Olaf Blanke

Olaf Blanke
Swiss Federal Institute of Technology in Lausanne | EPFL · Center for Neuroprosthetics CNP

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557
Publications
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26,278
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Introduction
Skills and Expertise

Publications

Publications (557)
Article
Because of the depth of the hippocampal-entorhinal complex (HC-EC) in the brain, understanding of its role in spatial navigation via neuromodulation was limited in humans. Here, we aimed to better elucidate this relationship in healthy volunteers, using transcranial temporal interference electric stimulation (tTIS), a noninvasive technique allowing...
Preprint
Full-text available
Motor awareness (MA) describes the level of conscious access we have to the details of our movements and as such is critical to the feeling of control we maintain over our actions (sense of agency). Although our movements rely on specific sensorimotor transformations as well as distinct reference frames for the active body part, or effector, numero...
Preprint
Experienced meditation practitioners often report altered states of their sense of self, including decentering and distancing the self from the body and current concerns. Altered states of the sense of self, such as disembodiment and distancing of the self from the body, have also been induced experimentally using virtual reality (VR) and linked ne...
Article
Background Deficits in self are commonly described through different neuro-pathologies, based on clinical evaluations and experimental paradigms. However, currently available approaches lack appropriate clinical validation, making objective evaluation and discrimination of self-related deficits challenging. Methods We applied a statistical standar...
Article
Autonoetic consciousness (ANC), the ability to re-experience personal past events links episodic memory and self-consciousness by bridging awareness of oneself in a past event (i.e. during its encoding) with awareness of oneself in the present (i.e. during the reliving of a past event). Recent neuroscience research revealed a bodily form of self-co...
Article
Full-text available
Functional connectivity patterns in the human brain, like the friction ridges of a fingerprint, can uniquely identify individuals. Does this “brain fingerprint” remain distinct even during Alzheimer’s disease (AD)? Using fMRI data from healthy and pathologically ageing subjects, we find that individual functional connectivity profiles remain unique...
Article
Full-text available
Hallucinations can occur in the healthy population, are clinically relevant and frequent symptoms in many neuropsychiatric conditions, and have been shown to mark disease progression in patients with neurodegenerative disorders where antipsychotic treatment remains challenging. Here, we combine MR-robotics capable of inducing a clinically-relevant...
Article
Full-text available
Episodic memory (EM) allows us to remember and relive past events and experiences and has been linked to cortical-hippocampal reinstatement of encoding activity. While EM is fundamental to establish a sense of self across time, this claim and its link to the sense of agency (SoA), based on bodily signals, has not been tested experimentally. Using r...
Preprint
Full-text available
Multisensory processing is enhanced for stimuli that appear in close proximity to our body. The so-called peripersonal space (PPS) not only serves as an evolutionary, protective mechanism but also localizes and demarcates our self in space. While our perceived self-location is generally unitary and firmly located at the position of our body, there...
Article
Objective Alice in Wonderland syndrome (AIWS) profoundly affects human perception of size and scale, particularly regarding one's own body and the environment. Its neuroanatomical basis has remained elusive, partly because brain lesions causing AIWS can occur in different brain regions. Here, we aimed to determine if brain lesions causing AIWS map...
Conference Paper
Full-text available
When performed at a high level, meditation and contemplative practices can give rise to altered states of consciousness, the study of which is key for cognitive neurosciences. Those effects indeed can help to better understand the underlying mechanisms of the self and its relation with the body. But reaching those states is rare and thus hard to ob...
Article
Full-text available
Background Sensory reafferents are crucial to correct our posture and movements, both reflexively and in a cognitively driven manner. They are also integral to developing and maintaining a sense of agency for our actions. In cases of compromised reafferents, such as for persons with amputated or congenitally missing limbs, or diseases of the periph...
Article
BACKGROUND Cortical excitation/inhibition dynamics have been suggested as a key mechanism occurring after stroke. Their supportive or maladaptive role in the course of recovery is still not completely understood. Here, we used transcranial magnetic stimulation (TMS)-electroencephalography coupling to study cortical reactivity and intracortical GABA...
Preprint
Subcortical brain structures such as the basal ganglia or the thalamus are involved in regulating motor and cognitive behavior. However, their contribution to perceptual consciousness is still unclear, due to the inherent difficulties of recording subcortical neuronal activity in humans. Here, we asked neurological patients undergoing surgery for d...
