Transcranial Magnetic Stimulation Can Be Used to Test Connections to Primary Motor Areas from Frontal and Medial Cortex in Humans

Macaque ventral premotor cortex exerts powerful facilitation of motor cortex outputs to upper limb motoneurons.

“…In contrast to the excitatory actions documented here, most reports on premotor-motor cortex interactions with TMS in humans have stressed inhibitory effects (Civardi et al, 2001;Mün-chau et al, 2002). We selected only F5 sites giving rise to excitation, and these excitatory effects were focal in nature (Fig.…”

Deficient intracortical inhibition (SICI) during movement preparation after chronic stroke

“…Recent animal data also showed changes in cortical excitability after small cortical lesions associated with functional recovery. In humans, enhanced resting motor cortical excitability (or reduced inhibition) has been proposed as a possible contributing mechanism 18 to the recovery process, 14,31 possibly influenced by interactions with secondary motor areas, such as the premotor cortex or the supplementary motor area 32,33 or even with homologous areas of the opposite hemisphere. 27,28 Because motor deficits in patients are most pronounced while performing a motor task, we hypothesized that abnormalities in intracortical function might manifest themselves more prominently in the premovement period, when patients intend to move the paretic hand.…”

Short-Latency Influence of Medial Frontal Cortex on Primary Motor Cortex during Action Selection under Conflict

“…Conditioning coil intensity was set at 120% of the resting motor threshold (RMT), which in turn was defined as the minimum intensity, when the coil was over the M1 hotspot, needed to elicit an MEP of Ͼ50 V in the relaxed FDI muscle on 5/10 trials. The IPI between conditioning and test pulses was 6 ms, which has been shown to be effective in a previous study of medial premotor areas (Civardi et al, 2001). The relative frequency of switch and stay trials remained the same in both experiments and, in both cases, TMS was delivered either 75, 125, or 175 ms after the onset of the central color cue [stimulus-onset asynchrony (SOA)] (Fig.…”