Localizing the origin of executive control over distributed processing to prefrontal cortex

Abstract

Event Abstract Back to Event Localizing the origin of executive control over distributed processing to prefrontal cortex Human cognition and behavior are characterized by flexibility. A fixed pattern of sensory input can evoke innumerable actions, depending on which goals or strategies the brain has engaged. The consensus is that prefrontal cortex is essential to this computational flexibility, but the neural mechanisms responsible are not fully understood. To address this question, we trained a monkey to flexibly assign visual stimuli to different spatial categories according to a variable grouping criterion that altered how categories were defined across trials. We then used dual, depth adjustable 16 microelectrode arrays to simultaneously record neural activity in parietal (309 neurons) and prefrontal (427 neurons) cortex during task performance. In this task, we presented a line that divided the display area into two regions. Each region comprised a spatial category containing a set of positions having the same spatial relationship to the category boundary. For example, when the category boundary was vertical, it divided the display area into the categories 'left' and 'right'. When the boundary was horizontal, it re-parsed the same set of spatial positions into the spatial categories 'above' and 'below'. By changing the orientation of the category boundary we required the brain to remap one set of spatial positions to alternative spatial categories according to a variable rule, placing spatial cognition under executive control. This enabled us to isolate neural signals coding spatial position and spatial category, as well as examine how these signals were modulated as a function of the rule mapping positions to categories. The first question we wished to answer was whether some neurons coded spatial category independently of spatial position. We found that the activity of significantly more neurons in prefrontal cortex (27% of task-related neurons) than parietal cortex (11% of task-related neurons) coded the spatial category of the stimulus independently of its spatial position. This suggested that the neural representation of category was more fully abstracted from stimulus feature information in prefrontal than in parietal cortex. The second question we wished to answer was where neural activity coding category was first or most strongly modulated by the rule in effect, in order to localize the origin of executive control in the network. For that purpose we applied linear discriminant analysis to decode spatial position, spatial rule, and spatial category (defined by the interaction between rule and position) from successive 50 ms bins of neural population activity in prefrontal and parietal cortex. We found that both parietal and prefrontal neurons sustained representations of category that exhibited rule-dependence (and therefore reflected executive control), but that signals coding category in prefrontal cortex were more powerfully modulated by the rule at earlier times in the trial. This is consistent with prefrontal cortex being the origin of executive control over distributed spatial cognitive processing mediated by the parietal-prefrontal network. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster and Short Oral Presentation Topic: Poster and Short Oral Presentations Citation: (2009). Localizing the origin of executive control over distributed processing to prefrontal cortex. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.226 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: 03 Feb 2009; Published Online: 03 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.