Attention modulates the phase coherence between macaque visual areas V1 and V4

Abstract

Event Abstract Back to Event Attention modulates the phase coherence between macaque visual areas V1 and V4 Simon Neitzel1*, Sunita Mandon1 and Andreas K. Kreiter1 1 University of Bremen, Brain Research Institute, Departement of Theoretical Neurobiology, Germany In a complex visual scene, typically multiple objects are present in the large receptive fields (RFs) of neurons in higher visual areas. Selective processing of the behaviourally relevant object is therefore faced with the problem that often only a small part of the entire synaptic input carries the relevant signals. It is therefore very remarkable that neurons are able to respond to the attended object, as if no others would be present (Moran & Desimone, 1985; Science, 229, 782-784). We therefore hypothesize that attention enhances dynamically the effective connectivity of such a neuron with those afferents representing the attended object and diminishes effective connectivity with others carrying irrelevant signals. Recently it has been proposed that changes of neuronal synchronization in the gamma-frequency range (40-100 Hz) may serve this purpose (Kreiter, 2006; Neural Networks, 19, 1443-1444). To test this hypothesis, we recorded local field potentials (LFPs) with multiple intracortical electrodes from visual areas V1 and V4 of a macaque monkey performing an attentionally demanding shape-tracking task. Two objects going through a sequence of continuous deformations of their shape were presented extrafoveally and simultaneously (see also Taylor et al., 2005; Cerebral Cortex, 15, 1424-1437). Both objects had the size of a classical V1 RF and were placed close to each other to fit into one V4 RF. The monkey had to respond to the reoccurrence of the initial shape for the cued object. Because the shapes were continuously morphing, and shape perception depends critically on attention (Rock & Gutman, 1981; Journal of Experimental Psychology: Human Perception and Performance, 7, 275-285), the monkey had to attend the cued stream continuously in order to recognize the reappearance of the target shape. We used Morlet-wavelets to extract phase information from the recorded LFPs for estimating the phase coherence as a measure of synchronization between V1 and V4 recordings sites. We found that the two populations of V1 neurons driven by the attended and by the non-attended stimulus showed strongly different strength of synchronization with the V4 population getting synaptic input from both of them. If the recorded V1 population was representing the attended stimulus robust phase coherence was measured. If the same population was representing the non-attended stimulus the phase coherence was strongly diminished. The stronger coupling between neurons in area V4 and that part of their afferent neurons in V1 carrying the behaviourally relevant information supports the hypothesis that information flow in the visual system is modulated by attention-dependent changes of neuronal synchronization. Thus, differential synchronization may serve as a mechanism to switch between different patterns of effective connectivity within the network of anatomical connections and thereby to route signals and information according to the quickly varying demands of information processing. Acknowledgments:Supported by BMBF Bernstein Group Bremen, "Functional adaption of the visual system" Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Information processing in neurons and networks Citation: Neitzel S, Mandon S and Kreiter AK (2009). Attention modulates the phase coherence between macaque visual areas V1 and V4. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.061 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: 26 Aug 2009; Published Online: 26 Aug 2009. * Correspondence: Simon Neitzel, University of Bremen, Brain Research Institute, Departement of Theoretical Neurobiology, Bremen, Germany, neitzel@brain.uni-bremen.de 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 Simon Neitzel Sunita Mandon Andreas K Kreiter Google Simon Neitzel Sunita Mandon Andreas K Kreiter Google Scholar Simon Neitzel Sunita Mandon Andreas K Kreiter PubMed Simon Neitzel Sunita Mandon Andreas K Kreiter 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.