Figure 6. Comparison of response frequencies, onset and offset latencies in Golgi and granule cells.

A, comparison of the likelihoods of Golgi cell long-lasting depression (LLD) responses relative to granule cell long-lasting excitation (LLE) responses (with/without SLEs, black and open bars, respectively). Granule cell LLE responses were significantly more frequently evoked from either side of the face compared to Golgi cell LLD responses, although no differences were found comparing limb responses. B shows a comparison of onset latencies and durations, revealing that the onsets of granule cell LLEs lag those of the Golgi cell LLDs by ∼100 ms, irrespective of the stimulus. Only ipsilateral trigeminal responses showed a significant difference in offset time. C plots the likelihood of granule cell early depressions against SLEs in Golgi cells. Early depressions were significantly more likely in granule cells than Golgi cell SLEs, which may mediate them. Although the sample of 51 Golgi cells used for this analysis did not include any with hindlimb evoked SLEs, such responses are seen in some Golgi cells in this region (see Holtzman et al. 2006). D plots onset latencies and durations for early granule cell depressions. E shows the occurrence of late inhibitions in our sample of granule cells (potentially underestimated due to low spontaneous firing rates). F re-plots the Golgi cell LLD data shown in D alongside comparable data for granule cell late inhibitions. Late depressions evoked from the contralateral forelimb were seen in other granule cells not included in the receptive field dataset. A relatively small sample size precludes statistical analysis, although late inhibitions appear to correlate with offset of Golgi cell LLDs, i.e. the restoration of Golgi cell firing. In all cases error bars represent 2 standard errors from the mean; no error bars for samples n < 4. Abbreviations: Ip., ipsilateral; Co., contralateral; Vib., Vibrissal skin; FL., forelimb; HL., hindlimb