Asymmetries of long-latency intracortical inhibition in motor cortex and handedness.
Paired-pulse transcranial magnetic stimulation was used in three experiments to measure the properties of long-latency intracortical inhibition (LICI) acting on the relaxed first dorsal interosseus muscle of the left and right hand in right-handed volunteers. The experiments show that LICI is asymmetrical: it emerges more rapidly and is greater in the dominant than non-dominant hand shortly after activation of the LICI circuits, and is greater with low-intensity conditioning stimulus intensities in the dominant than non-dominant hand. These findings suggest that asymmetrical function of long-latency inhibitory circuits in motor cortex might contribute to the asymmetrical dexterity between the hands, possibly through their inhibitory control of the circuits responsible for short-latency inhibition.
Hammond
Geoffrey R
GR
School of Psychology, The University of Western Australia, 6009 Crawley, WA, Australia. geoff@psy.uwa.edu.au
Garvey
Carrie-Anne
CA
D000293:Adolescent; D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology* / Q000528:radiation effects; D009433:Neural Inhibition / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation