BACKGROUND Biphasic pulses produced by most commercially available TMS machines have a cosine waveform, which makes it difficult to study the interaction between the two phases of stimulation. OBJECTIVE We used a controllable pulse TMS (cTMS) device delivering quasi-rectangular pulse outputs to investigate whether monophasic are more effective than biphasic pulses. METHODS Temporally symmet...

Motor control is integral to all types of human behavior, and the dorsal Anterior Cingulate Cortex (dACC) is thought to play an important role in the brain network underlying motor control. Yet the role of the dACC in motor control is under-characterized. Here we aimed to characterize the dACC's role in adolescent brain network interactions during a simple motor control task involving visually ...

The primary motor cortex has an important role in the precise execution of learned motor responses. During motor learning, synaptic efficacy between sensory and primary motor cortical neurons is enhanced, possibly involving long-term potentiation and N-methyl-D-aspartate (NMDA)-specific glutamate receptor function. To investigate whether NMDA receptor in the primary motor cortex can act as a co...

Movement sequences, defined both by the component movements and by the serial order in which they are produced, are fundamental building blocks of motor behavior. The serial order of sequence production is strongly encoded in medial motor areas. It is not known to what extent sequences are further elaborated or encoded in primary motor cortex. Here, we describe cells in the primary motor cortex...

The cholinergic basal forebrain projects throughout the neocortex, exerting a critical role in modulating plasticity associated with normal learning. Cholinergic modulation of cortical plasticity could arise from 3 distinct mechanisms by 1) "direct" modulation via cholinergic inputs to regions undergoing plasticity, 2) "indirect" modulation via cholinergic projections to anterior, prefrontal at...

Objective To investigate neural correlates associated with recovery of motor function over 6 months in patients with basal ganglia (BG) stroke using acetazolamide (ACZ) stress brain-perfusion single-photon emission computed tomography (SPECT). Methods Medical records of 22 patients presenting first-ever BG stroke were retrospectively reviewed. Regional cerebral blood flow (CBF) and cerebrovas...

Coincident hand and foot movements are more reliably performed in the same direction than in opposite directions. Using transcranial magnetic stimulation (TMS) to assess motor cortex function, we examined the physiological basis of these movements across three novel experiments. Experiment 1 demonstrated that upper limb corticomotor excitability changed in a way that facilitated isodirectional ...

OBJECTIVE Slow frequency repetitive transcranial magnetic stimulation (rTMS) reduces motor cortex excitability, but it is unclear whether this has behavioural consequences in healthy subjects. METHODS We examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 80% of active motor threshold) over left motor or left premotor cortex on performance in a visually cued choice reaction...

Stroke may trigger a number of cellular and molecular events in perilesional and remote brain regions enabling cortical reorganization and recovery of function. We here investigated the pattern and time course of acute stroke-induced changes in motor system activity during motor recovery using functional magnetic resonance imaging. Hand movement-related neural activity was assessed in 11 acute ...

Functional imaging studies have revealed recruitment of ipsilateral motor areas during the production of sequential unimanual finger movements. This phenomenon is more prominent in the left hemisphere during left-hand movements than in the right hemisphere during right-hand movements. Here we investigate whether this lateralization pattern is related specifically to the sequential structure of ...