Cerebellum climbing fibers

At the same time that the motor neurons send signals to the muscles, branches travel into other parts of the brain including the olivary nuclei, which send neurons into the cerebellum. The cerebellum acts as a kind of computer needed for fine tuning of the impulses to the muscles. Injury to the cerebellum leads to difficulty in finely coordinated motions. Input to the Purkinje cells arises from the climbing fibers, which originate in the inferior olive of the brain stem. Each climbing fiber activates a single Purkinje cell, but the dendrites of each Purkinje cell also form as many as 200,000 different synapses with parallel fibers that run across the cortex of the cerebellum (Fig. 30-15). 

Zollinger M., Brauchli-Theotokis J., Gutteck-Amsler U., Do K. Q., Streit P., and Cuenod M. (1994). Release of N-acetylaspartylglutamate from slices of rat cerebellum, striatum, and spinal cord, and the effect of climbing fiber deprivation. J. Neurochem. 63 1133-1142. 

Landsend AS, Amiry-Moghaddam M, Matsubara A, Bergersen L, Usami S, Wentbold RJ, Ottersen OP (1997) Differential localization of glutamate receptors in the rat cerebellum coexpression with AMPA receptors in parallel fiber-spine synapses and absence from climbing fiber-spine synapses. J Neurosci /7 834 842. 

Fig. 6. Summary histogram of development of glutamate receptors at parallel [postnatal day 10 (PI0) to adult] and climbing (P2 to adult) fiber synapses on Purkinje cells of the cerebellum. Note especially the peak in immunogold labeling of the delta receptors at PI0-PI4 in climbing fiber synapses (cO, the peaks of the AMPA receptors (GluR2, GluR2/3 antibodies) at P2-P5, and the inverse patterns of peaks for parallel fiber synapses (pf) and climbing fiber synapses in adults for AMPA versus delta receptors. Modified from Zhao et al. (1998).

In the adult cerebellum, as noted above, parallel fiber synapses have abundant delta receptors, while delta receptors are rare or absent from climbing fiber synapses. AMPA receptors are found at both excitatory synapse populations but are more abundant at climbing fiber synapses. In the first postnatal week, presumptive climbing fiber synapses have high... 

Marin-Padilla M (1985) Neurogenesis of the climbing fibers in the human cerebellum a Golgi study. J Comp Neurol 235 82-96. 

Fig. 14. Phaseolus vulgaris lectin-labelled climbing fibers of rat cerebellum. A, Sagittal section. B. Coronal section. Abbreviations G = granular layer M = molecular layer P = Zebrin- labelled Purkinje cells. Bar = 100 jum. Courtesy of Dr. T.J.H. Ruigrok.

Fig. 170. Laterality and somatotopical organization of the projection zones of the ventral funiculus spino-olivocerebellar climbing fiber path (VF-SOCP) in the cerebellum of the cat. A. Rostral aspect. B. Caudal aspect of the cerebellum. The position of the caudal border of the inferior colliculus (INF.COLL.) is indicated. Oscarsson and Sjolund (1977b).

Fig. 173. A summary diagram of nociceptive and non-nociceptive cutaneous climbing fiber input to lobules IV and V of the cerebellum of the cat. Forked arrows show branching of olivary axons to innervate pairs of zones (Ekerot and Larson, 1982). PF, primary fissure DAO, dorsal accessory olive MAO, medial accessory olive. Garwicz (1992).

Fig. 174. Minimum threshold sites for evoking short latency climbing fiber responses from the pericruciate cortex of the cat in the b, c, and d, zones of the anterior lobe of cat cerebellum. ASG = anterior sigmoid gyrus PSG = posterior sigmoid gyrus. Redrawn from Andersson and Nyquist (1983).

Fig. 175. Correspondence between the classical three-zonal subdivision of the cerebellum of Brodal (1940 upper panel), the sagittal projection zones of the spino-olivocerebellar climbing fiber paths of Oscarsson c.s. (middle panel) and the anatomical zones of Voogd (lower panel). Arrows indicate the transverse branching of climbing fibers between zones (Ekerot and Larson, 1982). Hatched zones receive short-latency input from the DF-SOCP (Ekerot and Larson, 1979a) and are activated by nociceptive stimuli. Garwicz et al. (1992) in Garwicz (1992).

Fig. 190. Distribution of CRF and CGRP-immunoreactive climbing fibers in P7 mouse cerebellum (A-C) and in neurons of the inferior olive (D-F). CRF-immunoreactive climbing fibers and neurons are indicated by dots, CGRP-immunoreactive climbing fibers and neurons by open circles, a, b and c = subnuclei a, b and c of the medial accessory olive beta -i- group beta Cl, C2 = Crus I and II DAO = dorsal accessory olive dc = dorsal cap EGL.ML = external granular layer and molecular layer F = flocculus IGL = internal granular layer PF = paraflocculus MAO = medial accessory olive PO = principal olive PL = Purkinje cell layer. Redrawn from Yamano and Tohyama (1993).

Fig. 191. Schematic line drawings of the unfolded opossum cerebellum modified after Larsell and Jansen (1972). The broken lines indicate the boundaries of the corticonuclear zones A-D after Klinkhachorn et al. (1984a). The distribution of the three types of enkephalinergic axons is indicated by the frequency and size of the symbols the beaded axons by asterisks (C), the mossy fibers by dots (A), and the climbing fibers by triangles (B). I-X indicate vermal lobules CR I, II, crura I and II, F, flocculus LS, lobulus simplex PFL, paraflocculus PML, paramedian lobule. D. Distribution of enkephalinergic axons in a horizontal section through the cerebellar nuclei. D, dentate nucleus, F, fastigial nucleus IPA, anterior interposed nucleus IPP, posterior interposed nucleus. From King et al. (1987).

Fig. 194. Three transverse sections through the cerebellum of the cat showing corticotrophin releasing factor (CRF)-like immunoreactivity in climbing fibers in the molecular layer (radial lines) and mossy fibers (dots) in the granular layer. Note corresponding positions (arrows) of strongly labelled climbing fibers and mossy fibers (arrows). Abbreviations CR I, II, Crus I and II FL, flocculus LS, simple lobule NIP, posterior interposed nucleus NL, lateral cerebellar nucleus NM, medial nucleus PFL, paraflocculus PML, paramedian lobule I-X, lobules I-X of Larsell. Cummings (1989).

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