Vestibular component Peripheral processes Bipolar vestibular ganglion Central Processes Vestibular Nerve Hair cells of maculae of Hair cells of saccule & utricle ampullary crests of three semicircular ducts Static equilibrium Kinetic equilibrium Fibres from ampullary crests of semicircular ducts Superior & medial vestibular nuclei Vestibular nuclei Fibres from maculae of saccule & Utricle Medial & inferior vestibular nuclei Facilitatory Fastigial nucleus of both sides of cerebellum Uncinate fasciculus Juxta-Restiform body Purkinje cells of Flocculo-nodular lobe Lateral Vestibular nuclei Inhibitory Cortex of Flocculo-nodular lobe of cerebellum Contralateral interstitial nucleus of Cajal Nucleus of Oculomotor nerve Nucleus of Afferents Trochlear Nerve Vestibular Nucleus Ascending & Descending fibres Medial Longitudinal Fasciculus Nucleus of Some of Ascending fibres Abducent Nerve Nuclei of ventral grey column of Nucleus of Nucleus of Magnocellular part of cervical segments of spinal cord hypoglossal Nerve facial nerve medial geniculate body Head region of post central gyrus Area 3, 1, 2 Ipsilateral flocculo-nodular lobe Vestibular Nuclei & fastigial nucleus Few fibres from superior & Retrace the course Sensitive hairs cells of maculae and Cristae to modulate lateral vestibular nucleus of vestibular nerve the sensory input or alter the threshold of the hair cells Most of efferents from Extends in the anterior funiculus Descend ipsilaterally Lateral vestibulo-spinal tract lateral vestibular nucleus along the whole length of spinal cord Efferents from Interneurons in the Alpha & gamma Medial vestibulo-spinal tract medial vestibular nucleus laminae 7 & 8 of the spinal cord neurons of lamina 9 Directly end Stimulates Extensor motor neurons Maintains Vestibulo-spinal tract erect posture of the trunk Flexor motor neurons Inhibits Cochlear component Spiral ganglion cells Central vprocesses Short ascending Dorsal & ( 1st order sensory neurons) ventral cochlear nuclei Long descending branches ( 2nd order sensory neurons) Fibres from apical Ventral cochlear nucleus turn ofv cochlea & ventralv part of ( low tone) dorsal cochlear nucleus Fibres from basal Dorsal part of turn ofv cochlea v dorsal cochlear nucleus ( high tone) Fibres from dorsal Pass horizontally across the midline Ascend through the Forms dorsal acoustic striae A cochlear nucleus in the posterior part of tegmentum contralateral lateral lemniscus Nucleus of lateral lemniscus & inferior colliculus Fibres from dorsal part of Pass horizontally Joins contralateral Forms intermediate acoustic striae B ventral cochlear nucleus through the tegmentum lateral lemniscus 3rd order of sensory neurons Terminate into Ascends uninterrupted ipsilateral & contralateral superior olivary nuclear complex Fibres from the ventral Decussate with the similar fibres C Traverse medially Forms ventral acoustic striae & cochlear nucleus of the opposite side nucleus of trapezoideum Form trapezoid body Acts as sorting station Nucleus of lateral lemniscus Parvocellular part of medial geniculate body Inferior colliculus of auditory pathway Through Auditory radiation Audito-sensory cortex ( areas 41 & 42 of the temporal lobe) Connect Fibres concerned with auditory reflexes Inferior colliculi of both sides By commissural fibres Superior colliculi Tectospinal & tectobulbar tracts.