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Time-dependent involvement of the dorsal hippocampus in trace fear conditioning in mice.
Hippocampus. 2005; 15(4):418-26.H

Abstract

Hippocampal and amygdaloid neuroplasticity are important substrates for Pavlovian fear conditioning. The hippocampus has been implicated in trace fear conditioning. However, a systematic investigation of the significance of the trace interval has not yet been performed. Therefore, this study analyzed the time-dependent involvement of N-methyl-D-aspartate (NMDA) receptors in the dorsal hippocampus in one-trial auditory trace fear conditioning in C57BL/6J mice. The NMDA receptor antagonist APV was injected bilaterally into the dorsal hippocampus 15 min before training. Mice were exposed to tone (conditioned stimulus [CS]) and footshock (unconditioned stimulus [US]) in the conditioning context without delay (0 s) or with CS-US (trace) intervals of 1-45 s. Conditioned auditory fear was determined 24 h after training by the assessment of freezing and computerized evaluation of inactivity in a new context; 2 h later, context-dependent memory was tested in the conditioning context. NMDA receptor blockade by APV markedly impaired conditioned auditory fear at trace intervals of 15 s and 30 s, but not at shorter trace intervals. A 45-s trace interval prevented the formation of conditioned tone-dependent fear. Context-dependent memory was always impaired by APV treatment independent of the trace interval. The results indicate that the dorsal hippocampus and its NMDA receptors play an important role in auditory trace fear conditioning at trace intervals of 15-30-s length. In contrast, NMDA receptors in the dorsal hippocampus are unequivocally involved in contextual fear conditioning independent of the trace interval. The results point at a time-dependent role of the dorsal hippocampus in encoding of noncontingent explicit stimuli. Preprocessing of long CS-US contingencies in the hippocampus appears to be important for the final information processing and execution of fear memories through amygdala circuits.

Authors+Show Affiliations

Department of Molecular Neuroendocrinology, Max Planck Institute for Experimental Medicine, Goettingen, Germany. ilga.misane@usask.caNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15669102

Citation

Misane, Ilga, et al. "Time-dependent Involvement of the Dorsal Hippocampus in Trace Fear Conditioning in Mice." Hippocampus, vol. 15, no. 4, 2005, pp. 418-26.
Misane I, Tovote P, Meyer M, et al. Time-dependent involvement of the dorsal hippocampus in trace fear conditioning in mice. Hippocampus. 2005;15(4):418-26.
Misane, I., Tovote, P., Meyer, M., Spiess, J., Ogren, S. O., & Stiedl, O. (2005). Time-dependent involvement of the dorsal hippocampus in trace fear conditioning in mice. Hippocampus, 15(4), 418-26.
Misane I, et al. Time-dependent Involvement of the Dorsal Hippocampus in Trace Fear Conditioning in Mice. Hippocampus. 2005;15(4):418-26. PubMed PMID: 15669102.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Time-dependent involvement of the dorsal hippocampus in trace fear conditioning in mice. AU - Misane,Ilga, AU - Tovote,Philip, AU - Meyer,Michael, AU - Spiess,Joachim, AU - Ogren,Sven Ove, AU - Stiedl,Oliver, PY - 2005/1/26/pubmed PY - 2005/8/12/medline PY - 2005/1/26/entrez SP - 418 EP - 26 JF - Hippocampus JO - Hippocampus VL - 15 IS - 4 N2 - Hippocampal and amygdaloid neuroplasticity are important substrates for Pavlovian fear conditioning. The hippocampus has been implicated in trace fear conditioning. However, a systematic investigation of the significance of the trace interval has not yet been performed. Therefore, this study analyzed the time-dependent involvement of N-methyl-D-aspartate (NMDA) receptors in the dorsal hippocampus in one-trial auditory trace fear conditioning in C57BL/6J mice. The NMDA receptor antagonist APV was injected bilaterally into the dorsal hippocampus 15 min before training. Mice were exposed to tone (conditioned stimulus [CS]) and footshock (unconditioned stimulus [US]) in the conditioning context without delay (0 s) or with CS-US (trace) intervals of 1-45 s. Conditioned auditory fear was determined 24 h after training by the assessment of freezing and computerized evaluation of inactivity in a new context; 2 h later, context-dependent memory was tested in the conditioning context. NMDA receptor blockade by APV markedly impaired conditioned auditory fear at trace intervals of 15 s and 30 s, but not at shorter trace intervals. A 45-s trace interval prevented the formation of conditioned tone-dependent fear. Context-dependent memory was always impaired by APV treatment independent of the trace interval. The results indicate that the dorsal hippocampus and its NMDA receptors play an important role in auditory trace fear conditioning at trace intervals of 15-30-s length. In contrast, NMDA receptors in the dorsal hippocampus are unequivocally involved in contextual fear conditioning independent of the trace interval. The results point at a time-dependent role of the dorsal hippocampus in encoding of noncontingent explicit stimuli. Preprocessing of long CS-US contingencies in the hippocampus appears to be important for the final information processing and execution of fear memories through amygdala circuits. SN - 1050-9631 UR - https://www.unboundmedicine.com/medline/citation/15669102/Time_dependent_involvement_of_the_dorsal_hippocampus_in_trace_fear_conditioning_in_mice_ L2 - https://doi.org/10.1002/hipo.20067 DB - PRIME DP - Unbound Medicine ER -