Facilitation of learning after lesions of the tuberomammillary nucleus region in adult and aged rats

The tuberomammillary nucleus (TM) located in the posterior part of the hypothalamus is the main source of neuronal histamine in the central nervous system. Recent work from our laboratories has indicated an involvement of the TM region in neuronal plasticity and reinforcement processes. In the prese...

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Bibliographic Details
Published in:Experimental brain research 1998-02, Vol.118 (4), p.447-456
Main Authors: FRISCH, C, HASENÖHRL, R. U, HAAS, H. L, WEILER, H. T, STEINBUSCH, H. W. M, HUSTON, J. P
Format: Article
Language:English
Subjects:
Aging - psychology
Animals
Avoidance Learning - physiology
Behavioral psychophysiology
Biological and medical sciences
Brain Chemistry - physiology
Brain research
Excitatory Amino Acid Agonists - toxicity
Fundamental and applied biological sciences. Psychology
Habituation, Psychophysiologic
Histamine
Histamine - metabolism
Hypothalamus
Ibotenic Acid - toxicity
Immunohistochemistry
Learning - physiology
Male
Mammillary Bodies - pathology
Mammillary Bodies - physiology
Maze Learning - physiology
Memory
Neurotransmission and behavior
Physiological aspects
Properties
Psychology. Psychoanalysis. Psychiatry
Psychology. Psychophysiology
Psychomotor Performance - physiology
Rats
Rats, Wistar
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Summary:The tuberomammillary nucleus (TM) located in the posterior part of the hypothalamus is the main source of neuronal histamine in the central nervous system. Recent work from our laboratories has indicated an involvement of the TM region in neuronal plasticity and reinforcement processes. In the present study, we investigated the effects of TM lesions on the performance of adult and aged Wistar rats in a set of learning tasks, which differed in terms of complexity and reward contingencies (habituation learning, inhibitory avoidance, discrimination learning, Morris water maze). An improvement was found in every test applied, indicating that TM lesions seem to generally enhance learning and memory capacities independent of the special demands of a given task. Age-related learning deficits were strongly diminished. Immunohistochemistry revealed that the excitotoxic lesions used to destroy the TM region led to a marked decrease in the number of histamine-positive neurons in the vicinity of the injection site, indicating an involvement of the brain histaminergic system in the observed behavioral changes.
ISSN:0014-4819
1432-1106
DOI:10.1007/s002210050301