Fig. 7: Preparatory activity is maintained by Purkinje cell SS but not CS.
From: Activity map of a cortico-cerebellar loop underlying motor planning
a, Recording from an example Purkinje cell. Top, raw voltage trace. Green circles mark the CS. Bottom left, waveforms of SS (blue) and CS (green) from three consecutive channels. Bottom right, cross-correlogram between SS and CS. The characteristic pause in SS after a CS confirms that these spikes originate from the same Purkinje cell. b, Population selectivity (mean ± s.e.m.) of Purkinje cells in conjunction regions. Selectivity of SS or CS in correct trials (black) and error trials (red). Selectivity is the spike rate difference between the preferred and non-preferred trial types. Trial-type preference was determined by SS activity during the delay epoch in correct trials. Separate trials were used to determine trial-type preference from the trials used to calculate selectivity (Methods). Trial type was defined by instructed lick directions. In error trials, SS exhibited negative selectivity, which indicates activity tracking the actual lick direction. Neurons with significant SS selectivity during the delay epoch: n = 19. c, Distinct Purkinje cell response types based on CS activity in correct trials. Left, CS activity of individual Purkinje cells within each response type. Right, population CS activity (mean ± s.e.m.) of each response type in correct trials (black) and error trials (red). ‘Lick left’ and ‘lick right’ trials were pooled. Peristimulus time histograms (PSTHs) were normalized by calculating the z-scored spike rate relative to the baseline spike rate before the sample epoch. Cluster 3 exhibited activity before the start of the sample epoch. This activity may be driven by the sound of the motor that repositions the pole before the start of each trial (Methods). d, Spatial distribution of Purkinje cells (n = 244 neurons) with distinct response types. Top, caudal and dorsal view of cerebellum with recorded Purkinje cells (dots). Color indicates response type identity as in c. Bottom, proportions of Purkinje cells within each response type in conjunction regions (n = 103 neurons), input-dominant regions (n = 74 neurons) and output-dominant regions (n = 67 neurons). Box-and-whisker plot shows the median and the 25th and 75th percentiles; the most extreme data points were not considered as outliers (bootstrap; Methods).
