Visual Neuroscience

Table of Contents - 2006 - Volume 23, Issue 3-4  


PHYSIOLOGY/ANATOMY

Do magnocellular and parvocellular ganglion cells avoid short-wavelength cone input?

HAO  SUN  a1 c1 , HANNAH E.  SMITHSON  a2 , QASIM  ZAIDI  a1 and BARRY B.  LEE  a1 a3
a1 State University of New York, State College of Optometry, New York, New York
a2 Department of Psychology, Durham University, Durham, United Kingdom
a3 Max Planck Institute for Biophysical Chemistry, Göttingen, Germany

Article author query
sun h   [Google Scholar] 
smithson he   [Google Scholar] 
zaidi q   [Google Scholar] 
lee bb   [Google Scholar] 
 

Abstract

We recently developed a new technique to measure cone inputs to visual neurons and used this technique to seek short-wavelength-sensitive (S) cone inputs to parasol, magnocellular (MC) and midget, parvocellular (PC) ganglion cells. Here, we compare our physiological measurements of S-cone weights to those predicted by a random wiring model that assumes cells' receptive fields receive input from mixed cone types. The random wiring model predicts the average weights of S-cone input to be similar to the total percentage of S-cones but with considerable scatter, and the S-cone input polarity to be consistent with that of PC cells' surround and of MC cells' center. This is not consistent with our physiological measurements. We suggest that the ganglion cells' receptive fields may have a mechanism to avoid S-cone inputs, as is the case in the H1 horizontal cells. Previous reports of S-cone inputs, in particular substantial input to MC cells, are likely to reflect variation in prereceptoral filtering and/or the failure to correct for variation in macular pigment.

(Received December 2 2005)
(Accepted December 5 2005)


Key Words: Random wiring; S-cone weight; S-cone polarity; Receptive field.

Correspondence:
c1 Address correspondence and reprint requests to: Hao Sun, State University of New York, State College of Optometry, 33 West 42nd Street, New York, New York, 10036, USA. E-mail: hsun@sunyopt.edu