Serotonin and Norepinephrine in Latent Inhibition.

Current learning theorists have noted variations in the associability of stimuli independent of their correlation with reinforcement. These anomalies are thought to reveal characteristics of the processing mechanisms of animal learning. In the past, relatively gross alterations of neurochemical levels in the brain have been used to examine the role of these chemicals in behavior. Recent advances in technique have enabled more detailed manipulations of neurochemicals. These discrete changes in neurotransmitter levels have been linked to changes in behavior. Depletions of the neurotransmitters norepinephrine and serotonin have been demonstrated to alter associative processes in the rat. This study investigated the effect of selective depletions of norepinephrine and serotonin on the formation of inhibitory associations. It was found that serotonin and norepinephrine depletions differentially affected subjects* performance in the latent inhibition paradigm. This evidence was correlated with earlier work which showed norepinephrine depletions attenuating performance in blocking, whereas serotonin-depleted rats behaved like normals in the paradigm. Thus, different neurochemicals are implicated in the two paradigms, both of which result in nonessential cues being prevented from entering into associations with reinforcements. It was suggested that the major theories of inhibitory associations formation, i.e., those advanced by Wagner and Mackintosh, stand in need of revision as they treat these two phenomena as mediated by a common mechanism.

Level thesis:degree_level

Thesis

Year

1981

Author dc:creator

• Berry, David Thomas

• Norepinephrine depletions
• Neurochemical levels
• Animal learning
• Serotonin

Repository record dc:identifier

https://digitalcommons.library.uab.edu/etd-collection/6948

OAI identifier oai:identifier

oai:digitalcommons.library.uab.edu:etd-collection-7940