Golgi Neurons
The Golgi cell is an essential cellular component of the cerebellar cortex and the only source of inhibition to the billions of granule cells forming the cortical input layer. While considered as a single neuronal class, separate from Lugaro cells, Golgi
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Katarzyna Pietrajtis and Ste´phane Dieudonne´
Abstract
The Golgi cell is an essential cellular component of the cerebellar cortex and the only source of inhibition to the billions of granule cells forming the cortical input layer. While considered as a single neuronal class, separate from Lugaro cells, Golgi cells form a highly heterogeneous population, both morphologically and immunohistochemically. Golgi cells are interconnected by electrical synapses and connected to other cortical cell types by chemical synapses, forming feedforward and feedback inhibitory loops onto granule cells. Golgi cells are thus ideally placed to control the gain and temporal pattern of granule cell discharge in response to afferent mossy fiber activity. In vivo Golgi cells fire irregularly and respond to peripheral stimuli with brief burst responses or prolonged pauses. In the behaving animal, the firing rate of Golgi cells is modulated and forms sensory-motor receptive fields. Furthermore, Golgi cell activity is coordinated with local field potential oscillations in the beta range both locally and along the parallel fiber beams. Detailed computer models have been generated and predict complex oscillatory behaviors of the granule cell layer network at various frequencies. The impact of these oscillations on the encoding capacity of the granular layer is still debated, and further recordings are needed to understand how Golgi cells affect granule cell spike timing.
Introduction Golgi neurons are the main inhibitory interneurons in the granule cell layer (GCL) of the cerebellum and provide the only source of inhibition to cerebellar granule
K. Pietrajtis (*) • S. Dieudonne´ Laboratoire de Neurobiologie, Inhibitory Transmission Team, IBENS, Ecole Normale Supe´rieure (CNRS UMR 8197; INSERM U 1024), 46 rue d’Ulm, 75005 Paris, France e-mail: [email protected], [email protected] M. Manto, D.L. Gruol, J.D. Schmahmann, N. Koibuchi, F. Rossi (eds.), 829 Handbook of the Cerebellum and Cerebellar Disorders, DOI 10.1007/978-94-007-1333-8_34, # Springer Science+Business Media Dordrecht 2013
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K. Pietrajtis and S. Dieudonne´
cells. Hence, the GCL output is under the control of Golgi cells activity, which is bound to play an important role in cerebellar function. It was first proposed that Golgi cells control the gain of the granular cell layer to enforce optimal decoding of granule cell activity by the Purkinje cells (Marr 1969). Early studies of Golgi cells have been based on extracellular recordings of units during complex motor behavior like locomotion (Edgley and Lidierth 1987), limb movement (Marple-Horvat and Stein 1987; van Kan et al. 1993), or vestibular reflex (Miles et al. 1980). The possibility to record from Golgi cells in brain slices (Dieudonne´ 1995) and the demonstration that the selective acute ablation of Golgi cells causes severe ataxia (Watanabe et al. 1998) fostered renewed interest in this cell type. With accumulating data, several putative functions of Golgi cells have been proposed, including the oscil
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