Preprint
Subcortical brain structures such as the basal ganglia or the thalamus are involved in regulating motor and cognitive behavior. However, their contribution to perceptual consciousness is still unclear, due to the inherent difficulties of recording subcortical neuronal activity in humans. Here, we asked neurological patients undergoing surgery for d...
Article
Full-text available
Grid cells in the entorhinal cortex (EC) encode an individual’s location in space, integrating both environmental and multisensory bodily cues. Notably, body-derived signals are also primary signals for the sense of self. While studies have demonstrated that continuous application of visuo-tactile bodily stimuli can induce perceptual shifts in self...
Article
Full-text available
Hallucinations are frequent non-motor symptoms in Parkinson’s disease (PD) associated with dementia and higher mortality. Despite their high clinical relevance, current assessments of hallucinations are based on verbal self-reports and interviews that are limited by important biases. Here, we used virtual reality (VR), robotics, and digital online...
Article
Full-text available
Visceral signals are constantly processed by our central nervous system, enable homeostatic regulation, and influence perception, emotion, and cognition. While visceral processes at the cortical level have been extensively studied using non-invasive imaging techniques, very few studies have investigated how this information is processed at the sing...
Preprint
Full-text available
Background. Deficits in self are commonly described through different neuro-pathologies, based on clinical evaluations and experimental paradigms. However, currently available approaches lack appropriate clinical validation, making objective evaluation and discrimination of self-related deficits challenging. Methods. We applied a statistical standa...
Article
Full-text available
Objective. A key challenge of virtual reality (VR) applications is to maintain a reliable human-avatar mapping. Users may lose the sense of controlling (sense of agency), owning (sense of body ownership), or being located (sense of self-location) inside the virtual body when they perceive erroneous interaction, i.e. a break-in-embodiment (BiE). How...
Preprint
Full-text available
Background: In Lewis Carroll s 1865 novel "Alice s Adventures in Wonderland", the protagonist experiences distortions in the size of her body and those of others. This fiction becomes reality in neurological patients with Alice in Wonderland Syndrome (AIWS). Brain lesions causing AIWS may offer unique insights into the syndrome s elusive neuroanato...
Article
Full-text available
Topographical disorientation refers to the selective inability to orient oneself in familiar surroundings. However, to date its neural correlates remain poorly understood. Here we use quantitative lesion analysis and a lesion network mapping approach in order to investigate seven patients with topographical disorientation. Our findings link not onl...
Article
The reported rate of the occurrence of unilateral spatial neglect (USN) is highly variable likely due to the lack of validity and low sensitivity of classical tools used to assess it. Virtual reality (VR) assessments try to overcome these limitations by proposing immersive and complex environments. Nevertheless, existing VR‐based tasks are mostly f...
Preprint
Full-text available
Out-of body experiences (OBEs) are characterized by the subjective experience of being located outside the physical body. Evidence supports that OBEs triggered by electrical stimulation and epileptic seizures are associated with disrupted brain activity in a distributed network centred at the temporo-parietal junction and the resulting multisensory...
Article
Full-text available
Most human navigation studies in MRI rely on virtual navigation. However, the necessary supine position in MRI makes it fundamentally different from daily ecological navigation. Nonetheless, until now, no study has assessed whether differences in physical body orientation (BO) affect participants’ experienced BO during virtual navigation. Here, com...
Preprint
Full-text available
p>We developed an untethered robotic system that provides walking-related sensory feedback remapped non-invasively to the wearer’s back. Using the so-called FeetBack system, we investigated how accurately healthy individuals can monitor remapped, tactile locomotor feedback (motor awareness) and how this affects their walking characteristics (adapta...
Preprint
Full-text available
p>We developed an untethered robotic system that provides walking-related sensory feedback remapped non-invasively to the wearer’s back. Using the so-called FeetBack system, we investigated how accurately healthy individuals can monitor remapped, tactile locomotor feedback (motor awareness) and how this affects their walking characteristics (adapta...
Article
Full-text available
Out-of-body experiences (OBEs) are characterized by the subjective feeling of being located outside one’s physical body and perceiving one’s own body from an elevated perspective looking downwards. OBEs have been correlated with abnormal integration of bodily signals, including visual and vestibular information. In two studies, we used mixed realit...
Article
Full-text available
Background Inducing hallucinations under controlled experimental conditions in non-hallucinating individuals represents a novel research avenue oriented toward understanding complex hallucinatory phenomena, avoiding confounds observed in patients. Auditory-verbal hallucinations (AVH) are one of the most common and distressing psychotic symptoms, wh...
