Habituation of acoustic startle in rats--a functional ablation study.

Data from lesion studies data indicate that the removal of the medial cerebellum prevents acquisition but not retention of long-term habituation (LTH) of the acoustic startle response (ASR). The spreading depression (SD) of the vermis was used to examine under more functional conditions the build-up of LTH of the ASR in Wistar rats. Our findings showed that reversible blockade of the vermis during training disrupted LTH of the ASR without changing within-trials habituation. In contrast to previous data, the present results suggest that SD strongly affects the amplitude of the startle response. The data are discussed in respect to a role of the vermis in the control of emotional behaviour in animals.