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Lecture X. Brain Pathways: Movement Bio 3411 Monday October 4, 2010 1Lecture X. Brain Pathways: Movement.

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Presentation on theme: "Lecture X. Brain Pathways: Movement Bio 3411 Monday October 4, 2010 1Lecture X. Brain Pathways: Movement."— Presentation transcript:

1 Lecture X. Brain Pathways: Movement Bio 3411 Monday October 4, 2010 1Lecture X. Brain Pathways: Movement

2 October 4, 2010Lecture X. Brain Pathways: Movement 2 Neuroscience 4 th ed Page(s)Feature 423-451Upper motor control of Brain Stem and Spinal Cord The Brain Atlas 3 rd ed Page(s)Feature 198-199 Vestibular Pathways 200-201 Direct Corticospinal tract 202-203 Rubrospinal and Tectospinal tracts 204-205 Reticulospinal Pathways Readings (background only)

3 October 4, 2010Lecture X. Brain Pathways: Movement 3 † Gleeson, J. G., Keeler, L. C., Parisi, M. A., Marsh, S. E., Chance, P. F., Glass, I. A., Graham Jr, J. M., Maria, B. L., Barkovich, A. J., & Dobyns, W. B. (2004). Molar tooth sign of the midbrain-hindbrain junction: occurrence in multiple distinct syndromes. Am J Med Genet A, 125A(2), 125-134; discussion 117. † Sicotte, N. L., Salamon, G., Shattuck, D. W., Hageman, N., Rub, U., Salamon, N., Drain, A. E., Demer, J. L., Engle, E. C., Alger, J. R., Baloh, R. W., Deller, T., & Jen, J. C. (2006). Diffusion tensor MRI shows abnormal brainstem crossing fibers associated with ROBO3 mutations. Neurology, 67(3), 519-521. † Tovar-Moll, F., Moll, J., Bramati, I. E., de Souza, A. S., Andreiuolo, P. A., & de Oliveira-Souza, R. (2007). The human pyramidal syndrome Redux. Neuroreport, 18(14), 1417-1421. † Vulliemoz, S., Raineteau, O., & Jabaudon, D. (2005). Reaching beyond the midline: why are human brains cross wired? Lancet Neurol, 4(2), 87-99. _________________ † (pdfs on course websites: [http://artsci.wustl.edu/~bio3411/] & [http://www.nslc.wustl.edu/courses/Bio3411/bio3411.html] References

4 October 4, 2010Lecture X. Brain Pathways: Movement 4 What the last Lecture was About Sensory Transduction Receptive Fields Adaptation Feature Detection Maps Sensory Integration

5 October 4, 2010Lecture X. Brain Pathways: Movement 5 Overview Corticospinal Tract: Activation & Somatotopy Activity of Motor Cortex Neurons Directs Movement: Force & Direction Four Other Motor Pathways to Spinal Cord Role(s) of Descending Pathways in Movement Control Effects of Corticospinal Tract Lesion Why is left right, and right left?

6 Corticospinal (Pyramidal) Pathway. This is the direct connection from the cerebral cortex for control of fine movements in the face and distal extremities, e.g., buttoning a jacket or playing at trumpet. October 4, 20106Lecture X. Brain Pathways: Movement

7 October 4, 2010Lecture X. Brain Pathways: Movement 7 THE BRAIN ATLAS 3 rd, pp. 36, 43 Corticospial Tract (Pyramid) at Medulla

8 October 4, 2010Lecture X. Brain Pathways: Movement 8 THE BRAIN ATLAS, 3 rd ed., p. 147 Pyramidal Tracts Cross Section Through Human Medulla

9 October 4, 2010Lecture X. Brain Pathways: Movement 9 THE BRAIN ATLAS 3 rd ed, pp. 20, 201

10 October 4, 2010Lecture X. Brain Pathways: Movement 10 Normal Pyramid Electrical stimulation of different points in motor cortex with small currents (thresholds) causes different movements Cartoons of movements evoked by direct cortical stimulation. The shading indicates the joint(s) moved. Currents required to just provoke the above movements (threshold).

11 October 4, 2010Lecture X. Brain Pathways: Movement 11 The left hemisphere of the monkey brain - Motor (Ms) and Somatosensory (Sm) Maps

12 October 4, 2010Lecture X. Brain Pathways: Movement 12 A neuron in the motor cortex of of an awake behaving monkey fires when the wrist is extended (red arrow in diagram above). It fires more when more force is required (flexors loaded) and not at all if no contraction is needed to extend the rest (extensors loaded).

13 October 4, 2010Lecture X. Brain Pathways: Movement 13 A neuron in the motor cortex of of an awake behaving monkey fires in relation to the direction of the movement (see “tuning” curve - left). Each small vertical line marks an action potential of the neuron.

