Abstract
The roles of the dorsal hippocampus and the central nucleus of the amygdala in the expression of contextual fear were assessed using two measures of conditioned fear: freezing and fear-potentiated startle. A discriminable context conditioning paradigm was developed that demonstrated both conditioned freezing and fear-potentiated startle in a context paired previously with foot shock, relative to a context in which foot shock had never been presented. Post-training lesions of the central nucleus of the amygdala completely blocked both contextual freezing and fear-potentiated startle. Post-training lesions of the dorsal hippocampus attenuated contextual freezing, consistent with previous reports in the literature; however, these same lesions had no effect on fear-potentiated startle, suggesting preserved contextual fear. These results suggest that lesions of the hippocampus disrupt the freezing response but not contextual fear itself.
Original language | English (US) |
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Pages (from-to) | 9353-9360 |
Number of pages | 8 |
Journal | Journal of Neuroscience |
Volume | 17 |
Issue number | 23 |
DOIs | |
State | Published - 1997 |
Keywords
- Amygdala
- Conditioning
- Context
- Fear
- Freezing
- Hippocampus
- Learning
- Memo ry
- Startle