Brain-Derived Neurotrophic Factor Gene Polymorphism Predicts Response to Continuous Theta Burst Stimulation in Chronic Stroke Patients.

Objectives: The efficacy of repetitive transcranial magnetic stimulation (rTMS) in clinically relevant neuroplasticity research depends on the degree to which stimulation induces robust, reliable effects. The high degree of interindividual and intraindividual variability observed in response to rTMS protocols, such as continuous theta burst stimulation (cTBS), therefore represents an obstacle to its utilization as treatment for neurological disorders. Brain-derived neurotrophic factor (BDNF) is a protein involved in human synaptic and neural plasticity, and a common polymorphism in the BDNF gene (Val66Met) may influence the capacity for neuroplastic changes that underlie the effects of cTBS and other rTMS protocols.

Variability in cTBS Aftereffects Attributed to the Interaction of Stimulus Intensity With BDNF Val66Met Polymorphism.

: To evaluate whether a common polymorphism (Val66Met) in the gene for brain-derived neurotrophic factor (BDNF)-a gene thought to influence plasticity-contributes to inter-individual variability in responses to continuous theta-burst stimulation (cTBS), and explore whether variability in stimulation-induced plasticity among Val66Met carriers relates to differences in stimulation intensity (SI) used to probe plasticity. : Motor evoked potentials (MEPs) were collected from 33 healthy individuals (11 Val66Met) prior to cTBS (baseline) and in 10 min intervals immediately following cTBS for a total of 30 min post-cTBS (0 min post-cTBS, 10 min post-cTBS, 20 min post cTBS, and 30 min post-cTBS) of the left primary motor cortex. Analyses assessed changes in cortical excitability as a function of BDNF (Val66Val vs.

High definition transcranial direct current stimulation modulates abnormal neurophysiological activity in post-stroke aphasia.

Recent findings indicate that measures derived from resting-state magnetoencephalography (rsMEG) are sensitive to cortical dysfunction in post-stroke aphasia. Spectral power and multiscale entropy (MSE) measures show that left-hemispheric areas surrounding the stroke lesion (perilesional) exhibit pathological oscillatory slowing and alterations in signal complexity. In the current study, we tested whether individually-targeted high-definition transcranial direct current stimulation (HD-tDCS) can reduce MEG abnormalities and transiently improve language performance.

Altered beta-band functional connectivity may be related to 'performance slowing' in good outcome aneurysmal subarachnoid patients.

Recent evidence suggests that good neurological outcome in subarachnoid hemorrhage (SAH) does not equate to good neuropsychological and cognitive outcome. These individuals continue to face cognitive difficulties in tasks involving mental flexibility, short-term memory and attention, resulting in decreased independence in daily living and reduced ability to return to work. In the current study, we examined the functional connectivity profiles using magnetoencephalography (MEG) in SAH patients, versus controls, during a visual short-term memory, 1-back, task.

Spontaneous oscillatory markers of cognitive status in two forms of dementia.

Abnormal oscillatory brain activity in dementia may indicate incipient neuronal/synaptic dysfunction, rather than frank structural atrophy. Leveraging a potential link between the degree of abnormal oscillatory activity and cognitive symptom severity, one could localize brain regions in a diseased but pre-atrophic state, which may be more amenable to interventions. In the current study, we evaluated the relationships among cognitive deficits, regional volumetric changes, and resting-state magnetoencephalography abnormalities in patients with mild cognitive impairment (MCI; N = 10; age: 75.

Visual Working Memory Encoding and Recognition in Good Outcome Aneurysmal Subarachnoid Patients.

Aneurysmal subarachnoid hemorrhage (aSAH) accounts for less than 5% of strokes but is associated with significant morbidity and mortality. Amongst survivors, neurocognitive complaints are common, often despite normal imaging. We used magnetoencephalography (MEG) to investigate neurophysiological function during a visual working memory task in aSAH survivors with good recovery and normal structural imaging.

Concussion Alters the Functional Brain Processes of Visual Attention and Working Memory.

Millions of North Americans sustain a concussion or a mild traumatic brain injury annually, and are at risk of cognitive, emotional, and physical sequelae. Although functional MRI (fMRI) studies have provided an initial framework for examining functional deficits induced by concussion, particularly working memory and attention, the temporal dynamics underlying these deficits are not well understood. We used magnetoencephalography (MEG), a modality with millisecond temporal resolution, in conjunction with a 1-back visual working memory (VWM) paradigm using scenes from everyday life to characterize spatiotemporal functional differences at specific VWM stages, in adults had had or had not had a recent concussion.

A pediatric institutional acute stroke protocol improves timely access to stroke treatment.

Aim: We aimed to evaluate whether an institutional acute stroke protocol (ASP) could accelerate the diagnosis and secondary treatment of pediatric stroke.

Method: We initiated an ASP in 2005. We compared 209 children (125 males, 84 females; median age 4.

Fields or flows? A comparative metaanalysis of transcranial magnetic and direct current stimulation to treat post-stroke aphasia.

Purpose: Aphasia-acquired loss of the ability to understand or express language-is a common and debilitating neurological consequence of stroke. Evidence suggests that transcranial magnetic (TMS) or direct current stimulation (tDCS) can significantly improve language outcomes in patients with aphasia (PWA). However, the relative efficacy between TMS and tDCS has not yet been explored.

Individualized treatment with transcranial direct current stimulation in patients with chronic non-fluent aphasia due to stroke.

While evidence suggests that transcranial direct current stimulation (tDCS) may facilitate language recovery in chronic post-stroke aphasia, individual variability in patient response to different patterns of stimulation remains largely unexplored. We sought to characterize this variability among chronic aphasic individuals, and to explore whether repeated stimulation with an individualized optimal montage could lead to persistent reduction of aphasia severity. In a two-phase study, we first stimulated patients with four active montages (left hemispheric anode or cathode; right hemispheric anode or cathode) and one sham montage (Phase 1).

It's the thought that counts: examining the task-dependent effects of transcranial direct current stimulation on executive function.

Background: Prior investigations employing transcranial direct current stimulation (tDCS) have shown that stimulation can elicit subsequent improvement on tests of various cognitive abilities, including working memory. While stimulation parameters such as intensity and duration are known to determine the effects of tDCS, the degree to which stimulation effects are influenced by the nature of cognitive activities during stimulation remains unclear.

Objective/hypothesis: To determine whether manipulating the working memory load of a task performed during stimulation would modulate tDCS-induced enhancement of performance on a different, related measure after stimulation.