This suggests that these neurons

cannot simply inherit high temporal frequency tuning from the population we characterized in V1. Encoding for fast frequency information in higher areas could emerge from input from other areas (e.g., lateral posterior nucleus of the thalamus; Simmons et al., 1982), other populations within V1 (e.g., deeper cortical layers; Gao et al., 2010 and Kreile et al., 2011), or local circuits. Selleck PD-1/PD-L1 inhibitor To address the sharpness of TF tuning across areas, we examined tuning bandwidth. A bandwidth value was computed for bandpass cells as the half width at half max in octaves (Heimel et al., 2005; Figure S4). All extrastriate areas had higher mean TF bandwidth values than V1. This effect was significant for areas LM, AL, and RL (Figure S4, one-way ANOVA F(6,191) = 5.2, p < 0.005; post-hoc comparisons p < 0.05, HSD), and indicates that these areas tend to respond to a broader range of TFs than V1. The cumulative distributions of preferred SF for each area's population of neurons showed that all of the visual areas had populations encoding the spectrum of SFs tested. One group of areas—AL, RL, and LM—consisted of neurons preferring relatively low SFs (Figure 5A). Area AM contained neurons which preferred intermediate SFs, and areas V1, LI, and PM all showed high SF

Selleckchem BKM120 tuning. Areas LI and PM show particularly interesting distributions. LI contains a relatively large subset of neurons that prefer the lowest SF, similar to area AL. However, the remaining distribution deviates toward high SFs, suggesting the presence of separate populations of neurons in LI, preferring distinct ranges of SFs (Figure 5A, Figure S6). Area PM’s distribution also has an interesting pattern, with a small population of neurons Urease preferring low SFs which deviates rapidly toward a larger population preferring high SFs (Figure 5A, Figure S6).

We compared the geometric mean preferred SF across each population (Figure 5B) and found a main effect of visual area on preferred SF (one-way ANOVA, F(6,1783) = 59.7576, p < 0.0005). Post-hoc multiple comparisons tests revealed that areas LM, AL, RL, and AM all prefer lower SFs than V1 ( Figure 5B, p < 0.05, HSD), while areas LI and PM cannot be distinguished from V1 based on mean preferred SF. Area AL had the lowest preferred SF, significantly lower than areas V1, LM, LI, AM, and PM ( Figure 5B, p < 0.05, HSD). Only area RL showed comparably low preferred SF. Areas LM and AM showed similar, intermediate preferred SF ( Figure 5B). In the same manner as for TF tuning, we characterized neurons as lowpass, highpass or bandpass for SF (Figure 5C). Areas LM, LI, AL, and RL all had relatively high proportions of neurons which were lowpass, however the populations of neurons from these areas differed in other respects.