Behavioural, psychophysiological and neuroimaging investigations on the role of temperature perception in body ownership

Project Information

Homeothermic Self

Grant agreement ID: 891175

DOI

10.3030/891175

Project closed

EC signature date 22 April 2020

Start date 1 June 2020

End date 31 May 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 191 852,16

EU contribution

€ 191 852,16

Coordinated by

KAROLINSKA INSTITUTET
Sweden

Periodic Reporting for period 1 - Homeothermic Self (Behavioural, psychophysiological and neuroimaging investigations on the role of temperature perception in body ownership)

Reporting period: 2020-06-01 to 2022-05-31

Summary of the context and overall objectives of the project

We usually take the ability to identify our body as our own for granted, but empirical research in the past few decades has shown that the sense of body ownership relies on our cognitive ability to combine information about the body originating from different sensory modalities. Recent studies have also suggested that homeostatically relevant somatosensory information might receive stronger weights in the process of multisensory integration than homeostatically less relevant information. That is, body representations are possibly coupled to fundamental homeostatic mechanisms, such as thermoregulation. However, little is known about the contribution of peripheral thermosensation to the awareness of our body as our own (i.e. sense of body ownership), which represents a fundamental aspect of the psychological self. Homeothermic Self has successfully addressed this outstanding question. By embracing a multidisciplinary approach, the present MSCA project successfully investigated for the first time the behavioural, psychophysiological, and neural mechanisms underlying the integration of thermal interoceptive and exteroceptive signals.
The project had three main objectives:
1. to elucidate the role of visuo-thermal, interoceptive congruency to the sense of body ownership. The results showed for the first time that thermal signals are important to the way we become aware of our body as our own.
2. to investigate the role of thermal signals on body ownership over and above tactile stimulation. The results showed that we can induce a contactless RHI, by selectively activating thermal skin receptors.
3. to identify the neural network responsible for the integration of interoceptive and exteroceptive signals in relation to body ownership. Data collection supporting this objective has been completed and data analysis is ongoing.

Thermoregulation is an evolutionary requirement for our survival, and it is not surprising that our sense of body ownership could be coupled to fundamental interoceptive mechanisms of thermosensation. To experience a coherent and unitary sense of self, what we feel and what we see on our skin should match at any given time, and any incongruency should be resolved.
The findings of Homeothermic Self might pave the way for a better understanding of disorders of body awareness associated with temperature dysregulation, such as body disownership following right-hemisphere stroke and eating disorders.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Despite the challenges related to COVID-19 pandemic, Homeothermic Self has achieved its objectives and milestones for the 24-month period. Furthermore, unexpected opportunities have raised during the the project which have paved the way for interesting collaborations and novel angles to address our research questions of interest.
The main results of Homeothermic Self and their dissemination activities are summarized below:
1. We can quantify thermal interoception by means of a novel thermal matching task, where participants are asked to recognise a previously presented temperature of reference when this is presented among several warmer or cooler trials (Crucianelli, Enmalm & Ehrsson, 2022). The results have been replicated in a second study, which also showed that visual deprivation does not influence the performance at the task (Radziun, Crucianelli & Ehrsson, 2022). Furthermore, the thermal matching task showed a strong test-retest reliability across two independent testing sessions (Crucianelli, Enmalm & Ehrsson, in preparation).
2. The thermal matching task might be used as an outcome measure of the rubber hand illusion (RHI), to investigate whether the seen temperature influences the perceived temperature. Furthermore, visuo-thermal congruency modulated the sense of body ownership (Crucianelli & Ehrsson, 2022; Crucianelli & Ehrsson, in preparation). We have also investigated visuo-thermal congruency in the context of another illusion of body ownership, namely the Somatic RHI, which is induced without vision (Radziun, Crucianelli, & Ehrsson, in preparation).
3. It is possible to induce a contactless RHI, by selectively activating thermal skin receptors above and beyond tactile stimulation by means of a heat lamp (Crucianelli & Ehrsson, in preparation).
4. Blind individuals are better at perceiving cardiac interoceptive signals (Radziun, Korczyk, Crucianelli, Szwed, & Ehrsson, 2022) as well as affective touch but only on the palm of the hands (Radziun, Crucianelli, Korczyk, Szwed, & Ehrsson, in preparation). These studies offer insight into the perception of interoceptive signals in absence of vision.
5. The perception of skin-mediated interoceptive signals can be described using a stable and reliable function (Crucianelli, Chancel & Ehrsson, 2022).
6. The fellow has worked towards writing one opinion paper (Crucianelli & Ehrsson, in press) and one book chapter (Crucianelli & Morrison, in press) suggesting a paradigm shift in the field of interoception, according to which more attention should be paid to the skin as an interoceptive organ.
7. The fMRI project investigating the neural network responsible for the integration of thermal interoceptive and exteroceptive signals in relation to body ownership was delayed due to COVID-19. However, data collection has now been completed and data analysis is currently ongoing (Crucianelli, Radziun & Ehrsson, in preparation).

The fellow presented the results of the present MSCA project in (6) invited oral presentations at academic institutions and (7) oral/poster presentations at international conferences and workshops. Furthermore, the fellow received the invite to act as Guest Associate Editor for a special issue in Frontiers in Human Neuroscience, Cognitive Neuroscience.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Homeothermic Self went beyond the state of the art by developing a novel method to quantify thermal interoception. We anticipate that the results of the project will have an important impact in the field of interoception, multisensory integration, somatosensation and embodied cognition more generally. Furthermore, a better understanding on the way we perceive and integrate thermal signals can provide some insight into the way the human body and brain can adapt to temperature changes; as such the results of Homeothermic Self can help to tackle an important societal challenge: What could be the consequences of extreme climate changes for the human bodies?

Public engagement was an important part of the Homeothermic Self project. The fellow was invited as a Marie Skłodowska-Curie Ambassador at the session ‘Uncovering the secrets of graduate school: The grant process’ during the convention of the Association for Psychological Science taking place in Chicago, USA in May 2022. The fellow participated to the following events: European Researchers’ Friday, Skype a Scientist. Pint of Science. She wrote several science communications pieces for the general public, gave radio interviews, and recorded podcasts. The Homeothermic Self results have been disseminated via social media (Twitter, ResearchGate, LinkedIn) and via the fellow’s website, www.lauracrucianelli.com.

Thermosensation modulates our sense of body ownership. Credit image Shutterstock