Suppression and facilitation of motion perception in humans

In a study that investigated the putative neuronal origin of suppression and facilitation in human motion perception Schallmo et al. (2018) used various techniques to investigate how motion perception is shaped by excitatory and inhibitory interactions within hMT+ or earlier areas. They further proposed that neuronal normalization is a sufficient account of the behavioural results, discounting accepted and precise neuronal mechanisms of excitation or inhibition. In this Research Advance, it is shown (1) that once the full computational model that predicts the psychophysical results is defined, it is not "divisive normalization" but actually excitatory and inhibitory processes that are the neuronal mechanisms shaping facilitation and suppression in the behavioural domain, then (2) that the experimental design they used allows a quantitative comparison and usage of such "contrast-size tuning" data.