motor periaqueductal gray

The term motor periaqueductal gray refers to the part of the functionally-defined central gray that largely surrounds the cerebral aqueduct in the midbrain tegmentum ( Swanson-2004 ). Based primarily on studies in the rat, it includes four nuclei in addition to the classical periaqueductal gray: the precommissural nucleus, medial accessory oculomotor nucleus, interstitial nucleus of Cajal, and nucleus of Darkshevich. In the motor definition, the periaqueductal gray is subdivided somewhat differently than in the classical version. It is composed of a narrow medial division of the periaqueductal gray, which surrounds the cerebral aqueduct throughout its course; the dorsomedial periaqueductal gray, which caps the aqueduct as it emerges from beneath the posterior commissure and extends caudally to the junction of the aqueduct with the fourth ventricle; the dorsolateral periaqueductal gray that lies lateral to it throughhalf of its course; the commissural nucleus, the rostromedial division of the periaqueductal gray, and the rostrolateral division of the periaqueductal gray, which occupy the area ventral to the dorsomedial and dorsolateral divisions and lateral to the medial division in the rostral quarter of the periaqueductal gray, and the ventrolateral division of the periaqueductal gray, which occupies that area in the caudal three quarters of the structure. Functionally the motor periaqueductal gray is a component of the behavior control column of the brainstem motor system ( Swanson-2004 ).

Also known as: periaqueductal gray, motor periaqueductal gray

NeuroNames ID: 3411

All Names & Sources

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Name:

periaqueductal gray

Language:

English

Organism:

rat

Source:

Swanson-2004

Citation:

Third Edition, Elsevier Academic Press, Oxford, 2004

Source Title:

Brain Maps: Structure of the Rat Brain.

Name:

motor periaqueductal gray

Language:

English

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

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Models Where It Appears

Functional CNS Model - Rat

The Functional CNS Model - Rat (FMrat) ( Swanson-2004) is one of three hierarchical models representing the internal organization of the central nervous system (CNS). The others are the Structural CNS Model - Human (SThmn) and the Functional CNS Model - Human (FMhmn). The FMrat model represents the basic organization of the mouse ( Hof-2000 AMBA-2024 ) and, presumably, other rodents. Functional CNS models differ from structural models in that structures are defined and named by connectivity rather than by proximity to other structures at the same level. Functional models are more useful for representing longitudinal components of are grouped based on information drawn from multiple neuroscientific disciplines. such as connections, neurochemical characteristics, and role in physiogical and behavioral processes. While the Functional Model was developed primarily for an atlas of the rat brain ( Swanson-2004 ), the hierarchical organization of structures is for the most part applicable to the human, macaque, mouse and other mammalian brains as well. Structures at lower levels of the Functional CNS hierarchy are largely the same as in the Classical and Developmental Models, i.e., they were originally identified by stains for gray matter (Nissl substance) and white matter (myelin). At the next higher level they are grouped into basic connectional and functional systems of the CNS, such as the subcortical sensory systems, the brainstem motor system and the behavioral state system. At the highest levels CNS structures are grouped on the basis of dissection and embryologic precursors into cerebrum ( cerebral cortex and cerebral nuclei ), cerebellum, and cerebrospinal trunk.