Similarities in the physiological bases of an abnormal grooming behavior in thyroidectomized cats and in cats with lesions of the central nervous system.

Abstract

Thyroidectomized cats display a dissociation of the appetitive and consummatory components of grooming behavior when the body surface is tactually stimulated, an abnormal behavior that also occurs in cats with pontile or frontal neocortical lesions. Systemic administration of 5-hydroxytryptophan (5-HTP) abolishes the abnormal behavior, whereas dihydroxyphenylalanine administration does not, and jj-chlorophenylalanine (PCPA) administration induces the abnormal grooming behavior in thyroidectomized cats that are not displaying the abnormal behavior because of spontaneous seasonal reversions. Microinjeetions of 5-HTP or serotonin into the superior colliculi also abolish the abnormal grooming behavior in thyroidectomized cats. Lesions of the superior colliculi prevent the development of the abnormal behavior after thyroidectomy, even with PCPA treatment. These pharmacological results in thyroidectomized cats parallel the behavioral effects observed in cats with pontile or frontal neocortical lesions.Cats display three types of consummatory sociation of the appetitive and consumgrooming responses-bites, licks, and matory components of the behavioral sescratches-and these responses are directed quence, occurs in cats with pontile lesions to the body surface by the appetitive, or (Randall, 1964) or frontal neocortical leorienting, components of grooming be-sions (Trulson, Nicolay, & Randall, 1975) havior. The bite and lick are used to groom and in thyroidectomized cats (Trulson, the posterior portion of the body and the 1974). During the abnormal grooming extremities, and the scratch is used to state, tactile stimulation of the cat's body groom the head, neck, and shoulders. When surface elicits a consummatory grooming the body surface of a normal cat is tactually response, which occurs immediately and stimulated, the cat often orients and grooms independently of the appetitive components the region that is stimulated but frequently of grooming behavior, i.e., the consummashows no response at all. An abnormal tory response is not directed to the body grooming behavior, consisting of a dis-surface. These "grooming fragments" occur in midair and are completely nonfunctional. This research was supported by National In-The type of consummatory response elicited stitute of Mental Health Grant MH-15402-05. is a response that is normally used to groom We wish to thank Barry L. Jacobs for his com-that area of the body surface that is tacments on this manuscript. tually stimulated. Thus, tactile stimulation Requests for reprints should be sent to Michael , •? , , , n u/M,i/l/»™ aUmte Trulson, Department of Psychology, Princeton of the head neck, or shoulders elicits