CHORDA TYMPANI TRANSECTION AND SELECTIVE DESALIVATION DIFFERENTIALLY DISRUPT 2-LEVER SALT DISCRIMINATION PERFORMANCE IN RATS

Water-restricted rats were trained to press 1 of 2 levers if a sampled stimulus was NaCl and the other lever if the stimulus was KCl (0.05, 0.1, or 0.2 M). Responses were reinforced with water. After training t he average rate of correct responses was 90%. Performance was unchange d following sham surgery. Chorda tympani (CT) transection reduced aver age discrimination performance to 67.7% correct, and extirpation of th e sublingual and submaxillary salivary glands reduced average performa nce to 80% correct. Although selective desalivation moderately reduced discriminability, a disrupted salivary environment does not explain t he effects of CT transection. More likely, the discrimination deficit in CT-transected rats reflects a loss of critical taste input conveyed by the CT about salts.