Fig. 1.

Data showing that PSTH of complex spikes contain high-frequency components. (a) Complex spikes recorded in a Purkinje cell during OFR in a monkey. The raster plot shows the large variability in the timing of complex spikes from trial to trial during 40 presentations of visual stimulus motion. (b) Temporal average of 487 trials from the individual Purkinje cell shows that the PSTH (2-msec time bins) carries high-frequency information (thin black line). The thick red line shows that a generalized linear model can accurately reproduce IO neuron firing rate; data are from ref. 15 with permission. (c and d) Diagrams illustrating the advantage of irregular and desynchronized firing of IO neurons. (c) A cluster of IO cells receive a common synaptic inputs of high firing rates (Top), and they fire regularly and synchronously by electrical coupling (Middle). Because all of the IO cells in a cluster fire synchronously at the synaptic input onset, they do not respond to the remaining part of the input; moreover, repetitive presentation of the same input induces very similar responses. Thus, the PSTH of each cell, or a cluster of IO cells, exhibits a sharp peak at the onset (Bottom). (d) On the other hand, if in response to the input (Top), IO firing is irregular and desynchronized (Middle), the same input induces different responses for each neuron over trials. Thus, the PSTH is more similar to the input waveforms (Bottom): the temporal resolution of the transmitted information is high after temporal averaging. [b is reproduced with permission from ref. 15 (Copyright 1998, Am. Physiol. Soc., Bethesda).]