Precise Spatial Relationships between Mossy Fibers and Climbing Fibers in Rat Cerebellar Cortical Zones

Abstract

Classically, mossy fiber and climbing fiber terminals are regarded as having very different spatial distributions in the cerebellar cortex. However, previous anatomical studies have not studied these two major cerebellar inputs with sufficient resolution to confirm this assumption. Here, we examine the detailed pattern of collateralization of both types of cerebellar afferent using small injections of the bidirectional tracer cholera toxin b subunit into the posterior cerebellum. The cortical and zonal location of these injections was characterized by mapping climbing fiber field potentials, the distribution of retrogradely labeled olivary neurons, and the intrinsic zebrin pattern of Purkinje cells.Labeled climbing fiber collaterals were distributed as longitudinal strips and were always accompanied by clusters of labeled mossy fiber rosettes in the subjacent granular layer. Two-and three-dimensional reconstructions and quantitative analysis showed that mossy fibers also collateralized to other stripe-like regions usually below Purkinje cells with the same zebrin-positive or zebrin-negative characteristics as that of the injection site and associated climbing fiber collaterals. The distribution of retrogradely labeled neurons in two major sources of mossy fibers, the lateral reticular and basilar pontine nuclei, revealed interlobular and some interzonal differences.These data indicate that nonadjacent cerebellar zones, sharing the same climbing fiber input and zebrin identity, also share a common mossy fiber input. Other cerebellar cortical regions that receive collaterals from the same mossy fibers usually also have the same zebrin signature. Together with the distribution of neurons in precerebellar centers, the findings suggest a revision of the modular hypothesis for information processing in the cerebellar cortex.

Current source density correlates of cerebellar Golgi and Purkinje cell responses to tactile input

“…After electrical stimulation of the LRN, Xu and Edgley (2010) observed latencies of excitatory responses ranging from 14.1 to 23.6 ms in 4 out of 27 GoCs. However, in Crus II, projections from pontine nuclei outnumber those from the LRN (Pijpers et al 2006;Wu et al 1999).…”

“…Mossy fibers originating in the trigeminal nuclei, basal pontine nuclei, and nucleus reticularis tegmenti pontis bifurcate to make multiple projections to Crus IIa, forming discontinuous patches or stripes (Pijpers et al 2006;Serapide et al 2002;Woolston et al 1981), colocalized with climbing-fiber projections of similar body representations (Sugihara and Shinoda 2004). Vos et al (2000) described four response patterns in GoCs occurring with almost equal frequency.…”

Molecular, Topographic, and Functional Organization of the Cerebellar Nuclei: Analysis by Three-Dimensional Mapping of the Olivonuclear Projection and Aldolase C Labeling

“…Even finer longitudinal compartmentalization in the cerebellar cortex is possible based on the expression pattern of aldolase C (zebrin II) (Hawkes and Leclerc, 1987). Recently, several groups have demonstrated a correspondence between the olivocortical projection pattern and aldolase C compartments of the cerebellar cortex (Voogd et al, 2003;Voogd and Ruigrok, 2004;Pijpers et al, 2005Pijpers et al, , 2006. This suggests that molecular expression, olivocortical topography, and functional compartmentalization are integrated within the organization of the cerebellar cortex.…”

Golgi Cell Dendrites Are Restricted by Purkinje Cell Stripe Boundaries in the Adult Mouse Cerebellar Cortex

“…The granular layer is also subdivided into stripes (for review, see Ozol and Hawkes, 1997) that also align with the overlying Purkinje cell compartments [e.g., mossy fiber terminal fields (Matsushita et al, 1991;Akintunde and Eisenman, 1994;Ji and Hawkes, 1994;Voogd et al, 2003;Pijpers et al, 2006)], and an elaborate mosaic of patches is revealed both in tactile receptive field maps (Welker, 1987) and by histological treatments (Hawkes et al, , 1998. Finally, functional studies have also demonstrated parasagittal stripes in the cerebellum Larson, 1973, 1980) (for review, see Voogd et al, 1996) with direct correlations with particular Purkinje cell stripes (Chockkan and Hawkes, 1994;Chen et al, 1996;Hallem et al, 1999).…”