Fig. 9.

Blocking inhibition in ELa affects small cell responses to peripheral spike timing differences. A: smoothed, normalized tuning curves (left) from a representative long-pass small cell before and after gabazine application, presented as in Fig. 2. This cell had long-pass tuning to both stimulus polarities before and after gabazine application. However, the minimum duration eliciting a response >0.5 decreased after gabazine application for both polarities (arrowheads), suggesting that inhibition was affecting excitatory input to the small cell at short durations. The bar graph (right) shows the minimum duration eliciting a response >0.5 (mean ± SE) for all 16 tuning curves that were long-pass before gabazine application. After gabazine application, there was a significant decrease in the minimum duration eliciting a response >0.5 (Wilcoxon matched-pairs test: n = 16, z = 2.9, P < 0.01). B: smoothed, normalized tuning curves (left) from a representative band-stop small cell before and after gabazine application. This cell had band-stop tuning to both stimulus polarities, but the tuning to both polarities changed to long-pass after gabazine application. The band-stop portion of the tuning curves that was <0.5 of the maximum response before gabazine (arrowheads) was no longer present after gabazine application, suggesting that inhibition was responsible for the decreased response at these durations. The bar graph (right) shows the range of durations eliciting a response <0.5 (mean ± SE) for all 13 tuning curves that were either band-pass or band-stop before gabazine application. After gabazine application, there was a significant decrease in the range of durations eliciting a response <0.5 (Wilcoxon matched-pairs test: n = 13, z = 2.4, P < 0.05).