Parallel modulation of interhemispheric inhibition and the size of a cortical hand muscle representation during active contraction.

Interhemispheric inhibition (IHI) between motor cortexes is thought to suppress unwanted mirror movements during voluntary behaviors and can be assessed using paired-pulse transcranial magnetic stimulation (TMS). The magnitude of IHI may be related to the size of the cortical representation for a given muscle as a mechanism for facilitating unimanual control. To date, the relationship between IHI and cortical muscle representations remains unknown.

Alterations in Motor Cortical Representation of Muscles Following Incomplete Spinal Cord Injury in Humans.

(1) Background: The primary motor cortex (M1) experiences reorganization following spinal cord injury (SCI). However, there is a paucity of research comparing bilateral M1 organization in SCI and questions remain to be answered. We explored the presence of somatotopy within the M1 representation of arm muscles, and determined whether anatomical shifts in these representations occur, and investigated the symmetry in organization between the two hemispheres.

Active and resting motor threshold are efficiently obtained with adaptive threshold hunting.

Transcranial magnetic studies typically rely on measures of active and resting motor threshold (i.e. AMT, RMT).

Short- and long-latency afferent inhibition; uses, mechanisms and influencing factors.

Transcranial magnetic stimulation (TMS) is an ideal technique for non-invasively stimulating the brain and assessing intracortical processes. By delivering electrical stimuli to a peripheral nerve prior to a TMS pulse directed to the motor cortex, the excitability and integrity of the sensorimotor system can be probed at short and long time intervals (short latency afferent inhibition, long latency afferent inhibition). The goal of this review is to detail the experimental factors that influence the magnitude and timing of afferent inhibition in the upper limb and these include the intensity of nerve and TMS delivery, and the nerve composition.

Transcranial Magnetic Stimulation with Intermittent Theta Burst Stimulation Alters Corticospinal Output in Patients with Chronic Incomplete Spinal Cord Injury.

Intermittent theta burst stimulation (iTBS) is intended primarily to alter corticospinal excitability, creating an attractive opportunity to alter neural output following incomplete spinal cord injury (SCI). This study is the first to assess the effects of iTBS in SCI. Eight individuals with chronic incomplete SCI were studied.

Modulation of long-latency afferent inhibition by the amplitude of sensory afferent volley.

Long-latency afferent inhibition (LAI) is the inhibition of the transcranial magnetic stimulation (TMS) motor-evoked potentials (MEP) by the sensory afferent volley following electrical stimulation of a peripheral nerve. It is unknown how the activation of sensory afferent fibers relates to the magnitude of LAI. This study investigated the relationship between LAI and the sensory nerve action potentials (SNAP) from the median nerve (MN) and the digital nerves (DN) of the second digit.

Physical activity levels determine exercise-induced changes in brain excitability.

Emerging evidence suggests that regular physical activity can impact cortical function and facilitate plasticity. In the present study, we examined how physical activity levels influence corticospinal excitability and intracortical circuitry in motor cortex following a single session of moderate intensity aerobic exercise. We aimed to determine whether exercise-induced short-term plasticity differed between high versus low physically active individuals.