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Neuroplasticity in normal and brain injured patients: Potential relevance of ear wiggling locus of control and cortical projections
... Currently, effective strategy for the management of TBI remains a challenge task. Research has confirmed that activation of higher-order cognitive processes create larger gains in recovery than repetitive tasks, most likely due to neuroplasticity, which supported the functional recovery after TBI or stroke subjects is associated to neuroplasticity processes [6]. Meanwhile, astrocytes have been found to play an important role in this process [7]. ...
Traumatic brain injury (TBI) induces cognitive impairments, motor and behavioral deficits. Previous evidences have suggested that neural stem cell (NSC) transplantation could facilitate functional recovery from brain insults, but their underlying mechanisms remains to be elucidated. Here, we established TBI model by an electromagnetic-controlled cortical impact device in the rats. Then, 5 μl NSCs (5.0 × 10⁵/μl), derived from green fluorescent protein (GFP) transgenic mouse, was transplanted into the traumatic brain regions of rats at 24 h after injury. After differentiation of the NSCs was determined using immunohistochemistry, neurological severity scores (NSS) and rotarod test were conducted to detect the neurological behavior. Western blot and RT-PCR as well as ELASA were used to evaluate the expression of synaptophysin and brain-derived neurotrophic factor (BDNF). In order to elucidate the role of BDNF on the neural recovery after NSC transplantation, BDNF knockdown in NSC was performed and transplanted into the rats with TBI, and potential mechanism for BDNF knockdown in the NSC was analyzed using microassay analysis. Meanwhile, BDNF antibody blockade was conducted to further confirm the effect of BDNF on neural activity. As a result, an increasing neurological function improvement was seen in NSC transplanted rats, which was associated with the upregulation of synaptophysin and BDNF expression. Moreover, transplantation of BDNF knockdown NSCs and BDNF antibody block reduced not only the level of synaptophysin but also exacerbated neurological function deficits. Microassay analysis showed that 14 genes such as Wnt and Gsk3-β were downregulated after BDNF knockdown. The present data therefore showed that BDNF-mediated neuroplasticity underlie the mechanism of NSC transplantation for the treatment of TBI in adult rats.
... Increased levels of synaptophysin are interpreted to indicate synaptogenesis [82]. Ischemic patients show motor and cognitive recovery some time after the stroke event [83], and the mechanisms involved are synaptogenesis, axon growth and generation of new cells and blood vessels [84,85]. Studies have shown that astrocytes play an important role in synaptogenesis through the release of mediators that maintain the brain microenvironment even under conditions in which neurons lose their functionality, which occurs in cere- Fig. 11. ...
Motor learning can improve movement performance and behavioral measurements, such as reaction time, by inducing brain plasticity. In this study, we investigated the effect of training with different task complexity on Electroencephalographic (EEG) signals. Two types of training (‘simple’ and ‘complex’) were performed by two groups of healthy volunteers. The complex training group (CTG) performed a trace tracking task using their dominant foot and the simple training group (STG) executed repetitive ankle dorsiflexion in the training phase. Frequency analysis was performed to study the effect of training on EEG signals. In addition, the coherence between paired-channels investigated to represent changes in brain region connectivity. Results revealed that the power in the Beta (15−31 Hz) was significantly reduced while gamma band power (32−80 Hz) was significantly enhanced in the CTG compared to the STG mainly in the frontal, central and centro-parietal channels. Theta power was also increased after training in fronto-central channel. Moreover, performance variations were mainly correlated to the beta and gamma power changes. Finally, the connectivity of gamma and beta band increased significantly particularly between frontal and central region in CTG while connectivity score of theta and delta band decreased after training. These findings confirm that training-induced brain plasticity depends on the complexity of the task, more complexity.
This is a reprint of a Cochrane protocol, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library 2013, Issue 12 http://www.thecochranelibrary.com Buprenorphine for treating cancer pain (Protocol)
Cognitive decline is a characteristic feature of normal human aging. Previous work has demonstrated marked interindividual variability in onset and rate of decline. Such variability has been linked to factors such as maintenance of functional and structural brain integrity, genetics, and lifestyle. Still, few, if any, studies have combined a longitudinal design with repeated multimodal imaging and a comprehensive assessment of cognition as well as genetic and lifestyle factors. The present paper introduces the Cognition, Brain, and Aging (COBRA) study, in which cognitive performance and brain structure and function are measured in a cohort of 181 older adults aged 64 to 68 years at baseline. Participants will be followed longitudinally over a 10-year period, resulting in a total of three equally spaced measurement occasions. The measurement protocol at each occasion comprises a comprehensive set of behavioral and imaging measures. Cognitive performance is evaluated via computerized testing of working memory, episodic memory, perceptual speed, motor speed, implicit sequence learning, and vocabulary. Brain imaging is performed using positron emission tomography with [(11)C]-raclopride to assess dopamine D2/D3 receptor availability. Structural magnetic resonance imaging (MRI) is used for assessment of white and grey matter integrity and cerebrovascular perfusion, and functional MRI maps brain activation during rest and active task conditions. Lifestyle descriptives are collected, and blood samples are obtained and stored for future evaluation. Here, we present selected results from the baseline assessment along with a discussion of sample characteristics and methodological considerations that determined the design of the study.
Objective: The authors evaluate the effectiveness of
noninvasive brain stimulation, in particular, transcranial
direct current stimulation (tDCS), for accelerating learning
and enhancing human performance on complex tasks.
Background: Developing expertise in complex
tasks typically requires extended training and practice.
Neuroergonomics research has suggested new methods
that can accelerate learning and boost human performance.
TDCS is one such method. It involves the
application of a weak DC current to the scalp and has
the potential to modulate brain networks underlying the
performance of a perceptual, cognitive, or motor task.
Method: Examples of tDCS studies of declarative
and procedural learning are discussed. This mini-review
focuses on studies employing complex simulations representative
of surveillance and security operations,
intelligence analysis, and procedural learning in complex
monitoring.
