Effects of complete immunotoxin lesions of the cholinergic basal forebrain on fear conditioning and spatial learning. Hippocampus 2004;14(2):244-54
Date
04/22/2004Pubmed ID
15098729DOI
10.1002/hipo.10169Scopus ID
2-s2.0-0842322454 (requires institutional sign-in at Scopus site) 58 CitationsAbstract
Administration of muscarinic cholinergic antagonists such as scopolamine impairs the acquisition of contextual fear conditioning, but the role of the basal forebrain (BF) cholinergic system in consolidation is unclear. To test the hypothesis that BF cholinergic neurons are critical for acquisition and consolidation of fear conditioning, male Sprague-Dawley rats with 192 IgG-saporin lesions of the entire cholinergic BF made either before or after fear conditioning were tested for conditioned fear to context and tone by assessing freezing and 22 kHz ultrasonic vocalization (USV) responses. Spatial learning in a 1-day water maze task provided a comparison for effects of the BF lesions on fear conditioning. In the test phase, neither pre-training nor posttraining BF lesions affected freezing to the context or tone. During both training and testing, pre-lesioned rats were impaired in production of USVs associated with fear. Postlesioned rats emitted fewer USVs only during testing. Acquisition of a spatial water maze task was mildly impaired in lesioned rats, although probe trial and cued performance was unimpaired. Nevertheless, these data suggest that conditioned fear-induced USVs are more sensitive to the loss of BF cholinergic neurons than is conditioned fear-induced freezing. The failure of BF cholinergic lesions to impair contextual fear conditioning indicates that scopolamine-induced impairments in fear conditioning may not be mediated by affecting cholinergic input to the hippocampus and neocortex.
Author List
Frick KM, Kim JJ, Baxter MGAuthor
Karyn Frick BA,MA,PhD Professor in the Psychology department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
AnimalsAntibodies, Monoclonal
Choline O-Acetyltransferase
Conditioning, Operant
Cues
Fear
Glutamate Decarboxylase
Immunohistochemistry
Immunotoxins
Male
Maze Learning
Memory
N-Glycosyl Hydrolases
Parasympathetic Nervous System
Prosencephalon
Rats
Rats, Sprague-Dawley
Ribosome Inactivating Proteins, Type 1
Vocalization, Animal