Behavioral Neuroseience Copyright 1990 by the American Psychological Association, Inc. 1990, Vol. 104, No, 5, 778-795 0735-7044/90/$00.75 Motivational-Sensorimotor Interaction Controls Aphagia and Exaggerated Treading After Striatopallidal Lesions Kent C. Berridge and Howard C. Cromwell University of Michigan This study examined the relationship between sensorimotor and motivational functions of the corpus striatum. In rats, excitotoxic lesions of the corpus striatum (neostriatum and globus pallidus) caused by kainic or quisqualic acid can produce both aversive aphagia and a "choreic" sensorimotor syndrome: an exaggerated treading of the forepaws that is triggered by oral sensory stimulation. Experiment l used a recovery-of-function approach to show that (a) aphagia in- duced by ventroposterior striatopallidal lesions was accompanied by an enhancement of aver- sion (a specific motivational process) to sweet stimuli, which was expressed in taste reactivity measures of affective evaluation; (b) aphagia and enhanced aversion recovered together; and (c) exaggerated treading did not disappear with aphagia-aversion but narrowed the range of its eliciting trigger to sour and bitter stimuli. Experiment 2 used a partial lesion approach to show that this dissociation of enhanced aversion and exaggerated treading could be reproduced by smaller lesions immediately after striatopallidal damage. Experiment 3 used a conditioned aversion procedure to show that the stimulus for exaggerated treading was aversion (natural or conditioned) and not a simple sensory feature of oral stimulation. Three conclusions were made: (a) Exaggerated treading after a small lesion or after partial recovery from a larger one results from a restructuring of a sensorimotor relations that is nested within a system of aversive reaction, (b) exaggerated treading is elicited only by tastes that elicit natural or conditioned aversion, and (c) more extensive lesions potentiate aversion to tastes that are normally palatable and expand the range of treading elicitors to include those tastes. In other words, affective and sensorimotor systems interact in a hierarchical manner in the production of choreic treading. These results demonstrate a specific hierarchical link between motivational and sensorimotor functions mediated by striatopallidal circuits. Motivational and sensorimotor concepts are used in be- havioral neuroscience to refer to different aspects of behavior. Motivational concepts generally refer to aspects such as af- fective displays, the homeostatic coordination of diverse in- puts and outputs, dynamic spontaneity, and flexible means- ends readiness to achieve goals (e.g., Epstein, 1982; Fentress, 1983; Gallistel, 1980; Miller, 1982; Teitelbaum, 1977; Tei- telbaum, Schallert, & Whishaw, 1983; Toates, 1986). Sen- sorimotor terms, on the other hand, typically denote inte- grations that create linkages between specific sensory modalities and motor systems. These integrations serve spe- cific roles in coordinating action that are not restricted to either purely sensory or purely motor functions but are nar- rower in scope than motivational (or other high-level) inte- grations (Gallistel, 1980; Lidsky, Manetto, & Schneider, 1985; Marshall, 1980; Schallert et al., 1982; Stricker & Zigmond, 1986; Teitelbaum, 1986; Whishaw, Kolb, & Sutherland, 1983; White, 1986). This study was supported by National Institutes of Health Grant NS-23959. We are grateful to J. Wayne Aldridge, Terry E. Robinson, and Philip Teitelbaum for their helpful comments on the manuscript of this article. Correspondence concerning this article should be addressed to Kent C. Berridge, Department of Psychology, University of Mich- igan, Neuroscience Laboratory Building, Ann Arbor, Michigan 48109. Although motivational and sensorimotor terms have sep- arable meanings, it often happens that both are needed to describe the behavioral consequences of even a single brain manipulation. Damage to any one of a number of different forebrain or brainstem structures can produce behavioral consequences that involve both sensorimotor and motiva- tional aspects. This study was concerned with interactions between sensorimotor and motivational processes. The globus pallidus provides a prime example of a brain structure in which damage can produce behavioral changes that have both motivational and sensorimotor components. Deficits produced by striatopallidal damage that have been viewed as motivational (at least in part) include aphagia and adipsia (Dunnett & Iversen, 1980; Levine & Schwartzbaum, l 973; Morgane, 1961; Sorenson & Ellison, 1970), which may be as severe as the aphagia and adipsia produced by lesions of the lateral hypolhalamus (Teitelbaum & Epstein, 1962). Changes that have been construed as sensorimotor include numerous passive deficits in posture control, oromotor co- ordination, and reaching to a target (Labuszewski, Lock- wood, McManus, Edelstein, & Lidsky, 1981; Levine & Schwartzbaum, 1973). Striatopallidal damage or pharma- cological manipulations also can induce positive or release symptoms of hyperkinesia, which generally are construed as sensorimotor (e.g., Schneider, 1984; Villablanca, Marcus, & Olmstead, 1976). In rats, striatopallidal lesions can induce a hyperkinesic 778