Transcript Last Lecture http://www.umich.edu/~psycours/345/

Last Lecture
http://www.umich.edu/~psycours/345/
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What is Cognitive Neuroscience?
Historical Roots
Phrenology
Modern Neuropsychology: Broca, Wernicke
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Study of lesion effects: Prism on the mind
Experimental vs. clinical neuropsychology
Today’s Lecture
Getting around the brain
 Orientational Terminology
 Gross Neuroanatomy
 Maps
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Cytoarchitectonic
 Projections Maps
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Directional Terms
Planes of Section
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Frontal plane:
coronal section
Sagittal plane :
medial and
parasagittal
section
Horizontal plane:
transaxial or
horizontal
section
Planes of Section
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Frontal plane:
coronal section
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Planes of Section
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Sagittal plane :
medial &
parasagittal section
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Planes of Section
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Horizontal plane:
horizontal or
transaxial
section
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Photo
PET
Major Subdivisions:
Forebrain, Midbrain, Hindbrain
Hindbrain
 Medulla
 Pons
 Cerebellum
Midbrain
 superior
colliculus
 inferior
colliculus
 Motor nuclei
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Major Subdivisions:
Forebrain, Midbrain, Hindbrain
Hindbrain
 Medulla
 Pons
 Cerebellum
Midbrain
 superior
colliculus
 inferior
colliculus
 Motor nuclei
Forebrain
 neocortex/cortex
 limbic system
 basal ganglia
 olfactory system
 thalamus /
hypothalamus
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Our primary focus: Neocortex
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Phylogenetically
youngest
structure
Well developed
only in mammals
Accounts for 9
billion of the 12
billion neurons in
the human
nervous system.
Terminology (for a
convoluted surface)
Fissure: Deep cleft
Sulcus: Shallow cleft
Gyrus: Ridge
Major Landmarks
Longitudinal Fissure: separates
Left & Right hemispheres
Central Fissure: separates parietal
and frontal
Lateral (Sylvian) Fissure
dorsal boundary of temporal lobe
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Four Lobes:
Named for overlying skull
bones
Offer "crude" functional
(sensory-motor) parse
 Frontal: voluntary motor
control
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Parietal: somatosensory
Temporal: auditory
Occipital: visual
Blood Supply to the Brain
(highlights)
Internal Carotid arteries- supply
only cortex
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anterior cerebral artery
middle cerebral artery
Vertebral Arteries- supply
brainstem, cerebellum and
cortex
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posterior cerebral artery
 occipital,
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tectum
temporal lobes
Principles of Cortical Organization:
Cytoarchitectonic Maps & Projection Maps
Map:
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system for classifying & defining cortical organization
orderly representation on cortical surface
structural basis for defining an area's function
function
can follow closely from structure
(e.g. projection maps)
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Cytoarchitecture
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Gray matter is 2 mm thick.
6 layers differing in number,
type, density of cells.
2 & 4 : receiving layers
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3, 5 & 6: sending layers
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fibers from sensory and
association cortex
thicker in sensory cortex
3 association cortex and
commissures
5 brainstem and spinal cord
6 thalamus
thicker in motor cortex
Thalamocortical, corticothalamic &
Corticocortical connections (intra
and interhemispheric)
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Cytoarchitectonic Maps:
Complex micro-structure of neural tissue
Brodmann's (1909) Map
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Classified regions based
on density of cell layers
Identified about 50
distinct areas
Structural classification -> functional differences
system widely used to
refer to areas of interest.
Cytoarchitectonic Maps:
Complex micro-structure of neural tissue
Brodmann's (1909)
Map
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Classified regions
based on cell layers
Identified 52 areas
Structural
classification -->
functional differences
system widely used
to refer to areas of
interest.
Projection Maps
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defined by their input
What gets mapped
depends on the
sensory modality
vision-- visual space
auditory-- pitch
(frequency)
touch-- body surface
Properties of Cortical
Organization
Hierarchical Organization
 ranking based on modality
specificity & complexity of
functions
Contralateral Organization
 e.g. LH represents:
 Right
Visual Field
 Right side of body
 Right Ear Input
 Vice versa for RH
Functional Segregation
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“modules” with specialized
functions
Generic (simplified)
Pathway:
SENSORY RECEPTOR
THALAMIC NUCLEUS
PRIMARY CORTEX
SECONDARY CORTEX
ASSOCIATION CORTEX