Branching point effects on the passive properties of the cerebellar granule cell axon

This paper describes a mathematical model of the axon of the cerebellar granule cell as it ascends into the molecular layer and branches into its two parallel fiber segments. We present a theoretical and computational analysis of the input resistance at the branching point and the degree of signal attenuation between the ascending segment of the axon and the parallel fibers. The results suggest considerable passive signal decay in this branch point. If correct, this result has important implications for cerebellar function, as granule cell activation would be expected to always propagate in the ascending but not necessarily the parallel fiber segments of the same axon. (C) 2000 Elsevier Science B.V. All rights reserved.