Abstract
Agents must balance speed of responding and accuracy of choosing to suit current goals and environmental demands. This speed-accuracy tradeoff is a fundamental phenomenon in behavioral science, and is pervasive across multiple task domains and species. Though it is exceptionally well characterized behaviorally and computationally, the underlying neural mechanisms have been elusive. To address this, I designed a nonhuman primate model of speed-accuracy tradeoff: Monkeys were trained to respond at 3 levels of speed or accuracy emphasis during a saccade visual search task. Emphasis conditions were cued by the color of a fixation point. Meanwhile, I recorded single-unit responses in frontal eye field, supplementary eye field, and superior colliculus. Here, I will demonstrate that the speed-accuracy tradeoff entails both local and global adjustments of neural activity across the brain. Briefly, the effect of speed/accuracy emphasis on perceptual processing appears global. Visually-responsive neurons in prefrontal cortex, medial frontal cortex, and tectum maintain an elevated background firing rate and become more responsive to identical perceptual input when under speed stress than accuracy stress. The form and magnitude of these adjustments are equivalent across brain sites. In contrast, the effect of speed/accuracy emphasis on movement-related responses is more complex, and differs markedly (but consistently) between brain regions. These data make clear that the speed-accuracy tradeoff is a multifaceted phenomenon involving several distinct adjustments in multiple brain areas.
Meeting abstract presented at VSS 2014