Figure 5.

Stimulus-specific adaptation index (SI) and peri-stimulus time histogram (PSTH) differences in the alternating oddball experiment. (A) The SI for the multi-unit activity (MUA) in the three experimental conditions. Each dot represents the SI from one MUA site. Each box shows the quartiles of the dataset while the whiskers extend to the rest of the distribution, except for the potential outliers. The SI in the control condition was significantly smaller than 0. The SI in the alternating condition was significantly larger than in the control condition. The inset shows the paired comparison between the SI in the alternating and control conditions. Most dots are below the diagonal line at 45 degrees, showing the SI in the alternating condition was larger than in the control condition. (B) The SI from single unit activity showed similar results as MUA. (C) The PSTH differences (calculated for 50 ms bins from MUA) in different experimental conditions. Each panel indicates one experimental condition and each row indicates the color-coded amplitude of the PSTH difference from one electrode. The PSTH difference was the PSTH of the deviant minus the PSTH of the standard. The black line indicates the stimulus onset. In the control condition, the blue color after stimulus onset shows that the neural responses to the 2nd stimulus of the repeated pair were smaller than to the 1st stimulus. In the alternating condition, the homogeneous color shows that the PSTHs of the two stimuli of the repeated pair were similar. In the typical oddball condition, the dark red color shows that the neural responses to the deviant were much stronger than to the standard. Color scale indicates difference in spikes per second.