Spinal Pathways CD-ROM Case V: Spinal Cord Injury Notes: Chapter 7, p

Spinal Pathways 1: Objectives Concepts: 1.Review: the general anatomical and functional regions within the gray and white matters of the spinal cord. 2.Conceptualize the arrangement of nucleus groups in the gray matter. 3a. Identify the major ascending and descending pathways. b. Conceptualize the somatotopic organization of the pathways. Descending Pathways: 3.Trace the pathway of the corticospinal/pyramidal tracts.

Objective 1: Anatomical & Function Regions CD-ROM, Introduction to Nervous System, Spinal Cord, frame 3-4, Notes: p. 53, Sections – 7.1.2

Objective 2: Arrangement of Gray Matter Notes: p. 53, Fig. 7-1 FYI Only

Objective 3a: Major Ascending & Descending Tracts Notes: p. 55, Sections, Fig.7-3 Major ascending pathway: dorsal column / lemniscal pathway spinothalamic tract dorsal spinocerebellar tract ventral spinocerebellar tract spinoreticular tract Major descending pathways: corticospinal tract (lateral and anterior) vestibulospinal tract descending autonomic tract tectospinal tract reticulospinal tract FYI Only

Objective 3b: Somatotopic organization of the tracts Notes: p. 54, Fig. 7-2 Sacral

Objective 4-1: Lateral Corticospinal /Pyramidal Tract Case V, Frame 4 Notes: p , Sections 7.4.1, Fig. 7-4 Upper motor neuron from L.L., Trunk, and U.L areas of the motor cortex descends in the pyramidal tract Corona radiata and internal capsule Through: Crus cerebri Deep to the pontine n. and pontocerebellar tract Pyramid Crosses to the contralateral side at the decussation of the pyramid Then: Descends as lateral corticospinal tract in the lateral funiculus Enters ventral horn, and

Objective 4-2: Ant. (Ventral) Corticospinal /Pyramidal Tracts Case V, Frame 5 Notes: p , Sections 7.4.2, Fig. 7-4 Upper motor neuron from Trunk area of the motor cortex descends in the pyramidal tract Corona radiata and internal capsule Through: Crus cerebri Deep to the pontine n. and pontocerebellar tract Pyramid Ventral funiculus of the spinal cord Then: At the level of exit, crosses to contralateral side of the spinal cord via the ant. white commissure and enters ventral horn. Synapses with alpha motor neuron (lower motor neuron) which then exits via ventral root to innervate deep muscles in the back in the cervical and upper thoracic levels.

Review: Corticobulbar Tract Case V, Frame 6 (Frame 6 typo: …except CN I, II, VIII) Notes: p , Sections 7.4.3

Summary: Spinal Pathways 1 - Introduction and Descending Pathways 1.Concepts: Organization of the gray and white matter. 2.Laminae of the gray matter. 3.Somatotopic representation of the tracts. 4.Corticospinal tracts: Lateral (90%, crosses at caudal pyramid) & anterior (10%, crosses at level of exit).

Spinal Pathways 2: Objectives Ascending Pathways: 4.Trace the dorsal column/lemniscal pathway. 5.Trace the pathway of the spinothalamic tract. 6.Trace the pathway of the dorsal spinocerebellar tract. Spinal cord lesions: 7.Examine the effects of lesions in the spinal cord.

Objective 3b: Somatotopic organization of the tracts Notes: p. 54, Fig. 7-2 Sacral

Objective 4: Dorsal Column/ Lemniscal tracts Case V, Frame Notes: p , Fig. 7-5 Upon reaching caudal medulla, axons of the f. gracilis and f. cuneatus synapse with 2nd order neurons in n. gracilis and n. cuneatus respectively. 1st order neuron from thoracic and cervical levels enter dorsal horn, and ascend in f. cuneatus 1st order neuron from sacral and lumbar levels enter dorsal horn, and ascend in f. gracilis Axons of the 2 nd order neurons immediately decussate to contralateral caudal medulla and ascends in medial lemniscus M Medial lemniscus Upon reaching VP nucleus of the thalamus, axons in the Medial lemnisus synapse with 3rd order neurons which travel to respective areas of sensory cortex

Objective 4: Somatotopic Representation of Dorsal Column/Lemniscal tracts FG: Fasciculus Gracilis FC: Fasciculus Cuneatus NG: Fasciculus Gracilis NC: Fasciculus Cuneatus Trigeminal Nucleus

Objective 5: Spinothalamic tract Case V, Frame 13 Notes: p , Fig st order neuron enters enter dorsal horn, and synapses with 2 nd order neuron 2 nd order neurons immediately decussate to lateral funiculus and ascend as spinothalamic tract 2 nd order neurons ascend through the brain stem Upon reaching VP nucleus of the thalamus, axons of spinothalamic tract synapse with 3rd order neurons which travel to respective areas of sensory cortex

Objective 5: Somatotopic Representation of the Spinothalamic Tract Spinothalamic Tract

Objective 6: Dorsal Spinocerebellar tract Case V, Frame 14 (FYI: 15) Notes: p , Fig st order neuron enters enter dorsal horn, and synapses with 2 nd order neuron. Axons of 2 nd order neurons immediately enter lateral funiculus on the ipsilateral side and ascend to brain stem Upon reaching rostral medulla, 2 nd order neuron enters cerebellum via inferior cerebellar peduncle

Objective 7-1: Spinal Cord Lesion – Ascending and Descending Tracts Case V, Frame 7, 16; Case Description and Discussion Notes: p. 60

Objective 7-2: Syringomyelia Case V, Frame 17 Notes: p. 60 Occurs mostly in the cervical area of the spinal canal. Results in bilateral loss of sensitivity to pain and temperature because of obliteration of spinothalamic tract decussating in the white commissure.

Objective 7-3: Arterial supply of the Spinal Cord Case V, Frame 18TYPO in Frame 18: Radiculospinal artery, Notes: p. 60not radicular artery

Spinal Pathways: Summary 4.Dorsal column/lemniscal tract: (x medulla oblongata) 5.Spinothalamic tract: (x level of entry) 6.Dorsal spinocerebellar tract: (no x) 7.Lesions

Limbic System CD-ROM Case VII: A Confused Alcoholic Notes: p Objectives: 1a. Identify the cortical components of the limbic system. 1b. Identify the subcortical components of the limbic system 2. Describe a general pathway of the Circuit of Papez.

Cingulate Gyrus (Mamillary Body) Uncus/ Amyglada Parahippcampal Gyrus Hippocampal Formation Fornix Objective 1a: Cortical Limbic Structures Cerebral Cortex Septal area N. accumbens Basal Forebrain

T H Mamillary Body (Fornix) Objective 1b. Subcortical Limbic Structures Reticular Formation

Cingulate Parahippocampal Prefrontal Association Visual Association Cortical: Neocortex Mesocortex Archiocortex Subcortical: Diencephalon Brain Stem Hippo. F. Hippocampal Formation Fornix (axonal tract) Amygdala (?) A F F F T HT MB: Mamillary Body TH: Hypothalamus T: Ant. Thalamic N. MB Reticular Formation Autonomic & Locomotive Ctr. BS Circuit Of Papez Recently Described Circuits Notes: p. 63, Fig. 8-1