title: Somatotopically organized transient projections from the primary somatosensory cortex to the cerebellar cortex.
abstract: The organization of transient projections from the primary somatosensory cortex (S-I) to the cerebellar cortex in neonatal kittens was examined using orthograde intraaxonal labeling techniques. Tritiated amino acid injections into face, forelimb and hindlimb areas of representation in S-I labeled mossy fiber-like terminals of cerebrocerebellar axons in different areas of the cerebellar cortex bilaterally. The hindlimb area of S-I projected to lobules I-IV in the anterior lobe and to ventral folia of the paramedian lobule (PML). Injections into forelimb areas of S-I labeled terminals in lobules IV and V and in intermediate and dorsal folia of the PML. The face area of S-I projected to the lobules V and VI, to medial folia in the ansiform and simplex lobules and to dorsal PML folia. Labeled terminals were more numerous in the cerebellar cortex contralateral to the S-I injections, except in lobules I and II and the ventral PML where the density of hindlimb input was approximately the same on both sides. These observations were supplemented by findings that small wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injections into the dorsal or ventral PML resulted in retrogradely labeled layer V pyramidal neurons in lateral (face and forelimb) and medial (hindlimb) areas of S-I respectively. The somatotopic organization of transient S-I cerebrocerebellar projections is very similar to the topography of cerebellar somatosensory afferent pathways in adult cats.
authors.affiliation: Francis and Doris Murphy Neuroanatomy Research Laboratory, Department of Anatomy, St. Louis University, MO 63104.
authors.forename: D L
authors.initials: DL
authors.lastname: Tolbert
mesh_terms: D000344:Afferent Pathways / Q000033:anatomy & histology; D000596:Amino Acids; D000818:Animals; D001345:Autoradiography; D001931:Brain Mapping; D002415:Cats; D002525:Cerebellar Cortex / Q000166:cytology* / Q000502:physiology; D009473:Neuronal Plasticity; D013003:Somatosensory Cortex / Q000166:cytology* / Q000502:physiology
chemical_list: D000596:Amino Acids