Object familiarity modulates effective connectivity during haptic shape perception.

Abstract

Event Abstract Back to Event Object familiarity modulates effective connectivity during haptic shape perception. Simon Lacey1, Gopikrishna Deshpande2, Randall Stilla1, Xiaoping Hu2 and K. Sathian1, 3, 4, 5* 1 Emory University, Department of Neurology, United States 2 Emory University Georgia Institute of Technology, Coulter Department of Biomedical Engineering, United States 3 Atlanta VAMC, United States 4 Emory University, Department of Rehabilitation Medicine, United States 5 Emory University, Department of Psychology, United States Visual cortical areas are routinely active in normally sighted individuals during haptic shape perception but there is debate about whether this is due to visual imagery, mediated by top-down pathways from prefrontal areas, or engagement of multisensory representations via bottom-up pathways from somatosensory areas. In two functional magnetic resonance imaging experiments, participants haptically discriminated the shape of unfamiliar (Experiment 1) or familiar (Experiment 2) objects (HS task). In separate sessions, the same participants in each experiment made shape judgments on visual images of objects represented by words they heard (VI task). Regardless of familiarity, VI- and HS-related activations overlapped in the lateral occipital complex (LOC) bilaterally, left ventral premotor cortex, left ventral intraparietal sulcus, and left pulvinar. For familiar objects, there were additional overlap zones in left prefrontal and posterior parietal cortex. We then performed multivariate Granger causality analyses of effective connectivity on task-specific time series data from these experiments, using a novel method that eliminates zero-lag correlations (correlation-purged Granger causality) thus yielding purer estimates of effective connectivity. These analyses showed that the VI and familiar HS tasks activated similar networks involving top-down paths into the LOC, consistent with the use of visual imagery during haptic perception of the shape of familiar objects. However, the unfamiliar HS task activated a different network characterized by bottom-up, somatosensory cortical inputs into the LOC. We conclude that LOC activation during haptic shape perception reflects visual imagery, but that this is mediated by object familiarity. Thus, shape representations in the LOC are flexibly accessible, either top-down or bottom-up, according to task demands. Conference: 2010 South East Nerve Net (SENN) and Georgia/South Carolina Neuroscience Consortium (GASCNC) conferences, Atlanta , United States, 5 Mar - 7 Mar, 2010. Presentation Type: Poster Presentation Topic: Posters Citation: Lacey S, Deshpande G, Stilla R, Hu X and Sathian K (2010). Object familiarity modulates effective connectivity during haptic shape perception.. Front. Neurosci. Conference Abstract: 2010 South East Nerve Net (SENN) and Georgia/South Carolina Neuroscience Consortium (GASCNC) conferences. doi: 10.3389/conf.fnins.2010.04.00055 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: 17 Mar 2010; Published Online: 17 Mar 2010. * Correspondence: K. Sathian, Emory University, Department of Neurology, Atlanta, United States, ksathia@emory.edu 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 Lacey Gopikrishna Deshpande Randall Stilla Xiaoping Hu K. Sathian Google Simon Lacey Gopikrishna Deshpande Randall Stilla Xiaoping Hu K. Sathian Google Scholar Simon Lacey Gopikrishna Deshpande Randall Stilla Xiaoping Hu K. Sathian PubMed Simon Lacey Gopikrishna Deshpande Randall Stilla Xiaoping Hu K. Sathian 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.