Key result
Heartbeat counting and discrimination correlate with distinct frontal and insular gray matter volumes.
Why the study?
The processes and neural substrates underlying individual differences in cardiac interoception assessed by heartbeat counting and discrimination tasks remain unknown.
Cross-Sectional (n=138)
Different cardiac interoception tasks (heartbeat counting vs. discrimination) are associated with distinct neuroanatomical substrates in fronto-insular brain regions.
Task-specific interoception associates with distinct fronto-insular volumes; hypothesis-generating and leaves open clinical relevance.
Individual differences in interoception have drawn attention because of their relevance to emotion-processing abilities and mental health. To assess individual differences, researchers have employed methods using cardioception, including the heartbeat counting task (HCT), where participants count their heartbeat for a certain duration, and the heartbeat discrimination task (HDT), where they judge whether presented tones with various delays to the R-peak are synchronized with their heartbeats. However, the processes and neural substrates underlying individual differences in cardiac interoception remain unknown. Based on our hypothesis that these tasks recruit fronto-insular brain regions, we investigated the neuroanatomical substrates underlying individual differences in HCT and HDT indices by conducting voxel-based morphometry analyses using brain structural images of 138 participants who underwent both tasks. HCT-derived interoceptive accuracy (IAcc) was positively associated with gray matter volume (GMV) in the left frontal pole, whereas an HDT index, reflecting response consistency across different delay conditions, was positively associated with the GMV of the left orbitofrontal cortex and right posterior insula. Conversely, the correlation between accuracy and confidence in the HCT, defined as interoceptive awareness, was associated with GMV, including the left posterior insula. These variations in the brain regions may reflect differences in the demands of the HCT and HDT.
No takes yet. Share an insight, caveat, or question.
Sasaoka et al. (2026) conducted a cross-sectional in Interoception (n=138). Heartbeat counting task (HCT) and heartbeat discrimination task (HDT) was evaluated on Association between HCT/HDT indices and gray matter volume (GMV). Heartbeat counting accuracy correlated with left frontal pole gray matter volume, while heartbeat discrimination consistency correlated with left orbitofrontal cortex and right posterior insula.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: