Individual capacity differences predict working memory performance and prefrontal activity following dopamine receptor stimulation.
Level 2 - randomized trial
Individual randomized controlled pharmacological trial
PubMed 16180627 · doi:10.3758/cabn.5.2.212
What was done
Participants performed a verbal delayed-recognition task during functional magnetic resonance imaging (fMRI) following the administration of either the dopamine receptor agonist bromocriptine or a placebo. The study assessed the interaction between baseline working memory span, drug condition, task performance, and prefrontal cortex (PFC) activation during the probe period.
What was found
The abstract does not report numerical data, sample sizes, or test statistics. Directionally, bromocriptine produced the greatest behavioral improvement in subjects with lower baseline working memory spans. Under bromocriptine, PFC activity correlated positively with reaction time slope (a metric of retrieval efficiency), where slower individuals exhibited higher PFC activity and faster individuals showed lower activity. In the placebo condition, PFC activity and retrieval efficiency were uncorrelated.
Why it matters
The findings demonstrate that dopamine receptor stimulation modulates prefrontal cognitive efficiency depending on an individual's baseline working memory capacity, supporting baseline-dependent models of dopaminergic drug effects.
Limits
The abstract does not state the sample size, demographic characteristics, drug dosages, or exact statistical values and effect sizes. The results represent acute administration effects in a specific verbal working memory paradigm and may not extend to other cognitive domains or long-term dosing.
Cited by
- supports Working memory is primarily modulated by dopamine signaling.