Fig. 2.

Complex spike firing in relation to errors. a Scatterplot of end point position relative to target center for all trials (black dots), CS occurrence trials marked by small red circles, during a reaching task to a target presented on a screen. Total of 88 CS occurred out of 1381 reaches, with the numbers of CSs in each quadrant as indicated. The large ellipses denote the equidistance points (Mahalanobis distance = 1) for each population (red–CS occurring trials, black–all trials). Black arrow illustrates the shift between the centers of the red and black ellipses that quantifies the CSs preferred error direction and defines the CSs error modulation (modified with permission from [41]). b Heat map of CS population response from 74 Purkinje cells during an inward saccade adaptation task. Right panel depicts the degree of saccade adaptation, which is inversely related to error magnitude. CS modulation is minimal at the start of the adaptation when errors are maximal and increases as adaptation develops and error magnitude decreases. Maximum CS firing occurs when errors are small (modified with permission from [54])