Bilateral force transients in the upper limbs evoked by single-pulse microstimulation in the pontomedullary reticular formation

摘要: Neurons in the pontomedullary reticular formation (PMRF) give rise to reticulospinal tract. The motor output of PMRF was investigated using stimulus-triggered averaging electromyography (EMG) and force recordings two monkeys (M. fascicularis). EMG recorded from 12 pairs upper limb muscles, forces were detected isometric force-sensitive handles. Of 150 stimulation sites, 105 (70.0%) produced significant responses, 139 (92.5%) responses. Based on average flexor onset latency 8.3 ms 15.9 poststimulation, an electromechanical delay ∼7.6 calculated. magnitude responses (∼10 mN) correlated with change activity (P < 0.001). A multivariate linear regression analysis used estimate contribution each muscle generation, flexors extensors exhibiting antagonistic effects. predominant pattern ipsilateral flexion contralateral extension observed response stimulation, 65.3% directed medially posteriorly 0.001) 78.6% laterally anteriorly This novel approach permits direct measurement outputs evoked by central nervous system microstimulation. Despite small poststimulus effects, low-intensity single-pulse microstimulation detectable forces. forces, showing combined effect all arms, are consistent reciprocal EMG.