Results: The evidence supports the view that tDCS
can accelerate learning and enhance performance in a
range of complex cognitive tasks. Initial findings also
suggest that such benefits can be retained over time,
but additional research is needed on training schedules
and transfer of training.
Conclusion: Noninvasive brain stimulation can accelerate
skill acquisition in complex tasks and may provide an
alternative or addition to other training methods.
Objective: To examine the efficacy of cognitive rehabilitation strategies specifically designed to improve memory after traumatic brain injury (TBI) and stroke vs. memory improvement with the passage of time.
Design and Method: A meta-analysis was performed on 26 studies of memory retraining and recovery that were published between the years of 1985 and 2013. Effect sizes (ESs) from each study were calculated and converted to Pearson's r and then analyzed to assess the overall effect size and the relationship among the ESs, patient demographics and treatment interventions.
Results: Results indicated a significant average ES (r=.51) in the treatment interventions conditions, as well as a significant average ES (r=.31) in the control conditions, in which participants did not receive any treatment. The largest ESs occurred in studies of stroke patients and studies concerning working memory rehabilitation.
Conclusions: Results showed that memory rehabilitation was an effective therapeutic intervention, especially for stroke patients and for working memory as a treatment domain. However, the results also indicated that significant memory improvement occurred spontaneously over time.
The mechanism of motor recovery after stroke may involve reorganization of the surviving networks. However, details of adaptive changes in structural connectivity are not well understood. Here, we show long-term changes in white matter microstructure that relate to motor recovery in stroke patients. We studied ten subcortical ischemic stroke patients who showed motor hemiparesis at the initial clinical examination and an infarcted lesion centered in the posterior limb of internal capsule of the unilateral hemisphere at the initial diffusion-weighted magnetic resonance imaging scan. The participants underwent serial diffusion tensor imaging and motor function assessments at three consecutive time points; within 2 weeks, and at 1 and 3 months after the onset. Fractional anisotropy (FA) was analyzed for regional differences between hemispheres and time points, as well as for correlation with motor recovery using a tract-based spatial statistics analysis. The results showed significantly increased FA in the red nucleus and dorsal pons in the ipsi-lesional side at 3 months, and significantly decreased FA in the ipsi-lesional internal capsule at all time points, and in the cerebral peduncle, corona radiata, and corpus callosum at 3 months. In the correlation analysis, FA values of clusters in the red nucleus, dorsal pons, midbody of corpus callosum, and cingulum were positively correlated with recovery of motor function. Our study suggests that changes in white matter microstructure in alternative descending motor tracts including the rubro-spinal pathway, and interhemispheric callosal connections may play a key role in compensating for motor impairment after subcortical stroke.
It is well established that aging and vascular processes interact to disrupt cerebral hemodynamics in older adults. However, the independent effects of cerebral perfusion on neurocognitive function among older adults remain poorly understood. We examined the associations among cerebral perfusion, cognitive function, and brain structure in older adults with varying degrees of vascular disease using perfusion magnetic resonance imaging (MRI) arterial spin labeling (ASL).
52 older adults underwent neuroimaging and were administered the Mini Mental State Examination (MMSE), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and measures of attention/executive function. ASL and T1-weighted MRI were used to quantify total brain perfusion, total brain volume (TBV), and cortical thickness.
Regression analyses showed reduced total brain perfusion was associated with poorer performance on the MMSE, RBANS total index, immediate and delayed memory composites, and Trail Making Test B. Reduced frontal lobe perfusion was associated with worse executive and memory function. A similar pattern emerged between temporal lobe perfusion and immediate memory. Regression analyses revealed that decreased total brain perfusion was associated with smaller TBV and mean cortical thickness. Regional effects of reduced total cerebral perfusion were found on temporal and parietal lobe volumes and frontal and temporal cortical thickness.
Reduced cerebral perfusion is independently associated with poorer cognition, smaller TBV, and reduced cortical thickness in older adults.
Prospective studies are needed to clarify patterns of cognitive decline and brain atrophy associated with cerebral hypoperfusion.
Motor recovery after stroke is related to neural plasticity, which involves developing new neuronal interconnections, acquiring new functions, and compensating for impairment. However, neural plasticity is impaired in the stroke-affected hemisphere. Therefore, it is important that motor recovery therapies facilitate neural plasticity to compensate for functional loss. Stroke rehabilitation programs should include meaningful, repetitive, intensive, and task-specific movement training in an enriched environment to promote neural plasticity and motor recovery. Various novel stroke rehabilitation techniques for motor recovery have been developed based on basic science and clinical studies of neural plasticity. However, the effectiveness of rehabilitative interventions among patients with stroke varies widely because the mechanisms underlying motor recovery are heterogeneous. Neurophysiological and neuroimaging studies have been developed to evaluate the heterogeneity of mechanisms underlying motor recovery for effective rehabilitation interventions after stroke. Here, we review novel stroke rehabilitation techniques associated with neural plasticity and discuss individualized strategies to identify appropriate therapeutic goals, prevent maladaptive plasticity, and maximize functional gain in patients with stroke.
Background:
Executive functions are the controlling mechanisms of the brain and include the processes of planning, initiation, organisation, inhibition, problem solving, self monitoring and error correction. They are essential for goal-oriented behaviour and responding to new and novel situations. A high number of people with acquired brain injury, including around 75% of stroke survivors, will experience executive dysfunction. Executive dysfunction reduces capacity to regain independence in activities of daily living (ADL), particularly when alternative movement strategies are necessary to compensate for limb weakness. Improving executive function may lead to increased independence with ADL. There are various cognitive rehabilitation strategies for training executive function used within clinical practice and it is necessary to determine the effectiveness of these interventions.
Objectives:
To determine the effects of cognitive rehabilitation on executive dysfunction for adults with stroke or other non-progressive acquired brain injuries.
