Anisotropic representation of forelimb position in the cerebellar cortex and nucleus interpositus of the rat.
The relationship between the spatial location of limb and the activity of cerebellar neurons has received little attention and its nature still remains ambiguous. To address this question we studied the activity of Purkinje and nucleus interpositus cells in relation to the spatial location of rat forelimb. A computer-controlled robot arm displaced the limb passively across 15 positions distributed on a parasagittal plane. The limb was upheld for 8 s in each position, which was identified by the Cartesian coordinates of the forepaw. We selected the neurons whose activities were significantly modulated by forepaw position and found that the majority represented preferentially one spatial dimension of the Cartesian plane both in the cerebellar cortex and nucleus interpositus. In particular, the antero-posterior axis was best represented in cerebellar neuronal discharges. This result suggests that the intermediate part of the cerebellum might encode limb position by way of an anisotropic representation of the spatial coordinates of the limb end-point.
Casabona
Antonino
A
Department of Physiological Sciences, University of Catania, viale Andrea Doria 6, 95125 Catania, Italy. casabona@unict.it
Valle
Maria Stella
MS
Bosco
Gianfranco
G
Garifoli
Angelo
A
Lombardo
Salvatore A
SA
Perciavalle
Vincenzo
V
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D016880:Anisotropy; D001391:Azo Compounds / Q000378:metabolism; D001931:Brain Mapping; D002525:Cerebellar Cortex / Q000033:anatomy & histology / Q000502:physiology*; D002529:Cerebellar Nuclei / Q000033:anatomy & histology / Q000502:physiology*; D005552:Forelimb / Q000502:physiology*; D016015:Logistic Models; D008297:Male; D009949:Orientation / Q000502:physiology; D011187:Posture / Q000502:physiology; D011689:Purkinje Cells / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014343:Trypan Blue
D001391:Azo Compounds; C009000:pontamine sky blue; D014343:Trypan Blue