these experiences, but personal (life) crises and death bed conditions are optimal. These temporal lobe microseizures can be learned as responses to existential trauma because stimulation is of powerful intrinsic reward regions and reduction of death anxiety occurs. The implications of these transients as potent modifiers of human behavior are considered.
The literature, classical and modern, on visual perceptual disturbances in the elderly is reviewed. The utility of the concept
of the Charles Bonnet Syndrome, an eponym originally coined to describe visual hallucinations in the elderly in the absence
of cognitive impairment and peripheral ophthalmopathy, is challenged, particularly as the syndrome has become progressively
enlarged. Three representative cases of elderly patients who have developed different types of visual perceptual disturbances
are described. It is proposed to undertake a systematic study of the frequency of such disturbances in the elderly and of
what other pathologies, particularly cognitive and visual, may be associated with them.
Abrupt, intense increases in global geomagnetic activity during the local night may precipitate a significant proportion of sudden unexpected (or unexplained) deaths (SUD) in epileptics. Over a 2-year period SUD in healthy chronic epileptic rats occurred when the average daily geomagnetic activity exceeded 50 nT (nanoTesla) and suddenly began during local night. Other experiments demonstrated that epileptic rats displayed more spontaneous seizures per night if there had been sudden increases in geomagnetic activity. Analyses of previously published data indicated that the number of SUDs/month in a population of human epileptics was positively associated with the number of days/month when the average geomagnetic activity exceeded 50 nT. The results support the hypothesis that suppression of the nocturnal concentrations of the endogenous anticonvulsant melatonin by sudden increases in geomagnetic activity may encourage fatal cardiac arrhythmias by uncoupling the insular/amygdaloid-paraventricular hypothalamic-solitary nucleus pathways.
A significant alteration in the hypnotizability of normal subjects after brief (15 min) exposures to weak (1 microT) pulsed magnetic fields over the temporal lobes was determined by the serial order of hemispheric stimulation. Only subjects who received the right hemispheric stimulation first displayed significantly elevated hypnosis induction profile scores (effect size equivalent to a correlation of 0.41). Implications for a technology that can: a) modify hypnotizability, b) encourage the consolidation of quasiexperiences that are reconstructed as autobiographical memory, and c) change the sense of self, are discussed.
20 male and 20 female undergraduate students were exposed singly for 20 min. to an exotic setting (partial sensory deprivation and weak, bilateral trans-temporal pulsed magnetic fields) that enhances relaxation and exotic experiences. The numerical incidence of subjective experiences described as old memories, dreams, emotions, or vestibular sensations did not differ significantly between the sexes; however, women who reported a greater prevalence of preexperimental complex partial epileptic-like signs were more likely to report experiences of “old memories” (r = 0.61) while men who exhibited these signs were more likely to report dream-like (r = 0.49) experiences. Because complex partial epileptic-like signs are positively associated with suggestibility, the potential contribution of this differential gender effect to the etiology of the False Memory Syndrome requires further investigation.
In two separate experiments a total of 71 volunteers were asked to generate spontaneous narratives that were scored automatically by the Whissell Dictionary of Affect. During the narratives, weak (1 microT; 10 mG) magnetic fields were applied briefly through the temporal planes. In Experiment I, subjects who were exposed to simple sine wave or pulsed fields generated more scorable words that indicated lower activation and evaluation than sham-field conditions. In Experiment II subjects exposed to a computer-generated wave form, designed to simulate neuronal burst firing, generated narratives dominated by more pleasantness and less activation than a reference group. The possibility that this approach could be utilized to study the affective dimension of language selection was indicated.
Over a 10-year period, a total of 447 men and 624 women between 18 and 61 years of age were administered an inventory whose items describe experiences that are similar to those evoked by electrical stimulation of the temporal lobes. Empirically determined factors contained experiences of sensory enhancement, affective-dissociation, ego alien intrusions, and literary emphasis. Using this population as a reference, T scores for these clusters were calculated for special normal populations (poets, drama students, false pregnancies) and for clinical groups (post-traumatic stress, anxiety-depersonalization, exotic dissociations, and complex partial epilepsy). Whereas only mild elevations (50 < T < 65) in indicators of temporal lobe signs and symptoms were noted in the special groups, moderate (65 < T < 75) and severe (T > 79) elevations were noted in the clinical populations.
Posttraumatic stress disorder is a disorder with an identifiable etiological factor (exposure to a traumatic event) and with a complex symptomatology (i.e. intrusive memories, avoidance, hyperarousal) that suggests dysfunction in multiple psychobiological systems. This review considers studies of the neurobiological consequences of acute and chronic stress showing that traumatic experiences can produce long-lasting alterations in multiple neurochemical systems. The role of the locus coeruleus noradrenergic system, prefrontal cortex dopaminergic system, endogenous opiates, hypothalamic-pituitary-adrenal axis, and cortico-releasing factors are reviewed. Several models of PTSD are highlighted, including fear conditioning, kindling, and sensitization. In particular, fear conditioning to explicit and contextual cues is proposed as a model for intrusive memories reactivated by trauma-related stimuli and hyperarousal, respectively. It is argued that the amygdala plays a crucial role in the encoding and retrieval of fear memories activated by specific stimuli that have been associated with aversive events. Association involving more complex environmental stimuli and aversive events may require the involvement of the hippocampus and the bed nucleus of the stria terminalis. Repeated activation of conditioned fear memories may produce a kindling-like process which results in spontaneous intrusive memories.
