Figure 2.

Contrast response properties of A17 and A18 neurons in young and old cats. (A) Example curve fit for contrast response functions (CRFs) of typical young neurons (black line) and typical old neurons (gray line) recorded from A17 (dotted lines) and A18 (solid lines) neurons. Each point represents the response to the stimulus at a given contrast. The fitted curves take the form of a Naka-Rushton function with the C₅₀ values marked with black (YC) and gray (OC) arrows. (B) Distribution of SNR values in areas A17 (black triangles for young cats, gray triangles for old cats), and A18 (black diamonds for young cats, gray diamonds for old cats), where histograms indicate mean values of SNR values in each group. The population results for fitted parameter values in A17 (dotted lines) and A18 (solid lines) are illustrated in panels 2C–F. The black and gray lines represent the data of young and old cats, respectively. Error bars indicate SEM.