Fig. 1: Target size affects the relationship between the variance and mean of pursuit initiation.
From: Neural structure of a sensory decoder for motor control
a Properties of pursuit stimuli. Top: Arrows indicate target speeds. Dot patches moved at a speed selected from a discrete uniform distribution with 5 values evenly spaced between 4 to 20 deg/s (colors). Bottom: Example dot patches corresponding to targets of three different sizes: 2 deg, 6 deg, and 20 deg. b Mean pursuit initiation behavior for monkey X, sorted by target speed (colors; see arrows in panel a) and patch size indicated at the top of each graph. Each trace shows trial-averaged eye speed as a function of time, starting at the time of target motion onset. Vertical dashed lines indicate the window of time averaging used for subsequent analyses. c Variance of eye speed of monkey X plotted against the mean eye speed for rightward pursuit. Symbols plot the behavior for different target speeds and sizes. Curves indicate the fit of a signal-dependent noise model where the Weber fraction is allowed to change with target size. d As in panel c, but for rightward pursuit in monkey R. e As in panel c, but for leftward pursuit in monkey X. f As in panel c, but for leftward pursuit in monkey R. c–f, Green, red, and black symbols and curves show results for target sizes of 2, 6, and 20 deg, respectively. Source data are provided as a Source Data file.
