brain
Acronym: Br
The term brain refers to one of two parts of the central nervous system (CNS) as defined by dissection in mature vertebrates. It is the part located in the cranial cavity; the other is the spinal cord. (Some biologists use 'brain' in reference to the central ganglion of the nervous system of invertebrate species as well ( Wikipedia )). Neuroanatomists subdivide the brain in three different ways. Most textbooks and brain atlases are organized according to the classical subdivision into forebrain, midbrain and hindbrain; below that level structures are grouped by proximity as the brain is dissected to finer and finer levels. The definition of the brain in the second model, the Developmental CNS Model, differs from the classical definition in that its substructures are grouped by the location of their precursors in the embryo and it includes the retina, a structure that originates in the Encephalon but that is located outside the cranial cavity in the mature animal. The retina is classically defined, on the basis of its postnatal location outside the cranial cavity, not as part of the central nervous system but as part of the peripheral nervous system. Because it develops embryologically from the Telencephalon, however, it is, in the Developmental CNS Model, part of the Encephalon. To avoid confusion, the standard NeuroNames terminology for structures defined by dissection of the mature brain are in English; standard names for subdivisions based on embryonic precursor are in Latin and capitalized. Thus, the highest level divisions of the Developmental CNS Model are the Telencephalon, Mesencephalon and Rhombencephalon. In the third model, the Functional CNS Model, structures are grouped by a combination of criteria, including embryonic origin, internal structure, connectivity and function. Division at the highest level is between cerebral cortex, cortical nuclei, subcortical nuclei, cerebellum and cerebrospinal trunk. The retina is included as a component of the cerebrospinal trunk. The hierarchical organization is derived almost entirely from Swanson-2004. The terminology of the Functional CNS Model - Rat is in English with the same standard term used for structures that are identical to structures in the classical model. Each of the models is more useful than the other for a certain purpose: the classical model for understanding the neuroanatomical literature of the past century, the developmental model for analyzing the genetic and embryonic origins of brain structure, and the functional model for addressing the fundamental challenge of neuroscience, understanding the relations between neural structure and function. The primary purpose of BrainInfo/NeuroNames is to clarify the relations between the terminologies and structural concepts of these and other ways of looking at the central nervous system.

Also known as: suprasegmental structures


Species Having or Lacking this Structure

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Internal Structure

Cells Found There

Genes Expressed There

Locus in Brain Hierarchy

Connections

Models Where It Appears

Publications About It






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