State-dependent associations between striatal dopamine transporter availability and large-scale functional networks in bipolar disorder: An exploratory multimodal imaging study.

Huang MH, Zhu JD, Tu PC, Chan YE, Mao WC, Su TP.

Journal ArticleAbstract only — full text under license

AI summary — for doctors, generated from the abstract only

In bipolar disorder, dorsal striatal dopamine transporter availability was lower during depression than euthymia and showed mood-state-dependent links to cortico-striatal connectivity.

What was studied

An exploratory longitudinal within-subject study of 33 outpatients with BD imaged during euthymic and depressive states using 99mTc-TRODAT-1 SPECT and resting-state fMRI.

Key findings

Lower bilateral dorsal striatal DAT availability during depression than euthymia
DAT related to stronger dorsal striatum-cingulate connectivity in euthymia but negatively to precuneus connectivity in depression
Mood-dependent DAT associations with precuneus, insula, and supramarginal connectivity
Reduced dorsal striatum-ACC and supramarginal connectivity in depression associated with greater depressive severity

Clinical relevance

These are early mechanistic findings on dopamine in bipolar depression and have no immediate clinical application, though they may inform future biomarker or treatment-target research.

Who should care

Psychiatry

Limitations

Small exploratory sample (N=33); multiple imaging comparisons; medication effects not described in the abstract.

Dopamine signaling and brain network connectivity shift with mood state in bipolar disorder, an early clue for future research.

This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.

Abstract

Background

Dopaminergic dysregulation has been implicated in the pathophysiology of bipolar disorder (BD), yet how state-dependent alterations in presynaptic dopaminergic markers relate to large-scale brain networks remains unclear. We aimed to examine longitudinal, within-subject associations between striatal dopamine transporter (DAT) availability and functional connectivity (FC) across mood states in BD.

Methods

Outpatients with BD underwent repeated neuroimaging during euthymic and depressive states. Striatal DAT availability was measured using ^99mTc-TRODAT-1 single-photon emission computed tomography, and resting-state functional magnetic resonance imaging was used to assess striatal seed-based FC. Paired t tests compared DAT availability across mood states. General linear and linear mixed models examined DAT-FC associations and DAT-mood interactions, adjusting for age and sex.

Results

Thirty-three patients were enrolled. Within-individual analyses showed lower bilateral dorsal-striatal DAT availability during depression than euthymia. During euthymia, DAT availability was associated with stronger dorsal striatum connectivity with the dorsal and middle cingulate regions, whereas during depression it was negatively associated with connectivity to the precuneus. Linear mixed models showed mood-dependent associations of dorsal-striatal DAT availability with connectivity involving the precuneus, insula, and supramarginal gyrus. Reduced dorsal striatum-ACC and supramarginal connectivity during depression was associated with greater depressive symptom severity.

Conclusion

Striatal DAT availability and cortico-striatal functional connectivity showed coordinated, state-dependent changes in BD. These findings provide evidence for state-dependent associations between presynaptic dopaminergic markers and large-scale functional networks in BD.

DOI

10.1016/j.ajp.2026.105137

PMID

42659872

Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.

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