The research, led by Giulia Mattavelli, Francesco Crottini, and Gerardo Salvato of the University of Pavia and Istituti Clinici Scientifici Maugeri, builds on a decade of intriguing but contested observations linking skin temperature to how we perceive our bodies. Earlier studies of the rubber hand illusion, in which synchronous stroking makes people adopt a fake hand as their own, reported cooling of the real limb, but later replications produced inconsistent results, likely because of differences in paradigms, measurement techniques, and how temperature changes were quantified. More robust effects emerged from the mirror box illusion, the paradigm used in the new study, in which participants tap the index fingers of both hands while viewing the reflection of their right hand in a mirror aligned with the body midline, leaving the left hand hidden from view. When the tapping is synchronous, many people come to feel that the reflected right hand is actually their concealed left hand, and their hands measurably cool.

Thirty-six healthy right-handed adults, aged 18 to 47, took part in the experiment. Each participant performed 100 tapping trials in a synchronous condition, where both index fingers moved toward and away from the mirrors simultaneously, and an asynchronous condition, where the fingers moved in opposite directions at the same tempo. Movement frequency and total movement count were matched, so only the visuomotor congruence differed between conditions. The setup created a deliberate conflict between what participants saw, a right hand reflected on the left side of space, and what they felt proprioceptively, a left hand hidden under a cloak. After each condition, participants rated how strongly the hand in the mirror felt like their left hand and verbally estimated the position of their hidden left index finger, while an infrared thermal camera captured the temperature of both hands before and after each block.

The illusion worked as expected. Synchronous stimulation produced significantly stronger agreement with the statement that the hand in the mirror felt like the participant’s left hand, with mean ownership ratings of 1.72 compared with minus 0.36 in the asynchronous condition. The perceived position of the hidden left index finger also drifted substantially toward the mirror after synchronous tapping, averaging nearly 47 millimeters of displacement versus about 11 millimeters after asynchronous tapping. Crucially, thermal imaging revealed a bilateral reduction in skin temperature following the synchronous condition, with an average decrease of 0.363 degrees Celsius compared with 0.155 degrees after asynchronous stimulation, a difference that was statistically significant for both hands. Within individual participants, larger temperature drops covaried with larger proprioceptive drift, directly tying the physiological change to the spatial recalibration of the body image.

The central novelty of the study lay in what happened in the brain during these manipulations. Using 64-channel EEG recordings and independent component analysis, the researchers identified a right-lateralized cluster of sources centered on premotor and supplementary motor areas and parietal cortex whose oscillatory activity differed between conditions in the theta to low-alpha range, roughly 4 to 9 hertz. Asynchronous tapping, which confronts the brain with a visuo-motor mismatch, produced stronger event-related desynchronization in this band around 300 milliseconds after movement onset, suggesting heightened engagement of sensorimotor circuits to process the sensory incongruence. Synchronous tapping, by contrast, was associated with greater inter-trial phase coherence around 400 milliseconds, indicating more consistent timing of neural responses when the multisensory signal was coherent and integrated.

When the researchers correlated the power in this 4-to-9-hertz band with the temperature changes measured by thermal imaging, a striking pattern emerged: within the same participant, increases in theta/low-alpha power during the illusion covaried with larger reductions in skin temperature, a significant repeated-measures correlation. Notably, the oscillatory power did not correlate with the subjective vividness of the illusion or with proprioceptive drift. This dissociation, the authors argue, fits the view that body ownership is not a single unified representation but an emergent construct supported by distributed neural systems that handle partially distinct aspects of bodily self-representation, with thermoregulatory signals coupled to the sensorimotor layer rather than to conscious ratings alone.

To probe whether these local oscillations were embedded in larger-scale communication, the team reconstructed activity at the cortical source level and computed functional connectivity using the debiased weighted phase lag index, a metric that quantifies phase synchronization while minimizing artifacts from volume conduction. Clustering the significant connections revealed six distinct connectivity patterns induced by the illusion. One of them, a distributed frontoparietal-insular network linking bilateral sensorimotor cortices, superior parietal regions, the right supramarginal gyrus, and the left anterior insula and operculum, was directly associated with temperature: stronger connectivity within this module in the theta/low-alpha band predicted greater subsequent drops in hand temperature. The insula’s involvement is particularly telling, since it is a well-established hub for thermosensory processing, receiving spinothalamic input about cutaneous temperature and integrating it with interoceptive and emotional states.

The network identified in healthy brains bears a remarkable resemblance to the circuitry disrupted in clinical conditions. In an earlier study by the same group, stroke patients with disturbed sensation of limb ownership showed reduced limb temperature alongside lesions involving the right insula and disconnection between bilateral parietal hubs, including the primary and secondary somatosensory cortices and the inferior parietal gyrus. Abnormal temperature patterns have also been documented in complex regional pain syndrome, body integrity dysphoria, and anorexia nervosa, all conditions in which bodily self-awareness is disturbed. The convergence between network-level dynamics in healthy participants and patterns of disconnection in patients suggests, the authors contend, that thermosensory signals constitute a fundamental component of the neural architecture supporting bodily self-awareness rather than an epiphenomenal consequence of ownership changes.

The findings also resonate with classic animal work. Lesion studies in non-human primates reported that damage to premotor and posterior parietal cortices produced persistent cooling of the contralateral limb even without direct autonomic injury, hinting that cortical regions classically associated with sensorimotor integration also help regulate peripheral vasomotor responses. The new human data extend this idea by showing that activity in frontoparietal regions covaries with temperature changes during an ownership manipulation in real time. From a predictive-processing perspective, ownership illusions may engage sensory reweighting in which visual information is prioritized over competing somatosensory signals, and thermosensory input, like touch, may be downweighted during multisensory conflict, with the present oscillatory and connectivity patterns providing complementary windows onto that process.

The study has limitations the authors acknowledge: the sample comprised only healthy young adults, EEG source localization cannot definitively pinpoint anatomical generators, temperature was sampled before and after each condition rather than continuously, and the correlational design precludes causal claims about whether thermosensory signals drive ownership updates. Even so, the practical implications are tantalizing. Warming a limb has been shown to strengthen body ownership in healthy people and to correlate with recovery of ownership disturbances in a patient with somatoparaphrenia, and thermal feedback is now being built into advanced prosthetic limbs that restore natural temperature sensation to amputees. Understanding the rhythmic dialogue between frontoparietal circuits, the insula, and the skin could therefore open new rehabilitation strategies for disorders of bodily self-awareness, from stroke to eating disorders, and may even guide the design of prostheses that feel genuinely like part of the body. For now, the message is vividly simple: the warmth of your hands and the feeling that they are yours are entangled in the same slow brainwaves.

Subject of Research: The neural oscillatory mechanisms by which thermosensory signals are integrated into body ownership

Article Title: Oscillatory dynamics within fronto-insular-parietal networks integrate thermosensory signals into body ownership

Article References: Mattavelli, G., Crottini, F., Gorrino, I., Arrigoni, E., Maiocchi, C., Pisoni, A., Bottini, G., & Salvato, G. (2026). Oscillatory dynamics within fronto-insular-parietal networks integrate thermosensory signals into body ownership. iScience, 29(10), Article 117679. https://doi.org/10.1016/j.isci.2026.117679

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117679

Keywords: body ownership, thermosensory signals, skin temperature, EEG, theta oscillations, mirror box illusion, insula, frontoparietal network, functional connectivity, bodily self-awareness, thermal imaging, neuroscience