Neuron Article Neural Mechanisms of Speed-Accuracy Tradeoff

Intelligent agents balance speed of responding with accuracy of deciding. Stochastic accumulator models commonly explain this speed-accuracy tradeoff by strategic adjustment of response threshold. Several laboratories identify specific neurons in prefrontal and parietal cortex with this accumulation process, yet no neurophysiological correlates of speed-accuracy tradeoff have been described. We trained macaque monkeys to trade speed for accuracy on cue during visual search and recorded the activity of neurons in the frontal eye field. Unpredicted by any model, we discovered that speed-accuracy tradeoff is accomplished through several distinct adjustments. Visually re-sponsive neurons modulated baseline firing rate, sensory gain, and the duration of perceptual pro-cessing. Movement neurons triggered responses with activity modulated in a direction opposite of model predictions. Thus, current stochastic accumu-lator models provide an incomplete description of the neural processes accomplishing speed-accu-racy tradeoffs. The diversity of neural mechanisms was reconciled with the accumulator framework through an integrated accumulator model con-strained by requirements of the motor system