Figure 1.

A, Grand averages of response-locked event-related potentials at midline electrodes in individuals homozygous for the C and T allele (DRD4–521). Depicted are ERPs for correct trials (dashed lines), error trials (solid thick lines) and the difference waveforms (solid thin lines). For illustration the data were bandpass filtered (bandpass 2–8 Hz). B, Isovoltage maps of the difference waveform for the time window 0–100 ms in homozygotes for the C and T allele (maximum and minimum values in microvolts are −4.5 and 0.5). C, Mean trough-to-peak amplitudes at Fz and Cz for the four different groups with the respective SEs.