HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 94/1/136    most recent 00980.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Ibbotson, M. R. Search for Related Content PubMed PubMed Citation Articles by Ibbotson, M. R.

Contrast and Temporal Frequency-Related Adaptation in the Pretectal Nucleus of the Optic Tract

Visual Sciences, Research School of Biological Sciences, Australian National University, Canberra, Australia

Submitted 20 September 2004; accepted in final form 12 February 2005

In mammals, many cells in the retino-geniculate-cortical pathway adapt during stimulation with high contrast gratings. In the visual cortex, adaptation to high contrast images reduces sensitivity at low contrasts while only moderately affecting sensitivity at high contrasts, thus generating rightward shifts in the contrast response functions (contrast gain control). Similarly, motion adaptation at particular temporal frequencies (TFs) alters the temporal tuning properties of cortical cells. For the first time in any species, this paper investigates the influence of motion adaptation on both the contrast and TF responses of neurons in the retino-pretectal pathway by recording from direction-selective neurons in the nucleus of the optic tract (NOT) of the marsupial wallaby, Macropus eugenii. This species is of interest because its NOT receives almost all input directly from the retina, with virtually none from the visual cortex (unlike cats and primates). All NOT cells show changes in their contrast response functions after adaptation, many revealing contrast gain control. Contrast adaptation is direction-dependent, preferred directions producing the largest changes. The lack of cortical input suggests that contrast adaptation is generated independently from the cortex in the NOT or retina. Motion adaptation also produces direction-selective effects on the TF tuning of NOT neurons by shifting the location of the optimum TF. Cells that show strong adaptation to contrast also tend to show large changes in TF tuning, suggesting similar intracellular mechanisms. The data are discussed in terms of the generality of contrast adaptation across mammalian species and across unconnected brain regions within the same species.

This article has been cited by other articles:

				A. Kohn Visual Adaptation: Physiology, Mechanisms, and Functional Benefits J Neurophysiol, May 1, 2007; 97(5): 3155 - 3164. [Abstract] [Full Text] [PDF]

				M. A. Hietanen, N. A. Crowder, and M. R. Ibbotson Contrast Gain Control Is Drift-Rate Dependent: An Informational Analysis J Neurophysiol, February 1, 2007; 97(2): 1078 - 1087. [Abstract] [Full Text] [PDF]

				N.S.C. Price, N. A. Crowder, M. A. Hietanen, and M. R. Ibbotson Neurons in V1, V2, and PMLS of Cat Cortex Are Speed Tuned But Not Acceleration Tuned: The Influence of Motion Adaptation J Neurophysiol, February 1, 2006; 95(2): 660 - 673. [Abstract] [Full Text] [PDF]