Abstract
Interoceptive accuracy refers to the ability to consciously perceive the physical condition of the inner body, including one’s heartbeat. In younger adults, interoceptive accuracy is correlated with insular and orbitofrontal cortical connectivity within the salience network (SN). As interoceptive accuracy and insular cortex volume are known to decrease with aging, we aimed to evaluate the correlation between SN connectivity and interoceptive accuracy in older adults. 27 older adults (mean age, 77.29 years, SD = 6.24; 19 female) underwent resting-state functional magnetic resonance imaging, followed by a heartbeat counting task and neuropsychological test. We evaluated the correlation between interoceptive accuracy and SN connectivity with age, sex, cognitive function, and total gray matter volume as covariates. Region of interest-to-region of interest analyses showed that interoceptive accuracy was positively correlated with the functional connectivity (FC) of the left rostral prefrontal cortex with the right insular, right orbitofrontal, and anterior cingulate cortices [F(6,16) = 4.52, false discovery rate (FDR)-corrected p < 0.05]. Moreover, interoceptive accuracy was negatively correlated to the FC of the left anterior insular cortex with right intra-calcarine and visual medial cortices (F(6,16) = 2.04, FDR-corrected p < 0.10). These findings suggest that coordination between systems, with a positive correlation between left rostral prefrontal cortex and the SN and a negative correlation between left insular cortex and vision-related exteroceptive brain regions, is important for maintaining interoceptive accuracy in older adults.
Highlights
Interoception collectively refers to afferent sensory information arising from the sensation, perception, and awareness of afferent feedback from the viscera, which maintains homeostatic function (Craig, 2002)
Higher heartbeat counting accuracy was associated with increased functional connectivity (FC) of the left rostral prefrontal cortical seed with the right insular cortex (t(21) = 4.86, false discovery rate (FDR)-corrected p < 0.05; Figure 2A), right orbitofrontal cortex (t(21) = 4.44, FDR-corrected p < 0.05; Figure 2B), and anterior cingulate cortex (ACC) (t(21) = 3.89, FDR-corrected p < 0.05; Figure 2C), even when controlling the effects of age, sex, Mini-Mental State Examination (MMSE) score, and gray matter (GM) volume
Higher heartbeat counting accuracy was associated with decreased FC of the left anterior insular cortical seed with right intra-calcarine cortices (t(21) = −4.20, FDR-corrected p < 0.05; Figure 2D), and visual medial cortex (t(21) = −4.04, FDR-corrected p < 0.05; Figure 2E), even after controlling the effects of age, sex, MMSE score, and total GM volume
Summary
Interoception collectively refers to afferent sensory information arising from the sensation, perception, and awareness of afferent feedback from the viscera, which maintains homeostatic function (Craig, 2002). Resting state fMRI studies, which use the temporal correlation between fluctuations in different areas as a measure of intrinsic functional connectivity (FC), have identified the salience network (SN), involving the bilateral anterior insular cortices and dorsal ACC, as well as the anterior prefrontal cortex (aPFC), supramarginal gyrus (SMG), striatum/basal ganglion, thalamus, and cerebellum, as important for integrating highly processed sensory data with visceral, autonomic, and hedonic markers, to guide the appropriate behavior (Seeley et al, 2007; Guo et al, 2012). Chong et al (2017) examined the relationship between SN connectivity and interoceptive accuracy in 26 healthy young adults and found a positive correlation between heartbeat counting accuracy and salience network functional connectivity (SN FC) of the right and left posterior insular cortices, but no correlation was found for the FC of the ACC Resting state fMRI studies, which use the temporal correlation between fluctuations in different areas as a measure of intrinsic functional connectivity (FC), have identified the salience network (SN), involving the bilateral anterior insular cortices and dorsal ACC, as well as the anterior prefrontal cortex (aPFC), supramarginal gyrus (SMG), striatum/basal ganglion, thalamus, and cerebellum, as important for integrating highly processed sensory data with visceral, autonomic, and hedonic markers, to guide the appropriate behavior (Seeley et al, 2007; Guo et al, 2012). Chong et al (2017) examined the relationship between SN connectivity and interoceptive accuracy in 26 healthy young adults and found a positive correlation between heartbeat counting accuracy and salience network functional connectivity (SN FC) of the right and left posterior insular cortices, but no correlation was found for the FC of the ACC
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