Research findings related to the functional significance of the gustatory neocortical system of the rat are reviewed and interpreted. Studies of gustatory neocortex (GN) involvement in taste-related cognitive processes are emphasized after briefly reviewing GN anatomy and physiology. Evidence is presented supporting the conclusion that the GN contributes relatively little to fundamental taste reactivity, but is deeply involved in cognitive (learning and memorial) taste processes; that is, "reactive salience" to taste stimuli is preserved following GN ablation, while "associative salience" is markedly degraded. Apparent functional similarities between GN and other sensory neocortical areas are emphasized throughout the paper, and a hierarchical view of gustatory system functioning is addressed.Patton began his 1950 review of the chemical senses by pointing out that taste and smell essentially had been neglected relative to the other sensory systems. As a partial explanation for this neglect, he men-

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Consummatory behavior and weight-regulation capacity were measured in 12 normal rats and in 43 rats that survived complete (C), sequential unilateral (U), anterolateral (A), or posterior (P) neocortical ablations. Groups C and A displayed aphagia and adipsia followed by a sequence of recovery stages qualitatively identical to, but shorter than, recovery typically seen following lateral hypothalamic lesions. After recovery, Group C displayed long-term effects of finickiness and prandial drinking. These effects as well as a measure of recovery of body-weight-regulation capacity were significantly intercorrelated with lesion size, and body-weight set point remained significantly lower than normal. Group TJ was relatively unaffected by the first unilateral ablation and showed, relative to Group C, facilitated recovery of consummatory behaviors following the second ablation but displayed the long-term effects. Group P, though significantly affected bj' the lesion, did not display the pattern or intensity of effects described for the other bilaterally ablated groups.

Rats presented with a distinctive taste cue (salt or sucrose) followed by rotational stimulation subsequently displayed an aversion to the specific cue that had been paired with rotation. Evidence of such learning was noted after a single trial when the taste cue and rotational treatment had been presented in separate places several minutes apart. This observation was attested to through comparisons of four groups of rats, two of which received a specific and different taste cue paired with rotation, one which received rotational stimulation paired with plain water, and one Whl~h was not rotated. A discrimination procedure was employed in which the consumption of all solutions (salt, sucrose, and water) was measured for all rats throughout eight training and two testing cycles.