Learning-related interpositus activity is conserved across species as studied during eyeblink conditioning in the rat

Single-unit activity was monitored in the interpositus nucleus of the cereb ellum during standard delay conditioning of the eyeblink response in freely -moving rats. The rats were implanted with recording electrodes in the inte rpositus nucleus then received paired presentations of a tone-conditioned s timulus (CS) and eye-shock unconditioned stimulus during acquisition traini ng. The acquisition training was followed by CS-alone extinction training. Learning-related activity in the interpositus nucleus developed over the co urse of acquisition training and then activity returned to baseline levels during subsequent extinction training. These findings are consistent with r abbit studies that have demonstrated similar changes in neuronal activity i n the interpositus nucleus over the course of acquisition and extinction of the eyeblink response, thus providing strong evidence for the generality o f the neural substrates of eyeblink conditioning across species. (C) 2001 P ublished by Elsevier Science B.V.