Receptive field size, firing rates, and temporal frequency response. A , Receptive field size measured with small sweeping bars, segregated by layer and cell type. n = 108 units. B , Mean receptive field size of each group. C , Logarithmic plot of spontaneous firing rate for all units, by layer and cell type. n = 231 units. D , Median spontaneous firing rate of each group. E , Firing rate in response to optimal grating stimulus, for all visually responsive units (n = 204), averaged over 1.5 s presentation. [Instantaneous firing rates are shown in supplemental Fig. S3 (available at www.jneurosci.org as supplemental material).] F , Median response to optimal stimulus for each group. G , Median peak temporal frequency, averaged for layers and cell type, showing higher temporal frequency response in layer 4. n = 96 units. H , Mean temporal frequency tuning, comparing response in layers 2/3 and 4. exc, Putative excitatory units; inh, putative inhibitory units.