Transcript somatosensory&motor

Somatosensory Sensation
& Motor Functions
Interdisciplinary Program in Neuroscience
Eye Movement & Vision Research LAB
Hwang, Jae Won
Somatosensory Sensation
 Somatosensory Sensation
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Modalities
Receptors
Somatosensory Pathways
Somatosensory Cortex
 Motor Functions
 Disorders
Somatosensory Modalities
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Touch
Proprioception
Nociception
Temperature Sense
Ref. 1. Ch 22 p. 431
Morphology of DRG Cell
Ref. 1. Ch 22 p. 433
Mechanoreceptors (touch)
Ref. 1. Ch 21 p. 415
Mechanoreceptors (proprioception)
Ref. 1. Ch 22 p. 432
Receptor Types
Ref. 1. Ch 22 p. 434
Receptive Field (touch)
Ref. 1. Ch 22 p. 436
Two Point Discrimination
Distribution of Dermatomes
Ref. 1. Ch 22 p. 445
Spinal Cord
Ref. 1. Ch 18 p. 339 & Ref. 2. Ch 3 p.76
Ref. 3. http://thalamus.wustl.edu/course/bassens.html
Touch & Proprioception(joint) Pathway
Ref. 2. Ch 5 p. 195
Decussation of Medial Lemnisci
Ref. 3. http://thalamus.wustl.edu/course/body.html
Proprioception(muscle & tendon) Pathway
Ref. 1. Ch 24 p. 473-474
Nociceptive Afferent Fibers
Ref. 3. http://thalamus.wustl.edu/course/body.html
Pain & Temperature Pathway
Ref. 1. Ch 22 p. 447
Sensory Pathways (summary)
Ref. 1. Ch 22 p. 447
Sensory Pathways (summary)
Comparison of sensory pathway
description among the references
Decussation of
Medial Lemnisci
Spinocerebellar
Anterolater
(spinothalamic)
Ref. 1
Touch &
Proprioception
Pain &
Temperature
Ref. 2
Discriminative
touch, Vibration, &
Proprioception
Light Touch &
Pressure
Pain &
Temperature
Ref. 3
Discriminative
touch
Proprioception
Pain &
Temperature
Ref. 2. Ch 4 p. 145
Ascending & Descending Tracts
Ref. 2. Ch 4 p. 168
Segmental Organization of SC
Ref. 1. Ch 18 p. 343
Thalamus
Ref. 1. Ch 23 p. 453
Somatosensory Cortex
Ref. 1. Ch 23 p. 456
RF of Cell in a Column in SSC
Ref. 1. Ch 23 p. 455
Receptive Fields of Neurons in SSC
Ref. 1. Ch 23 p. 459
Columnar
Organization
of Sensory Input
Ref. 1. Ch 18 p. 344
Sensory Homunculus
Ref. 1. Ch 18 p. 345
Processing of Sensory Information
Motor Functions
 Somatosensory Sensation
 Motor Functions
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Brain Structures Involved in Motor Control
Motor Pathways
Motor Neurons
Neuromuscular Junction
 Disorders
Ref. 4. Ch 4 p. 144 & Ref. 1. Ch 38 p. 760
Motor Cortices
Ref. 1. Ch 19 p. 356
Flow of Motor Information
Ref. 1. Ch 38 p. 773
Supplementary & Premotor Areas
Ref. 4. Ch 4 p.148 & Ref. 1. Ch 28 p. 567
Parietal Cortex
Ref. 5. Ch 8 p. 216
Command Flow of Left PL
Ref. 1. Ch 42 p. 835
Cerebellum
Ref. 1. Ch 43 p. 856
Basal Ganglia
Ref. 3. http://thalamus.wustl.edu/course/basmot.html
Corticospinal
Tract
anterior corticospinal tract (about 10%)
lateral corticospinal tract
Ref. 2. Ch 5 p. 195
Pyramidal Decussation
Ref. 1. Ch 18 p. 346
Corticospinal Tract
Ref. 1. Ch 18 p. 346
Corticospinal Tract
Ref. 5. Ch 8 p. 212
Corticobulbar & Rubrospinal Tracts
Ref. 5. Ch 8 p. 213
Ventromedial
Pathways
Ref. 2. Ch 4 p. 165
Motor Neurons
Ref. 1. Ch 11 p. 188
Neuromuscular Junction
Disorders
 Somatosensory Sensation
 Motor Functions
 Disorders
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Spinal Cord Syndromes
Phantom Limb
Agnosia & Apraxia
Subcortical Motor Disorders
Neurogenic Diseases of Motor Unit
Ref. 2. Ch 4 p. 173
Spinal Cord Syndromes
Ref. 1. Ch 20 p. 393
Phantom Limb
Ref. 6. Ch 2 p. 32 & Ref. 7. p. 1610
MEG of Amputee
Agnosia
 The Inability to perceive or identify a stimulus by means of a
particular sensory modality, even though its details can be
detected by means of that modality and the person retains
relatively normal intellectual capacity
– Apperceptive visual agnosia
 People with apperceptive visual agnosia may have normal
visual acuity, but they cannot successfully recognize objects
visually by their shape.
