C-Fos expression in the deep cerebellar nuclei in a rat model of conditioned fear

In contrast to what was previously believed, there is increasing evidence that the cerebellum is involved in emotional and cognitive behaviour. Preclinical and clinical research points towards a role of the cerebellum in impulsivity and panic. Deep brain stimulation (DBS) of the dorsolateral periaqueductal gray (dlPAG) in rats has proved to elicit escape behaviour directly, but can also be used for conditioning of context-dependant fear responses. We used this model to study the activation in the deep cerebellar nuclei (DCbN) after conditioned fear. For this purpose, we performed c-Fos immunohistochemistry in the DCbN. We found no statistically significant difference in c-Fos expression in the DCbN between the subgroups in this animal model. We hypothesize that the lack of a significant difference in activation of the DCbN may be related to fear consolidation which takes place after dlPAG stimulation, after which retrieval of behaviour, whether adequate or inadequate, does not lead to a different activation of the DCbN. On the other hand the effect of conditioned fear may be smaller than the effect of panic behaviour elicited by DBS, requiring a larger study population.