Impaired acquisition of temporal differentiation performance following lesions of the ascending 5-hydroxytryptaminergic pathways
Autor: | C. M. Bradshaw, E. Szabadi, Mary A. Wogar |
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Rok vydání: | 1992 |
Předmět: |
Serotonin
medicine.medical_specialty Reinforcement Schedule 5 7-Dihydroxytryptamine Posterior parietal cortex Hippocampus Nucleus accumbens Amygdala Lesion Norepinephrine Dopamine Internal medicine Neural Pathways medicine Animals Learning 5-HT receptor Brain Chemistry Pharmacology Rats Inbred Strains Hydroxyindoleacetic Acid Rats Endocrinology medicine.anatomical_structure Hypothalamus Time Perception Female medicine.symptom Psychology Neuroscience medicine.drug |
Zdroj: | Psychopharmacology. 107:373-378 |
ISSN: | 1432-2072 0033-3158 |
Popis: | Nineteen rats received injections of 5,7-dihydroxytryptamine into the dorsal and median raphe nuclei; 16 rats received sham injections. The rats underwent 50 daily training sessions under an interresponse-time-greater-than-15-seconds (IRT greater than 15 s) schedule of sucrose reinforcement. The lesioned group showed impaired acquisition of temporal differentiation, in that their response rates remained significantly higher and their obtained reinforcement frequencies significantly lower than those of the control (sham-lesioned) group. Comparison of the IRT frequency distributions obtained from the two groups during the last 5 days of training showed that the lesioned group produced a significantly higher proportion of very short IRTs (less than 3 s) than the control group; when these short IRTs were disregarded, the lesioned group displayed a significantly lower mean IRT and a significantly higher coefficient of variation than the control group. The levels of 5-hydroxytryptamine (5HT) and 5-hydroxyindoleacetic acid in the parietal cortex, hippocampus, amygdala, nucleus accumbens and hypothalamus were markedly reduced in the lesioned group, but the levels of noradrenaline and dopamine were not significantly affected by the lesion. The results suggest that destruction of the ascending 5HTergic pathways may reduce animals' capacity to inhibit positively reinforced operant behaviour, and may impair temporal discrimination. |
Databáze: | OpenAIRE |
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