Abstract: | Recorded unit activity from electrodes chronically implanted in various hippocampal areas of 17 male Holtzman albino rats during differential classical conditioning. 1 auditory frequency signaled food, another signaled electric shock. Unit activity was recorded during 1 sec. prior to applications of the tones and during the 1-sec CS-UCS intervals. Response latencies and changes in frequency of unit activity throughout the recording period were determined. Units in the dentate had longer latencies than units in the hippocampus, some of which responded within 16 msec. of the application of the CS. The dentate was the only area to show excitation in response to a positive signal and inhibition in response to a negative signal. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |