Trait-level somatic anxiety modulates functional magnetic resonance imaging (fMRI) neural synchrony to naturalistic stimuli

Klamer et al., 2024, published in Behavioral Neuroscience:
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Somatic anxiety refers to the tendency to perceive situations as threatening, resulting in heightened physiological arousal. Symptoms often include an increased awareness of heartbeat, difficulty breathing, and palpitations, reflecting autonomic arousal and heightened threat perception. Somatic anxiety is often associated with increased stimulus-driven attention; however, its impact on neural synchrony during complex audiovisual experiences, measured through intersubject correlations (ISC), is not well understood. This study uses fMRI data from the Naturalistic Neuroimaging Database to investigate how different levels of somatic anxiety influence neural synchrony during audiovisual stimuli, using ISC and intersubject representational similarity analyses. It was hypothesized that individuals with higher somatic anxiety would show increased ISC in regions associated with stimulus-driven attention, such as the superior parietal lobule, supplementary motor area, and precentral gyrus. Findings revealed that higher levels of somatic anxiety were associated with widespread heightened ISC, particularly in areas related to perceptual processing and stimulus-driven attention, while lower levels were linked to neural synchrony in regions associated with higher-level visual processing. These results highlight the importance of measuring and controlling for somatic anxiety in naturalistic fMRI studies, as it significantly influences synchronous brain activity during complex stimuli processing.

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