Fig. 1 |. Different forms of attentional modulation on contrast response functions.

a, Contrast gain change: attention horizontally shifts the response function as if attention scales the input contrast. b, Response gain change: attention scales neural response by a multiplicative gain factor, modulating the asymptotic response of the neuron. The NMA²¹ predicts that attention exhibits different modulations depending on the relative size of the attention field and the stimulus. A large attention field size (relative to the stimulus size) leads to contrast gain changes (a) and a small attention field size leads to response gain changes (b).