Using signaled barpressing tasks to study the neural substrates of appetitive and aversive learning in rats: Behavioral manipulations and cerebellar lesions.

Abstract

The development of standard within-subject conditioning tasks for studying similarities and differences in the neural substrates of appetitive and aversive learning is described. Rats learned to press a bar during a brief tone presentation to receive a food pellet reward (the appetitive task). Using the same tone signal, conditioning chamber, and trial timing parameters, the same rats were then trained to press the bar during the tone presentation to avoid a mild footshock (the aversive task). As an initial study of the neural substrates of these forms of learning, the involvement of the cerebellum was assessed. Bilateral lesions of the deep cerebellar nuclei prevented the learning of the aversive task but had no effect on the learning of the appetitive task.

Functional brain activation during retrieval of visceral pain-conditioned passive avoidance in the rat

“…The cerebellum plays a critical role in classical conditioning and motor learning [59], as well as in mediating autonomic nervous system responses [74]. Steinmetz et al [58] showed that bilateral lesions of deep cerebellar nuclei impair the learning of an aversive bar pressing task, but not an appetitive task, suggesting a critical role in aversive operant learning. Activation of the cerebellum has been noted in anticipation of somatic [25,49,50], as well as visceral pain [72] in humans, although the functional implication is not well understood.…”

Inactivation of the superior cerebellar peduncle blocks expression but not acquisition of the rabbit's classically conditioned eye-blink response.

“…Cerebellar vermis appears to be essentially involved in acquisition and expression of aversive, Pavlovian conditioned bradycardia in rabbit since lesions of this structure prevent acquisition and abolish retention of CRs without affecting unconditioned heart rate responses and electrophysiological recordings reveal learning-related changes in neuronal activity (37). The lateral cerebellar hemispheres appear to be critically involved in an instrumental avoidance bar pressing task (38). Finally, there is growing evidence that, within humans, the cerebellum is involved in complex cognitive tasks (for review for instance, see ref.…”

Eyeblink Conditioning Circuitry: Tracing, Lesion, and Reversible Lesion Experiments

“…A broad interpretation that all memories can be explained by the cerebellum is refuted by Bloedel and colleagues (Bloedel, Bracha, Kelly & Wu, 1991). This is consistent with studies showing that the role of the cerebellumin conditioning does not include heart rate conditioning (Lavond, Lincoln, McCormick & Thompson, 1984), operant conditioning of a treadle-press response (Holt, Mauk & Thompson, unpublished), appetitive bar pressing (Steinmetz, Logue & Miller, 1993) and discriminative locomotor avoidance (Steinmetz, Sears, Gabriel, Kubota & Poremba, 1991). The effect of cerebellar lesions is qualified to classical conditioning of somatic responses to an aversive stimulus as we indicated earlier.…”