Baseline-dependent effect of dopamine's precursor L-tyrosine on working memory gating but not updating

source extracted confidence: high 2026-04-09
#adult #dopamine #double-blind-method #female #goals

Baseline-dependent effect of dopamine's precursor L-tyrosine on working memory gating but not updating

Jongkees et al., 2020 | Cogn Affect Behav Neurosci | Rct

Citation

Jongkees Bryant J. Baseline-dependent effect of dopamine's precursor L-tyrosine on working memory gating but not updating. Cogn Affect Behav Neurosci. 2020-Jun;20(3):521-535. doi:10.3758/s13415-020-00783-8

Abstract

Adaptive goal-directed behavior requires a dynamic balance between maintenance and updating within working memory (WM). This balance is controlled by an input-gating mechanism implemented by dopamine in the basal ganglia. Given that dopaminergic manipulations can modulate performance on WM-related tasks, it is important to gain mechanistic insight into whether such manipulations differentially affect updating (i.e., encoding and removal) and the closely-related gate opening/closing processes that respectively enable/prevent updating. To clarify this issue, 2.0 g of dopamine's precursor L-tyrosine was administered to healthy young adults (N = 45) in a double-blind, placebo-controlled, within-subjects study. WM processes were empirically distinguished using the reference-back paradigm, which isolates performance related to updating, gate opening, and gate closing. L-tyrosine had a selective, baseline-dependent effect only on gate opening, which was evidenced by markedly reduced variance across subjects in gate opening performance in the L-tyrosine compared with the placebo condition, whereas the whole-sample average performance did not differ between conditions. This indicates a pattern of results whereby low-performing subjects improved, whereas high-performing subjects were impaired on L-tyrosine. Importantly, this inverted U-shaped pattern was not explained by regression to the mean. These results are consistent with an inverted-U relationship between dopamine and WM, and they indicate that updating and gating are differentially affected by a dopaminergic manipulation. This highlights the importance of distinguishing these processes when studying WM, for example, in the context of WM deficits in disorders with a dopaminergic pathophysiology.

Key Findings

This highlights the importance of distinguishing these processes when studying WM, for example, in the context of WM deficits in disorders with a dopaminergic pathophysiology.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 45
Age Range See abstract
Condition See abstract

MeSH Terms

  • Adult
  • Dopamine
  • Double-Blind Method
  • Female
  • Goals
  • Humans
  • Male
  • Memory, Short-Term
  • Neuropsychological Tests
  • Psychomotor Performance
  • Stroop Test
  • Tyrosine
  • Young Adult

Evidence Classification

  • Level: Rct
  • Publication Types: Journal Article, Randomized Controlled Trial
  • Vertical: tyrosine

Provenance

Source extracted via PubMed E-utilities API on 2026-04-10