Basal forebrain cholinergic lesions enhance conditioned approach responses to stimuli predictive of food.
This study examined the effects of lesions to different neuronal populations within the basal forebrain on reward-related learning. Rats received bilateral alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) or quinolinate lesions that preferentially destroy the cholinergic nucleus basalis magnocellularis (NBM) or noncholinergic ventral pallidal neurons, respectively. Both lesions enhanced conditioned approach responses to stimuli predictive of food but did not increase the locomotor stimulating effect of d-amphetamine. Although both lesions disrupted the discriminative control over behavior by a conditioned stimulus, they did not impair the subsequent acquisition of instrumental responding with conditioned reinforcement (CR). Indeed, both lesions were associated with an increased responding with CR following intra-accumbens infusions of d-amphetamine (0, 1, 3, 10, and 20 microg). Quinolinate lesions also increased responses on an inactive control lever. Neither lesion altered consummatory responses to food or sucrose. Results suggest that NBM lesions may disrupt the balance between cortical and subcortical dopamine levels, and/or produce a deficit in attentional mechanisms that is manifested as increased responding to specific stimuli.
Olmstead
M C
MC
Department of Experimental Psychology, University of Cambridge, England. olmstead@pavlov.psyc.queensu.ca
Robbins
T W
TW
Everitt
B J
BJ
D000661:Amphetamine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology*; D002799:Cholinergic Fibers / Q000187:drug effects / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D003259:Consummatory Behavior / Q000187:drug effects / Q000502:physiology; D003463:Cues; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology; D015259:Dopamine Agents / Q000494:pharmacology; D004347:Drug Interactions; D018690:Excitatory Amino Acid Agonists; D005502:Food; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009042:Motivation; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D017378:Quinolinic Acid; D051381:Rats; D012201:Reward; D013377:Substantia Innominata / Q000187:drug effects / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000009:adverse effects
D015259:Dopamine Agents; D018690:Excitatory Amino Acid Agonists; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D000661:Amphetamine; D017378:Quinolinic Acid