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Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats.
Behav Brain Res. 2006 Apr 03; 168(2):289-98.BB

Abstract

Pavlovian delay conditioning, in which a conditioned stimulus (CS) and unconditioned stimulus (US) co-terminate, is thought to reflect non-declarative memory. In contrast, trace conditioning, in which the CS and US are temporally separate, is thought to reflect declarative memory. Hippocampal lesions impair acquisition and expression of trace conditioning measured by the conditioned freezing and eyeblink responses, while having little effect on the acquisition of delay conditioning. Recent evidence suggests that lesions of the ventral hippocampus (VH) impair conditioned fear under conditions in which dorsal hippocampal (DH) lesions have little effect. In the present study, we examined the time-course of fear expression after delay and trace conditioning using the fear-potentiated startle (FPS) reflex, and the effects of pre- and post-training lesions to the VH and DH on trace-conditioned FPS. We found that both delay- and trace-conditioned rats displayed significant FPS near the end of the CS relative to the unpaired control group. In contrast, trace-conditioned rats displayed significant FPS throughout the duration of the trace interval, whereas FPS decayed rapidly to baseline after CS offset in delay-conditioned rats. In experiment 2, both DH and VH lesions were found to significantly reduce the overall magnitude of FPS compared to the control group, however, no differences were found between the DH and VH groups. These findings support a role for both the DH and VH in trace fear conditioning, and suggest that the greater effect of VH lesions on conditioned fear might be specific to certain measures of fear.

Authors+Show Affiliations

Department of Psychology, Northern Illinois University, DeKalb, IL 60115, USA. mt2@medicine.wisc.eduNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

16413066

Citation

Trivedi, Mehul A., and Gary D. Coover. "Neurotoxic Lesions of the Dorsal and Ventral Hippocampus Impair Acquisition and Expression of Trace-conditioned Fear-potentiated Startle in Rats." Behavioural Brain Research, vol. 168, no. 2, 2006, pp. 289-98.
Trivedi MA, Coover GD. Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats. Behav Brain Res. 2006;168(2):289-98.
Trivedi, M. A., & Coover, G. D. (2006). Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats. Behavioural Brain Research, 168(2), 289-98.
Trivedi MA, Coover GD. Neurotoxic Lesions of the Dorsal and Ventral Hippocampus Impair Acquisition and Expression of Trace-conditioned Fear-potentiated Startle in Rats. Behav Brain Res. 2006 Apr 3;168(2):289-98. PubMed PMID: 16413066.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats. AU - Trivedi,Mehul A, AU - Coover,Gary D, Y1 - 2006/01/18/ PY - 2005/09/12/received PY - 2005/11/18/revised PY - 2005/11/18/accepted PY - 2006/1/18/pubmed PY - 2006/5/10/medline PY - 2006/1/18/entrez SP - 289 EP - 98 JF - Behavioural brain research JO - Behav Brain Res VL - 168 IS - 2 N2 - Pavlovian delay conditioning, in which a conditioned stimulus (CS) and unconditioned stimulus (US) co-terminate, is thought to reflect non-declarative memory. In contrast, trace conditioning, in which the CS and US are temporally separate, is thought to reflect declarative memory. Hippocampal lesions impair acquisition and expression of trace conditioning measured by the conditioned freezing and eyeblink responses, while having little effect on the acquisition of delay conditioning. Recent evidence suggests that lesions of the ventral hippocampus (VH) impair conditioned fear under conditions in which dorsal hippocampal (DH) lesions have little effect. In the present study, we examined the time-course of fear expression after delay and trace conditioning using the fear-potentiated startle (FPS) reflex, and the effects of pre- and post-training lesions to the VH and DH on trace-conditioned FPS. We found that both delay- and trace-conditioned rats displayed significant FPS near the end of the CS relative to the unpaired control group. In contrast, trace-conditioned rats displayed significant FPS throughout the duration of the trace interval, whereas FPS decayed rapidly to baseline after CS offset in delay-conditioned rats. In experiment 2, both DH and VH lesions were found to significantly reduce the overall magnitude of FPS compared to the control group, however, no differences were found between the DH and VH groups. These findings support a role for both the DH and VH in trace fear conditioning, and suggest that the greater effect of VH lesions on conditioned fear might be specific to certain measures of fear. SN - 0166-4328 UR - https://www.unboundmedicine.com/medline/citation/16413066/Neurotoxic_lesions_of_the_dorsal_and_ventral_hippocampus_impair_acquisition_and_expression_of_trace_conditioned_fear_potentiated_startle_in_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-4328(05)00504-8 DB - PRIME DP - Unbound Medicine ER -