olfactory system - BrainInfo

olfactory system (OSY)

The term olfactory system (OSY) refers to a histologically and functionally defined set of sensory structures involved in the processing of oderant information and the sense of smell ( Yilmazer-Hanke-2012, Buck-2013 ). It is composed bilaterally of a main olfactory system (OSYm) and an accessory olfactory system (OSYa). Both the OSYm and OSYa are fully developed in the rat ( Swanson-2004 ) and the mouse ( AMBA-2024 ), but current evidence does not support the existence of a significantly functional OSYa in the human or the macaque ( Witt-2002, Zhang-2003, Francia-2014 ). Evolutionary biologists attribute the virtual absence of the OSYa in Primates to their greater reliance on the visual and auditory systems for adaptation to social stimuli ( Witt-2002 ). Such an interpretation is consistent with findings that the OSYa provides rodent a prominent pathway from accessory olfactory receptor neurons (OLRa) to the medial amygdalar nucleus (MEA) where neurons sensitive to adult levels of circulating sex hormones (estrogens and androgens) ( Simerly-1990 ) enable the brain (BRN) to evaluate the age and sex of another individual compared to its own age (prepubertal vs. adult) and sex (male vs. female) by its own levels of circulating estrogenic and andorgenic hormones. Primates, on the other hand, lacking significant input to MEA by way of an OSYa, have prominent visual and auditory pathways to MEA. One passes directly through the lateral amygdalar nucleus (LAN) to MEA and a second passes indirectly from LAN through the basolateral amygdalar nucleus (BLA) to MEA ( Amaral-1992 ). The evolutionary interpretation of species differences in the role that olfaction plays in sexual and aggressive behavior is not inconsistent with findings that olfactory functions of the human are equally as effective as of other animals and that the human olfactory bulb (OLB) has more neurons than that of the rat ( McGann-2017 ). In rodent, pheromone oderants trigger reproductive behaviors and physiological changes in other members of the same species ( Zhang-2003 ). They influence hormonal systems via the MEA through the hypothalamus (HYP) to the hypothalamic-pituitary-gonadal axis ( Sonne-2023 ) and mating behavior through the MEA and HYP to the periaqueductal gray (PAG) and other brainstem extrapyramidal motor nuclei (EXM) ( Bowden-2021 ). Thus, the prominent influence of social oderants on rodent behavior is mediated by the the accessory olfactory bulb (AOB) component of the OLB, and the human has no AOB ( Buck-2013 ). Final 20 Jan 2025.

Also known as: olfactory areas, olfactory system, olfactory nervous system, rhinencephalon

NeuroNames ID: 2867

All Names & Sources

1 of 6

Showing 6 synonym(s) - Use arrows to navigate

Showing 6 synonym(s)

Name:

olfactory areas

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:

OLF

Language:

acronym

Organism:

rat

Source:

Swanson-2004

Citation:

Third Edition, Elsevier Academic Press, Oxford, 2004

Source Title:

Brain Maps: Structure of the Rat Brain.

Name:

olfactory system

Language:

English

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

olfactory nervous system

Language:

English

Organism:

Unspecified

Source:

Takagi-1986

Citation:

Source Title:

Studies on the olfactory nervous system of the Old World monkey

Name:

OSY

Language:

acronym

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

rhinencephalon

Language:

English

Organism:

human

Source:

Carpenter-1983

Citation:

Baltimore: Williams and Wilkins Co., 1983

Source Title:

Human Neuroanatomy

Illustrations

Showing 2 illustration(s)

Nissl stain & diagram of
coronal section in
mouse

Nissl stain & diagram of
sagittal section in
mouse

Species With The Structure

Equivalent By	Human	Macaque	Rat	Mouse
Multiple Criteria	Relevant Data Not Located	Relevant Data Not Located	Has The Structure	Relevant Data Not Located

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Showing 1 record(s)

Basis:

Multiple Criteria

Has Equivalent:

Yes

Organism:

Rattus (rat)

Their Name:

olfactory areas

Source:

Swanson-2004

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.