Cortical Glial and Neural Stem Cell Coupling in Chemosensory Circuit Plasticity

Chemosensory systems exhibit remarkable plasticity that supports adaptive perception, learning, and behavioral responses to changing environmental and physiological conditions. Although synaptic mechanisms have traditionally been regarded as the principal basis of chemosensory plasticity, accumulating evidence indicates that this view is incomplete. This review synthesizes experimental findings showing that adaptive changes in chemosensory circuits arise through coordinated interactions across multiple biological levels. It examines how cortical feedback reshapes circuit dynamics and sensory representations, how astrocytes and microglia regulate the synaptic, metabolic, and inflammatory environments that constrain or enable plasticity, and how neural stem cell–mediated neurogenesis contributes structural remodeling across longer timescales. By integrating these mechanisms, the review proposes a multiscale coupling framework of chemosensory plasticity in which circuit-level modulation, glial regulation, and neurogenic remodeling function as interconnected rather than isolated processes. This perspective provides a more comprehensive account of how olfactory and broader chemosensory systems adapt to experience, internal state, and environmental change, and offers a conceptual basis for understanding how disruption of these coordinated mechanisms may contribute to chemosensory dysfunction in aging, neurodegenerative, metabolic, and post-viral conditions.