NEURONAL MODELING. Single-trial spike trains in parietal cortex reveal discrete steps during decision-making

Science. 2015 Jul 10;349(6244):184-7. doi: 10.1126/science.aaa4056.

Abstract

Neurons in the macaque lateral intraparietal (LIP) area exhibit firing rates that appear to ramp upward or downward during decision-making. These ramps are commonly assumed to reflect the gradual accumulation of evidence toward a decision threshold. However, the ramping in trial-averaged responses could instead arise from instantaneous jumps at different times on different trials. We examined single-trial responses in LIP using statistical methods for fitting and comparing latent dynamical spike-train models. We compared models with latent spike rates governed by either continuous diffusion-to-bound dynamics or discrete "stepping" dynamics. Roughly three-quarters of the choice-selective neurons we recorded were better described by the stepping model. Moreover, the inferred steps carried more information about the animal's choice than spike counts.

Publication types

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

MeSH terms

  • Animals
  • Choice Behavior / physiology*
  • Decision Making / physiology*
  • Macaca
  • Male
  • Models, Neurological
  • Neurons / physiology
  • Parietal Lobe / physiology*