The auditory and vestibular pathways are anatomically related but discrete pathways that permit conscious perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment of and reaction to sound and spatial orientation Spatial orientation Change in position or alignment in response to an external stimulus. Psychiatric Assessment. Stimulation of specialized hair cells in the cochlea Cochlea The part of the inner ear (labyrinth) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the vestibular labyrinth. Ear: Anatomy and vestibular apparatus excite and send signals through partitions of the vestibulocochlear nerve Vestibulocochlear nerve The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (cochlear nerve) which is concerned with hearing and a vestibular part (vestibular nerve) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the spiral ganglion and project to the cochlear nuclei (cochlear nucleus). The fibers of the vestibular nerve arise from neurons of scarpa's ganglion and project to the vestibular nuclei. The 12 Cranial Nerves: Overview and Functions (CN VIII) to the brainstem, where they synapse Synapse The junction between 2 neurons is called a synapse. The synapse allows a neuron to pass an electrical or chemical signal to another neuron or target effector cell. Synapses and Neurotransmission on various targets, send and receive other projections, and ultimately contribute to spatial orientation Spatial orientation Change in position or alignment in response to an external stimulus. Psychiatric Assessment and perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment of sound.
Last updated: 5 Apr, 2022
The auditory pathway of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification begins with the external auditory canal External Auditory Canal Otitis Externa and includes the middle/ inner ear Inner ear The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. Ear: Anatomy and eventually the brainstem nuclei before sending final signals to the primary auditory cortex Primary auditory cortex The region of the cerebral cortex that receives the auditory radiation from the medial geniculate body. Cerebral Cortex: Anatomy in the temporal lobe Temporal lobe Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the occipital lobe. Cerebral Cortex: Anatomy.
This image illustrates the nuclei involved in auditory sensation. Each of the parts plays an important role in the conduction of auditory information from CN VIII up to the cortex.
Image by Lecturio.Outer ear Outer ear The outer part of the hearing system of the body. It includes the shell-like ear auricle which collects sound, and the external ear canal, the tympanic membrane, and the external ear cartilages. Ear: Anatomy → inner ear Inner ear The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. Ear: Anatomy → depolarization Depolarization Membrane Potential of cochlear hair cells in the cochlea Cochlea The part of the inner ear (labyrinth) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the vestibular labyrinth. Ear: Anatomy → both the ipsilateral and contralateral superior olivary nucleus Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. The Cell: Organelles → lateral lemniscus → inferior colliculus Inferior colliculus The posterior pair of the quadrigeminal bodies which contain centers for auditory function. Brain Stem: Anatomy → medial geniculate bodies Geniculate Bodies Part of the diencephalon inferior to the caudal end of the dorsal thalamus. Includes the lateral geniculate body which relays visual impulses from the optic tract to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the auditory cortex. Thalamus: Anatomy of the thalamus Thalamus The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem. Thalamus: Anatomy → auditory cortex of temporal lobe Temporal lobe Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the occipital lobe. Cerebral Cortex: Anatomy
Image depicting the pathway of sound from the cochlea Cochlea The part of the inner ear (labyrinth) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the vestibular labyrinth. Ear: Anatomy to the level of the auditory cortex with multilevel axial Axial Computed Tomography (CT) slices through the brainstem
Image: “Auditory Pathway” by Jonathan E. Peelle. License: CC BY 4.0The vestibular pathway of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification begins with the utricle and saccule, with additional input from the semicircular canals. Information eventually reaches the brainstem nuclei before sending final signals to the thalamus Thalamus The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem. Thalamus: Anatomy and cerebellum Cerebellum The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum: Anatomy.
This image demonstrates the intricate pathways of the vestibular system.
Note the
flow
Flow
Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.
Vascular Resistance, Flow, and Mean Arterial Pressure of information.
Depolarization
Depolarization
Membrane Potential of hair cells in the
inner ear
Inner ear
The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth.
Ear: Anatomy sends auditory information to the vestibular ganglia, which transmits this information to the
vestibular nuclei
Vestibular nuclei
The four cellular masses in the floor of the fourth ventricle giving rise to a widely dispersed special sensory system. Included is the superior, medial, inferior, and lateral vestibular nucleus.
Vertigo (also receives input from the
cerebellum
Cerebellum
The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis.
Cerebellum: Anatomy).
From here, the
vestibular nuclei
Vestibular nuclei
The four cellular masses in the floor of the fourth ventricle giving rise to a widely dispersed special sensory system. Included is the superior, medial, inferior, and lateral vestibular nucleus.
Vertigo send information to CN III, IV, and VI to dictate eye movement. The
vestibular nuclei
Vestibular nuclei
The four cellular masses in the floor of the fourth ventricle giving rise to a widely dispersed special sensory system. Included is the superior, medial, inferior, and lateral vestibular nucleus.
Vertigo also send information to the
thalamus
Thalamus
The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem.
Thalamus: Anatomy,
cerebellum
Cerebellum
The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis.
Cerebellum: Anatomy, and medial and lateral vestibulospinal tracts, allowing for
perception
Perception
The process by which the nature and meaning of sensory stimuli are recognized and interpreted.
Psychiatric Assessment, integration, and adjustments of body position within space.
Anatomical structure | Function |
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Cranial nerve nuclei | Control over eye movements |
Thalamus Thalamus The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem. Thalamus: Anatomy | Conscious perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment of movement and gravity through connections to cortex |
Cerebellum Cerebellum The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum: Anatomy ( flocculonodular lobe Flocculonodular lobe Cerebellum: Anatomy) | Coordination Coordination Cerebellar Disorders of postural adjustments |
Lateral vestibulospinal tract | Walking upright |
Medial vestibulospinal tract | Assisting in integration of head and eye movements |