Cerebral Cortex the outer layer of the Cerebrum

Cerebral Cortex: the outer layer of the Cerebrum gyri Grey matter 灰質 White matter 白質 Sulci ♦ thickness from 2 to 4 mm ♦ surface area ~ 0. 12 m 2 Cerebral Cortex & White matter

Types of Cerebral Cortex Neocortex (新皮質) ♦ “new” cortex ♦ 6 -layered cortex ♦ covering 90% of the cortex Allocortex (異源皮質) Paleocortex ♦ 3 -layered cortex ♦ Olfactory system (嗅覺系統) Archicortex ♦ 3 -layered cortex ♦ Hippocampus (海馬迴) ♦ Memory consolidation Cerebral Cortex & White matter

Division of Cerebral Cortex 額葉 Central sulcus 頂葉 Lateral sulcus 顳葉 枕葉 Cerebral Cortex & White matter

Principal neurons of Cerebral Cortex apical dendrite soma basal dendrites Pyramidal cell (錐體細胞) ♦ is an excitatory neuron. ♦ glutamate (谷胺酸) as the neurotransmitter (glutamatergic). ♦ has a pyramidal shape cell body or soma. ♦ has an apical dendrite and multiple basal dendrites with many dendritic spines on them. ♦ has one axon that projects locally or to long-distance targets. ♦ Betz cells are the largest pyramidal cells found in primary Cerebral Cortex & White matter motor cortex.

Interneurons of Cerebral Cortex Glutamate, excitatory GABA, inhibitory Cerebral Cortex & White matter

Laminar organization of Cerebral Cortex Molecular External granular External pyramidal Afferent = incoming Internal granular (視丘) Internal pyramidal Multiform Efferent = outgoing Cerebral Cortex & White matter

Cytoarchitecture-based area system Cerebral Cortex & White matter

Brodmann areas 布羅德曼分區 Korbinian Brodmann, 1909 Cerebral Cortex & White matter

Ways to study Brain Functions Invasive ♦ Accidents ♦ Brain surgeries ♦ In Vivo electrical stimulation/recording ♦ EEG (Electroencephalogram) Non-invasive ♦ CT scan (Computerized Tomography) ♦ MRI (Magnetic Resonance Imaging) ♦ PET scan (Positron Emission Tomography) ♦ Functional MRI Cerebral Cortex & White matter

Phineas Gage (1823 -1860) (An accident leading to frontal lobe injury) His personality and behaviors were reported to be drastically changed from before the accident. Since then, he was unable to hold a job. He died in 1860 from status epilepticus, almost 13 years after the accident. A recent study estimates 11% white matter and 4 % cortex of his frontal lobe was damaged (Van Horn 2012). In 1848, a 25 -year-old American railroad construction foreman Gage accidently had his head impaled by an iron rod while surprisingly survived this head trauma. Cerebral Cortex & White matter

Electroencephalogram (EEG) 腦電圖 Cerebral Cortex & White matter

CT (電腦斷層掃描) and MRI (核磁共振造影) Tools for detecting brain morphological changes CT MRI CT *FLAIR: fluid-attenuated inversion recovery *PD: proton density *GRE: gradient echo sequences MRI X-ray radio frequency radiation magnetic field low cost high cost 30 s ~ 5 min 10 min~2 hr Bone soft tissues Cerebral Cortex & White matter

Positron Emission Tomography (PET) 正子斷層掃描造影 Cerebral Cortex & White matter

Functional MRI (f. MRI) - detecting blood oxygenation-level dependent (BOLD) contrast Cerebral Cortex & White matter

Sensory areas ♦ Primary Somatosensory Cortex (S 1; BA 3, 1 & 2) ♦ Primary Visual Cortex (V 1; BA 17) Secondary Visual Cortex (V 2; BA 18) Associative Visual Cortex (V 3, V 4 & V 5/MT; BA 19) ♦ Primary Auditory Cortex (A 1; BA 41, 42) ♦ Primary Gustatory Cortex (G 1; BA 43) ♦ Primary Olfactory Cortex (BA 27) Cerebral Cortex & White matter

