NSC 3319 Lecture Notes - Lecture 15: Spinothalamic Tract, Trigeminal Nerve, Thalamus
10 May 2016
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Discriminative touch: highly localized, something is touching my skin, upper body, all mechanoreceptor (primary) afferents (abeta) enter in the dorsal root ganglia of sc. Other is for the lower body: they the ascend in the dorsal columns. Upper body: cuneatus, lateral- anatomical orientation, they continue to ascend into medulla into the dorsal column nuclei into ( both are 2nd order neurons) Nucleus gracilis: lower body, axons of the 2nd order neurons cross midline in the medulla. Upper is now medial and the lower is lateral: synapse on 3rd order neurons in the vpl, from vpl to s1. Via internal capsule: anterolateral system, pain and temperature- discussed later in other chapters, trigeminal for somatosensory -face only, purpose. Pain/temp- discussed in later chapters: trigeminal ganglion. Primary afferents large fibers (abeta) in the sensory portion of the trigeminal nerve. Enter here through the pons: principle nucleus- 2nd order neurons.