Search methods:
We searched the Cochrane Stroke Group Trials Register (August 2012), the Cochrane Central Register of Controlled Trials (The Cochrane Library, August 2012), MEDLINE (1950 to August 2012), EMBASE (1980 to August 2012), CINAHL (1982 to August 2012), PsycINFO (1806 to August 2012), AMED (1985 to August 2012) and 11 additional databases. We also searched reference lists and trials registers, handsearched journals and conference proceedings, and contacted experts.
Selection criteria:
We included randomised trials in adults after non-progressive acquired brain injury, where the intervention was specifically targeted at improving cognition including separable executive function data (restorative interventions), where the intervention was aimed at training participants in methods to compensate for lost executive function (compensative interventions) or where the intervention involved the training in the use of an adaptive technique for improving independence with ADL (adaptive interventions). The primary outcome was global executive function and the secondary outcomes were specific components of executive function, working memory, ADL, extended ADL, quality of life and participation in vocational activities. We included studies in which the comparison intervention was no treatment, a placebo intervention (i.e. a rehabilitation intervention that should not impact on executive function), standard care or another cognitive rehabilitation intervention.
Data collection and analysis:
Two review authors independently screened abstracts, extracted data and appraised trials. We undertook an assessment of methodological quality for allocation concealment, blinding of outcome assessors, method of dealing with missing data and other potential sources of bias.
Main results:
Nineteen studies (907 participants) met the inclusion criteria for this review. We included 13 studies (770 participants) in meta-analyses (417 traumatic brain injury, 304 stroke, 49 other acquired brain injury) reducing to 660 participants once non-included intervention groups were removed from three and four group studies. We were unable to obtain data from the remaining six studies. Three studies (134 participants) compared cognitive rehabilitation with sensorimotor therapy. None reported our primary outcome; data from one study was available relating to secondary outcomes including concept formation and ADL. Six studies (333 participants) compared cognitive rehabilitation with no treatment or placebo. None reported our primary outcome; data from four studies demonstrated no statistically significant effect of cognitive rehabilitation on secondary outcomes. Ten studies (448 participants) compared two different cognitive rehabilitation approaches. Two studies (82 participants) reported the primary outcome; no statistically significant effect was found. Data from eight studies demonstrated no statistically significant effect on the secondary outcomes. We explored the effect of restorative interventions (10 studies, 468 participants) and compensative interventions (four studies, 128 participants) and found no statistically significant effect compared with other interventions.
Authors' conclusions:
We identified insufficient high-quality evidence to reach any generalised conclusions about the effect of cognitive rehabilitation on executive function, or other secondary outcome measures. Further high-quality research comparing cognitive rehabilitation with no intervention, placebo or sensorimotor interventions is recommended.
Unlabelled:
Abstract Primary objective: To provide an overview of useful clinical information for healthcare providers involved in traumatic brain injury (TBI) rehabilitation, including current methods used with survivors of TBI, therapeutic considerations in light of this population's cognitive, emotional and social difficulties and issues regarding the therapeutic working alliance from both survivor and provider perspectives.
Research design:
Non-systematic clinical review.
Method:
The literature was intended to be comprehensive to reflect both past and present contributions to the field. To that end, citations were included from seminal and current texts as well as relevant original and review articles from 1985-2012 in PubMed and PubMedCentral online research databases.
Main outcomes and results:
This article highlights the usefulness of psychotherapy for treatment of psychiatric symptoms in the TBI population, reviews available modalities and offers considerations and suggestions to facilitate and improve treatment.
Conclusions:
Although challenging and perhaps frustrating at times, psychotherapy with this population can be validly attempted and ultimately very rewarding for both the survivor and therapist. Future research should seek to perform controlled studies to examine therapeutic efficacy and compare gains by injury severity in the hopes of creating best practice guidelines for practitioners.
According to World Health Organization, approximately 15 million people are affected by cerebrovascular accident in the world. We study the effect of brain stimulation plus an imaging procedure used as biofeedback training for recovery of motor functions impaired by CVA. Four individuals aged between 33 and 72 years were included in the study, of both genders, with hemiparesis on the left arm due to the CVA. They had their brain activity monitored by EEG. Functional tasks were evaluated according to an observational model proposed by the international classification of functioning and by runtime. The training was composed of 12 sessions of 30 minutes of stimulation by light and sound, as well as imaging procedures. Results revealed that improvements in the performance of the task, with regard to both the runtime and the functional quality of movements, are more related to the increase of effectiveness of neuronal function.
The study sample consisting of 429 people (207 males, 222 females) of Han nationality in Shaanxi, China. Five types of tongue movements were investigated, including tongue rolling, tongue folding, tongue twisting, pointed tongue and clover-leaf tongue. The results revealed that the frequencies of tongue rolling, tongue folding, tongue twisting, pointed tongue and clover-leaf tongue were 63.6, 14.0, 12.6, 54.8 and 0 %, respectively. There were no significant gender differences except with pointed tongue. Compared with other nationalities, tongue rolling, tongue folding, and pointed tongue of Han in Shaanxi had an average frequency. Tongue twisting and clover-leaf tongue had low frequencies. There were significant differences in frequency of clover-leaf tongue between Han and another seven nationalities of China (P < 0.01). Furthermore, only three pairs of trait correlations were exhibited among ten pairs of types of tongue movement combination traits when analyzed using Pearson's correlation coefficient. The data indicated that the correlations of tongue movement were between tongue rolling and tongue folding, between pointed tongue and tongue rolling, and also between tongue folding and pointed tongue, respectively. Additionally, there were significant differences in frequency of tongue movements with age. The possible mechanism of variations of tongue movements with aging may involve the degradation of tongue function, and differential gene activation and modulation, or protein translation.