Preprint
Full-text available
Episodic memory (EM) allows us to remember and relieve past events and experiences, depending on cortical-hippocampal reinstatement involved during encoding. Although it has been claimed that EM is fundamental to establish a sense of self across time, this has never been shown experimentally. Here we combine immersive virtual reality and fMRI and r...
Article
Full-text available
Background Immersive virtual reality (iVR)-based digital therapeutics (DTx) are gaining clinical attention in the field of pain management. Based on known analogies between pain and dyspnea, we investigated the effects of visual-respiratory feedback, on persistent dyspnea in patients recovering from COVID-19 pneumonia. Methods We performed a contr...
Preprint
Full-text available
Our sense of agency, the subjective experience of controlling our actions, is a crucial component of self-awareness and motor control. It is thought to originate from the comparison between intentions and actions across broad cortical network. However, the underlying neural mechanisms are still unknown. We hypothesized that oscillations in the thet...
Preprint
Full-text available
Grid cells in entorhinal cortex (EC) encode an individual's location in space and rely on environmental cues and multisensory bodily cues. Body-derived signals are also primary signals for the sense of self as the continuous application of visuo-tactile bodily stimuli elicits illusory drifts in perceived self-location. It is unknown whether illusor...
Preprint
Full-text available
Self-initiated behavior is accompanied by the experience of willing our actions. Here, we leverage the unique opportunity to examine the full intentional chain, from will (W) to action (A) to environmental effects (E), in a tetraplegic person fitted with a primary motor cortex (M1) brain machine interface (BMI) generating hand movements via neuromu...
Article
Full-text available
Reduplicative paramnesia refers to the delusional belief that there are identical places in different locations. In this case-control study we investigated the clinical, phenomenological, neuropsychological and neuroanatomical data of eleven patients with reduplicative paramnesia and compared them against a control group of eleven patients with sev...
Article
Full-text available
Knowing where objects are relative to us implies knowing where we are relative to the external world. Here, we investigated whether space perception can be influenced by an experimentally induced change in perceived self-location. To dissociate real and apparent body positions, we used the full-body illusion. In this illusion, participants see a di...
Preprint
Full-text available
Hallucinations are frequent non-motor symptoms in Parkinson's disease (PD) associated with dementia and higher mortality. Despite their high clinical relevance, current assessments of hallucinations are based on verbal self-reports and interviews that are limited by important biases. Here, we used virtual reality (VR), robotics, and digital online...
Article
Full-text available
The brain mechanism of embodiment in a virtual body has grown a scientific interest recently, with a particular focus on providing optimal virtual reality (VR) experiences. Disruptions from an embodied state to a less- or non-embodied state, denominated Breaks in Embodiment (BiE), are however rarely studied despite their importance for designing in...
Article
Full-text available
Background Unilateral spatial neglect (USN) is a debilitating neuropsychological syndrome that often follows brain injury, in particular a stroke affecting the right hemisphere. In current clinical practice, the assessment of neglect is based on old-fashioned paper-and-pencil and behavioral tasks, and sometimes relies on the examiner’s subjective j...
Article
Full-text available
Introduction Dopaminergic scintigraphic imaging is a cornerstone to support the diagnosis in dementia with Lewy bodies. To clarify the current state of knowledge on this imaging modality and its impact on clinical diagnosis, we performed an updated systematic review of the literature. Methods This systematic review was carried out according to PRI...
Article
Full-text available
One's own voice is one of the most important and most frequently heard voices. Although it is the sound we associate most with ourselves, it is perceived as strange when played back in a recording. One of the main reasons is the lack of bone conduction that is inevitably present when hearing one's own voice while speaking. The resulting discrepancy...
Preprint
Full-text available
Most human navigation studies in MRI rely on virtual navigation. However, the necessary supine position in MRI makes it fundamentally different from daily ecological navigation. Nonetheless, until now, no study has assessed whether differences in physical body orientation (BO) affect participants' experienced BO during virtual navigation. Here, com...
Preprint
Full-text available
Background and Objectives Stroke is the leading cause of long-term disability, making the search for successful rehabilitation treatment one of the most important public health issues. A better understanding of the neural mechanisms underlying impairment and recovery and the development of associated markers is critical for tailoring treatments to...
Article
Full-text available
Background: Phantom boarder (PB) is the sensation that someone uninvited is in the patient's home despite evidence to the contrary. It is mostly reported by patients with neurodegenerative disorders such as Alzheimer's disease, dementia with Lewy bodies or Parkinson's disease (PD). Presence hallucination (PH) is frequent in neurodegenerative disea...