 Prosopagnosia (Prosopon means “face”)
– Associative visual agnosia
 People with associative visual agnosia appear to be able to
perceive normally but cannot name what they have seen.
Ref. 1. Ch 62 p. 1235
Example of Agnosia
Apraxia
 The inability to properly execute a
learned skilled movement
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Limb apraxia
Constructional apraxia
Oral apraxia
Apraxic agraphia
Ref. 5. Ch 8 p. 215
Limb Apraxias
 Limb apraxia is character-
ized by movement of the
wrong part of the limb,
incorrect movement of the
correct part, or correct
mevements but in the
incorrect sequence.
Ref. 5. Ch 8 p. 216
Constructional Apraxia
 The primary deficit in
constructional apraxia
appears to involve the
ability to perceive and
imagine geometrical
relations.
 Dressing Apraxia
Ref. 5. Ch 6 p. 163
Balint’s syndrome
 Balint’s syndrome occurs in people with bilateral damage to
posterior parietal and prestriate cortex.
 Balint’s syndrome consists of three major symptoms.
– Optic ataxia (ataxia comes from the Greek word for “disorderly”)
 A person with BS might be able to perceive and recognize a particular
object, but when he or she tries to reach for it, the movement is often
misdirected.
– Ocular apraxia (“without visual action”)
 If an object moves, or if a light flashes, the person with BS may report
seeing something but will not be able to make an eye movement that
directs the gaze toward the target.
– Simultanagnosia
 If the gaze of a person with BS happens to fall on an object, he or she
will perceive it. But only one object will be perceived at a time.
Ref. 1. Ch 20 p. 394-396
Hemineglect
Ref. 1. Ch 43 p. 860
Parkinson’s Disease
Ref. 1. Ch 43 p. 860
Huntington’s Disease
Ref. 1. Ch 35 p. 697
Diseases of the Motor Unit
Ref. 1. Ch 16 p. 299
Myasthenia Gravis
References
1. Eric R. Kandel, James H. Schwartz, Thomas M. Jessell (2000) Principles of Neural Science, 4th ed.
New York, NY: McGraw-Hill
2. Richard S. Snell (2001) Clinical neuroanatomy for medical students, 5th ed. Baltimore, MD: Lippincott
Williams & Wilkins
3. Diani W. Molavi (1997) Neuroscience tutorial Retrieved from WWW April 19, 2003.
http://thalamus.wustl.edu/course/
4. Marie T. Banich (1997) Neuropsychology Boston, MA: Houghton Miffin
5. Neil R. Carson (1995) Foundations of physiological psychology, 3rd ed. Needham, MA: Allyn & Bacon
6. V.S. Ramachandran, Sandra Blakeslee (1998) Phantoms in the brain New York, NY: HarperCollins
7. Ramachandran VS, Hirstein W. (1998) The perception of phantom limbs. The D. O. Hebb lecture Brain,
121, 1603-1630