Previous structural data obtained with diffusion tensor imaging axonal tracking have demonstrated possible in vivo connections between the human red nucleus (RN) and the sensorimotor and associative cortical areas. However, tractographic reconstructions can include false trajectories because of, for instance, the low spatial resolution of diffusion images or the inability to precisely detect fiber crossings. The rubral network was therefore reassessed by functional connectivity during the brain resting state. Because the RN is located very close to the substantia nigra (SN), the nigral network was also studied to ensure that these 2 circuits were correctly dissociated.
Data from 14 right-handed healthy volunteers were acquired at rest and analyzed by region-of-interest (ROI)-based functional connectivity. The blood oxygen level-dependent (BOLD) signal intensity fluctuations of separate ROIs located in the RN and SN were successively used to identify significant temporal correlations with BOLD signal intensity fluctuations of other brain regions.
Low-frequency BOLD signal intensity of the RN correlated with signal intensity fluctuations in the cerebellum; mesencephalon; SN; hypothalamus; pallidum; thalamus; insula; claustrum; posterior hippocampus; precuneus; and occipital, prefrontal, and fronto-opercular cortices. Despite some cortical and subcortical overlaps with nigral connectivity, this rubral network was clearly distinct from the nigral network, which showed a strong correlation with the striatum; cerebellar vermis; and more widespread frontal, prefrontal, and orbitofrontal cortical areas.
During the brain resting state, the human RN participates in cognitive circuits related to salience and executive control, and that may partly represent a subclass of its structural connectivity as revealed by tractography.
W. R. Brown and C. R. Thore (2011) Neuropathology and Applied Neurobiology37, 56–74 Cerebral microvascular pathology in ageing and neurodegeneration
This review of age-related brain microvascular pathologies focuses on topics studied by this laboratory, including anatomy of the blood supply, tortuous vessels, venous collagenosis, capillary remnants, vascular density and microembolic brain injury. Our studies feature thick sections, large blocks embedded in celloidin, and vascular staining by alkaline phosphatase. This permits study of the vascular network in three dimensions, and the differentiation of afferent from efferent vessels. Current evidence suggests that there is decreased vascular density in ageing, Alzheimer's disease and leukoaraiosis, and cerebrovascular dysfunction precedes and accompanies cognitive dysfunction and neurodegeneration. A decline in cerebrovascular angiogenesis may inhibit recovery from hypoxia-induced capillary loss. Cerebral blood flow is inhibited by tortuous arterioles and deposition of excessive collagen in veins and venules. Misery perfusion due to capillary loss appears to occur before cell loss in leukoaraiosis, and cerebral blood flow is also reduced in the normal-appearing white matter. Hypoperfusion occurs early in Alzheimer's disease, inducing white matter lesions and correlating with dementia. In vascular dementia, cholinergic reductions are correlated with cognitive impairment, and cholinesterase inhibitors have some benefit. Most lipid microemboli from cardiac surgery pass through the brain in a few days, but some remain for weeks. They can cause what appears to be a type of vascular dementia years after surgery. Donepezil has shown some benefit. Emboli, such as clots, cholesterol crystals and microspheres can be extruded through the walls of cerebral vessels, but there is no evidence yet that lipid emboli undergo such extravasation.
Repetitive transcranial magnetic stimulation of the brain given as intermittent theta burst stimulation (iTBS) can induce
long-term potentiation (LTP)–like changes in the stimulated hemisphere and long-term depression (LTD)–like changes in the
opposite hemisphere. We evaluated whether LTP- and LTD-like changes produced by iTBS in acute stroke correlate with outcome
at 6 months. We evaluated the excitability of affected hemisphere (AH) and unaffected hemisphere (UH) by measuring motor threshold
and motor-evoked potential (MEP) amplitude under baseline conditions and after iTBS of AH in 17 patients with acute ischemic
stroke. Baseline amplitude of MEPs elicited from AH was significantly smaller than that of MEPs elicited from UH, and baseline
motor threshold was higher for the AH. Higher baseline MEP values in UH correlated with poor prognosis. iTBS produced a significant
increase in MEP amplitude for AH that was significantly correlated with recovery. A nonsignificant decrease in MEP amplitude
was observed for the UH. When the decrease in the amplitude of UH MEPs was added to the regression model, the correlation
was even higher. Functional recovery is directly correlated with LTP-like changes in AH and LTD-like changes in UH and inversely
correlated with the baseline excitability of UH.
The human red nucleus (Nr) is comparatively less well-studied than that of cats or monkeys. Given the functional importance of reticular and midbrain structures in control of movement and locomotion as well as from an evolutionary perspective, we investigated the nature and extent of any differences in Nr projections to the olivary complex in quadrupedal and bipedal species. Using neuroanatomical tract-tracing techniques we developed a "neural sheet" hypothesis allowing us to propose how rubro-olivary relations differ among the three species.
Wheat germ agglutinin-horseradish peroxidase staining supports findings that the cat's nucleus accessories medialis of Bechtrew (NB) projects mainly to the lateral bend of the principal olive. We clarified boundaries among nucleus of Darkschewitsch (ND), NB and parvicellular red nucleus (pNr) of the cat's neural sheet. The macaque's ND-medial accessory olivary projection is rostro-caudally organized and the dorsomedial and ventrolateral parts of the macaque's pNr may project to the principal olive's rostral and caudal dorsal lamella; in cat it projects as well to pNr. Myelin- and Nissl-stained sections show that a well-developed dorsomedial part of the human Nr consists of densely packed cells, deriving small myelinated fibers that continue into the medial central tegmental tract.
Based on these findings we suggest there are distinct bipedal-quadrupedal differences for Nr projections to the olivary complex. We propose the Nr of cats and monkeys comprise the ND, NB and pNr in a zonal sheet-like structure, retaining clear nuclear boundaries and an isolated, well-developed mNr. The human NB may be distinguished from its more specialised ND (ND lies alongside a well-developed pNr) in the human central gray. Phylogenetically, the NB may have been translocated into a roll-shaped Nr in the reticular formation, the dorsomedial portion of which might correspond to the cat's and monkey's NB.
