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
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
Apraxia The inability to execute a voluntary motor movement despite being able to demonstrate normal muscle function.
Language Speech Writing Calculation 3D perception Singing Playing Musical instrument
Roger Sperry (1913-1994) 1981 Nobel Laureate Split Brain Commissuratomy (split corpus callosum) Two minds in one brain?
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
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
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
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
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
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
Muhammad Ali in Alanta Olympic Parkinson’s Disease Disease of mesostriatal dopaminergic system PD normal
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
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
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