Origin of Contingent Negative Variation (CNV) and its Functional Features

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1. Nine monkeys were trained to move their hand in response to an Imperative Stimulus (I. S.) given 1 s after a Warning Stimulus (W. S.) (W. S. - I. S. task). Much shorter reaction times were observed on the W. S. - I. S. task than on the simple visuo-initiated movements. With electrodes implanted ii cerebral cortices, thereby, surface-negative, depth-positive (sーN, d-P) sustained potentials toward I. S. were recorded in the prefrontal, premotor and supplementary motor areas on both hemispheres, and s-N, d-P slowly increasing potentials were in the motor and somatosensory cortices contralateral to the hand. These potentials are considered to be composed mainly of electric dipoles due to EPSP currents generated in superficial parts of apical dendrites in pyramidal neurons in the cortical areas. They appear to correspond to CNV in the human. It is suggested that the sustained and slowly increasing potentials may be respectively related to cortical activities associated with expectation a … More nd anticipation of the I. S., and preparation for the movement like the readiness potential on the self-paced movement.2. Eight monkeys were trained to move the hand in response to I. S. given 1 s after go to W. S., but not after no-go to W. S.. S-N, d-P slow potentials (CNV) were obtained on the go W. S., whereas slow sーP, d-N potentials (CPV) were obtained in the prefrontal areas on the no-go W. S.. CPV is considered to be likely produced by electrical dipoles in the areas caused by disfacilitation of background EPSPs in the superficial parts of the apical dendrites.3. In order to learn possible contribution of cerebellar activity to CNV, cerebellar hemispherectomy ipsilateral to the operant hand was made in 3 monkeys. The slowly increasing potential in the motor cortex was entirely eliminated in all cases, whereas that in the somatosensory cortex was enhanced considerably. The result indicates the cerebellar hemisphere contributes to generation of CNV through the thalamo-motor cortex projection. Less