Nonneuronal

Nonneuronal is an adjective used to describe cells or tissues that are not neurons. In neuroscience and neuroanatomy, the term distinguishes electrically excitable neurons from other cell types that support, nourish, or participate in the function of the nervous system. In this context, nonneuronal cells include glial cells such as astrocytes, oligodendrocytes, and microglia in the central nervous system, as well as Schwann cells in the peripheral nervous system, and other supporting cells like ependymal cells along the ventricles. Vascular and meningeal components such as endothelial cells and pericytes, and immune cells that reside in the CNS, are also considered nonneuronal.

Nonneuronal cells perform essential roles: astrocytes regulate extracellular ion balance and neurotransmitter levels, provide metabolic support to neurons, and participate in synaptic regulation; oligodendrocytes and Schwann cells form myelin; microglia act as resident immune cells and phagocytose debris; ependymal cells line cerebrospinal fluid-filled spaces; endothelial cells and pericytes contribute to the blood–brain barrier. Together, nonneuronal cells support neural circuits, influence development, and participate in repair after injury.

In a broader biological sense, nonneuronal refers to all cells in a tissue that are not neurons and includes muscle, epithelial, and connective tissue cells. The term emphasizes functional relationships within tissue architecture rather than neuronal identity alone.