Modelling Cortical Representations

Abstract

Event Abstract Back to Event Modelling Cortical Representations Klaus Obermayer1* 1 Technische Universitaet, Bernstein Center for Computational Neuroscience, Germany In my talk I will first present results from a map model of primary visual cortex, where we analysed how much evidence recent single unit recordings from cat area 17 provide for a particular cortical "operating point". Using a Bayesian analysis we find, that the experimental data most strongly support a regime where the local cortical network provides dominant excitatory and inhibitory recurrent inputs (compared to the feedforward drive). Most interestingly, the data supports an operating regime which is close to the border to instability, where cortical responses are sensitive to small changes in neuronal properties. Secondly, I will show results of a study where we investigated visual attention in humans in a probabilistic reward-based visual discrimination task. We find that behavioural performance is not optimal but consistent with a heuristic based on a moving average estimate of stimulus predictability and reward. We also found that the amplitudes of early visual, attention-related EEG signals quantitatively reflect these estimates. Thus, information about stimulus statistics and reward are already integrated by low-level attentional mechanisms. Finally, I will discuss results of developmental perturbations imposed on the visual system through retinal lesions in adolescent cats. Using a computational model of visual cortical responses, I will show that the lesion induced changes of neuronal response properties are consistent with spike timing-dependent plasticity (STDP) learning rules. STDP causes visual cortical receptive fields to converge by creating a competition between neurons for the control of spike timing within the network. The spatial scale of this competition appears to depend on the balance of excitation and inhibition and and can in principle be controlled by synaptic scaling type mechanisms. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Oral Presentation Topic: Sensory processing Citation: Obermayer K (2009). Modelling Cortical Representations. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.129 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: 27 Aug 2009; Published Online: 27 Aug 2009. * Correspondence: Klaus Obermayer, Technische Universitaet, Bernstein Center for Computational Neuroscience, 82152 Planegg-Martinsried, Germany, oby@cs.tu-berlin.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 Klaus Obermayer Google Klaus Obermayer Google Scholar Klaus Obermayer PubMed Klaus Obermayer 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.