Electromyographic study of unlateral and bilateral measurement conditions of reflex, premotor, and simple reaction time to joint displacement.
The purpose of the study was to study the effects of cross-transfer on fractionated reaction time components in the unilateral and bilateral measurement conditions. Ss (N = 30) responded to a sudden arm displacement from an electromagnet by abducting the falling arm (unilateral ipsilateral trial, N = 15), by abducting the non-stimulus limb from a RT switch (unilateral contralateral trial, N = 15), or by performing both of these responses simultaneously (bilateral trial, N = 15). EMGs from the 45 randomized trials were monitored from the middle portions of the relaxed deltoideus muscles. Dependent variables were ipsilateral reflex latency (IRL), ipsilateral premotor time (IPMT), contralateral premotor time (CPMT), and contralateral reaction time (CRT). The following statistical procedures were applied to the data: an interclass correlation, a subjects-by-trials analysis of trends for each variable, and a single-groups subjects by two within-group variables analysis of variance for the six logical comparisons. IPMT was the only latency decreased by the addition of the bilateral measurement condition; however IPMT remained slower than CPMT even in the bilateral measurement condition. IRLs, CPMTs, and CRTs remained the same. The addition of a bilateral measurement condition appeared to result in less delay from the synchronous reflex volley to IPMT than in the unilateral measurement condition.
D000200:Action Potentials; D000328:Adult; D001132:Arm / Q000502:physiology; D004576:Electromyography; D006801:Humans; D007596:Joints / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology; D009132:Muscles / Q000502:physiology*; D010812:Physical Stimulation; D011930:Reaction Time; D012018:Reflex; D013997:Time Factors