Cerebro-Cerebellar Connections
The cerebro-cerebellar system is one of the largest pathways in the central nervous system, yet knowledge of its structure and function remains far from complete. This is an important gap in understanding because anatomical connectivity is a key determina
- PDF / 889,909 Bytes
- 24 Pages / 439.37 x 666.142 pts Page_size
- 84 Downloads / 210 Views
48
Richard Apps and Thomas C. Watson
Abstract
The cerebro-cerebellar system is one of the largest pathways in the central nervous system, yet knowledge of its structure and function remains far from complete. This is an important gap in understanding because anatomical connectivity is a key determinant of cerebellar function. This chapter focuses on recent advances in understanding the anatomical and physiological properties of cerebro-cerebellar connections in nonhuman species. There are two main routes by which cerebral information can gain access to the cerebellum: cerebro-pontocerebellar pathways that terminate in the cerebellar cortex as mossy fibers and cerebro-olivocerebellar pathways that terminate as climbing fibers. A common principle of organization seems to be the convergence of somatotopically corresponding pathways, with the climbing fiber system playing a key role in imposing this order. In addition to this well-ordered spatial arrangement, there is also precise timing of integration of ascending and descending inputs. The spatial and temporal congruence of inputs is consistent with the one-map hypothesis of cerebellar organization (Apps and Hawkes 2009). The functional significance of this precise arrangement remains to be determined but is likely to have a major impact on cerebellar activity.
R. Apps (*) School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol, BS8 1TD, UK e-mail: [email protected] T.C. Watson Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK e-mail: [email protected] M. Manto, D.L. Gruol, J.D. Schmahmann, N. Koibuchi, F. Rossi (eds.), 1131 Handbook of the Cerebellum and Cerebellar Disorders, DOI 10.1007/978-94-007-1333-8_48, # Springer Science+Business Media Dordrecht 2013
1132
R. Apps and T.C. Watson
Introduction For a full understanding of the functions of the cerebellum, it is essential to have a thorough description of projections to and from this major sensorimotor structure. This is because differences in input and output connectivity play a key role in conferring differences in function on the uniform architecture of the cerebellum. Such differences have been studied extensively in terms of peripheral sensory inputs, suggesting that an important principle of cerebellar organization is a division into a series of longitudinally oriented modules (for review and references, see Angaut 1970; Oscarsson 1980a; Buisseret-Delmas and Angaut 1993; Voogd and Glickstein 1998; Apps and Garwicz 2005; Apps and Hawkes 2009; Voogd 2011). Each cerebellar module is defined by its climbing fiber afferents from a specific subdivision of the contralateral inferior olivary complex, which targets one or more longitudinal zones of Purkinje cells within the cerebellar cortex. There are multiple spino-olivocerebellar paths arising from the periphery that convey sensory signals via the climbing fiber system to the different cortical zones (for review and references, see, e.g., Oscarsson 1980a; Apps 1999). These spino-olivocere
Data Loading...
