Impairments in conditioned stimulus processing and conditioned responding after combined selective removal of hippocampal and neocortical cholinergic input.
Previous studies indicated that changes in attentional processing of conditioned stimuli (CSs) are regulated by the basal forebrain (BF) cholinergic system. In those studies, destruction of BF innervation of the neocortex interfered with enhancements in CS processing, and destruction of BF innervation of the hippocampus prevented reductions in CS processing. In the current experiments, the performance of rats with 192 IgG-saporin lesions of both hippocampal and neocortical cholinergic input was examined. These combined lesions disrupted both enhancements and reductions in CS processing. Lesioned rats also showed more general impairments in conditioned responding. These results indicate that, although the neural systems for increasing and decreasing attentional processing may be largely independent, combined loss of hippocampal and neocortical cholinergic input may produce behavioral impairments that are not apparent after either lesion alone.
Baxter
M G
MG
Curriculum in Neurobiology, University of North Carolina at Chapel Hill, USA. mbaxter@wjh.harvard.edu
Bucci
D J
DJ
Holland
P C
PC
Gallagher
M
M
D000818:Animals; D001288:Attention; D018680:Cholinergic Antagonists / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000187:drug effects / Q000473:pathology; D003213:Conditioning, Psychological; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology*; D000922:Immunotoxins; D008297:Male; D018782:Maze Learning; D008959:Models, Neurological; D009699:N-Glycosyl Hydrolases; D019579:Neocortex / Q000473:pathology* / Q000503:physiopathology*; D009415:Nerve Net; D009949:Orientation; D010940:Plant Proteins / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D054789:Ribosome Inactivating Proteins, Type 1; D000076985:Saporins
D018680:Cholinergic Antagonists; D000922:Immunotoxins; D010940:Plant Proteins; D054789:Ribosome Inactivating Proteins, Type 1; D009699:N-Glycosyl Hydrolases; D000076985:Saporins