Abstract
Attention allows us to focus sensory processing on behaviorally relevant aspects of the visual world. Directing attention has been associated with a number of changes in sensory representation including multiplicative gain as well as shifts in the size and location of neuron receptive fields in early visual cortex. But, which, if any, of these physiological effects can account for the behavioral benefits of attention? Here we use a large scale computational model of primate visual cortex to perform a set of experiments in which we decouple changes in spatial tuning from changes in gain. We show that increased gain at cued locations in a neural network observer model mimics the improvement of human subjects on an attentional task with a spatial cue. Increasing gain resulted in changes in receptive field size and location similar to physiological effects, yet when we forced the model to use only these spatial tuning changes the model failed to produce any behavioral benefit. Instead, we found that gain alone was both necessary and sufficient to explain behavioral improvement during attention. Our results suggest that receptive field shifts are a result of the signal gain that boosts behavioral performance rather than the core mechanism of spatial attention.
Competing Interest Statement
The authors have declared no competing interest.