Neuroscience 2003 Abstract
| Presentation Number: | 938.5 |
|---|---|
| Abstract Title: | Electrolytic lesions of the dorsal but not ventral hippocampus decrease trace conditioned fear-potentiated startle. |
| Authors: |
Coover, G. D.*1
; Trivedi, M. A.1
1Dept. Psychology, Northern Illinois Univ, De Kalb, IL |
| Primary Theme and Topics |
Cognition and Behavior - Animal Cognition and Behavior -- Emotional learning & memory systems and modulation of memory |
| Secondary Theme and Topics | Cognition and Behavior<br />- Motivation and Emotion |
| Session: |
938. Cognitive Learning and Memory Systems: Hippocampus III Poster |
| Presentation Time: | Wednesday, November 12, 2003 1:00 PM-2:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # J10 |
| Keywords: | Fear Conditioning, Anxiety, Rat, TIMING |
Lesions of the ventral hippocampus (VH) but not the dorsal hippocampus (DH) reduce the expression of conditioned freezing to a discrete, auditory stimulus (Trivedi & Coover, SFN, 2002). This complements other findings that VH lesions reduce freezing to context cues. VH lesions also reduce passive avoidance of the open arms on the elevated T-maze anxiety test (Coover & Trivedi, SFN, 2002). To further examine whether VH damage reduces fear, rats were tested in the present experiment for fear-potentiation of the auditory startle response (ASR) using trace-conditioning procedures.
Subjects were male, albino, Charles-River derived Sprague-Dawley rats aged 65-70 days at the time of surgery. One week after receiving lesions of the VH or the dorsal hippocampus (DH), or sham surgery, they were given 3 daily sessions of 10 trials of presentation of a 3.8-s white-noise CS followed after a 12-sec period of silence (trace interval) by a 0.5-s footshock of .8 mA intensity. On Day 4, the rats were tested for fear-potentiated startle (FPS) using three different startle stimulus intensities (95, 105, 115 dB). Trace FPS was defined as the difference in magnitude of the ASR 12 s after CS offset compared to baseline ASR during the intertrial interval.
VH lesions produced a mean FPS only 30% less than the mean of the control group (a non-significant difference). By contrast, the DH lesions significantly reduced the fear potentiation, to a mean value 75% less than that of the control group (p < .03, Bonferoni). The results confirm the role of the DH in trace conditioning of fear, and suggest a VH role in controlling aversive behaviors rather than fear learning.
Subjects were male, albino, Charles-River derived Sprague-Dawley rats aged 65-70 days at the time of surgery. One week after receiving lesions of the VH or the dorsal hippocampus (DH), or sham surgery, they were given 3 daily sessions of 10 trials of presentation of a 3.8-s white-noise CS followed after a 12-sec period of silence (trace interval) by a 0.5-s footshock of .8 mA intensity. On Day 4, the rats were tested for fear-potentiated startle (FPS) using three different startle stimulus intensities (95, 105, 115 dB). Trace FPS was defined as the difference in magnitude of the ASR 12 s after CS offset compared to baseline ASR during the intertrial interval.
VH lesions produced a mean FPS only 30% less than the mean of the control group (a non-significant difference). By contrast, the DH lesions significantly reduced the fear potentiation, to a mean value 75% less than that of the control group (p < .03, Bonferoni). The results confirm the role of the DH in trace conditioning of fear, and suggest a VH role in controlling aversive behaviors rather than fear learning.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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