Fig. 6.

Attention results from target-present trials. Shading represents ± 1 SE. A and B: firing rate (Hz; A) and spike count correlation (r_sc; B) for fast-spiking (red; n = 1,341 neurons; 4,431 pairs) and regular-spiking (blue; n = 4,958 neurons; 48,347 pairs) cells when the stimulus in the receptive field was attended (solid lines) and when the stimulus in the receptive field was unattended (dashed lines). Mixed-class pairs are plotted in gray, and pairs of cells recorded on the same electrode were excluded. r_sc was calculated in 150 ms sliding time bins; note that the magnitude of r_sc can be small when measured in short time windows (Cohen and Kohn 2011). The r_sc value for each bin is plotted at the right-most edge (i.e., the first plot point reflects r_sc, calculated using spike counts in the gray-hatched time window). C and D: attention effect on firing rate (C) and r_sc (D), calculated for each neuron or pair by subtracting the unattended response from the attended response (Δ). Firing rates were greater, and r_sc was lesser for attended (att.) than unattended (unatt.) stimuli. Effect sizes of attention were greater for fast-spiking than for regular-spiking cells. Lines along the bottom of the plots reflect time points with significant nonzero attention effects for fast-spiking cells (red), regular-spiking cells (blue), and pairs of cells with mixed-class membership (gray), as well as significant differences between classes (black); P < 0.05, corrected for multiple comparisons. Only data up to the time of target onset on each trial were used for analysis (n = 246.7 ± 9.5 trials/session for each condition until the start of the target-onset window at 0.25 s, decreasing roughly linearly thereafter to n = 51.0 ± 5.7 trials/session by 0.7 s).