A neural mechanism of speed-accuracy tradeoff in macaque area LIP

Elife. 2014 May 27;3:e02260. doi: 10.7554/eLife.02260.

Abstract

Decision making often involves a tradeoff between speed and accuracy. Previous studies indicate that neural activity in the lateral intraparietal area (LIP) represents the gradual accumulation of evidence toward a threshold level, or evidence bound, which terminates the decision process. The level of this bound is hypothesized to mediate the speed-accuracy tradeoff. To test this, we recorded from LIP while monkeys performed a motion discrimination task in two speed-accuracy regimes. Surprisingly, the terminating threshold levels of neural activity were similar in both regimes. However, neurons recorded in the faster regime exhibited stronger evidence-independent activation from the beginning of decision formation, effectively reducing the evidence-dependent neural modulation needed for choice commitment. Our results suggest that control of speed vs accuracy may be exerted through changes in decision-related neural activity itself rather than through changes in the threshold applied to such neural activity to terminate a decision.

Keywords: decision making; neuroscience; parietal cortex; rhesus macaque monkey; speed-accuracy tradeoff.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bayes Theorem
  • Behavior, Animal
  • Choice Behavior
  • Decision Making*
  • Macaca
  • Models, Neurological*
  • Motion Perception
  • Neurons / physiology*
  • Neurophysiology
  • Photic Stimulation
  • Reaction Time
  • Reproducibility of Results
  • Time Factors