neocortikala

Neocortex, also called the isocortex, is the six-layered part of the cerebral cortex that forms the largest portion of the cortex in most mammals. ItUnderpins higher-order brain functions such as perception, attention, cognition, language, and conscious thought, and is organized into many specialized functional areas.

Cytoarchitecture and connectivity: The neocortex has six horizontal layers, I to VI. Layer IV typically receives major thalamic input; layers II and III project to other cortical areas; layer V sends outputs to subcortical targets (including brainstem and spinal cord); layer VI provides feedback to the thalamus. Pyramidal neurons are the principal excitatory cells, with interneurons shaping local circuits. The cortex contains minicolumns and macrocolumns that serve as functional units.

Organization and regions: The neocortex is divided into primary sensory areas (vision, audition, somatosensation), a primary motor area, and numerous association areas that integrate information and support complex functions such as planning and reasoning. In humans it accounts for the majority of cortical volume and shows extensive regional specialization.

Development and evolution: The six-layered isocortex arises from the dorsal pallium during embryonic development, via neuronal migration and lamination processes. Across evolution, the neocortex expanded most in mammals, particularly primates, correlating with advanced cognitive abilities. The term isocortex distinguishes it from allocortex, which includes the three-layered archicortex and paleocortex.

Clinical relevance: Neocortical dysfunction or damage can produce focal deficits in sensation, movement, or cognition. Altered development and connectivity are linked to neurological and psychiatric conditions such as epilepsy, autism, and schizophrenia. The neocortex remains a central focus in studies of learning, memory, and plasticity.