Navigation-associated medial parietal neurons in monkeys

doi:10.1073/pnas.0604277103

Navigation-associated medial parietal neurons in monkeys

*Division of Applied System Neuroscience, Advanced Medical Research Center, Nihon University Graduate School of Medical Science, Ohyaguchi-Kamicho 30-1, Itabashi, Tokyo 173-8610, Japan;
^†Japan Society for the Promotion of Science, Kojimachi 5-3-1, Chiyoda, Tokyo 102-8471, Japan;
^‡Laboratory for Anatomy and Physiology, Tokyo Seiei College, Nishi-Shinkoiwa 1-7-5, Katsushika, Tokyo 124-8530, Japan;
^§Department of Physiology and Biochemistry, Chiba University School of Nursing, Inohana 1-8-1, Chuo, Chiba 260-8672, Japan; and
^¶Advanced Research Institute for the Sciences and Humanities (ARISH), Nihon University, Kudan-Kita 4-2-1, Chiyoda, Tokyo 102-0073, Japan

Edited by Dale Purves, Duke University Medical Center, Durham, NC, and approved September 14, 2006 (received for review May 23, 2006)

Abstract

To examine the neural basis of route knowledge by which one can reach one's destination, we recorded the activity of 580 neurons in the monkey medial parietal region (MPR) while monkeys actively navigated through a virtual environment. One hundred eighty of these neurons (31%) showed significant responses to the monkeys' movements in the virtual environment. Of these responsive neurons, 77% (139/180) showed responses associated with a specific movement at a specific location (navigation neurons), 8% (14/180) showed responses associated with a specific movement (movement-selective neurons), and the remaining 27 neurons (15%) were nonselective. We found navigation neurons whose responses to the same movement at the same location were modulated depending on the route that the monkey was currently taking, that is, in a route-selective manner (32 of 59 tested neurons among 139 navigation neurons, route-selective navigation neurons). The reversible inactivation of MPR neurons by muscimol resulted in a monkey becoming lost during the navigation task trial. These results suggest that MPR plays a critical role in route-based navigation by integrating location information and self-movement information.

Footnotes

^‖To whom correspondence should be addressed. E-mail: masato{at}med.nihon-u.ac.jp
Author contributions: N.S. and H.S. designed research; N.S. and Y.T. performed research; N.S. and M.T. analyzed data; and N.S. and M.T. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS direct submission.
Abbreviations:

MPR,

medial parietal region;

SP,

starting point;

CP,

checkpoint.
Freely available online through the PNAS open access option.