What are vestibular afferents?
Efferent circuits within the nervous system carry nerve impulses from the central nervous system to sensory end organs. Vestibular efferents originate in the brainstem and terminate on hair cells and primary afferent fibers in the semicircular canals and otolith organs within the inner ear.
What is the primary vestibular cortex?
Vestibular cortex is the portion of the cerebrum which responds to input from the vestibular system. The insula of the left side, exposed by removing the opercula. (Image is of left side, but there is some evidence that there may be right-sided dominance.)
What is the primary role of the vestibular nuclei?
The major vestibular nuclei are highly interconnected with many overlapping functions. It plays an essential role in maintaining equilibrium, posture, head position, and clear vision with movement.
Where is the primary vestibular cortex?
The vestibular cortex differs in various ways from other sensory cortices. It consists of a network of several distinct and separate temporoparietal areas. Its core region, the parietoinsular vestibular cortex (PIVC), is located in the posterior insula and retroinsular region and includes the parietal operculum.
What is the vestibular cortex function?
The two major cortical functions of the vestibular system are spatial orientation and self-motion perception. These functions, however, are not exclusively vestibular; they also rely on visual and somatosensory input.
What is the primary function of the vestibular projections to the spinal cord?
The main projections from these nuclei are to the spinal cord (controlling head and body position), to the three, extraocular motor nuclei (III, IV, VI, controlling eye movements), to the thalamus (VPI, eventually reaching the cortex and conscious perception of movement and gravity), and to the cerebellum (coordinating …
What is the utriculus?
u•tric•u•li (-lī′) An anatomical sac or pouch, especially the one within the inner ear; utricle. GOOSES. GEESES.
What part of the brain controls vestibular?
The cerebellum controls a number of functions including movement, speech, balance, and posture. But the cerebellum doesn’t work alone. There are several other parts of the brain that also contribute to balance functions, including something known as the vestibular system.
Where is the primary vestibular cortex located?
posterior insula
The vestibular cortex differs in various ways from other sensory cortices. It consists of a network of several distinct and separate temporoparietal areas. Its core region, the parietoinsular vestibular cortex (PIVC), is located in the posterior insula and retroinsular region and includes the parietal operculum.
What are the vestibular-nerve afferents?
Vestibular-nerve afferents innervate vestibular receptors and carry signals to the vestibular nuclei (VN). Afferents can be functionally grouped on the basis of the regularity of their resting discharge (Figure 3 A, left, inset), measured by a normalized coefficient of variation (CV*) (Goldberg et al. 1984).
Where do vestibular efferent fibers originate?
Efferent fibers originate from a group of cells near the abducens nucleus in the brainstem and project bilaterally to the vestibular periphery. B. Vestibular efferents fibers contact both irregular and regular afferent fibers, as well as type II haircells of the peripheral vestibular system.
What is the function of the efferent vestibular system in toadfish?
Efferent vestibular system in the toadfish: action upon horizontal semicircular canal afferents. J Neurosci 10: 1570-1582, 1990. Brandt T, Dieterich M, and Danek A. Vestibular cortex lesions affect the perception of verticality.
Are efferent projections excitatory or inhibitory?
Vestibular efferent projections are excitatory and increase the resting discharge of the afferents, while decreasing their sensitivity (squirrel monkeys: (Goldberg and Fernandez 1980), toadfish: (Highstein and Baker 1985)). Thus, theoretically, efferents can increase the dynamic range of afferent responses.