Featured Paper of the Month – November 2026
Published in Communications Biology by Justine Hill and Amy Janes, et al. of the NIDA IRP Translation & Clinical Neuroimaging Section.
Summary
Researchers examined whether differences in physiological arousal—how activated the body’s arousal systems are—help explain why functional brain networks look different across people on functional magnetic resonance imaging (fMRI). They analyzed resting-state scans from 462 healthy young adults and used a slow, body-wide fluctuation in blood oxygenation measured by fMRI as an indicator of arousal.
Arousal was strongly linked to both communication between major brain networks and the amount of time the brain spent in different network states. Higher arousal was associated with greater separation between the default mode network, which supports internally focused thought, and networks involved in attention and detecting important information. These relationships were similar across scan sessions, were reproduced in an independent sample, and were also seen with measures such as breathing and heart-rate variability. Overall, arousal accounted for roughly 30% to 50% of the variation in some brain network measures.
In a separate study of 59 healthy adults, changes in arousal after methylphenidate or haloperidol were accompanied by corresponding changes in brain network organization. The findings suggest that physiological state is an important source of variation in fMRI measures that are often interpreted mainly as differences in brain function. Accounting for arousal may therefore improve the interpretation of brain-network studies, including research on psychiatric disorders and medication effects, although the clinical significance remains to be established.
Publication Information
Physiological arousal as a predominant source of individual differences in functional brain networks Journal Article
In: Commun Biol, 2026, ISSN: 2399-3642.
