Trial reportPsychopharmacology2005
The effects of acute tyrosine and phenylalanine depletion on spatial working memory and planning in healthy volunteers are predicted by changes in striatal dopamine levels.
Trial report in Psychopharmacology, 2005. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 26 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
26 citing papers in PubMed, 1 synthesis or guideline pooled it, 63 citations in OpenAlex.
- Differential Associations of Dopamine and Serotonin With Reward and Punishment Processes in Humans: A Systematic Review and Meta-Analysis.JAMA psychiatry · 2025Pooled it
- Dopamine and Temporal Discounting: Revisiting Pharmacology and Individual Differences.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2025Trial
- Trial
- Differential, but not opponent, effects of L -DOPA and citalopram on action learning with reward and punishment.Psychopharmacology · 2014Trial
- Effects of acute dopamine precusor depletion on immediate reward selection bias and working memory depend on catechol-O-methyltransferase genotype.Journal of cognitive neuroscience · 2013Trial
- Trial
- Reliance on habits at the expense of goal-directed control following dopamine precursor depletion.Psychopharmacology · 2012Trial
- Acute dopamine and/or serotonin depletion does not modulate mismatch negativity (MMN) in healthy human participants.Psychopharmacology · 2010Trial
- Acute dopamine depletion with branched chain amino acids decreases auditory top-down event-related potentials in healthy subjects.Schizophrenia research · 2009Trial
- Dopamine depletion impairs frontostriatal functional connectivity during a set-shifting task.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2008Trial
- Dopamine D2 receptor occupancy levels of acute sulpiride challenges that produce working memory and learning impairments in healthy volunteers.Psychopharmacology · 2008Trial
- Mood-elevating effects of d-amphetamine and incentive salience: the effect of acute dopamine precursor depletion.Journal of psychiatry & neuroscience : JPN · 2007Trial
- Striatal dopamine release during performance of executive functions: A [(11)C] raclopride PET study.NeuroImage · 2006Trial
- Combined D1/D2 receptor stimulation under conditions of dopamine depletion impairs spatial working memory performance in humans.Psychopharmacology · 2005Trial
- Dopamine precursor depletion affects performance and confidence judgements when events are timed from an explicit, but not an implicit onset.Scientific reports · 2023Article
- The metabolic changes in the hippocampus of an atherosclerotic rat model and the regulation of aerobic training.Metabolic brain disease · 2020Article
- Effects of dietary tryptophan and phenylalanine-tyrosine depletion on phasic alertness in healthy adults - A pilot study.Food & nutrition research · 2015Article
- A study on the mechanism by which MDMA protects against dopaminergic dysfunction after minimal traumatic brain injury (mTBI) in mice.Journal of molecular neuroscience : MN · 2014Article
- Gastrodin ameliorates memory deficits in 3,3'-iminodipropionitrile-induced rats: possible involvement of dopaminergic system.Neurochemical research · 2014Article
- Presynaptic regulation of extracellular dopamine levels in the medial prefrontal cortex and striatum during tyrosine depletion.Psychopharmacology · 2013Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 3 institutions in 2 countries.
Funding
Abstract
rationaleDopamine (DA) is considered important in the modulation of tasks of spatial working memory. However, the findings from studies in humans to date are mixed. While this may be due to the characteristics of the tasks used, it is also possible that these findings are explained by variable central effects of the manipulations used.
objectiveTo test the effects of acute tyrosine and phenylalanine depletion (TPD, which reduces synthesis and release of brain DA) on cognitive function and relate changes in performance accuracy to the central effects of TPD measured with [11C]raclopride positron emission tomography (PET).
methodsFourteen participants were given tests of spatial working memory, planning, verbal memory span and trial-and-error learning after acute TPD, seven of whom also received PET scans to measure changes in striatal DA levels.
resultsAlthough TPD produced a clear reduction in tyrosine and phenylalanine availability to the brain, no impairments on any of the cognitive tests were observed. However, changes in spatial working memory and planning accuracy after TPD showed a highly significant relationship with the changes in striatal DA levels.
conclusionsOur findings suggest that the effects of TPD on spatial working memory and planning may be unreliable due to the variability of the changes in brain DA levels achieved with this manipulation.
Indexed as
Identifiers
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.