Therapies for motor recovery after stroke or traumatic brain injury are still not satisfactory. To date the best approach seems to be the intensive physical therapy. However the results are limited and functional gains are often minimal. The goal of motor training is to minimize functional disability and optimize functional motor recovery. This is thought to be achieved by modulation of plastic changes in the brain. Therefore, adjunct interventions that can augment the response of the motor system to the behavioural training might be useful to enhance the therapy-induced recovery in neurological populations. In this context, noninvasive brain stimulation appears to be an interesting option as an add-on intervention to standard physical therapies. Two non-invasive methods of inducing electrical currents into the brain have proved to be promising for inducing long-lasting plastic changes in motor systems: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). These techniques represent powerful methods for priming cortical excitability for a subsequent motor task, demand, or stimulation. Thus, their mutual use can optimize the plastic changes induced by motor practice, leading to more remarkable and outlasting clinical gains in rehabilitation. In this review we discuss how these techniques can enhance the effects of a behavioural intervention and the clinical evidence to date.
Interventions for improvement of cognitive problems in patients with traumatic brain injury (TBI) include electroencephalography biofeedback, also known as neurofeedback. Quantitative electroencephalography (QEEG) patterns are assessed in TBI patients and then compared to a database obtained from a normative population. Deviations in QEEG patterns from the normative group are the basis for an intervention plan. While QEEG patterns, obtained under an eyes closed, resting condition, provide information about deviations at rest, QEEG patterns obtained while the patient engages in cognitive tasks reflect specific deficiencies in brain functioning. This paper reviews and assesses QEEG patterns collected under both resting conditions as well as cognitive tasks. The article provides a theoretical and empirical base for QEEG interventions with TBI.
The mammalian orienting response to sounds consists of a gaze shift that can be a combination of head and eye movements. In animals with mobile pinnae, the ears also move. During head movements, vision is stabilized by compensatory rotations of the eyeball within the head because of the vestibulo-ocular reflex (VOR). While studying the gaze shifts made by cats to sounds, a previously uncharacterized compensatory movement was discovered. The pinnae exhibited short-latency, goal-directed movements that reached their target while the head was still moving. The pinnae maintained a fixed position in space by counter-rotating on the head with an equal but opposite velocity to the head movement. We call these compensatory ear movements the vestibulo-auricular reflex (VAR) because they shared many kinematic characteristics with the VOR. Control experiments ruled out efference copy of head position signals and acoustic tracking (audiokinetic) of the source as the cause of the response. The VAR may serve to stabilize the auditory world during head movements.
The induction of long interval cortical inhibition (LICI) in motor cortex with paired pulse transcranial magnetic stimulation (ppTMS) is an established paradigm for the assessment of cortical inhibition, proposed to be related to GABA(B) receptor inhibitory neurotransmission. This study aimed to further evaluate recent methods of the assessment of LICI in non motor regions with ppTMS and electroencephalography (EEG).
ppTMS was applied using a single coil to the motor and dorsolateral prefrontal cortex (DLPFC) in 14 healthy subjects, and in the parietal lobe in 5 of those subjects.
In the motor cortex, LICI resulted in significant suppression in mean cortical evoked activity on EEG between 75 and 250 ms following delivery of the test stimulus. Maximal inhibition was seen from 50 to 250 ms in DLPFC, and between 50 and 175 ms in the parietal lobe.
ppTMS may be used to produce LICI in several cortical regions with a time course similar to known GABA(B) activity.
ppTMS induction of LICI can be recorded by combining TMS with EEG and seems to relate to GABA(B) activity.
The role of the cerebellar cortex in motor learning was investigated by comparing the paramedian lobule of adult rats given difficult acrobatic training to that of rats that had been given extensive physical exercise or had been inactive. The paramedian lobule is activated during limb movements used in both acrobatic training and physical exercise. Acrobatic animals had greater numbers of synapses per Purkinje cell than animals from the exercise or inactive groups. No significant difference in synapse number or size between the exercised and inactive groups was found. This indicates that motor learning required of the acrobatic animals, and not repetitive use of synapses during physical exercise, generates new synapses in cerebellar cortex. In contrast, exercise animals had a greater density of blood vessels in the molecular layer than did either the acrobatic or inactive animals, suggesting that increased synaptic activity elicited compensatory angiogenesis.
Describes the facial musculature and its lower motor neuron innervation. Upper motor neuron innervation from pyramidal and extrapyramidal circuits is explored, with special attention to the respective roles of these systems in voluntary vs emotional facial movements. Also discussed are the evolution of volitional and emotional motor systems, the behavioral and neurological differences between the upper and lower face, the mechanisms of proprioceptive feedback from the face, and asymmetry in facial expression. (117 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
We have attempted to develop a behavioral and neuronal model for classical conditioning in the corticorubrospinal system. A conditioned stimulus (CS) was applied to the cerebral peduncle (CP) in cats which had lesions that interrupted the corticofugal fibers caudal to the red nucleus. The unconditioned stimulus (US) was an electric shock to the skin of the forelimb that produced flexion of the limb. After pairing of the CS and US in close temporal association, an initially ineffective stimulus to the cerebral peduncle was found to give rise to the flexion of the elbow. Extinction of the conditioned response was achieved by applying the CS alone or by reversing the sequence of the stimuli (US-CS: backward pairing). Furthermore, the US alone did not produce an increase in the effectiveness of the CS stimulus. Finally, pairing the fixed CS stimuli with the US at random intervals did not produce any increase in performance in response to the CS. In these respects, the observed behavioral modification has the features of associative conditioning. Because the thresholds for and the strength of elbow flexion induced by stimulation of the nucleus interpositus of the cerebellum were identical in the experimental and control animals, the interpositorubrospinal system cannot be the site of the plastic change. Since the conditioned response is most probably mediated by the corticorubrospinal system, it is likely that a modification of the corticorubral synapses underlies this behavioral change.
