The effect of latent inhibition on the neuronal activities ofamygdala and anterior cingulate cortex in rat

• Main Authors: Yu-Ling Hsu, 許毓玲
• Other Authors: Chung-Chih kuo
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/43843650964413461499

碩士 === 慈濟大學 === 神經科學研究所 === 97 === Emotion can have a powerful impact on memory, and can strengthen the formation of memory. Emotional memory can be affected by many factors. For example, pre-exposure of context may induced the phenomenon of latent inhibition to interfere the emotional memory. The amygdala (AMY) involvs in the learning and memory processes of emotion events and anterior cingulate cortex (ACC) plays an important role in the latent inhibition. This study examined how the pre-exposure of context affected the neuronal activities of AMY and ACC in the inhibitory avoidance task. The micro-wire electrodes were chronically implanted in the AMY and ACC of Long-Evans rats. The neuronal activities of AMY and ACC in conscious rats were recorded extracellularly during the pre-exposure of context and inhibitory avoidance (IA) training. The animals of pre-exposure (PE) group were exposed to the context of IA for five days before training. The animals of non-pre-exposure (NPE) group were exposed to the context different from the shuttle box. On the sixth day, the rats was tested before training and then received the foot-shock (0.4 mA , 1s) in the dark side of apparatus. The rats were tested on the next day of foot shock training. The retention latencies of both PE and NPE groups were enhanced after the IA training. However, shorter retention latency was shown in the PE group than the NPE group. These results suggested that the rats learned the IA task and pre-exposure of context induced latent inhibition (LI) effect. Multiple single-unit activities of AMY and ACC in both groups were recorded simultaneously during the pre-exposure period and IA task. After training, the unit activities of AMY and ACC were change. The change of AMY unit activities in the PE group was less then the one in the NPE group. The change of ACC unit activities in the PE group was more then the one in the NPE group. These results showed that the process of context pre-exposure induced the latent inhibition in IA paradigm and the neuronal activities of AMY and ACC were affected in the phenomenon of latent inhibition. It has been suggested that AMY and ACC might be involved in the modulation of fear emotion and memory.