Abstract:
The biological sense of temperature, or thermoreception, is fundamental to survival, guiding behaviors from thermoregulation to object identification. For decades, neuroscience has modeled this sense primarily as a one-dimensional process, where neural firing rates encode a scalar value corresponding to ambient temperature. While this model has been foundational, it fails to account for a rich tapestry of perceptual phenomena, including the identification of materials by their thermal “feel” and paradoxical sensations like the thermal grill illusion. This paper introduces a novel theoretical framework, termed the Thermostate Manifold, which posits that thermoreception is not a scalar measurement but a high-dimensional computational process. We propose that the nervous system represents the thermal interaction between an organism and its environment as a state vector within a ten-dimensional manifold. These dimensions are derived from fundamental physics and known somatosensory mechanisms, encompassing not only thermodynamic variables (absolute temperature, rate of change) but also material properties (conductivity, heat capacity, effusivity), spatiotemporal dynamics (spatial gradient), integrated mechanosensory inputs (pressure, texture), non-contact energy transfer (infrared radiation), and the intrinsic thermodynamic state of the sensory receptors themselves (change in molar heat capacity). We formalize the neural implementation of this model using the mathematical language of state-space representation, common in control theory and theoretical physics. In this framework, the 10D Thermostate Vector is encoded by the distributed activity of a population of primary sensory neurons, and its processing in the central nervous system is described by a set of linear differential equations that map the peripheral input to a latent cortical representation and, ultimately, to a conscious percept. This theory provides a unified explanation for disparate thermal phenomena, reframes multisensory integration as an intrinsic feature of the initial sensory encoding, and makes specific, falsifiable predictions for future neurophysiological and psychophysical experiments. By reconceptualizing thermoreception as a problem in high-dimensional state estimation, the Thermostate Manifold offers a new paradigm for understanding how the brain constructs a sophisticated physical model of its interaction with the world.
Yıldırım, E. (2025). The Thermostate Manifold: A Ten-Dimensional State-Space Model of Neuronal Thermoreception. Zenodo. https://doi.org/10.5281/zenodo.17049987
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