Primary Somatosensory Cortex (Postcentral gyrus of parietal lobe) Cerebral Cortex & White matter

Somatosensory Homunculus Somatosensory Motor Penfield and Rasmussen 1950 Cerebral Cortex & White matter

Wilder Penfield – first to identify motor and somatosensory homunculus Wilder Penfield 1891 -1976 Penfield and Boldrey 1934 Cerebral Cortex & White matter

Data from the original paper Penfield and Boldrey 1934 Cerebral Cortex & White matter

Primary Visual Cortex (striate cortex of occipital lobe) Cerebral Cortex & White matter

Where and What Visual Pathways ♦ Posterior Parietal Cortex (PPC; BA 5, 7) V 3: colors V 4: objects V 5: movement Cerebral Cortex & White matter

Primary Auditory Cortex (Temporal lobe ) Cerebral Cortex & White matter

Primary Auditory Cortex Cerebral Cortex & White matter

Primary Gustatory Cortex Cerebral Cortex & White matter

Primary Olfactory Cortex Periamygdaloid, Pirifrom and Entorhinal cortex Vaughan & Jackson 2014 Cerebral Cortex & White matter

Motor areas ♦ Primary Motor Cortex (M 1; BA 4) ♦ Premotor Cortex (PMA; BA 6) ♦ Supplementary Motor Cortex (SMA; BA 6) ♦ Frontal Eye Fields (FEF; BA 8) ♦ Broca’s area (BA 44, 45) Cerebral Cortex & White matter

Motor areas ♦ Primary Motor Cortex: movement of body parts ♦ Premotor Cortex: postural stability ♦ Supplementary Motor Cortex: motor planning Akinesia: inability to initiate movement ♦ Frontal Eye Fields (FEF; BA 8): voluntary saccades ♦ Broca’s area (BA 44, 45): speech production

Higher Order Association areas ♦ Prefrontal cortex (PFC; BA 9, 10, 11, 12, 46, 47) ♦ Language areas Broca’s area (BA 44, 45) Wernicke’s area (BA 22) ♦ Fusiform face area (FFA; BA 37) Cerebral Cortex & White matter

Prefrontal Cortex Representing your human qualities abstract thinking, thought analysis, data analysis, regulating behavior, making choices between right and wrong, predicting possible outcome, attention, intelligence, short-term memory satisfaction, reward, food flavor. Cerebral Cortex & White matter

Language areas Aphasia (失語症): language and speech disorder often caused by damages to language areas (generally left hemisphere) Broca’s aphasia ♦ Impaired speech fluidity ♦ Intact comprehension ♦ Expressive aphasia Wernicke’s aphasia ♦ Impaired comprehension ♦ Intact speech fluidity but incomprehensible ♦ Receptive aphasia Cerebral Cortex & White matter

Fusiform Face Area (Fusiform gyrus of temporal lobe) Prosopagnosia (臉盲症): Face blindness, unable to recognize faces (including one’s own face), caused by damage to occipital and/or fusiform face areas. Apperceptive prosopagnosia ♦ is unable to recognize “face”. ♦ may be able to recognize a person via other cues such as voice and clothing. Associative prosopagnosia ♦ is able to recognize face but is unable to associate the face with any information. Cerebral Cortex & White matter

White matter ♦ contains myelinated axons. ♦ Association fibers connect cortical areas of the same hemisphere. ♦ Commissural fibers connect cortical areas of the opposite hemisphere and go across corpus callosum (胼胝體) and anterior commissure. ♦ Projection fibers go to subcortical areas including basal ganglia, thalamus and spinal cord. Cerebral Cortex & White matter

Myelin ♦ is lipid-based substance that provides insulation to axons of neurons and helps electrical transmission. ♦ Myelination is done by oligodendrocytes (central) and schwann cells (peripheral). ♦ Demyelination is the loss of myelin sheath of the neurons and may result from autoimmune problems. Cerebral Cortex & White matter

Questions Cerebral Cortex & White matter