The abilities to move ears and eyebrows were examined in 442 subjects (204 men, 238 women) categorized as right-handed (n = 382) and left-handed (n = 60, including mixed and ambidextrous-handed subjects). Approximately 22% could move one or the other ear and about 18% could move both ears simultaneously, but significantly more men could move both ears simultaneously. Significantly more men than women were able to move both the left and right eyebrow and the left ear. No differences were observed between right- and left-handers. Significant contingency correlations were observed between raising eyebrows and moving ears. Results are discussed with reference to a possible left ear-right hemisphere advantage for localising environmental sounds, primitive ear-moving abilities no longer functional in modern humans, and epiphenomenal by-products of other adaptive sex differences.
1. We used transcranial magnetic stimulation (TMS) to study the role of plastic changes of the human motor system in the acquisition of new fine motor skills. We mapped the cortical motor areas targeting the contralateral long finger flexor and extensor muscles in subjects learning a one-handed, five-finger exercise on the piano. In a second experiment, we studied the different effects of mental and physical practice of the same five-finger exercise on the modulation of the cortical motor areas targeting muscles involved in the task. 2. Over the course of 5 days, as subjects learned the one-handed, five-finger exercise through daily 2-h manual practice sessions, the cortical motor areas targeting the long finger flexor and extensor muscles enlarged, and their activation threshold decreased. Such changes were limited to the cortical representation of the hand used in the exercise. No changes of cortical motor outputs occurred in control subjects who underwent daily TMS mapping but did not practice on the piano at all (control group 1). 3. We studied the effect of increased hand use without specific skill learning in subjects who played the piano at will for 2 h each day using only the right hand but who were not taught the five-finger exercise (control group 2) and who did not practice any specific task. In these control subjects, the changes in cortical motor outputs were similar but significantly less prominent than in those occurring in the test subjects, who learned the new skill.(ABSTRACT TRUNCATED AT 250 WORDS)
The distribution of phenotypes in the tongue-rolling polymorphism in two samples of university undergraduates, totalling 1066 individuals, shows no difference between the sexes but large differences between groups drawn from different faculties and particularly between the life sciences and the arts. There are also indications of a difference in distribution between arts students living in halls of residence and those living elsewhere.The genetics of tongue-rolling is not yet critically established but, on
the assumption that most of the phenotypic variation observed has a genetic basis, the data suggest that the loci governing this character may also contribute to variation in personality characteristics which influence choice of subject of study.
The oculo-auricular phenomenon consists of bilateral coactivation of external car muscles during lateral gaze. The electromyogram of the transverse auricular muscle was recorded in 25 healthy volunteers and 1186 patients. In normal subjects bilateral coactivation was observed with lateral gaze (96%), convergence (61%), active and intended head rotation (100%) and passive head rotation (50%). Uni-and bilateral labyrinthine excitation (60 and 80%) and proprioceptive input from the neck muscles (38%) are also effective. In patients with brainstem disease abnormal transverse auricular muscle coactivation is characterized by absence of activity in one or both ear muscles during lateral gaze in either or both directions. The most frequent abnormality was absence of transverse auricular muscle activity homolateral to right or left gaze (type Ia pattern). It was related to homolateral impairment of the blink reflex R1-response (90%) and the caloric response (90%), and to contralateral masseter reflex abnormality (70%). Electrophysiological data, clinical signs and imaging findings indicate that the type Ia pattern is caused by homolateral pontine or contralateral midbrain lesions. It is suggested that the supranuclear organization of the oculo-auricular phenomenon is based on descending tracts crossing at a mid-pontine level.
Synaptic effects of the red nucleus on motoneurons of the facial nucleus were studied in cats. Impulses from the red nucleus activate motoneurons innervating the auricular, buccal, and orbicularis oculi muscles. Monosynaptic EPSPs appeared in all motoneurons which responded to stimulation. Their mean latent period was 1.5±0.04 msec, duration 12.3 ± 0.34 msec, and rise time between 1.5 and 3.2 msec. Repetitive stimulation of the red nucleus led to marked facilitation of the testing EPSP. Facilitation was maximal when the interval between stimuli was 3.5 msec; it was reduced by either a decrease or an increase in the interval. The functional role of the monosynaptic connections of neurons of the red nucleus and of the facial motoneurons is discussed.
Primary Objective: To provide an overview of useful clinical information for healthcare providers involved in traumatic brain injury rehabilitation, including current methods used with survivors of TBI, therapeutic considerations in light of this population’s cognitive, emotional, and social difficulties, and issues regarding the therapeutic working alliance from both survivor and provider perspectives. Research Design: Non-systematic clinical review. Method: The literature was intended to be comprehensive to reflect both past and present contributions to the field. To that end, we included citations from seminal and current texts as well as relevant original and review articles from 1985-2012 in PubMed and PubMedCentral online research databases. Main Outcomes and Results: This article highlights the usefulness of psychotherapy for treatment of psychiatric symptoms in the TBI population, reviews available modalities, and offers considerations and suggestions to facilitate and improve treatment. Conclusions: Although challenging and perhaps frustrating at times, psychotherapy with this population can be validly attempted and ultimately very rewarding for both the survivor and therapist. Future research should seek to perform controlled studies to examine therapeutic efficacy and compare gains by injury severity in the hopes of creating best practice guidelines for practitioners.
Studies on nonhuman primates have demonstrated that the cortico-rubro-spinal system can compensate for damage to the pyramidal tract (PT). In humans, so-called alternate motor fibers (aMF), which may comprise the cortico-rubro-spinal tract, have been suggested to play a similar role in motor recovery after stroke. Using diffusion tensor imaging, we examined PT and aMF in the context of human motor recovery by relating their microstructural properties to functional outcome in chronic stroke patients.
PT and aMF were reconstructed based on their origins in primary motor, dorsal premotor, and supplementary motor cortices in 18 patients and 10 healthy controls. The patients' degree of motor recovery was assessed using the Wolf Motor Function Test (WMFT).
