In non- @entity1 primates, invasive tracing and electrostimulation studies have identified strong ipsilateral cortico-cortical connections between dorsal premotor- (PMd) and the primary motor cortex ( @entity25089 ). Here, we applied dual-site transcranial magnetic stimulation (dsTMS) to left PMd and @entity25089 through specifically designed minicoils to selectively probe ipsilateral PMd-to- @entity25089 connectivity in @entity1 . A suprathreshold @entity1062 ( @entity1062 ) was applied to @entity25089 producing a motor evoked potential (MEP) of about 0.5 mV in the relaxed right first dorsal interosseus muscle (FDI). A subthreshold conditioning stimulus (CS) was given to PMd 2.0-5.2 ms after the @entity1062 at intensities of 50-, 70-, or 90% of @entity1062 . The CS to PMd facilitated the MEP evoked by @entity1062 over @entity25089 at interstimulus intervals (ISI) of 2.4 or 2.8 ms. There was a second facilitatory peak at ISI of 4.4 ms. PMd-to- @entity25089 facilitation did not change as a function of CS intensity. Even at higher intensities, the CS alone failed to elicit a MEP or a cortical silent period in the pre-activated FDI, excluding a direct spread of excitation from PMd to @entity25089 . No MEP facilitation was present while CS was applied rostrally over lateral prefrontal cortex. Together our results indicate that our dsTMS paradigm probes a short-latency facilitatory PMd-to- @entity25089 pathway. The temporal pattern of MEP facilitation suggests a PMd-to- @entity25089 route that targets intracortical @entity25089 circuits involved in the generation of indirect corticospinal volleys. This paradigm opens up new possibilities to study context-dependent intrahemispheric PMd-to- @entity25089 interactions in the intact @entity1 brain.

The XXXX dorsal premotor cortex facilitates the excitability of ipsilateral primary motor cortex via a short latency cortico-cortical route.

@entity1 :: ('9606', 'Species') :: ['humans', 'human'] @entity25089 :: ('100507027', 'Gene') :: ['M1(HAND)'] @entity1062 :: ('MESH:D013736', 'Disease') :: ['test stimulus', 'TS']
@entity1 :: (9606,Species) :: ['human']
