Cerebral Cortex


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Cerebral Cortex

  1. 1. Nabeel Kouka, MD, DO, MBA www.brain101.info Cerebral Cortex
  2. 14. Brodman’s Map of Motor and Sensory Areas
  3. 16. Sensory area primary sensory area secondary sensory area Motor area primary motor area secondary motor area supplementary motor area Association area parietal, occipital and temporal cortex - conceptual elaboration of sensory data prefrontal (frontal) cortex - judgement, foresight Functional Localization of Cerebral Cortex
  4. 17.  Agnosia Tactile agnosia Visual agnosia Alexia Auditory agnosia  Apraxia  Aphasia Wernicke’s (receptive) aphasia Broca’s (Motor) aphasia conduction aphasia global aphasia Disorders of Association Cortex
  5. 18. Apraxia The inability to execute a voluntary motor movement despite being able to demonstrate normal muscle function.
  6. 19. Cerebral Dominance (Lateralization, Asymmetry) Dominant Hemisphere Language – speech, writing Calculation Non-dominant Hemisphere Spatial Perception (3D subject) Singing Playing musical instrument
  7. 20. Language Speech Writing Calculation 3D perception Singing Playing Musical instrument
  8. 21. Roger Sperry (1913-1994) 1981 Nobel Laureate Split Brain Commissuratomy (split corpus callosum) Two minds in one brain?
  9. 22. Sensory Language Area (Wernike's area) ---- 22, 39, 40 Receptive Aphasia - area 22 defect in comprehension, good spontaneous speech Anomic Aphasia - word finding difficulty Jargon aphasia - fluent, but unintelligiable jargon 39 (supramarginal gyrus), 40 (angular gyrus) Superior Longitudinal (Arcuate) Fasciculus Conduction Aphasia good comprehension, good spontaneous speech poor repetition, poor response Motor Language Area (Broca’s area) --- 44, 45 Motor Apahsia good comprehension, no speech, agraphia Language Areas
  10. 23. Arcuate Fasciculus The groups of fibers that connect Broca's area with Wernicke's area (these fibers connect to the angular gyrus) and are located below the supramarginal gyrus. According to Geschwind, damage to this area results in Conduction Aphasia
  11. 24. Language Areas (Geschwind Model)
  12. 25. Photograph of the brain of Paul Broca’s patient called “Tan” (real name is Leborgne). Broca’s Area Pars triangularis and pars opercularis of the inferior frontal gyrus of dominant hemisphere.
  13. 26. Paul Broca (1824-1880) Carl Wernicke (1848-1905)
  14. 27. PET (positron emission tomography) scan
  15. 28. PET (positron emission tomography) scan
  16. 29. Composite radioisotope brain scan
  17. 30. Sensory Homunculus
  18. 31. Motor Homunculus
  19. 42. Diencephalon Dorsal surface
  20. 43. Diencephalon Ventral surface
  21. 44. Diencephalon Medial Surface
  22. 45. THALAMUS
  23. 46. Classification of Thalamic Nuclei I. Lateral Nuclear Group II. Medial Nuclear Group III. Anterior Nuclear Group IV. Posterior Nuclear Group V. Metathalamic Nuclear Group VI. Intralaminar Nuclear Group VII. Thalamic Reticular Nucleus
  24. 47. Classification of Thalamic Nuclei
  25. 48. Basal Ganglia
  26. 50. Traditional Concepts of Basal Ganglia Corpus Striatum Caudate Nucleus Lenticular Nucleus Putamen Globus Pallidus Paleostriatum Pallidum Corpus Amygdaloideum Archistriatum Neostriatum Striatum Basal Ganglia Introduction
  27. 51. Afferent Connections of Basal Ganglia
  28. 52. Efferent Connections of Basal Ganglia
  29. 53. Clinical Feature Principal Pathologic Lesion: Corpus Striatum (esp. caudate nucleus) and Cerebral Cortex - Predominantly autosomal dominantly inherited chronic fatal disease (Gene: chromosome 4) - Insidious onset: Usually 40-50 - Choreic movements in onset - Frequently associated with emotional disturbances - Ultimately, grotesque gait and sever dysarthria, progressive dementia ensues. HUNTINGTON’S CHOREA
  30. 54. SYDENHAM’S CHOREA - Complication of Rheumatic Fever - Fine, disorganized , and random movements of extremities, face and tongue - Accompanied by Muscular Hypotonia - Typical exaggeration of associated movements during voluntary activity - Usually recovers spontaneously in 1 to 4 months Clinical Feature Principal Pathologic Lesion: Corpus Striatum
  31. 55. HEMIBALLISM - Usually results from CVA (Cerebrovascular Accident) involving subthalamic nucleus - sudden onset - Violent, writhing, involuntary movements of wide excursion confined to one half of the body - The movements are continuous and often exhausting but cease during sleep - Sometimes fatal due to exhaustion - Could be controlled by phenothiazines and stereotaxic surgery Clinical Feature Lesion: Subthalamic Nucleus
  32. 56. Muhammad Ali in Alanta Olympic Parkinson’s Disease Disease of mesostriatal dopaminergic system PD normal
  33. 57. Substantia Nigra, Pars Compacta (SNc) DOPAminergic Neuron Slowness of Movement - Difficulty in Initiation and Cessation of Movement Clinical Feature (1) Parkinson’s Disease - Paralysis Agitans
  34. 58. Clinical Feature (2) Resting Tremor Parkinsonian Posture Rigidity-Cogwheel Rigidity Parkinson’s Disease Paralysis Agitans
  35. 59. Numerical Data  Number of neuronal cells in cerebral cortex neurons ----------- 10-15 billion glial cells ---------- 50 billion  Estimation of number of cortical neurons von Economo and Koskinas (1925) 14.0 billion Shariff (1953) 6.9 billion Sholl (1956) 5.0 billion Pakkenberg (1966) 2.6 billion Cerebral Cortex
  36. 60. Subdivision of Cerebral Cortex Allocortex Archicortex (Archipallium) Palaeocortex (Paleopallium) Isocortex Neocortex (Neopallium) cf. mesocortex, juxtallocortex, mesallocortex
  37. 61. Isocortex – typical 6 layered cortex I. Molecular Layer II. External Granular Layer III. External Pyramidal Layer IV. Internal Granular Layer V. Internal Pyramidal Layer VI. Polymorphic Layer
  38. 62. I. Molecular Layer II. External Granular Layer III. External Pyramidal Layer Line of Kaes-Bechterew IV. Internal Granular Layer Outer band of Baillarger - Line of Gennari in area 17 V. Internal Pyramidal Layer Giant pyramidal cell of Betz Inner Band of Baillarger VI. Polymorphic Layer Golgi Nissl Weigert