The axons of most paleospinothalamic 3° (nucleus proprius) afferents cross in the anterior white commissure to collect bilaterally in the spinothalamic tracts of the anterior (predominantly) and lateral funiculi. The 2° paleospinothalamic afferents (axons of the substantia gelatinosa) travel a short distance to terminate in or near the ipsilateral nucleus proprius on 3° afferents. The 3° neospinothalamic VPL neurons send their axons to the primary somatosensory cortex (i.e., the postcentral gyrus of the parietal lobe). Note that these 3° neospinothalamic VPL afferents differ from the VPL neurons synapsing with 2° afferent axons of the medial lemniscus. These 2° neospinothalamic afferent axons ascend the spinal cord and brain stem in the spinothalamic tract to terminate on 3° afferents in the ventral posterolateral (VPL) nucleus of the thalamus. The 2° neospinothalamic afferents (nucleus posteromarginalis axons) cross in the anterior white commissure to collect in the spinothalamic tract within the contralateral anterior and lateral (predominantly) funiculi. The paleospinothalamics end on 2° afferents in the substantia gelatinosa. The neospinothalamics end on 2° afferents in the nucleus posteromarginalis. The 1° afferents of the spinothalamic systems may end in the segment of root entry or one or two segments up. The lateral division axons branch and send fibers to the gray matter at the segment of entry and into the tract of Lissauer. Recall that fibers entering via the medial division of the posterior root are concerned with tactile, pressure, proprioception, and vibration sensations. The central processes of these 1° afferent neurons are the pseudounipolar cells of the posterior root ganglia and enter the spinal cord in the lateral division of the posterior root.
#Ventricular system of the brain free
The 1° afferents of the spinothalamic pathways send A-delta (neospinothalamic) and C (paleospinothalamic) fibers to the periphery where they form free nerve endings in skin, muscle, tendon, joint capsules and viscera. The archeospinothalamic pathway is a poorly defined pathway involved in a generalized sense of discomfort and diffuse pain. The “slower” conducting paleospinothalamic pathway is involved in conveying the “dull/burning” pain that accompanies the later inflammatory reaction in the damaged tissue as well as temperature and crude touch information.
The “fast” conducting neospinothalamic pathway is involved in conveying the “sharp/cutting” pain elicited at the time tissue is damaged. There are two well-defined spinothalamic pathways, chiefly concerned with pain and temperature sensations and with crude touch. Moderate to high quality evidence found increases in lateral and third ventricle volume, but not CSF, over time (4-520 weeks from baseline), which was not explained by antipsychotic use or duration of illness.Lab 3 (ƒ5) - Somatosensory, Viscerosensory and Spinocerebellar Pathways Spinothalamic Pathways Larger ventricular volume was associated with poorer overall functioning. Moderate to low quality evidence also found increased ventricular volume in children with schizophrenia. Moderate to high quality evidence found increased ventricular and CSF volume in people with schizophrenia compared to controls. What is the evidence for altered ventricular volume? The fourth ventricle is continuous with the central canal in the spinal cord, as well as three subarachnoid foramina allowing CSF to surround the brainstem and cortices. The interventricular foramen connects the lateral ventricles to the third ventricle, and the cerebral aqueduct connects the third ventricle to the fourth. The lateral ventricles have four sections, the frontal (anterior) horns temporal (inferior) horns body and occipital (posterior) horns. The system comprises the bilateral cerebral lateral ventricles, the midline third and fourth ventricles, and the central canal of the spinal cord. The ventricular system of the brain functions to provide support to surrounding tissues with cerebrospinal fluid (CSF), produced in the choroid plexus tissue lining many of the ventricles.
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