Purkinje Cell Spike Firing in the Posterolateral Cerebellum: Correlation With Visual Stimulus, Oculomotor Response, and Error Feedback

Abstract

Complex (CS)- and simple-spike (SS) discharge from single Purkinje cells (Pc) in the posterolateral cerebellum of two monkeys was recorded during a visually guided reach-touch task. A visual target appeared (TA) off-gaze at a random location on a screen. On initiation of arm reach, the target disappeared, then reappeared (TR) after a fixed delay. TR was either at the same location (baseline condition) or a shifted location at a fixed distance and direction from TA location (shift condition). Across trials, we observed one or two peaks of CS activity, depending on the reach condition. The first CS (T1 CS) peak was tuned to the location of TA on the screen, following TA by approximately 150 ms. The second CS (T2 CS) peak occurred only in the shift condition, was tuned to the shift location of TR, and followed TR by approximately 150 ms. The locational preferences of T1 and T2 CS peaks were the same. T1 and T2 CSs preceded saccades to TA and TR at the preferred location and occurred during reaches with either arm. T1 CSs occurred during trials in which the target appeared, and there was a saccade to target, but no subsequent arm reach followed. SS firing varied with TA/TR in the same preferred location as for the accompanying CS. We conclude that posterolateral Pc CS and SS firing changes following an off-gaze visual target appearance in a preferred location when there is a subsequent saccade to that location.

Neural and Electromyographic Correlates of Wrist Posture Control

“…The hypothesis that the cerebellum and its input/output pathways (including posterior parietal cortex) contribute to the detection and correction of movement errors is consistent both with findings of single-unit recording studies of reaching movements in nonhuman primates (Horne and Butler 1995;Kitazawa et al 1998;Norris et al 2004) and human psychophysical studies of pointing to visual targets involving either neuroimaging (Desmurget et al 2001) or transcranial magnetic stimulation (TMS) (Desmurget et al 1999). In monkeys trained to produce rapid pointing movements to visually presented targets, Purkinje cells in the intermediate and lateral cerebellar hemispheres (lobules IV-VI) encode positioning errors (i.e., the hand position relative to the target) at the end of movement [although they appear to encode the intended final hand position at the beginning of a reach, (Kitazawa et al 1998)].…”

The multiple roles of Purkinje cells in sensori-motor calibration: to predict, teach and command

“…This tight relationship between neural activity and motor output implies that if the kinematics of a particular movement change during sensori-motor calibration, that is swing the golf club faster to compensate for a strong headwind, the firing rate of Purkinje cells would have to change accordingly. In support of this hypothesis, there is now overwhelming evidence clearly demonstrating parallel changes in Purkinje cell activity and motor output in many sensori-motor learning tasks [9,10,11•,12•,13••,14-18]. …”

“…Eyeblink conditioning [30], another staple in the field of cerebellar-dependent learning, can also be construed as an SD task [31]; here, the sensory disturbance is an air-puff to the cornea, and sensori-motor calibration can be thought of as a process that gradually adjusts the motor command in a way that ultimately leads to the protective closing of the eyelid in response to a conditioned stimulus. In every single one of these cerebellar-dependent SD tasks, the modification of movement kinematics is accompanied by obvious alterations in the activity of Purkinje cells in the relevant parts of cerebellar cortex [10,11•,12•,13••,14-16]. …”

What Features of Limb Movements are Encoded in the Discharge of Cerebellar Neurons?

“…In contrast, the simple spike firing of PCs in posterolat-eral regions of the cerebellar cortex is highly influenced by visual inputs and visuomotor dissociations [122–125]. During a reaching task in which the direction of cursor movement was opposite from the hand movement, the majority of laterally located PCs modulated with the direction of the cursor movement and not the arm movement [124].…”