Fig. 8.

A and B: mean firing rates of primate V4 neurons. We recorded the mean firing rates of single well-isolated neurons, recorded extracellularly during active search component of the free-viewing visual search task. The mean of the resulting distribution is 16.5 Hz. This rate is higher than the theoretical upper bounds on neuronal firing rates proposed by Attwell and Laughlin (2001; 4 Hz) and Lennie (2003; 0.94 Hz). This suggests that the firing rates observed during this challenging task could not be maintained throughout the brain for long periods of time.