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Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task

The use of stimulants (methylphenidate and amphetamine) as cognitive enhancers by the general public is increasing and is controversial. It is still unclear how they work or why they improve performance in some individuals but impair it in others. To test the hypothesis that stimulants enhance signa...

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Autores principales: Volkow, Nora D., Fowler, Joanna S., Wang, Gene-Jack, Telang, Frank, Logan, Jean, Wong, Christopher, Ma, Jim, Pradhan, Kith, Benveniste, Helene, Swanson, James M.
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2291196/
https://www.ncbi.nlm.nih.gov/pubmed/18414677
http://dx.doi.org/10.1371/journal.pone.0002017
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author Volkow, Nora D.
Fowler, Joanna S.
Wang, Gene-Jack
Telang, Frank
Logan, Jean
Wong, Christopher
Ma, Jim
Pradhan, Kith
Benveniste, Helene
Swanson, James M.
author_facet Volkow, Nora D.
Fowler, Joanna S.
Wang, Gene-Jack
Telang, Frank
Logan, Jean
Wong, Christopher
Ma, Jim
Pradhan, Kith
Benveniste, Helene
Swanson, James M.
author_sort Volkow, Nora D.
collection PubMed
description The use of stimulants (methylphenidate and amphetamine) as cognitive enhancers by the general public is increasing and is controversial. It is still unclear how they work or why they improve performance in some individuals but impair it in others. To test the hypothesis that stimulants enhance signal to noise ratio of neuronal activity and thereby reduce cerebral activity by increasing efficiency, we measured the effects of methylphenidate on brain glucose utilization in healthy adults. We measured brain glucose metabolism (using Positron Emission Tomography and 2-deoxy-2[18F]fluoro-D-glucose) in 23 healthy adults who were tested at baseline and while performing an accuracy-controlled cognitive task (numerical calculations) given with and without methylphenidate (20 mg, oral). Sixteen subjects underwent a fourth scan with methylphenidate but without cognitive stimulation. Compared to placebo methylphenidate significantly reduced the amount of glucose utilized by the brain when performing the cognitive task but methylphenidate did not affect brain metabolism when given without cognitive stimulation. Whole brain metabolism when the cognitive task was given with placebo increased 21% whereas with methylphenidate it increased 11% (50% less). This reflected both a decrease in magnitude of activation and in the regions activated by the task. Methylphenidate's reduction of the metabolic increases in regions from the default network (implicated in mind-wandering) was associated with improvement in performance only in subjects who activated these regions when the cognitive task was given with placebo. These results corroborate prior findings that stimulant medications reduced the magnitude of regional activation to a task and in addition document a “focusing” of the activation. This effect may be beneficial when neuronal resources are diverted (i.e., mind-wandering) or impaired (i.e., attention deficit hyperactivity disorder), but it could be detrimental when brain activity is already optimally focused. This would explain why methylphenidate has beneficial effects in some individuals and contexts and detrimental effects in others.
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spelling pubmed-22911962008-04-16 Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task Volkow, Nora D. Fowler, Joanna S. Wang, Gene-Jack Telang, Frank Logan, Jean Wong, Christopher Ma, Jim Pradhan, Kith Benveniste, Helene Swanson, James M. PLoS One Research Article The use of stimulants (methylphenidate and amphetamine) as cognitive enhancers by the general public is increasing and is controversial. It is still unclear how they work or why they improve performance in some individuals but impair it in others. To test the hypothesis that stimulants enhance signal to noise ratio of neuronal activity and thereby reduce cerebral activity by increasing efficiency, we measured the effects of methylphenidate on brain glucose utilization in healthy adults. We measured brain glucose metabolism (using Positron Emission Tomography and 2-deoxy-2[18F]fluoro-D-glucose) in 23 healthy adults who were tested at baseline and while performing an accuracy-controlled cognitive task (numerical calculations) given with and without methylphenidate (20 mg, oral). Sixteen subjects underwent a fourth scan with methylphenidate but without cognitive stimulation. Compared to placebo methylphenidate significantly reduced the amount of glucose utilized by the brain when performing the cognitive task but methylphenidate did not affect brain metabolism when given without cognitive stimulation. Whole brain metabolism when the cognitive task was given with placebo increased 21% whereas with methylphenidate it increased 11% (50% less). This reflected both a decrease in magnitude of activation and in the regions activated by the task. Methylphenidate's reduction of the metabolic increases in regions from the default network (implicated in mind-wandering) was associated with improvement in performance only in subjects who activated these regions when the cognitive task was given with placebo. These results corroborate prior findings that stimulant medications reduced the magnitude of regional activation to a task and in addition document a “focusing” of the activation. This effect may be beneficial when neuronal resources are diverted (i.e., mind-wandering) or impaired (i.e., attention deficit hyperactivity disorder), but it could be detrimental when brain activity is already optimally focused. This would explain why methylphenidate has beneficial effects in some individuals and contexts and detrimental effects in others. Public Library of Science 2008-04-16 /pmc/articles/PMC2291196/ /pubmed/18414677 http://dx.doi.org/10.1371/journal.pone.0002017 Text en This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
spellingShingle Research Article
Volkow, Nora D.
Fowler, Joanna S.
Wang, Gene-Jack
Telang, Frank
Logan, Jean
Wong, Christopher
Ma, Jim
Pradhan, Kith
Benveniste, Helene
Swanson, James M.
Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title_full Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title_fullStr Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title_full_unstemmed Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title_short Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task
title_sort methylphenidate decreased the amount of glucose needed by the brain to perform a cognitive task
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2291196/
https://www.ncbi.nlm.nih.gov/pubmed/18414677
http://dx.doi.org/10.1371/journal.pone.0002017
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