Middle temporal visual area microstimulation influences veridical judgments of motion direction

J Neurosci. 2002 Nov 1;22(21):9530-40. doi: 10.1523/JNEUROSCI.22-21-09530.2002.

Abstract

Microstimulation of direction columns in the middle temporal visual area (MT, or V5) provides a powerful tool for probing the relationship between cortical physiology and visual motion perception. In the current study we obtained "veridical" reports of perceived motion from rhesus monkeys by permitting a continuous range of possible responses that mapped isomorphically onto a continuous range of possible motion directions. In contrast to previous studies, therefore, the animals were freed from experimenter-imposed "categories" that typify forced choice tasks. We report three new findings: (1) MT neurons with widely disparate preferred directions can cooperate to shape direction estimates, inconsistent with a pure "winner-take-all" read-out algorithm and consistent with a distributed coding scheme like vector averaging, whereas neurons with nearly opposite preferred directions seem to compete in a manner consistent with the winner-take-all hypothesis, (2) microstimulation can influence direction estimates even when paired with the most powerful motion stimuli available, and (3) microstimulation effects can be elicited when a manual response (instead of our standard oculomotor response) is used to communicate the perceptual report.

Publication types

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

MeSH terms

  • Algorithms
  • Animals
  • Brain Mapping
  • Electric Stimulation / methods
  • Fixation, Ocular / physiology
  • Judgment / physiology*
  • Macaca mulatta
  • Microelectrodes
  • Models, Neurological
  • Motion Perception / physiology*
  • Neurons / physiology
  • Photic Stimulation / methods
  • Reproducibility of Results
  • Saccades / physiology
  • Temporal Lobe / physiology*
  • Visual Cortex / physiology*