Fig. 5.

Proportions of neurons showing increases or decreases in discharge rate at masked threshold and their average masked thresholds. A, Histogram of the number of units in our population that yielded positive (type P) or negative (type N)D values at the masked threshold in response to So (filled bars) or Sπ (open bars) 500 Hz tones. B, Averages of the masked thresholds for So (filled circles) and Sπ (open squares) tones computed separately for units yielding positive and negative D values, as indicated by thearrows from the histogram bars to the corresponding masked thresholds.