Compared to controls, fractional anisotropy (FA) was lower along ipsilesional PT and aMF in chronic stroke patients, but clusters of higher FA were found bilaterally in aMF within the vicinity of the red nuclei. FA along ipsilesional PT and aMF and within the red nuclei correlated significantly with WMFT scores. Probabilistic connectivity of aMF originating from ipsilesional primary motor cortex was higher in patients, whereas the ipsilesional PT exhibited lower connectivity compared to controls.
The strong correlations observed between microstructural properties of bilateral red nuclei and the level of motor function in chronic stroke patients indicate possible remodeling during recovery. Our results shed light on the role of different corticofugal motor tracts, and highlight a compensatory function of the cortico-rubro-spinal system which may be used as a target in future restorative treatments.
Bell’s palsy is a common disorder involving facial nerve. Branches of the facial nerve innervating auriculares muscles could
be involved in patients with Bell’s palsy. Functions of auriculares muscles were degenerated in the most of human beings,
therefore, paralysis of the auriculares muscles in patients with Bell’s palsy may be unnoticeable. However, unilateral loss
of ear wiggling may be an interesting sign of Bell’s palsy in natural ear wigglers who can move their ears voluntarily. The
mechanism and muscles responsible for the ear wiggling and the innervations to these muscles were illustrated.
Current evidence indicates that repetitive motor behavior during motor learning paradigms can produce changes in representational organization in motor cortex. In a previous study, we trained adult squirrel monkeys on a repetitive motor task that required the retrieval of food pellets from a small-diameter well. It was found that training produced consistent task-related changes in movement representations in primary motor cortex (M1) in conjunction with the acquisition of a new motor skill. In the present study, we trained adult squirrel monkeys on a similar motor task that required pellet retrievals from a much larger diameter well. This large-well retrieval task was designed to produce repetitive use of a limited set of distal forelimb movements in the absence of motor skill acquisition. Motor activity levels, estimated by the total number of finger flexions performed during training, were matched between the two training groups. This experiment was intended to evaluate whether simple, repetitive motor activity alone is sufficient to produce representa tional plasticity in cortical motor maps. Detailed analysis of the motor behavior of the monkeys indicates that their retrieval behavior was highly successful and stereotypical throughout the training period, suggesting that no new motor skills were learned during the performance of the large-well retrieval task. Comparisons between pretraining and posttraining maps of M1 movement representations re vealed no task-related changes in the cortical area devoted to individual distal forelimb movement representations. We conclude that repetitive motor activity alone does not produce functional reorganization of cortical maps. Instead, we propose that motor skill acquisition, or motor learning, is a prerequisite factor in driving representational plasticity in M1.
Training of tongue function is an important part of rehabilitation of patients with brain damage. A standardized tongue-training task has been shown to induce cortical plasticity. This study tested the possible influence of the natural ability to roll the tongue and modulations of tongue-training parameters on tongue-training performance.
A total of 44 healthy adult subjects participated. 29 subjects (15 with and 14 without ability to roll their tongue) performed 1h standard tongue-training task. Another 15 subjects participated in 2 sessions: Standard and Modulation in randomized order. Standard session: 1h tongue-training with fixed training parameters; Modulation session: 1h tongue-training with modulation of training parameters every 20 min (3 different settings - A, B, C, with different timing of task). Perceived task difficulty was evaluated on a 0-10 numerical rating scale (NRS).
All participants improved performance during training (P<0.001). The ability to roll the tongue did not influence tongue-training performance (P=0.617). Modulation of training parameters influenced baseline training performance (P<0.018) and improvement (P=0.039). The mean perceived difficulty on NRS was: Standard: 6 ± 2; Modulation: A: 6 ± 2; B: 7 ± 1;C: 4 ± 1. Perceived task difficulty (ρ=-0.740, P<0.001) and performance improvement (ρ=-0.610, P<0.001) were inversely correlated with baseline training performance.
The natural ability to roll the tongue did not influence tongue-training performance. Modulation of tongue-training parameters by alteration of timing of the training task influenced tongue-training performance and perceived task difficulty.
Approximately one-third of patients with stroke exhibit persistent disability after the initial cerebrovascular episode, with motor impairments accounting for most poststroke disability. Exercise and training have long been used to restore motor function after stroke. Better training strategies and therapies to enhance the effects of these rehabilitative protocols are currently being developed for poststroke disability. The advancement of our understanding of the neuroplastic changes associated with poststroke motor impairment and the innate mechanisms of repair is crucial to this endeavor. Pharmaceutical, biological and electrophysiological treatments that augment neuroplasticity are being explored to further extend the boundaries of poststroke rehabilitation. Potential motor rehabilitation therapies, such as stem cell therapy, exogenous tissue engineering and brain-computer interface technologies, could be integral in helping patients with stroke regain motor control. As the methods for providing motor rehabilitation change, the primary goals of poststroke rehabilitation will be driven by the activity and quality of life needs of individual patients. This Review aims to provide a focused overview of neuroplasticity associated with poststroke motor impairment, and the latest experimental interventions being developed to manipulate neuroplasticity to enhance motor rehabilitation.
Few imaging studies have been devoted to the structural and functional connectivity of the red and inferior olivary nuclei although these two nuclei represent two main targets of the cerebellum within the brainstem. However, the RN is anatomically and functionally related to a widespread sensorimotor, limbic, and executive brain network. It projects massively onto the principal olive with which it contributes to a cerebello-rubro-olivo-cerebellar loop modulated by cortical and subcortical afferents. Despite a minor role in planning and execution of rhythmic movements, the red nucleus in conjunction with the inferior olive, more specifically involved in the detection of "unexpected" events, contributes to sensorimotor, sensory and, likely, cognitive higher functions.
