(a) Upper plot, the mean bout-triggered complex spike rate with shaded SEM for this cell for all swim bouts during the blank recordings (no stimuli presented, orange trace) and during trials with visual stimuli (red trace). N = 16 bouts (blanks), 76 bouts (stimuli). Lower traces, example excerpt from a blank recording from this Purkinje cell (PC, black trace) with simultaneous ventral root recording (VR, gray trace, shown as a moving standard deviation). Complex spikes are indicated by orange dots above the trace. (b) Upper traces, a subset of bouts are plotted aligned to bout onset for swim episodes during which a complex spike (orange dot) occurred. Below, a normalized histogram for all CS-positive bouts in this recording show that the majority of the complex spikes are triggered in the period 100–150 ms following bout onset (N = 34/76 CS-positive bouts). (c) Upper plot, the mean bout off-triggered complex spike rate with shaded SEM for this cell for blank and visual stimuli trials. N = 12 bouts (blanks), 468 bouts (stimuli). Lower traces, example excerpt from a blank electrophysiological recording from this cell. (d) Heatmap of bout on- and off-triggered mean complex spike rates for all cells with significant motor coefficients arranged by peak CS firing rate from bout onset. The lower three rows correspond to cells that have a decrease in CS activity during bouts which increases following bout offset. The example cells from a) and c) are indicated. (e) The locations of these Purkinje cells with CS activity correlated with bout onset (green) or bout offset (black) are plotted on the right lobe of a reference cerebellum (some coordinates were flipped from left to right). The example cells from a) and c) are indicated. Scale bar = 50 microns. (f) The 12 eye motor regressors used for multilinear least squares regression (MLR) of electrophysiological data with eye movements in the semi-paralyzed zebrafish (see Materials and methods for details; see Figure 1—figure supplement 2 for the description of sensory regressors). All eye motor regressors are calculated for each cell based on the motor activity of each eye (tracked independently) in that trial. A representative set of regressors computed from eye movement in one trial in the dataset is shown here. (g) Heatmap of all 30 regressor coefficient weights (18 sensory and 12 eye motor) for the complex spike (left) and simple spike (right) firing rates of 13 cells (N = 11 fish). The sensory regressors with the largest coefficient weights for complex spike rates are indicated. For complex spike phenotypes, 11/13 Purkinje cells have a stronger ‘sensory’ phenotype, whereas 13/13 Purkinje cell have a simple spike ‘motor’ phenotype. The two remaining Purkinje cells with a motor complex spike phenotype are indicated as ci and cii (arrowheads). (h) Location of all cells, color-coded for complex spike phenotype as determined by MLR and additional analyses (see subsequent panels). Scale bar = 50 microns. (i) Left, mean activity and SEM for the complex spike rate and best eye movement regressor excerpted from the rotational stimulus portion of the experiment for Purkinje cell two as indicated in g) and classified as having a motor complex spike phenotype. The single correlation coefficient between the best motor and sensory regressors across trials are very high (r = 0.60 across the full trial). Right, mean activity and SEM for the complex spike rate and best eye movement regressor excerpted from the rotational stimulus and flash portion of the experiment for Purkinje cell three as indicated in b) and the only other cell classified as having a ‘motor’ complex spike phenotype. The single correlation coefficient values for the complex spike rate with the indicated regressors across trials for just the rotational stimulus period or just the luminance period are shown. (j) Heatmap of eye movement (left eye, nasal) and complex spike rates across all trials of an experiment for a representative Purkinje cell in the left caudolateral cerebellum (cell seven as indicated in g,h). Note the variability of the eye movement across trials (left) compared to the complex spike rate (right). Clockwise velocity is indicated for reference. (k) The best motor regressors for each eye and the best sensory regressor are plotted against the complex spike rate of the cell in j) for the first (left) and last (right) trial of the experiment. Single correlation coefficient values are shown between each regressor and the complex spike rate for this trial. Time scale is same as for j).