Early definitions of interoception described it as sensing internal bodily states and distinguished it from exteroception. Contemporary views have broadened interoception to include not only visceral receptors but also their emotional and cognitive consequences. Interoceptive stimuli include mechanical, chemical, osmotic, glucose, and hormonal signals sensed by specialised receptors-mechanoreceptors, thermoreceptors, chemoreceptors, osmoreceptors, glucoreceptors, humoral receptors, and free nerve endings. Gut to brain communication involves extrinsic afferent neurons as well as immune mediators, gut hormones, metabolic factors, and microbial metabolites; these signals evoke sensations like hunger, satiety, nausea, and visceral pain. Endocrine messengers such as leptin, ghrelin, and cholecystokinin regulate hunger and satiety via hypothalamic receptors. Conversely, brain outputs modulate gut motility, secretion, blood flow, and digestion. Understanding these bidirectional pathways is essential for linking external stimuli to internal homeostatic signals and for clarifying why sensory disorders often co occur.

This Research Topic seeks to unify investigations into how the nervous system processes external sensory stimuli—such as pain, temperature, touch, and itch—and internal sensory signals, including hunger, satiety, digestion, and hormonal release. The aim is to map circuits that link peripheral mechanotransduction channels and receptors to vagal and spinal afferents carrying gut‑derived information, and to central structures such as the spinal dorsal horn, brainstem nuclei, hypothalamus, and insula. By highlighting cross‑talk between exteroceptive and interoceptive pathways, the Topic will explore how these signals jointly influence behaviour, emotion, and homeostasis, and encourage translational dialogue aimed at new strategies for chronic pain, itch, irritable bowel syndrome, and metabolic disorders.

We are particularly interested (but not limited to) to following themes:

1. Peripheral transduction mechanisms for pain, thermosensation, mechanical and chemical itch, and interoceptive signals such as hunger, satiety, digestion, and hormonal release.

2. Neural circuits integrating exteroceptive and interoceptive inputs, including spinal dorsal horn networks, vagal and spinal afferent pathways, brainstem nuclei, hypothalamus, insula, anterior cingulate cortex, and other higher order regions.

3. Interactions between neural, endocrine, and immune signals in shaping sensory perception and maintaining homeostasis.

4. Cross modal mechanisms and shared pathways in chronic pain, chronic itch, irritable bowel syndrome, metabolic syndrome, and related conditions where external and internal sensory systems intersect.

5. Innovative therapeutic approaches targeting the integration of external and internal sensory signals to improve sensory and metabolic health.

Are you interested in contributing a manuscript to this Research Topic?

Neurobiology of external and internal sensory integration: From pain and temperature to hormonal and digestive signals