Fig. 3.
Laminar profile of V1 repetition-induced spiking suppression. A: change in population response between each subsequent stimulus presentation P1–P5. Color represents percent change of evoked spiking. Laminar compartment is denoted at left. *q < 0.05, significant differences (see materials and methods); ○q < 0.1, differences approaching significance. B: distribution of single-unit response differences in percent change between P1 and P4. Values <0 denote response suppression. Median response (Med%c) is indicated by a red dashed line. Enhc., enhancement; Supp., suppression. C: correlation of each unit’s average baseline firing rate with its spiking difference between P1 and P4 (spk/s, spikes/s). Baseline firing was defined as the average firing rate during 100 ms of fixation immediately before the first stimulus presentation. Laminar compartment is indicated by color. No significant correlation (P < 0.05) was found for the majority of laminar compartments, with the exception of supragranular layers. D: correlation of response change between P1 and P4 and average maximum firing rate for each unit during the stimulation epoch (40 ms post onset to offset). No significant correlation was found for any laminar compartment. E: median spike density function (SDF) of an example unit before (solid lines) and after (dashed lines) elimination of trials contaminated with microsaccades. Black lines are the SDF for P1 (Init.), and purple lines are the SDF for P4 (Rep.). A paired-samples t-test revealed no significant difference between the two SDFs.