Spatiotemporal response properties of cerebellar Purkinje cells to animal displacement: a population analysis

• Published in: Neuroscience 1997-12, Vol.81 (3), p.609-626
• Main Authors: Pompeiano, O, Andre, P, Manzoni, D
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cats; cerebellar vermis; Cerebellum - cytology; Cerebellum - physiology; Decerebrate State; Electrophysiology; Fundamental and applied biological sciences. Psychology; head tilt direction; Head-Down Tilt; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Physical Stimulation; Posture - physiology; Purkinje cells; Purkinje Cells - physiology; Reaction Time; Reflex - physiology; Rotation; Space life sciences; Space Perception - physiology; spatiotemporal coding; Spinal Cord - physiology; Vertebrates: nervous system and sense organs; vestibular input; Vestibule, Labyrinth - physiology; vestibulospinal reflex
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(97)00201-7

The hypothesis that corticocerebellar units projecting to vestibulospinal neurons contribute to the spatiotemporal response characteristics of forelimb extensors to animal displacement was tested in decerebrate cats in which the activity of Purkinje cells and unidentified cells located in the cerebellar anterior vermis was recorded during wobble of the whole animal. This stimulus imposed to the animal a tilt of fixed amplitude (5°) 1 This stimulus amplitude was used since, in a previous study, [18]the responses to a roll tilt of a large population of P-cells located in the vermal cortex of the cerebellar anterior lobe showed a linearity in the range of 2–15°. 1 , with a direction moving at a constant angular velocity (56.2°/s), both in the clockwise and counterclockwise directions over the horizontal plane. Eighty-three percent (143/173) of Purkinje cells and 81% (42/52) of unidentified cells responded to clockwise and/or counterclockwise rotations. In particular, 116/143 Purkinje cells (81%) and 32/42 unidentified cells (76%) responded to both clockwise and counterclockwise rotations (bidirectional units), while 27/143 Purkinje cells (19%) and 10/42 unidentified cells (24%) responded to wobble in one direction only (unidirectional units). For the bidirectional units, the direction of maximum sensitivity to tilt ( S max) was identified. Among these units, 24% of the Purkinje cells and 26% of the unidentified cells displayed an equal amplitude of modulation during clockwise and counterclockwise rotations, indicating a cosine-tuned behavior. For this unit type, the temporal phase of the response to a given direction of tilt should remain constant, while the sensitivity would be maximal along the S max direction, declining with the cosine of the angle between S max and the tilt direction. The remaining bidirectional units, i.e. 57% of the Purkinje cells and 50% of the unidentified cells displayed unequal amplitudes of modulation during clockwise and counterclockwise rotations. For these neurons, a non-zero sensitivity along the null direction is expected, with a response phase varying as a function of stimulus direction. As to the unidirectional units, their responses to wobble in one direction predict equal sensitivities along any tilt direction in the horizontal plane and a response phase that changes linearly with the stimulus direction. By comparing these data with those obtained previously during selective stimulation of macular receptors by a 5° off-ver