Paper available: Retinal computation of motion direction

[Hiroyuki UCHIYAMA]

The following paper (pdf file) is now available from
   http://www.ics.kagoshima-u.ac.jp/~uchiyama/preprint.html

This is a preprint of an article that will appear in Visual Neurosciece.

----------------------------------------------------------

Computation of Motion Direction by Quail Retinal Ganglion Cells
That Have a Nonconcentric Receptive Field

Hiroyuki Uchiyama, Takahide Kanaya and Shoichi Sonohata

Abstract
       One type of retinal ganglion cells prefers object motion in a particu
lar direction.  Neuronal mechanisms for the computation of motion direction
are still unknown.  We quantitatively mapped excitatory and inhibitory regio
ns of receptive fields for directionally selective retinal ganglion cells in
the Japanese quail, and found that the inhibitory regions are displaced abou
t 1-3 deg. toward the side where the null sweep starts, relative to the exci
tatory regions.  Directional selectivity thus results from delayed transient
suppression exerted by the nonconcentrically-arranged inhibitory regions, an
d not by local directional inhibition as hypothesized by Barlow and Levick
(1965) .

-----------------------------------------------------------

----------------------------------------------
Hiroyuki Uchiyama, Ph.D.
Department of Information & Computer Science,
Faculty of Engineering, Kagoshima University
Korimoto 1-21-40, Kagoshima 890-0065, JAPAN
phone +81-99-285-8449
fax +81-99-285-8464
http://www.ics.kagoshima-u.ac.jp/~uchiyama