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Cerebral Cortex
Lecture 4
Functional Specialization So Far
• Neurons and Nerves– Afferent, Efferent,
Interneurons• Peripheral Nervous
System– Autonomic
• Sympathetic, Parasympathetic
– Somatic• Afferent, Efferent
Pathways
• Brain– Hindbrain
• Pons, Medulla, Cerebellum
– Midbrain• Reticular Formation
– Forebrain Subcortical Structures
• Hypothalamus• Hippocampus• Amygdala
2
3
Topography of Cerebral CortexTelencephalon
Lateral View
Medial View
4
Locating Yourself in the Brain
5
Folds in Cerebral Cortex
•Gyrus (Gyri)•Inferior Frontal•Superior Temporal
•Sulcus (Sulci)•Central Sulcus•Parieto-Occipital•Pre-Occipital Notch
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Cytoarchitectonicsof the
Cerebral CortexBrodmann (1909)
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Primary Motorand
Somatosensory Areas
•Primary Motor Cortex•Precentral Gyrus
•Brodmann Area 4•Premotor Cortex
•Brodmann Area 6•Brodmann Area 8
•Postcentral Gyrus•Brodmann Areas 1-3
8
Consequences of StrokeInsufficient Blood Supply to Brain
• Paralysis – voluntary motor function
• Anesthesia– tactile sensation
• Aphasia – speech, language
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Sensory and Motor HomunculusPenfield & Jasper (1954)
ScientificAmerican
11/79
FrontalLobe
ParietalLobe
Lateral Fissure
Longitudinal Fissure
Central Fissure
10
•Primary Auditory Cortex•Superior Temporal Gyrus
•Heschl’s Gyrus (AI)•Brodmann Areas 41, 42•“Tonotopic” Organization
•Primary Visual Cortex•Striate Cortex (VI)
•Brodmann Area 17•“Retinotopic” Organization
•Extrastriate Cortex•Brodmann’s Areas 18, 19
Primary Auditoryand Visual Areas
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Specialization in Extra-Striate Cortex
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“Association Areas”
• Posterior– Perceptual Integration
• Frontal– Executive Functions– Problem-solving
• “Prefrontal” Cortex– Frontal Gyri
• Superior, Middle, Inferior
– Frontal Sulci• Superior, Inferior
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Some Common Neurological Symptoms
Amnesia AphasiaAlexia
Agraphia AcalculiaApraxiaAgnosia
(Memory)(Speech)(Reading)(Writing)(Math)
(Action)(Knowledge)
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Major Syndromes of Aphasia
• Broca’s Aphasia: “Expressive”– Slow, Labored, Inarticulate Speech
• Possible Problems with Writing, Reading Aloud– Speech Comprehensible– No Problems Understanding Speech, Reading
• Wernicke’s Aphasia: “Receptive”– Fluent (Phonetics, Grammar)– Paraphasias– Semantic Deviance– Problems Understanding Speech, Writing
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Language Centers in the Brain
Scientific American
16
Coordination of Language FunctionsPetersen et al. (1988, 1989)
Scientific American
fMRI
Electrocorticogram of Verb GenerationEdwards et al. (2007, 2010)
Courtesy of R.T. Knight
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Wernicke’sArea
MotorCortex
Broca’sArea
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Face Recognition in the Fusiform Gyrus
• Prosopagnosia– Bodamer (1947)– Brodmann Area 37
• Also Areas 18, 19
• fMRI in Face Recognition• “Fusiform Face Area” (?)
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Self-Regulation in the Anterior Cingulate Gyrus
• Part of Limbic Lobe– Anterior Cingulate Cortex
• “ACC”
• Executive Functions– Controlled Processing
• Self-Regulation– Error Detection– Conflict Monitoring
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The Parietal Cortex and Attention
• Hemispatial Neglect– Contralateral
• Temporoparietal JunctionTypical performance by a “neglect” patient on the line-bisection task
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Imaging the Stage Model of AttentionFan et al. (2005), after Posner & Peterson (1990)
• Alerting and Interruption– Fronto-Parietal– Thalamus
• Orienting and Localizing– Superior Parietal
• Executive Control– Anterior Cingulate Gyrus– Frontal
• Disengage• Move (Shift)• (Re-) Engage• Inhibit
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Old and New Views of Specialization
Cerebral CortexFunctional Specialization So FarTopography of Cerebral Cortex�TelencephalonLocating Yourself in the BrainFolds in Cerebral Cortex�Primary Motor�and � Somatosensory �AreasConsequences of Stroke� Insufficient Blood Supply to BrainSensory and Motor Homunculus�Penfield & Jasper (1954)Primary Auditory�and Visual AreasSpecialization in Extra-Striate Cortex“Association Areas”Some Common Neurological SymptomsMajor Syndromes of AphasiaLanguage Centers in the BrainCoordination of Language Functions�Petersen et al. (1988, 1989)Slide Number 17Face Recognition in the Fusiform GyrusSelf-Regulation �in the Anterior Cingulate GyrusThe Parietal Cortex and AttentionImaging the Stage Model of Attention�Fan et al. (2005), after Posner & Peterson (1990)Old and New Views of Specialization