Effect of the number of response alternatives on brain activity in response selection.

Full Abstract

It is well-known in motor control literature that a response time (RT) increases as a logarithmic function of the number of response alternatives (NA) (Hick's law). In this study, we identified neural correlates for this relationship using event-related functional MRI and a choice finger-movement task. Behaviorally, average RTs of all subjects increased as a logarithmic function of the NA in accordance with the law. From a voxel-wise search for brain areas where the activity was correlated with NA and thence the RT, a positive correlation was found at the posterior cingulate and left superior frontal gyri, whereas a negative correlation was observed at areas in bilateral inferior parietal lobules. This differential modulation by the task context, namely, the NA available for a choice response with identical stimulus and response, indicates that these regions are involved in various aspects of response selection, intentional retrieval of motor program, or spatial expectancy. Wiley-Liss, Inc.

Author information

Author/s: Woo, Sung-Ho (SH); Lee, Kyoung-Min (KM);

Affiliation: Interdisciplinary program of Cognitive Sciences, College of Medicine, Seoul National University, Chongno-Gu, Seoul, Korea.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Human brain mapping (Hum Brain Mapp), published in United States. (Language: eng)

Reference: 2007-Oct; vol 28 (issue 10) : pp 950-8

Dates: Created 2007/09/20; Completed 2007/12/14;

PMID: 17094117, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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.