Delta-Band Dynamics of CaMKI-Positive Preoptic Neurons Encode Thermal Homeostatic Information

Thermal homeostasis is critical for mammalian physiology. The hypothalamic preoptic area (POA) is a key center for thermoregulation and contains calcium/calmodulin-dependent protein kinase type I (CaMKI)-positive temperature-insensitive neurons, whose functional roles remain unclear. Here, we found that calcium oscillations of CaMKI-positive POA (POA^CaMKI) neurons decreased during adenosine monophosphate (AMP)-induced hypothermia via the adenosine A₁ receptor, with the power spectral density of the delta-band exhibiting a power-scaling law associated with changes in core body temperature (~ΔT_core³). This suggests that POA^CaMKI neurons encode T_core reference information via delta-band dynamics. The observed power-law scaling indicated a robust association between POA^CaMKI neuronal activity and thermoregulatory dynamics, suggesting that these neurons may contribute to both body temperature sensing and control. This study reveals a negative feedback mechanism for thermal homeostasis and provides a paradigm shift for decoding information in the frequency domain and understanding the neural regulation of physiological homeostasis.