J Physiol Boston Smyposia
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Physiol Volume 586, Number 18, 4377-4384, September 15, 2008 DOI: 10.1113/jphysiol.2008.156638
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
586/18/4377    most recent
jphysiol.2008.156638v1
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Google Scholar
Right arrow Articles by Demb, J. B.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Demb, J. B.
Related Collections
Right arrow Review articles
Right arrow Neuroscience

SYMPOSIUM REPORT

Functional circuitry of visual adaptation in the retina

 Jonathan B. Demb1

1 Department of Ophthalmology & Visual Sciences and Department of Molecular, Cellular & Developmental Biology, University of Michigan, 1000 Wall Street, Ann Arbor, MI 48105, USA

The visual system continually adjusts its sensitivity, or ‘adapts’, to the conditions of the immediate environment. Adaptation increases responses when input signals are weak, to improve the signal-to-noise ratio, and decreases responses when input signals are strong, to prevent response saturation. Retinal ganglion cells adapt primarily to two properties of light input: the mean intensity and the variance of intensity over time (contrast). This review focuses on cellular mechanisms for contrast adaptation in mammalian retina. High contrast over the ganglion cell's receptive field centre reduces the gain of spiking responses. The mechanism for gain control arises partly in presynaptic bipolar cell inputs and partly in the process of spike generation. Following strong contrast stimulation, ganglion cells exhibit a prolonged after-hyperpolarization, driven primarily by suppression of glutamate release from presynaptic bipolar cells. Ganglion cells also adapt to high contrast over their peripheral receptive field. Long-range adaptive signals are carried by amacrine cells that inhibit the ganglion cell directly, causing hyperpolarization, and inhibit presynaptic bipolar terminals, reducing gain of their synaptic output. Thus, contrast adaptation in ganglion cells involves multiple synaptic and intrinsic mechanisms for gain control and hyperpolarization. Several forms of adaptation in ganglion cells originate in presynaptic bipolar cells.

(Received 9 May 2008; accepted after revision 7 July 2008; first published online 10 July 2008)
Corresponding author J. Demb: Kellogg Eye Center, 1000 Wall Street, Ann Arbor, MI 48105, USA. Email: jdemb{at}umich.edu

This report was presented at The Journal of Physiology Symposium on Retinal ganglion cells in model organisms: development, function and disease, which took place in Fort Lauderdale, FL, USA, 26 April 2008. It was commissioned by the Editorial Board and reflects the views of the authors.




This article has been cited by other articles:


Home page
 J. Physiol.Home page
D. L. Beaudoin, M. B. Manookin, and J. B. Demb
Distinct expressions of contrast gain control in parallel synaptic pathways converging on a retinal ganglion cell
J. Physiol., November 15, 2008; 586(22): 5487 - 5502.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
Z. J. Zhou and M. A. McCall
Retinal ganglion cells in model organisms: development, function and disease
J. Physiol., September 15, 2008; 586(18): 4343 - 4345.
[Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 The Physiological Society.