|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1988 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1987 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1986 : ¥2,000,000 (Direct Cost : ¥2,000,000)
Investigations of scalp-recorded ERPs(event-related brain potentials) in man have advanced our understanding of "neural bases" or "neurophysiological correlated" of mental activity listed under such headings as "perception","cognition" and "emotion". Appropriate animal studies will help to deepen our neurophysiological understanding of ERPs, because in animal models intracortical and subcortical potentials can be obtained to reveal ERPs, neural generators. In this study we try to search for P300, which is the most important ERP related to cognition, from the rats brain under stimulus discrimination operant conditioning.
In Experiment 1 (go/nogo type), four rats were trained to respond to 1500Hz tones (S+) and not to respond to 4000Hz tones (S-). Three ERP components (P100,N200,P700) were elicited by S+ at the cortical recordings, while no clear component was elicited by S-. These components were not observed after an extinction procedure(1).
In Experiment 2 (go/go type), ERPs were recorded during a discrimination learning with two positive discriminative stimuli. At the cortical recordings, the same components (P100,N300,P700) as those obtained in Experiment 1 were observed. Amplitude of P700 was influenced by probabilities of the discriminative stimuli(2). Furthermore, it was larger in the late stage of the learning than in the early one(3).
Since P700 show above mentioned three characteristics as are observed in human scalp P300, we conclude that rat P700 is an analogue of human P300.