This multimodal MRI study compared striatal subregional gray matter volume, resting-state functional connectivity (RSFC), and neurotransmitter spatial correlations among 36 bvFTD patients, 21 late-life schizophrenia patients, and 56 healthy controls, alongside neurocognitive and behavioral assessments.
bvFTD showed the greatest striatal gray matter loss, followed by late-life schizophrenia. Both groups shared aberrant RSFC in the right nucleus accumbens and bilateral dorsolateral putamen, but bvFTD had unique intra-striatal dysconnectivity (left nucleus accumbens ↔ right putamen; left dorsal caudate ↔ left ventral caudate). bvFTD also showed lower RSFC spatial correlations with 5-HT₆, α4β2, M1, mGluR5, and D₂ receptor density maps versus schizophrenia, and Hamilton Depression scores negatively correlated with bilateral dorsal caudate volume only in the schizophrenia group.
Small sample sizes (especially late-life schizophrenia, n=21) limit statistical power and generalizability. Cross-sectional design prevents causal inference. Neurotransmitter spatial correlations rely on atlas-derived density maps rather than direct in vivo receptor imaging.
When differentiating bvFTD from late-life schizophrenia, striatal structural and functional MRI patterns—particularly unique intra-striatal connectivity disruptions and receptor-system divergence—may help distinguish the two conditions despite overlapping clinical presentations. Clinicians should consider these neurobiological differences when interpreting neuropsychiatric symptoms, especially depression, in late-life schizophrenia patients with caudate atrophy.
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