Changes of visual response properties in area MT due to eye movements

Abstract

Event Abstract Back to Event Changes of visual response properties in area MT due to eye movements Humans perform about three eye movements per second. Each of these eye movements changes the image on the retina, but despite this we perceive the visual world as perceptually stable. Researchers have shown that the visibility and perceived location of targets presented in the temporal vicinity of fast and slow eye movements are altered. Our goal is to understand the neural computations underlying these effects and thereby obtain a more general understanding of perceptual stability. We created a stimulus to map the receptive field (RF) properties of cells in the middle temporal area (MT) of the macaque. The animal observed randomly positioned, flickering bars and either kept its eyes stationary on a central fixation point or performed optokinetic nystagmus (OKN). The OKN was induced by a random dot pattern that moved to the left or to the right and filled the entire screen. In the analysis we corrected for eye position and used reverse correlation to determine RF kernels in retinal coordinates. First, we found that during the slow phase of OKN a significant subset of MT cells shifted their RFs in the direction of the eye movement. To gain a better understanding of the underlying circuitry we investigated whether this shift occurred for both putative interneurons and projection neurons. We calculated the width of the spike waveforms and found that cells with narrow spikes - likely to be interneurons - showed either small shifts or did not shift at all, while cells with broad spikes - probably projection neurons - showed strong shifts. Second, we found that the firing rates of the neurons were strongly modulated around the time of the fast phase of OKN. While some neurons firing rate was decreased, others was increased. We hypothesize that these changes may play a role in saccadic suppression. For many neurons these changes started at saccade onset or even slightly before, which rules out that the retinal signal change induced by the eye movement caused the rate changes. We could not find any consistent relationship between the changes in firing and the width of the spike waveform. This suggests that these firing rate changes may be independent of cell type. Our finding that putative interneurons have constant RFs provides new constraints for models of RF shifting. One possibility is that the shifts occur due to feedback from other areas, without the involvement of local interneuron circuitry in MT. The alternative that we are pursuing is that a reduction in the response of a subset of interneurons can lead to the unmasking of inputs to projection neurons and thereby shift their receptive fields. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). Changes of visual response properties in area MT due to eye movements. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.322 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Feb 2009; Published Online: 04 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.