A new perceptual illusion reveals mechanisms of sensory decoding.

Full Abstract

Perceptual illusions are usually thought to arise from the way sensory signals are encoded by the brain, and indeed are often used to infer the mechanisms of sensory encoding. But perceptual illusions might also result from the way the brain decodes sensory information, reflecting the strategies that optimize performance in particular tasks. In a fine discrimination task, the most accurate information comes from neurons tuned away from the discrimination boundary, and observers seem to use signals from these 'displaced' neurons to optimize their performance. We wondered whether using signals from these neurons might also bias perception. In a fine direction discrimination task using moving random-dot stimuli, we found that observers' perception of the direction of motion is indeed biased away from the boundary. This misperception can be accurately described by a decoding model that preferentially weights signals from neurons whose responses best discriminate those directions. In a coarse discrimination task, to which a different decoding rule applies, the same stimulus is not misperceived, suggesting that the illusion is a direct consequence of the decoding strategy that observers use to make fine perceptual judgments. The subjective experience of motion is therefore not mediated directly by the responses of sensory neurons, but is only developed after the responses of these neurons are decoded.

Learn Faster Today Improve your study skills

Author information

Author/s: Jazayeri, Mehrdad (M); Movshon, J Anthony (JA);

Affiliation: Center for Neural Science, New York University, 4 Washington Place, New York, New York 10003, USA. mjaz(-atsign-)cns.nyu.edu

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: Nature (Nature), published in England. (Language: eng)

Reference: 2007-Apr; vol 446 (issue 7138) : pp 912-5

Dates: Created 2007/04/19; Completed 2007/05/10;

PMID: 17410125, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Humans
Illusions - physiology
Models, Neurological

Models, Neurological
Motion
Neurons - physiology
Visual Perception - physiology

These are the highest related articles currently in the database:

See 100+ related articles.