Aivokudos

Aivokudos, the Estonian term for brain tissue, denotes the soft tissue inside the skull that constitutes the brain. It includes both gray matter, which is rich in neuronal cell bodies and synapses, and white matter, composed mainly of myelinated axons that connect different brain regions. The tissue is organized into networks that support perception, movement, memory, and complex cognition.

Cellularly, aivokudos comprises neurons and glial cells—astrocytes, oligodendrocytes, and microglia—along with the brain’s vascular system and extracellular matrix. Neurons transmit electrical signals; astrocytes regulate the chemical environment; oligodendrocytes form myelin to insulate axons; microglia provide immune surveillance. Blood vessels within the tissue supply oxygen and nutrients and contribute to the blood-brain barrier, which helps protect neural tissue.

Developmentally, brain tissue arises from the neural tube, with neuronal populations produced early and glial cells differentiating subsequently. In adulthood, plasticity—the brain’s ability to adapt networks through experience—persists, though neurogenesis is limited to certain regions.

Clinically, damage to aivokudos can arise from traumatic injury, stroke, infection, or neurodegenerative disease, disrupting neural circuits. Histopathological examination can reveal changes such as neuronal loss, gliosis (scarring), demyelination, or tumor formation from glial cells (for example, gliomas). Imaging modalities like magnetic resonance imaging (MRI) and computed tomography (CT) assess structural integrity, while advanced techniques such as diffusion MRI and tractography evaluate white matter connectivity.