Journal: Journal of Neurophysiology

Article Title: Contrast sensitivity, V1 neural activity, and natural vision

doi: 10.1152/jn.00635.2016

Figure Lengend Snippet: Background image power spectra, RF locations, and adaptation. A: the locations of RFs are indicated by 1° yellow circles (the average RF size) at their locations on the background image during fixation 1. Adaptation appears to have occurred in the RFs on the first fixation and been over into the second fixation. The red square indicates the aggregate RF area for all neurons studied. In addition to the RFs, we show white circles to indicate the corresponding upper visual field locations where stimuli would appear on the second fixation; these were included for the 2AFC behavioral task, and presumably, adaptation occurred at these sites as well. B, left: a 2-dimensional (2-D) FFT (MATLAB fft2) of the entire background image (blue border). The red boxes show the aggregate RF area on the background image and its 2-D FFT. In both the overall image and the aggregate RF area, low spatial frequencies were dominant. C: radially averaged power spectra are shown for three 1° background-image RF areas used in the contrast sensitivity task (cyc/deg, cycles/degree). We examined the power spectra of all background-image RF areas and found them to be similarly dominated by lower spatial frequencies.

Article Snippet: Each curve was then fit with a logistic function using the Palamedes toolbox in MATLAB (Prins and Kingdom 2014).

Techniques: