Lesions in the magnocellular preoptic nucleus decrease olfactory investigation in rats

• Published in: Behavioural brain research Vol. 81; no. 1; pp. 223 - 231
• Main Authors: Paolini, A.G., McKenzie, J.S.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01-11-1996; Elsevier Science
• Subjects: Anatomical correlates of behavior; Animals; Basal forebrain; Behavior; Behavioral psychophysiology; Biological and medical sciences; Discrimination (Psychology) - physiology; Exploratory Behavior - physiology; Fundamental and applied biological sciences. Psychology; Habituation, Psychophysiologic - physiology; Horizontal limb of the diagonal band nucleus; Lesion; Magnocellular preoptic nucleus; Male; Medial forebrain bundle; Medial Forebrain Bundle - physiology; Memory - physiology; Odorants; Olfaction; Olfactory Pathways - physiology; Preoptic Area - anatomy & histology; Preoptic Area - physiology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rat; Rats; Rats, Wistar; Smell - physiology; Medial forebrain bundle; MCPO; Horizontal limb of the diagonal band nucleus; Rat; Magnocellular preoptic nucleus; Olfaction; HDB; MFB; Basal forebrain; Behavior; Lesion; Exploratory behavior; Rodentia; Central nervous system; Telencephalon; Male; Vertebrata; Mammalia; Animal; Perception; Chemical stimulus; Brain (vertebrata)
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/S0166-4328(96)89082-6

The nuclear complex of the horizontal limb of the diagonal band and the magnocellular preoptic nucleus, components of the basal forebrain magnocellular system affected in Alzheimer-type dementia, supply centrifugal innervation to the olfactory bulb. The lateral magnocellular preoptic nucleus provides significant GABAergic input. Since its stimulation may facilitate olfactory bulb mitral cells, we have investigated the effect of sub-total electrolytic lesions in this nucleus on performance in a simple test of olfactory investigation and its habituation. Two groups of rats were used with lesions which occupied restricted volumes, approximately 30 and 15%, of the magnocellular preoptic nucleus. Behaviourally, there was interference with olfactory investigation, with increased investigation latency and decreased investigation times, in the group with larger lesions at 6 and 16 days after operation. There was no significant effect of the smaller lesions. No effects on patterns of olfactory habituation or discrimination were seen. The impairment of olfactory investigation could not be explained by interruption of medial forebrain bundle fibres traversing the nucleus. It is suggested that bilateral partial destruction of magnocellular preoptic neurones may produce significant deficits in either olfactory sensitivity or olfactory motivation.