T2 showed a more uniform distribution in cerebral cortex and subcortical nuclei of an apparently lesser amount of Pr[P.sup.D]; T3 appeared to preferentially affect the hemispheric white matter and other subcortical regions such as the alveus, the corpus callosum, the anterior commissure, and fascicles surrounding thalamus as well as other white matter formations such as fimbria, brachium of superior colliculus, medial lemniscus
, and cerebral peduncles.
Notably, different stages of the auditory pathway are evaluated using the eCAP recordings (peripheral action potentials of auditory nerve, corresponding to wave I) and eABR recordings (central responses of the VIII nerve, wave II; cochlear nuclei, wave III; nucleus of the lateral lemniscus
, wave IV-not pronounced in eABR; inferior colliculus, wave V) .
SEPs are generated at different levels of the sensory pathway leading to the primary sensory cortex through the dorsal column and medial lemniscus
. N9 notch is generated by the brachial plexus, and N13 by postganglionic fibers of the first sensory neuron, that is, posterior radix and/or dorsal column of the cervical spinal cord, while N20 originates in the primary sensory cortex of the contralateral parietal lobe, at the location of somatotopic representation of the hand.
Wave II originates from cochlear nucleus, Wave III from superior olivary nucleus, Wave IV from lateral lemniscus
, and Wave V from inferior colliculi in the midbrain.
SEP were recorded to evaluate functional integrity of posterior column/medial lemniscus
sensory ascending pathways.
IC plays a strategic role in relaying and processing auditory information; indeed, receiving innervation from both the lateral lemniscus
and the auditory cortex, the IC can be considered as an interface between the lower auditory pathway and the auditory cortex .
Henkel, "Development of afferent patterns in the inferior colliculus of the rat: projection from the dorsal nucleus of the lateral lemniscus
," The Journal of Comparative Neurology, vol.
The borders of the PSA include the posterior border of the STN anteriorly, the dorsal SN inferiorly, the ventral thalamic nuclei superiorly, the anterolateral red nucleus posteromedially, the medial lemniscus
posteriorly, and the internal capsule laterally [24, 25].
Spinal afferent fiber goes upward within spinothalamic tract and spinal tract to the thalamus (spinothalamic tract) and gracile nucleus and cuneate nucleus of medulla oblongata (spinal tract), respectively, then project fiber to thalamus through lemniscus
I wave originated from the peripheral portion of eighth cranial nerve adjacent to cochlea, II wave from cochlear nucleus, III wave from superior olivary nucleus, IV wave from lateral lemniscus
, and V wave from inferior colliculus.