Preprint
Full-text available
How does neuronal activity give rise to our conscious experience of the outside world? This question has fascinated philosophers for centuries and is being increasingly addressed empirically. Current methods to investigate the neural correlates of consciousness aim at contrasting the neural activity associated with different percepts under constant...
Article
Full-text available
Visuo-motor integration shapes our daily experience and underpins the sense of feeling in control over our actions. The last decade has seen a surge in robotically and virtually mediated interactions, whereby bodily actions ultimately result in an artificial movement. But despite the growing number of applications, the neurophysiological correlates...
Article
Full-text available
In immersive Virtual Reality (VR), users can experience the subjective feeling of embodiment for the avatar representing them in a virtual world. This is known to be strongly supported by a high Sense of Agency (SoA) for the movements of the avatar that follows the user. In general, users do not self-attribute actions of their avatar that are diffe...
Preprint
Full-text available
Inducing hallucinations under controlled experimental conditions in non-hallucinating individuals represents a novel research avenue oriented towards understanding complex hallucinatory phenomena, avoiding confounds observed in patients. Auditory-verbal hallucinations (AVH) are one of the most common and distressing psychotic symptoms, whose etiolo...
Preprint
Full-text available
Cognitive decline and hallucinations are common and debilitating non-motor symptoms, occurring during later phases of Parkinson's disease (PD). Minor hallucinations (MH), appear at early phases and have been suggested to predict cognitive impairment in PD, however, this has not been well-established by clinical research. Here, we investigated wheth...
Article
Previous research has suggested that bodily signals from internal organs are associated with diverse cortical and subcortical processes involved in sensory-motor functions, beyond homeostatic reflexes. For instance, a recent study demonstrated that the preparation and execution of voluntary actions, as well as its underlying neural activity, are co...
Article
Full-text available
Despite recent improvements, complete motor recovery occurs in <15% of stroke patients. To improve the therapeutic outcomes, there is a strong need to tailor treatments to each individual patient. However, there is a lack of knowledge concerning the precise neuronal mechanisms underlying the degree and course of motor recovery and its individual di...
Preprint
Full-text available
Objective Cortical excitation/inhibition dynamics have been suggested as a key mechanism occurring after stroke. Their supportive or maladaptive role in the course of recovery is still not completely understood. Here, we used TMS-EEG coupling to study cortical reactivity and intracortical GABAergic inhibition, as well as their relationship to resid...
Article
Although hallucinations are important and frequent symptoms in major psychiatric and neurological diseases, little is known about their brain mechanisms. Hallucinations are unpredictable and private experiences, making their investigation, quantification and assessment highly challenging. A major shortcoming in hallucination research is the absence...
Preprint
Full-text available
Personality changes following neurosurgical procedures pose a major concern for patients and remain poorly understood both by clinicians and neuroscientists. Here we report a case of a female patient in her 50s who underwent resection of a large sagittal sinus meningioma with bilateral extension, including resection and ligation of the superior sag...
Preprint
Full-text available
The brain mechanism of embodiment in a virtual body has grown a scientific interest recently, with a particular focus on providing optimal virtual reality (VR) experiences. Disruptions from an embodied state to a less- or non-embodied state, denominated Breaks in Embodiment (BiE), are however rarely studied despite their importance for designing in...
Article
Full-text available
The continuous stream of multisensory information between the brain and the body during body-environment interactions is crucial to maintain the updated representation of the perceived dimensions of body parts (metric body representation) and the space around the body (the peripersonal space). Such flow of multisensory signals is often limited by u...
Preprint
Full-text available
Visceral signals are constantly processed by our central nervous system, enable homeostatic regulation, and influence perception, emotion, and cognition. While visceral processes at cortical level have been extensively studied using non-invasive imaging techniques, very few studies have investigated how this information is processed at the single n...
Preprint
Full-text available
One’s own voice is one of the most important and most frequently heard voices and the sound we associate most with ourselves, and yet, it is perceived as strange when played back in a recording. One of the main reasons is the lack of bone conduction that is inevitably present when hearing own voice while speaking. The resulting discrepancy between...
Preprint
Full-text available
One’s own voice is one of the most important and most frequently heard voices and the sound we associate most with ourselves, and yet, it is perceived as strange when played back in a recording. One of the main reasons is the lack of bone conduction that is inevitably present when hearing own voice while speaking. The resulting discrepancy between...