The role of feedforward and, feedback inhibition on frequency-dependent information processing in a cerebellar granule cell

Multi-modal sensory information entering the cerebellum via mossy fibers is processed through the granule cell (GC) network, the major cellular elements of which are the GC and an inhibitory interneuron, the Golgi cell. A GC model supporting both feedforward (FF) and feedback (FB) inhibition to its dendritic arbor was constructed. This model was used to examine the influence of Golgi cell inhibition on GC responses to mossy fiber inputs ranging from 10 - 100 Hz. Both FF and FB inhibitory signals reduced GC output. When both inhibitory loops accessed the same GC dendrite, the greatest decrement in GC output was produced by FB inhibition alone. However, if each inhibitory loop accessed a different GC dendrite, both inhibitory inputs were required to produce the greatest decrement in GC output.