Tic disorders are commonly considered to be childhood syndromes. Newly presenting tic disorders during adulthood are uncommon and mostly described in relation to an acquired brain lesion or as incidental tics, particularly in context with other neurological or psychiatric diseases. Tic disorder involving the ears is extremely uncommon with only few studies in English literature. In the present case, we describe an adult patient with new-onset idiopathic tics disorder involving both ears, causing social embarrassment. In addition, our patient had recent onset of the tics without any childhood or family history of tic disorders. The single most important component of management is an accurate diagnosis. At the same time, tics should be differentiated from other movement disorders such as chorea, stereotypy, and dystonias.
The distribution of phenotypes in the tongue-rolling polymorphism in two samples of university undergraduates, totalling 1066 individuals, shows no difference between the sexes but large differences between groups drawn from different faculties and particularly between the life sciences and the arts. There are also indications of a difference in distribution between arts students living in halls of residence and those living elsewhere.The genetics of tongue-rolling is not yet critically established but, on
the assumption that most of the phenotypic variation observed has a genetic basis, the data suggest that the loci governing this character may also contribute to variation in personality characteristics which influence choice of subject of study.
The use of epidemiological studies of twins as a means of determining the existence of genetic factors in various conditions is well known. To be of value, the zygosity of the twin pairs must be identified with as great a degree of confidence as possible. A method of determining twin zygosity, using concordance in general likeness, hair colour, hair type, eye colour, ear form, tongue roll and phenylthiocarbamide (PTC) taste sensitivity, was developed for use in a survey of 244 pairs of like-sexed twins aged 5 to 15 years. The results obtained and the problems raised when applying this method are discussed. The method was sinple to apply to a large group of twin pairs, and monozygotic pairs were identified with a degree of confidence greater than 95%.
The purpose of this study was to analyze recovery of motor function in a cohort of patients presenting with an acute occlusion in the carotid distribution. Analysis of recovery patterns is important for estimating patient care needs, establishing therapeutic plans, and estimating sample sizes for clinical intervention trials.
We prospectively measured the motor deficits of 104 stroke patients over a 6-month period to identify earliest measures that would predict subsequent motor recovery. Motor function was measured with the Fugl-Meyer Assessment. Fifty-four patients were randomly assigned to a training set for model development; 50 patients were assigned to a test set for model validation. In a second analysis, patients were stratified on basis of time and stroke severity. The sample size required to detect a 50% improvement in residual motor function was calculated for each level of impairment and at three points in time.
At baseline the initial Fugl-Meyer motor scores accounted for only half the variance in 6-month motor function (r2 = 0.53, p less than 0.001). After 5 days, both the 5-day motor and sensory scores explained 74% of the variance (p less than 0.001). After 30 days, the 30-day motor score explained 86% of the variance (p less than 0.001). Application of these best models to the test set confirmed the results obtained with the training set. Sample-size calculations revealed that as severity and time since stroke increased, sample sizes required to detect a 50% improvement in residual motor deficits decreased.
Most of the variability in motor recovery can be explained by 30 days after stroke. These findings have important implications for clinical practice and research.
The author describes 10 patients with tics of the ear. The pathogenesis of this disorder is uncertain, but psychological factors may play an important role. This may be the first report of this disorder in the English literature.
948 undergraduates at The Ohio State University were administered the 10-item Edinburgh Handedness Inventory and asked to indicate the extent to which they could turn up the sides of their tongues. Significantly fewer left-handers than right-handers (62.8% and 74.8%, respectively) reported being able to turn up either or both sides. Sex differences in tongue-rolling ability were also noted. Among the 403 men included in the final sample, 77.4% could roll their tongues, whereas only 69.7% of the 491 women could do so.
The presence of acromial dimples in two unrelated children is reported, neither of whom was affected by the 18q- syndrome. The family investigation revealed male-to-male transmission in one case, which has not previously been recorded.
The projection of the red nucleus to certain nuclei of the medulla has been studied by the silver impregnation methods of Nauta and Glees. The course of the rubro-bulbo-spinal tract at mesencephalic, pontine and medullary levels has been described and illustrated. After unilateral lesions in the red nucleus, degenerated fibres have been observed in the contralateral facial and lateral reticular nuclei. No termination was found in the ambiguous nucleus. In the facial nucleus, only the dorsomedial and intermediate groups receive rubral afferents. In the lateral reticular nucleus, the projection is restricted to the dorsal and lateral parts of the principal portion and to the subtrigeminal portion. No somatotopical organisation of the projection to the latter nucleus could be demonstrated. In addition, the present results suggest the presence of a bilateral projection from the mesencephalic reticular formation to the facial nucleus. In the discussion, the possible functional significance of the rubrofacial projection is analysed. It is also pointed out that the reticulofacial projection could provide an explanation for the paresis limited to the lower facial muscles which is observed in cases of capsular hemiplegia.
The oculo-auricular phenomenon consists of bilateral coactivation of external ear muscles during lateral gaze. The electromyogram of the transverse auricular muscle was recorded in 25 healthy volunteers and 1186 patients. In normal subjects bilateral coactivation was observed with lateral gaze (96%), convergence (61%), active and intended head rotation (100%) and passive head rotation (50%). Uni- and bilateral labyrinthine excitation (60 and 80%) and proprioceptive input from the neck muscles (38%) are also effective. In patients with brainstem disease abnormal transverse auricular muscle coactivation is characterized by absence of activity in one or both ear muscles during lateral gaze in either or both directions. The most frequent abnormality was absence of transverse auricular muscle activity homolateral to right or left gaze (type Ia pattern). It was related to homolateral impairment of the blink reflex R1-response (90%) and the caloric response (90%), and to contralateral masseter reflex abnormality (70%). Electrophysiological data, clinical signs and imaging findings indicate that the type Ia pattern is caused by homolateral pontine or contralateral midbrain lesions. It is suggested that the supranuclear organization of the oculo-auricular phenomenon is based on descending tracts crossing at a mid-pontine level.