THE LITERATURE ON THE BEHAVIORAL EFFECTS OF HIPPOCAMPAL LESIONS IS REVIEWED AND IT IS CONCLUDED THAT A LESION PRODUCES A UNITARY DEFICIT. ON A PURELY DESCRIPTIVE LEVEL THIS DEFICIT CONSISTS OF AN ABILITY TO WITHHOLD A PREPOTENT RESPONSE, WHETHER LEARNED OR UNLEARNED. MANY HYPOTHESES ABOUT HIPPOCAMPAL FUNCTION ARE SHOWN TO BE INCONSISTENT WITH THE DATA OR OTHERWISE INADEQUATE. 4 IDEAS APPEAR TO BE GENERALLY SUPPORTED BY THE RESULTS IN THE LITERATURE, AND THESE ESSENTIALLY REPRESENT SLIGHTLY DIVERGENT VIEWS ABOUT POSSIBLE CAUSES FOR THE DEFICIT ABOVE. IN 3 OF THESE, THE HIPPOCAMPUS IS POSTULATED TO HAVE AN INHIBITORY FUNCTION, WHETHER PAVLOVIAN, STIMULUS-RESPONSE BOND SUPPRESSION, OR INHIBITION OF ATTENTION AND/OR STIMULUS INPUT. IN THE 4TH IDEA, THE HIPPOCAMPUS IS POSTULATED TO PLAY A CRUCIAL ROLE IN A WORKING MEMORY MECHANISM. (5 P. REF.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This book brings to date the reports and conclusions from the Montreal Neurological Institute's clinical, physiological, and neuro-surgical studies of epilepsy, and is, in a sense, a sequal to "Epilepsy and cerebral localization," published in 1941. There is extensive addition of new material on subcortical mechanisms, functional cortical localization, surgical and medical treatment and electroencephalography. The book is illustrated with 8 color plates and 314 black and white illustrations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Pictorial cognition is one of many forms of thinking in nonverbal representations. The author describes the kinds of visual imagery and the circumstances of their occurrence and enhancement, and considers the relevant problems of reality testing, content, purpose, and sequential organization. He suggests that pictorial cognition is a developmentally more primitive system than verbal-conceptual thinking and has special psychologic utility as a carrier of affectively charged memories, ideas, and impulses.
: In 1949 and in 1965 unusual subjective experiences were described as "dream scintillations." These experiences occur during wakefulness and include rapid successions of imagery which are hard to remember. The present report adds introspective data and emphasizes that the visual images of such occurrences have a quality, rhythm, and organization different from those of hypnagogic reverie or dreams. Similar events were not frequent in dream-deprivation experiments but did occur during experimental stimulation of the brain. Psychologically such events are seen as a form of derailment of thought from verbal to pictorial cognition, and a theoretical consideration of pictorial cognition is presented. Neurophysiologically, the phenomenon bears sufficient resemblance to occurrences in persons with temporal-lobe seizures that it might be considered a minor variant or forme fruste of temporal-lobe epilepsy triggered by metabolic fatigue or local circulatory factors. Copyright (C) 1967 by American Psychosomatic Society
Electrical stimulation of the temporal lobe was performed in chronic schizophrenic patients to treat the auditory hallucinations. During electrical stimulation, there appeared different kinds of hallucinations.
The characteristics of the hallucinations produced by the temporal lobe stimulation greatly differ from those of the schizophrenic hallucinations. Visual and auditory hallucinations by the temporal lobe stimulation might depend on different pathopysiological mechanisms. The kinesthetic and vestibular hallucinations could be considered as a basis of the pathophysiological mechanism of the auditory hallucinations. The temporal lobe stimulation for the auditory hallucinations in schizophrenic patients showed some therapeutic effectiveness.
: During interviews, intracerebral electrical stimulation of sharply localized areas in the temporal lobe of a young woman with psychomotor epilepsy consistently produced ego-alien ideational experiences similar to those observed by Penfield. The responses were associated with considerable anxiety and with evoked electrical seizure activity. The use of the interview as the observational situation and careful study of the interview tape-recordings made it possible to discover that the content of the ideational experiences was often a function of her prestimulation "mental content." This finding led to an examination of Penfield's formulations and to some alternative hypotheses about mechanisms that might be involved in psychic responses to temporal-lobe stimulation. Copyright (C) 1964 by American Psychosomatic Society
Future of stereotaxic surgery
- J E Adams
- JE Adams
Studies of clinical and electrical responses to deep temporal stimxilation in men with some considerations of functional anatomy”. The Brain and Behavior
- H H Jasper
- T Rasmussen
- HH Jasper