Cancelled CNS Seminar
For the past thirty years, the central focus of attention research has been modulation of mean firing rate. Recently attention has also been found to reduce neuronal response variability (Mitchell, Sundberg & Reynolds, 2007; Mitchell, Sundberg & Reynolds, 2009; Cohen & Maunsell, 2009), and 80% of the benefit of attention is attributable to this newly discovered form of attentional modulation, with the remaining 20% attributable to changes in mean firing rate. Therefore, in order to understand the neural mechanisms of attention, one must understand (1) what gives rise to response variability and (2) how does attention reduce this variability. We have therefore developed a conductance-based model to account for both attention-dependent changes in mean firing rate and attention-dependent reductions of response variability. We have tested and found support for several surprising predictions of the model using extracellular recordings and optogenetic stimulation in the awake macaque.