Miniaturized Bidirectional Thermal Stimulation System Integrated With an Electrode Array for Recording Neural Activities.

Investigating the neural mechanisms underlying brain function is essential for advancing both our understanding of neurological processes and the development of effective treatments. However, traditional neuromodulation techniques typically provide only unidirectional control-either excitation or inhibition-limiting their capacity to investigate dynamic brain circuits. Here, we present a miniaturized, bidirectional thermal stimulation system integrated with a multichannel electrode array, enabling real-time, bidirectional modulation through localized heating and cooling. This innovative system allows precise and reversible control of brain temperature, facilitating both excitation and inhibition within a single, compact platform. We demonstrate its capability by targeting the locus coeruleus (LC) in head-fixed mice, inducing robust, directionally dependent changes in neural activity and accompanying behavioral responses, such as pupil dilation and constriction. In contrast to conventional approaches, our system achieves high temporal resolution and seamless integration of stimulation and recording. The proposed system provides a powerful and versatile tool for dissecting the dynamic regulation of neural circuits and opens new avenue for developing interventions for neurological and neurodegenerative disorders.