Cargando…

Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task

The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal...

Descripción completa

Detalles Bibliográficos
Autores principales: Wardak, Claire, Ben Hamed, Suliann, Olivier, Etienne, Duhamel, Jean-René
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3386550/
https://www.ncbi.nlm.nih.gov/pubmed/22754512
http://dx.doi.org/10.3389/fnint.2012.00039
_version_ 1782236982708011008
author Wardak, Claire
Ben Hamed, Suliann
Olivier, Etienne
Duhamel, Jean-René
author_facet Wardak, Claire
Ben Hamed, Suliann
Olivier, Etienne
Duhamel, Jean-René
author_sort Wardak, Claire
collection PubMed
description The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal area (LIP) and of the frontal eye field (FEF) in the monkey which showed impairments in covert visual search performance, characterized mainly by an increase in the mean reaction time (RT) necessary to detect a contralesional target. Only subtle differences were observed between the inactivation effects in both areas. In particular, the magnitude of the deficit was dependant of search task difficulty for LIP, but not for FEF. In the present study, we re-examine these data in order to try to dissociate the specific involvement of these two regions, by considering the entire RT distribution instead of mean RT. We use the LATER model to help us interpret the effects of the inactivations with regard to information accumulation rate and decision processes. We show that: (1) different search strategies can be used by monkeys to perform visual search, either by processing the visual scene in parallel, or by combining parallel and serial processes; (2) LIP and FEF inactivations have very different effects on the RT distributions in the two monkeys. Although our results are not conclusive with regards to the exact functional mechanisms affected by the inactivations, the effects we observe on RT distributions could be accounted by an involvement of LIP in saliency representation or decision-making, and an involvement of FEF in attentional shifts and perception. Finally, we observe that the use of the LATER model is limited in the context of a visual search as it cannot fit all the behavioral strategies encountered. We propose that the diversity in search strategies observed in our monkeys also exists in individual human subjects and should be considered in future experiments.
format Online
Article
Text
id pubmed-3386550
institution National Center for Biotechnology Information
language English
publishDate 2012
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-33865502012-07-02 Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task Wardak, Claire Ben Hamed, Suliann Olivier, Etienne Duhamel, Jean-René Front Integr Neurosci Neuroscience The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal area (LIP) and of the frontal eye field (FEF) in the monkey which showed impairments in covert visual search performance, characterized mainly by an increase in the mean reaction time (RT) necessary to detect a contralesional target. Only subtle differences were observed between the inactivation effects in both areas. In particular, the magnitude of the deficit was dependant of search task difficulty for LIP, but not for FEF. In the present study, we re-examine these data in order to try to dissociate the specific involvement of these two regions, by considering the entire RT distribution instead of mean RT. We use the LATER model to help us interpret the effects of the inactivations with regard to information accumulation rate and decision processes. We show that: (1) different search strategies can be used by monkeys to perform visual search, either by processing the visual scene in parallel, or by combining parallel and serial processes; (2) LIP and FEF inactivations have very different effects on the RT distributions in the two monkeys. Although our results are not conclusive with regards to the exact functional mechanisms affected by the inactivations, the effects we observe on RT distributions could be accounted by an involvement of LIP in saliency representation or decision-making, and an involvement of FEF in attentional shifts and perception. Finally, we observe that the use of the LATER model is limited in the context of a visual search as it cannot fit all the behavioral strategies encountered. We propose that the diversity in search strategies observed in our monkeys also exists in individual human subjects and should be considered in future experiments. Frontiers Media S.A. 2012-06-29 /pmc/articles/PMC3386550/ /pubmed/22754512 http://dx.doi.org/10.3389/fnint.2012.00039 Text en Copyright © 2012 Wardak, Ben Hamed, Olivier and Duhamel. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
spellingShingle Neuroscience
Wardak, Claire
Ben Hamed, Suliann
Olivier, Etienne
Duhamel, Jean-René
Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title_full Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title_fullStr Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title_full_unstemmed Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title_short Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
title_sort differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3386550/
https://www.ncbi.nlm.nih.gov/pubmed/22754512
http://dx.doi.org/10.3389/fnint.2012.00039
work_keys_str_mv AT wardakclaire differentialeffectsofparietalandfrontalinactivationsonreactiontimesdistributionsinavisualsearchtask
AT benhamedsuliann differentialeffectsofparietalandfrontalinactivationsonreactiontimesdistributionsinavisualsearchtask
AT olivieretienne differentialeffectsofparietalandfrontalinactivationsonreactiontimesdistributionsinavisualsearchtask
AT duhameljeanrene differentialeffectsofparietalandfrontalinactivationsonreactiontimesdistributionsinavisualsearchtask