Fig. 4.

Typical examples of lifetime sparseness distributions of neural responses evoked by natural stimuli. A–C: neurons from area V1. D–F: neurons from area V2. G–I: neurons from area V4. Lifetime-sparse distributions with many 0 values (such as those in A, B, D, E, and G) are found in all 3 areas. Distributions that are closer to linear (e.g., C) or truncated Gaussians (e.g., H) are also found. A small number of neurons with spontaneous firing rates of ≥60 Hz (e.g., F and I) are found in V2 and V4 only.