Thermosensory cues influence bodily awareness

Comment on: Salvato, G. Jenkinson, P.M. Sellitto, M. et al. The contribution of cutaneous thermal signals to bodily self-awareness. Nature Communications 16, 569 (2025). https://doi.org/10.1038/s41467–025-55,829-7.

The skin continuously relays thermosensory signals, which are crucial in maintaining homeostasis and ensuring survival [1]. This information, indeed, provides cues about the temperature of the body-insulated superficial layer and offers feedback to the central thermoregulatory system [2]. Interestingly, cutaneous thermosensory information may also contribute to higher-level cognitive constructs, such as bodily self-awareness. Bodily self-awareness refers to the conscious feeling that sensory and motor experiences are intrinsically linked to the self, contributing to a coherent and unified identity. Such a multifaceted concept encompasses the feeling of one’s own body as belonging to oneself and the feeling that a given body part belongs to one’s body (i.e. the sense of ownership). Traditionally, the sense of ownership has been ascribed to the integration of multiple sensory inputs from internal and external sources, such as touch, vision, proprioception, and motor signals. Emerging evidence also highlights the role of skin temperature and thermoception in this process.

Our new study [3] investigated the role of thermosensory signals in bodily self-awareness in a clinical population presenting with Disturbed Sensation of Ownership (DSO) affecting the left plegic limb following a right-hemisphere stroke. Patients with DSO may not recognize their paralyzed hand as part of their body, often denying ownership and attributing it to someone else, such as a familiar person or medical staff. We examined 45 patients with right-hemisphere brain damage, categorized into three groups: those with both hemiplegia and DSO for the left hand, those with hemiplegia but no DSO, and those without hemiplegia or DSO. We assessed baseline hands and feet skin temperature and hand thermoception for warm and cold stimuli, revealing that patients with DSO for their left hand, compared to the other two groups, exhibited lower hairy skin temperatures of both left and right hands. Interestingly, feet skin temperature was equal between the groups. Additionally, we demonstrated impaired thermoception (involving both warm and cold thermal stimuli) on their affected (left) hand. To further explore the neural basis of these findings, we applied advanced neuroimaging techniques, including voxel-based lesion-symptom mapping (VLSM) and connectome-based lesion-symptom mapping (CLSM). These techniques provide a powerful tool to examine how specific brain lesions or disruptions in structural connectivity between brain regions relate to behavioral impairments. By mapping damaged or disconnected brain regions to observed deficits, critical areas involved in specific functions can be identified (i.e. lower skin temperature and thermoception deficits). The VLSM analyses identified the right Rolandic Operculum and Insula as key regions associated with reduced hands temperature and impaired thermoception. A decrease in hairy skin temperature of both hands – characterizing patients with DSO – was linked to lesions in the right posterior insula, while deficits in thermoception of the left hand – found in patients with DSO- were associated with lesions in more anterior regions of the right insula. CLSM analyses further revealed that disruptions in bilateral parietal connections were linked to reduced hands temperature, while impairments in a right-lateralized thalamus-parietal network correlated with thermoception deficits of the left hand (see Figure 1).

Figure 1.

The figure depicts the main findings from the study by Salvato and colleagues [3]. The hand skin temperature and hand perception of warm and cold help us feel that this body part belongs to our body; that is, the sense of ownership (“My hand!”). In the brain, the link between these thermosensory signals and the sense of ownership is primarily subserved by a region called insula, particularly in the right cerebral hemisphere (highlighted in red and blue in the figure on the left). The right posterior insula (shown in blue) subserves processes related to hand skin temperature. In contrast, more anterior parts of the right insula (shown in red) play a crucial role in our conscious perception of temperature changes detected by the hand. Besides the insula, two major brain pathways are also involved in these processes. One connects the thalamus and parietal regions (illustrated in the upper right part of the figure), helping us detect shifts in temperature. The other links both sides of the parietal lobe (depicted in the lower right part of the figure), integrating skin temperature into our overall sense of body ownership. This figure has been created in BioRender.

This study represents a significant advancement in understanding the role of thermosensory signals in shaping bodily self-awareness. Over the past two decades, research explored this relationship in healthy individuals, primarily through lab-based paradigms that transiently alter the sense of ownership for a limb. However, these studies yielded correlational and sometimes contradictory findings, highlighting the complexity of this phenomenon. The investigation of patients with brain lesions provided crucial causal evidence, offering a unique opportunity to dissect the neurophysiological mechanisms underlying bodily self-awareness. Right-brain lesions can induce disorders of bodily self-awareness (e.g., DSO), profoundly altering an individual’s perception of their own body. By studying such cases, we gain insight into how thermosensory signals contribute to constructing and maintaining a coherent sense of ownership. Notably, prior to this work, no neuroimaging studies had systematically examined the neural correlates of this contribution. Our lesion-symptom mapping approach has now shed light, for the first time, on the specific brain structures and their functional connections that underpin the integration of thermosensory signals into a coherent sense of the self.

These findings carry significant implications from both theoretical and applied perspectives. The lesional correlates identified through VLSM analyses of skin temperature and thermoception alterations supported the Bud Craig’s hypothesis of a posterior-to-anterior functional gradient within the insular cortex subserving human awareness [4,5]. Specifically, the posterior insula would primarily support the implicit processing of bodily signals, while more conscious representations would emerge as these signals are progressively integrated along the anterior regions of the insular cortex, ultimately contributing to subjective awareness [6]. Our findings reinforce this hypothesis by providing evidence that posterior insular regions are associated with implicit bodily-related processes, such as basal hairy skin temperature regulation, whereas more anterior insular regions support the conscious perception of temperature changes. This complex processing of bodily (thermosensory) signals plays a crucial role in shaping human bodily awareness.

Furthermore, by elucidating the neural mechanisms that link thermosensory processing to bodily awareness, our new study provides a foundation for innovative therapeutic interventions. One promising avenue is the targeted modulation of thermosensory signals as a potential strategy to mitigate disturbances in bodily self-awareness observed in neurological conditions. Notably, a previous study by our group demonstrated that the transient remission of disorders of hand ownership in a right brain-damaged patient was accompanied by increased hands temperature [7]. This suggests that thermosensory signals are not merely passive sensory inputs but actively contribute to the dynamic regulation of the representation of the body in the brain. Beyond clinical implications, our findings may also support technological advancements in prosthetic design. Recent innovations enabled prosthetic devices to convey thermoception to amputees, allowing them to perceive temperature changes through their artificial limbs [8]. In light of our results, such thermosensory feedback could play a pivotal role in enhancing prosthesis embodiment, improving the sense of ownership, and facilitating more natural functional integration into daily life. Future developments in neuroprosthetics might incorporate personalized temperature modulation to optimize user experience, improving motor control and reducing phantom limb discomfort.

Several fundamental questions remain unanswered. Future research should explore the role of the central thermoregulatory system in sh aping bodily self-awareness, the peripheral physiological mechanisms driving these effects, and the broader significance of thermosensory contributions to bodily self-awareness. Additionally, studying how internal and external inputs interact in bodily self-awareness may show how temperature signals combine with other senses to create a stable sense of self. Addressing these gaps will be crucial for refining our theoretical understanding of bodily self-awareness and unlocking new translational applications in medicine, neurorehabilitation, and assistive technologies.