The effects of volatile halogenated anesthetics on information flow at the cerebellum input stage

The cerebellum is of crucial importance for sensory-motor integration and is also involved in cognitive processing. Blended anesthesia employs different molecules whose mechanisms of action are not fully understood. Among these, sevoflurane and desflurane are currently used in clinic for maintenance of general anesthesia. In this work, we have tested how anesthetics affect the flow of excitatory information transmitted by cerebellum granule cells (GCs). It is in fact still unknown the way the neuronal network activity is modulated during anesthesia. Whole-cell patch clamp recordings from GCs were performed in current-clamp mode in rat cerebellar slices. The bath application of sevoflurane (8%), on one hand dramatically reduced the total number of synaptically evoked spikes (-79%±10; n=4), on the other hand, the first spike latency and the temporal precision were increased (+23%±5; +32%±5 respectively). Furthermore, the spike timing data were used to estimate how anesthetics can modulate information transmission through the measure of Mutual Information (MI). Preliminary results show that the effect of sevoflurane perfusion was to reduce up to the 80% (n=4, p<0.05) the MI measured in control condition. Interestingly, the control condition was fully recovered after the removal of the anesthetic. These evidences indicate that anesthetics perfusion can potentially affect the cerebellar network which is fundamental for sensory-motor integration, memory formation and consolidation.