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In patients with chronic stroke, the primary motor cortex of the intact hemisphere (M1(intact hemisphere)) may influence functional recovery, possibly through transcallosal effects exerted over M1 in the lesioned hemisphere (M1(lesioned hemisphere)). Here, we studied interhemispheric inhibition (IHI) between M1(intact hemisphere) and M1(lesioned hemisphere)(More)
Movements of the paretic hand in patients with chronic subcortical stroke are associated with high interhemispheric inhibition (IHI) targeting the motor cortex in the lesioned hemisphere relative to healthy controls. The purpose of this investigation was to determine whether this abnormality also involves IHI operating during movements of the non-paretic(More)
Interhemispheric inhibition (IHI) between motor cortical areas is thought to play a critical role in motor control and could influence manual dexterity. The purpose of this study was to investigate IHI preceding movements of the dominant and nondominant hands of healthy volunteers. Movement-related IHI was studied by means of a double-pulse transcranial(More)
Unilateral hand movements are accompanied by a transient decrease in corticospinal (CS) excitability of muscles in the opposite hand. However, the rules that govern this phenomenon are not completely understood. We measured the amplitude of motor evoked potentials (MEP) in the left first dorsal interosseus (FDI) elicited by transcranial magnetic stimulation(More)
Mirror neurons discharge with both action observation and action execution. It has been proposed that the mirror neuron system is instrumental in motor learning. The human primary motor cortex (M1) displays mirror activity in response to movement observation, is capable of forming motor memories, and is involved in motor learning. However, it is not known(More)
Inhibitory mechanisms are critically involved in goal-directed behaviors. To gain further insight into how such mechanisms shape motor representations during response preparation, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and H-reflexes were recorded from left hand muscles during choice reaction time tasks. The(More)
One of the most devastating consequences of early corticospinal lesions is the impaired dexterity that results in a noticeable deficit while manipulating small objects. One purpose of the present study was to investigate the extent to which a deficit in the coordination of fingertip forces when grasping and lifting an object between the thumb and index(More)
The ability of motor training to encode a motor memory is reduced in older adults. Here, we tested the hypothesis that training-dependent memory encoding, an issue of relevance in neurorehabilitation, is enhanced in elder individuals by action observation which alone can contribute to learning processes. A group of 11 healthy older adults participated in(More)
Top-down control processes are critical to select goal-directed actions in flexible environments. In humans, these processes include two inhibitory mechanisms that operate during response selection: one is involved in solving a competition between different response options, the other ensures that a selected response is initiated in a timely manner. Here,(More)
The precise contribution of the ipsilateral primary motor cortex (iM1) to hand movements remains controversial. To address this issue, we elicited transient virtual lesions of iM1 by means of transcranial magnetic stimulation (TMS) in healthy subjects performing either a grip-lift task or a step-tracking task with their right dominant hand. We found that,(More)