Somatosensory Flashcards
(33 cards)
Lesions of Area 1 of primary sensory cortex?
Loss of texture discrimination
Lesions of Area 2 of primary sensory cortex?
Loss of size and shape discrimination (astereognosis)
Lesions of Area 3b of primary sensory cortex?
Both diminished texture discrimination and astereognosis
Lesion in posterior spinal artery will affect?
Posterior column
Lesion in anterior spinal artery will affect?
Medial lemniscus
Lesion of Thalamogeniculate branches of the posterior cerebral artery will affect?
VPL and VPM
Lesion of the anterior and middle cerebral arteries?
Primary sensory cortex
Lesion of the basilar and superior cerebellar arteries?
Principal sensory and mesencephalic trigeminal nuclei
Posterior Column Medial Lemniscus pathway?
Primary afferent fibers ascend through the posterior column and synapse in the gracile (LE) or Cuneate (UE) nuclei. Crosses at the medial lemniscus. Synapses again in teh VPL of the thalamus and then goes to somatosensory cortex
Mesencephalic Nucleus carries what?
Proprioceptive info from muscles of mastication, muscles of facial expression, and EOM
Chief sensory nucleus of CN V carries what?
Discriminative touch from skin and mucosa of head
Spinal trigeminal nucleus caries what?
Pain and temperature information from skin and mucosa of head
Anterior trigeminothalamic tract?
ATTT synapses in either the mesenscephalic nucleus, chief sensory nucleus, or spinal trigeminal nucleus (depending on the type of info being carried). Crosses and ascends just posterior to medial lemniscus and as the medial lemniscus shifts in the midbrain, the ATTT remains medial. Some of the reticular formation recieves input from the ATTT. Synapses in the VPM of the thalamus. Then goes to primary somatosensory cortex.
Posterior trigeminothalamic tract?
Synapses in the mesencephalic, chief sensory, or spinal trigeminal nulcei. Ascends just anterior to the periaqueductal gray. Remains uncrossed. Synapses in VPM of thalamus, then goes to primary somatosensory cortex.
Spinocerebellar pathways transmit what kind of info?
Nonconscious proprioceptive info to the cerebellum
Nonconscious proprioception for LE transmitted through what pathways?
Anterior and posterior spinocerebellat tracts
Nonconscious proprioception for UE transmitted through what pathways?
Rostral spinocerebellar and Cuneocerebellar tracts
Friedrich ataxia?
Congenital autosomal recessive disease. Degeneration of spinal cord pathways, including the major spinocerebellar tracts. Leads to lack of coordination during walking and other movements (no sensory feedback to the cerebellum necessary to regulate movements)
Anterior spinocerebellar tract?
Info from mostly cutaneous mechanoreceptors in the lower limb synapse in lamina V, VII, and the spinal boarder cells of L3-L5. Crosses at the anterior comissure at the level of the synapse. Ascends through the anterior spinocerebellar tract. Enters Superior cerebellar peduncle. Then goes to the lateral cerebellar vermis (most of the fibers recross)
Posterior spinocerebellar tract?
Info from proprioceptors and some mechanoreceptors in teh LE synapse in the Dorsal nucleus of Clark (Lamina VII, T1-L2). Remain ipsilateral. Ascend through the posterior spinocerebellar tract. Go through the restiform body and into the medial cerebellar vermis.
Rostral spinocerebellar tract?
Info from cutaneous mechanoreceptors of the UE synapse in lamina VII of the cervical enlargement (C4-C8). Ascend ipsilaterally through teh anterior spinocerebellar tract. Go through the restiform body/superior cerebellar peduncle. Enter the lateral cerebellar vermis.
Cuneocerebellar tract?
Info from proprioceptors and a few cutaneous mechanoreceptors of the UE ascend ipsilaterally through the cuneocerebellar tract. Synapse in the lateral cuneate nucleus. Enter the restiform body and enter the medial cerebellar vermis.
ALS: Spinothalamic tract?
Primary afferent fibers synapse in lamina I, V, or II. Ascends one or two levels and crosses at the anterior commisure. Ascends and synapses in the VPL of the thalamus (some fibers have also gone to the reticular formation). From the VPL fibers enter the somatosensory cortex.
ALS: spinoreticular tract?
Primary afferent fibers synapse in Lamina II, III and then interneurons synapse in lamina V, VIII. Crossing occurs at the anterior commissure (1-2 levels up). Synapses in reticular formation. Synapses again in intralaminar and posterior nuclei of the thalamus. Then goes intralaminar nuclei of the cortex and striatum if the info is localized pain, or in the post-thalamic nuclei in the secondary somatosensory and retroinsular cortex if the info is dull, persistent pain.
