Which internal bodily signals reach conscious awareness, and what neural and physiological conditions gate access to consciousness?

Which internal signals can become conscious?

The body constantly generates signals from the heart, gut, skin, and other organs. Some of these—like a pounding heartbeat or a full stomach—can rise to conscious awareness, especially with practice or attention [4]. Skin temperature is another example: patients who had strokes in the right hemisphere and lost the sense that their paralyzed arm belonged to them also showed lower hand temperatures and impaired ability to perceive cold and warm stimuli, suggesting that thermosensory signals contribute to bodily self-awareness [2].

However, not all internal signals are consciously perceived all the time. Many remain subconscious unless they become relevant or intense enough. The process by which these signals enter awareness is not passive; it involves active neural computations and can be disrupted by factors such as brain lesions or competing external stimuli [1][3].

The insula as a gatekeeper for internal sensations

A central brain region for conscious access to internal signals is the insular cortex. In mice, researchers used optogenetics to activate specific vagal sensory neurons that carry information from the gut, and found that the insular cortex is generally required for the animals to report detecting these internal signals [4]. Moreover, when the task was made more difficult and uncertain, the insula played an additional role in supporting perception, suggesting it helps gate access to awareness under conditions of uncertainty [4].

In humans, stroke patients with disturbed body ownership had lesions or disconnections in the right Rolandic operculum and insula, regions linked to both skin temperature regulation and thermoception [2]. This aligns with the idea that the insula and connected networks are critical for integrating internal signals into a coherent sense of bodily self-awareness [1].

Attention and competing signals shape what we feel

Even when internal signals are strong, they must compete with external stimuli for access to awareness. In a heartbeat-counting task, healthy volunteers were less accurate and less confident about their heartbeats when an irrelevant sound was played, and they also rated their heartbeat as less intense [3]. This suggests that interoceptive awareness depends on attention and the relative precision of internal versus external signals—a predictive processing framework where the brain weighs the reliability of different sensory inputs [3].

Individuals with higher heart rate variability and a greater tendency to worry about bodily states experienced a stronger distracting effect, indicating that physiological and psychological traits can modulate how easily internal signals reach consciousness [3].

How internal signals build the sense of owning a body

Conscious awareness of internal signals is closely tied to the broader experience of bodily self-awareness—the feeling that your body is yours and distinct from the external world. This sense involves integrating signals from vision, touch, and proprioception, but internal signals like temperature and heartbeat also contribute [1][2]. For example, the strong conscious access to body ownership appears specific to the bodily self, not just general multisensory integration, and it remains consistent across different levels of sensory evidence [5].

Disruptions in interoceptive pathways can therefore disturb bodily self-awareness, as seen in stroke patients with abnormal body ownership [1][2]. These findings suggest that the brain's ability to gate internal signals into consciousness is fundamental to maintaining a coherent sense of self.

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