Abstract 4372178: Neural Connectivity Underlying Somatic Awareness in Patients with Heart Failure

Background: Neural mechanisms underlying somatic awareness involve dynamic interactions between frontal executive regions and sensorimotor areas responsible for processing bodily signals. However, the relationship between somatic awareness and brain connectivity remains underexplored in patients with heart failure (HF). Objective: To examine the association between increased somatic awareness and brain connectivity in patients with HF. Methods: 19 adults with HF (aged 58±9 years, 11 male) were studied. Somatic awareness was measured by the Heart Failure Somatic Perception Scale, with higher scores indicating greater somatic awareness. Resting-state MRI assessed brain connectivity. Effective connectivity was calculated by fitting a linear multivariable autoregressive model (MVAR) to time series data, estimating directional influences between a region of interest (ROI) and other predefined ROIs based on an atlas template. After fitting the MVAR model, we obtained coefficients that describe how the past values of one region influence another. The sum of the estimated coefficients between the two regions was used as a measure of effective connectivity, which was correlated with the somatic awareness score using Pearson correlation. A one-tailed significance test was performed using the null distribution, and a significance level of corrected p < 0.001 was used for thresholding. BrainNetViewer was used to visualize the brain maps of significant connectivity. Results: Several connections from frontal regions (e.g., the middle frontal gyrus and anterior cingulate cortex) to sensory and somatomotor regions (e.g., the postcentral gyrus) were significantly correlated with somatic awareness. The frontal lobe exerts top-down control over sensory processing, meaning that attention, expectations, and goal-directed processes originating in frontal areas can modulate how bodily sensations are perceived and brought into conscious awareness. The increased effective connectivity from frontal to sensory regions associated with higher somatic awareness may reflect the interoceptive processing. Conclusion: Higher somatic awareness was linked to stronger connectivity between frontal regions and sensorimotor regions in patients with HF.