Poster No:
940
Submission Type:
Late-Breaking Abstract Submission
Authors:
Anna Rieckmann1, Katharina Roscher1, Alireza Salami2
Institutions:
1University of the Bundeswehr Munich, Neubiberg, Bavaria, 2Umea University, Umea, Sweden
First Author:
Co-Author(s):
Introduction:
Age-related differences in prefrontal fMRI activation during cognitive control have been associated with both mechanisms that support maintained performance and maladaptive changes that contribute to cognitive decline.
Because the specificity of positron emission tomography (PET) imaging supplements patterns of whole-brain fMRI task activation with information about underlying molecular processes, combining fMRI and neurotransmitter PET in the same data collection is valuable for further interpretation of activation changes in aging. Age-related decreases in dopamine functions are a key target for understanding the mechanisms of neurocognitive aging.
Methods:
The current study included 172 participants aged 20 – 78 years (mean = 50, SD = 17.37) from the Swedish DyNAMiC cohort who performed a numerical working memory N-back task during fMRI scanning and a PET scan with the D1 receptor antagonist radioligand [11C]SCH23390. PET data were used to compute caudate D1 receptor densities and these values, along with chronological age, were entered into a Partial Least Square (PLS) analysis of the fMRI task data. PLS was used to identify data-driven patterns of fMRI activation across working memory load conditions, capturing associations with individual differences in age and caudate D1 receptor density without imposing a priori assumptions about load effects or directionality.
Results:
The analysis identified two different activation components: (1) 'Task-general' activations, observed in the striatum and frontal cortex, do not vary by working memory load (1–3-back) and co-occur with lower D1 density and older age; (2) 'Task-specific' activations within the frontoparietal control increase with working memory load and are associated with higher D1 density and younger age.
Conclusions:
Dopamine D1 receptor density and age exhibit distinct associations with task-general and task-specific fMRI activation patterns during working memory. A data-driven analysis revealed that higher activations outside a canonical task-specific network associated with older age are also linked to lower D1 receptor density. Given that lower dopamine receptor densities have been linked to aging, neurodegeneration and cognitive decline, increased activation outside a task-specific network may reflect maladaptive processes. Integrating fMRI and neurotransmitter PET enhances our understanding of brain function by linking the indirect fMRI signal to molecular correlates. This multimodal approach is particularly valuable in aging and disease, offering insights into potential pharmacological targets for restoring brain function in aging.
Learning and Memory:
Working Memory 2
Lifespan Development:
Aging 1
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI)
PET Modeling and Analysis
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Subcortical Structures
Keywords:
Aging
Cognition
FUNCTIONAL MRI
Positron Emission Tomography (PET)
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Task-activation
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Healthy subjects
Was this research conducted in the United States?
No
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
NOTE: Any animal studies without IACUC approval will be automatically rejected.
Not applicable
Please indicate which methods were used in your research:
PET
Functional MRI
For human MRI, what field strength scanner do you use?
3.0T
Which processing packages did you use for your study?
SPM
Provide references using APA citation style.
not applicable
No