Trial reportCNS drugs2013
Effect of tolcapone on brain activity during a variable attentional control task: a double-blind, placebo-controlled, counter-balanced trial in healthy volunteers.
Trial report in CNS drugs, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT00044083 (Randomized, Double-Blinded, Placebo Controlled Study of the Effects of Tolcapone and Entacapone on Cognitive Function in Patients With Schizophrenia and Normal Controls Based on COMT Genotype), which is not on this map. Cited by 8 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Randomized, Double-Blinded, Placebo Controlled Study of the Effects of Tolcapone and Entacapone on Cognitive Function in Patients With Schizophrenia and Normal Controls Based on COMT Genotype
Who cites it
8 citing papers in PubMed, 1 synthesis or guideline pooled it, 16 citations in OpenAlex.
- Pooled it
- Effects of COMT Suppression in a Randomized Trial on the Neural Correlates of Inhibitory Processing Among People With Alcohol Use Disorder.Biological psychiatry. Cognitive neuroscience and neuroimaging · 2025Trial
- Cortical dopamine reduces the impact of motivational biases governing automated behaviour.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2022Trial
- Tolcapone-Enhanced Neurocognition in Healthy Adults: Neural Basis and Predictors.The international journal of neuropsychopharmacology · 2017Trial
- The therapeutic potential of COMT inhibition: cognition and beyond.Molecular psychiatry · 2026Review
- Opicapone Improves Global Non-Motor Symptoms Burden in Parkinson's Disease: An Open-Label Prospective Study.Brain sciences · 2022Article
- Systems pharmacogenomics - gene, disease, drug and placebo interactions: a case study in COMT.Pharmacogenomics · 2019Article
- Effect of Pharmacological Interventions on the Fronto-Cingulo-Parietal Cognitive Control Network in Psychiatric Disorders: A Transdiagnostic Systematic Review of fMRI Studies.Frontiers in psychiatry · 2016Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
11 authors at 4 institutions in 1 country.
Funding
Abstract
backgroundAttention is the capacity to flexibly orient behaviors and thoughts towards a goal by selecting and integrating relevant contextual information. The dorsal cingulate (dCC) and prefrontal (PFC) cortices play critical roles in attention. Evidence indicates that catechol-O-methyltransferase (COMT) modulates dopaminergic tone in the PFC and dCC.
objectiveIn this study, we explored the effect of tolcapone, a CNS penetrant COMT inhibitor that increases cortical dopamine levels, on brain activity during a Variable Attentional Control (VAC) task. STUDY
designWe performed a double-blinded, placebo-controlled, counter-balanced trial with tolcapone (Tasmar, tablets, 100 mg three times a day for 1 day and then 200 mg three times a day for 6 days; ClinicalTrials.gov identifier: NCT00044083).
settingThe study was conducted in the Clinical Center of the National Institute of Mental Health from 2005 to 2009. PATIENTS: Twenty healthy volunteers (11 males; mean age = 32.7 years) with good imaging and performance data on both arms of the study were investigated.
interventionParticipants underwent 3T blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) while performing the event-related VAC task, which varies attention over three levels of load: LOW, INT (intermediate), and HIGH.
main outcome measureChanges in behavioral data and individual contrast images were analyzed using ANOVA with drug and task load as co-factors.
resultsThere was a significant main effect of increasing task load, with resulting decreased accuracy and increased reaction time. While there was no significant effect of tolcapone on these behavioral measures, the neuroimaging data showed a significant effect on load-related changes in dCC, with significantly lower dCC activation on tolcapone compared with placebo. Further, neural activity in dCC correlated positively with COMT enzyme activity (i.e., lower COMT activity and presumably more dopamine was associated with lower activation in dCC, i.e., more efficient information processing).
conclusionOur results show that pharmacological reduction of COMT activity modulates the engagement of attentional mechanisms, selectively enhancing the efficiency of dCC processing in healthy volunteers, reflected as decreased activity for the same level of performance.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.