14 October 4, 2010Lecture X. Brain Pathways: Movement 14 Sources of Descending Pathways for Movement Control 4. 3. 2. 1. 4. Medulla (Reticular Formation and Vestibular Nuclei) 3. Pons (Reticular Formation) 2. Midbrain (Red Nucleus & Superior Colliculus) 1. Forebrain (Cortex)

15 October 4, 2010Lecture X. Brain Pathways: Movement 15 THE BRAIN ATLAS, 3 rd ed, p. 203 Rubrospinal Pathway. This pathway (from the red nucleus) mediates voluntary control of movements, excepting the fine movements of the fingers, toes and mouth.

16 October 4, 2010Lecture X. Brain Pathways: Movement 16 THE BRAIN ATLAS, 3 rd ed, p. 203 Tectospinal Pathway. This pathway (from the superior colliculus) mediates head and body orientation in response to localized visual, auditory and tactile stimuli, often from the same source.

17 October 4, 2010Lecture X. Brain Pathways: Movement 17 THE BRAIN ATLAS, 3 rd ed, pp. 199, 205 Vestibulospinal Pathways. These pathways (from the vestibular nuclei) mediates head and body orientation in response to changes in head linear and angular velocity and with respect to gravity. Reticulospinal Pathways. These pathways carry information from the brain stem reticular formation to the spinal cord to stabilize movement on uneven surfaces.

18 October 4, 2010Lecture X. Brain Pathways: Movement 18 Descending systems from the brain influence cells in the spinal cord to create movements. The cerebellum and the basal ganglia indirectly influence movements as indicated schematically here.

19 October 4, 2010Lecture X. Brain Pathways: Movement 19 NEUROSCIENCE (1 st ed), p. 319, Fig 16.8 Other cortical areas influence the initiation of movements to achieve particular goals through specific sequences, as in playing a scale on the piano. These areas are also activated when a person is instructed to think about performing the sequence without actually moving.

20 October 4, 2010Lecture X. Brain Pathways: Movement 20 THE BRAIN ATLAS 3 rd ed, pp. 36, 43 Corticospial Tract (Pyramid) at Medulla

21 October 4, 2010Lecture X. Brain Pathways: Movement 21

22 October 4, 2010Lecture X. Brain Pathways: Movement 22 After the pyramid was cut (lesioned) the opposite hand (the right hand) was used to try to get food from a well but all fingers were used. The monkey could not get food from the smallest well. The hand opposite the normal pyramid (the left hand) was used to get food from the small well by opposing the thumb and fore finger. The monkey got the food from the smallest well.

23 October 4, 2010Lecture X. Brain Pathways: Movement 23 Cut PyramidNormal Pyramid Electrical stimulation of different points in motor cortex with small currents (thresholds) causes different movements After the pyramid was cut the movements were coarser and the currents required to produce them were larger.

24 October 4, 2010Lecture X. Brain Pathways: Movement 24 (Tovar-Moll et al., 2007) Pyramid (CST) Normal Pathological

25 Normal Pathological October 4, 2010Lecture X. Brain Pathways: Movement 25 (Tovar-Moll et al., 2007) Pyramid (CST)

26 October 4, 2010Lecture X. Brain Pathways: Movement 26 The corticospinal (pyramidal) tract controls fine movements particularly of the lips, fingers and toes. When it is cut, other descending pathways such as the rubrospinal pathway can be used for grasping movements. These lack the precision of those activated by the corticospinal pathway and the monkey cannot pickup its food.

27 October 4, 2010Lecture X. Brain Pathways: Movement 27 Relative Size of Different Brain Parts In Phylogeny - The forebrain becomes relatively larger as new pathways (functions) are added.

28 October 4, 2010Lecture X. Brain Pathways: Movement 28 S. Ramón y Cajal, (1911) Histology of the Nervous System, Volume II. (English translation by N. & L. Swanson, Oxford: New York pp 309-310, 1995). Ramón y Cajal suggested that brain pathways are crossed to preserve the appropriate relationships after optical inversion by the lens as indicated schematically by the arrows in the uncrossed (left) and the crossed (right) visual pathways. Why are brain pathways “crossed”?

29 October 4, 2010Lecture X. Brain Pathways: Movement 29 (Vulliemoz, Raineteau, & Jabaudon, 2005) HGPS (horizontal gaze paralysis and progressive scoliosis)

30 October 4, 2010Lecture X. Brain Pathways: Movement 30 What this Lecture was about Corticospinal Tract: Activation & Somatotopy Activity of Motor Cortex Neurons Directs Movement: Force & Direction Four Other Motor Pathways to Spinal Cord Role(s) of Descending Pathways in Movement Control Effects of Corticospinal Tract Lesion Why is left right, and right left?

31 END October 4, 201031Lecture X. Brain Pathways: Movement


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