Parietal activity and the perceived direction of ambiguous apparent motion

Ziv M. Williams, John C. Elfar, Emad N. Eskandar, Louis J. Toth, John A. Assad

Research output: Contribution to journalArticlepeer-review

130 Scopus citations


We recorded from parietal neurons in monkeys (Macacca mulatta) trained to report the direction of an apparent motion stimulus consisting of regularly spaced columns of dots surrounded by an aperture. Displacing the dots by half their inter-column spacing produced vivid apparent motion that could be perceived in either the preferred or anti-preferred direction for each neuron. Many neurons in the lateral intraparietal area (LIP) responded more strongly on trials in which the animals reported perceiving the neurons' preferred direction, independent of the hand movement used to report their percept. This selectivity was less common in the medial superior temporal area (MST) and virtually absent in the middle temporal area (MT). Variations in activity of LIP and MST neurons just before motion onset were also predictive of the animals' subsequent perceived direction. These data suggest a hierarchy of representation in parietal cortex, whereby neuronal responses become more aligned with subjective perception in higher parietal areas.

Original languageEnglish (US)
Pages (from-to)616-623
Number of pages8
JournalNature Neuroscience
Issue number6
StatePublished - Jun 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • General Neuroscience


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