Effect of motor-response-deprivation on contingent negative variation (CNV). I: Normal adult data

CNV's were obtained in S1-S2-MR paradigm from 22 normal subjects between the ages of 19 and 67 years (the mean age, 33.5+/-12.5). And then the effect of the presence or absence of a motor response on the CNV was studied. Results were as follows; (1) In the control session (S1-S2-MR), the mean CNV amplitude was 14+/-5 muV, and the mean response time was 291+/-76 msec. There was no significant difference with age, but the mean CNV amplitude for female was significantly higher than that for male. (2) Under the nonresponse condition (S1-S2) where the subject was instructed to attend to S1-S2 without a motor response, CNV amplitude significantly reduced for all subjects (7+/-5 muV). The mean voltage of the attentive-to-stimuli group was significantly higher than that of the inattentive group, and sex difference was not significant for the attentive group. However, CNV of the inattentive male disappeared completely, while the CNV of the inattentive female was significantly higher (8+/-5 muV). (3) Under the response condition (S1-S2-MR), CNV recovered almost to the magnitude level of the control condition (14+/-3 muV), in spite of the fact that the mean response time was significantly shortened between the control and response sessions. (4) We speculate that CNV changes may be dependent upon the dynamic balance of the excitatory-inhibitory activity.