Download Neuro Anatomy

S D U M C
K O L A R
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Structure-function relationships
◦ Localization of function in the CNS
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Non-invasive brain imaging
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CAT: structure, low resolution
MRI: structure, high resolution
PET: function, low resolution
fMRI: function, high resolution
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Functional anatomy
◦ Neural structures that serve particular functions; e.g.,
pain path from skin to cortex for perception
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Regional anatomy
◦ Localization of structures in particular brain regions
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nissl
myelin
golgi
autoradiography
Immunohistochemistry
In vivo imaging
Arc-positive cells after varying amounts of sleep deprivation
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Neurons
◦ The main information processors
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Glia
◦ Important supporting roles
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Astrocytes
◦ support, nurturance
Oligodendroglia or Schwann cells
•insulation
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insulation
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Microglia
Represent the immune system in the brain
(protect from invasion, clean up debris)
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cell body
nucleus
dendrite
axon
myelin
boutons
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shape
◦ multipolar, unipolar, bipolar
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by shape
◦ multipolar, unipolar, bipolar
 by
size
◦ large (pyramidal, eg)
◦ small (granule, eg)
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by shape
◦ multipolar, unipolar, bipolar
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by size
◦ large (pyramidal, eg)
◦ small (granule, eg)
 by
function
◦ sensory neuron
◦ motor neuron
◦ interneuron
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Neurons communicate at synapses
synapses can be chemical or electrical, but
chemical synapses are more common
Synaptic terminology
Boutons, cleft, dendritic spines, postsynaptic membrane,
vesicles, transmitter, receptors
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Anterograde vs retrograde
microtubules and neurofilaments
Anterograde vs retrograde axonal transport
Terminology:
Afferents and efferents
convergence (many:one) and divergence
(one:many)
nuclei (containers of DNA) and
nuclei (collections of neurons)
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Rostral vs.
caudal
Dorsal vs.
ventral
Medial vs.
lateral
Superior vs.
inferior
Terminology:
Central nervous system (CNS) vs
Peripheral nervous system (PNS)
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Dura mater (tough mother)
arachnoid
pia mater
Major divisions of the brain
Sulci and gyri maximize surface area
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Thalamus
◦ A large mosaic of nuclei which contribute to
sensory and motor processing (you’ll meet several
of the nuclei later in the course when we look at
systems).
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Hypothalamus
◦ Located just inferior to the thalamus
◦ A collection of nuclei involved in motivated
behaviour (feeding, drinking, sexual behaviour)
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Tectum (roof)
◦ Superior and
inferior colliculi
Tegmentum
(floor)
◦ Some reticular
nuclei and
cerebellar relay
nuclei
◦ Also contains
substantia
nigra and crus
cerebri
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Cerebellum
◦ A ‘mini’ brain for computing skilled movements and
many other things
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Pons
◦ Many cranial nerve nuclei, reticular nuclei, long
tracts
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Pons (contains cranial nerve nuclei, reticular
nuclei)
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Cerebellum
◦ Many fine folds (folia) increase surface area
◦ Very large # of cells with very tight organization
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Some nuclei related to breathing, heart rate
(so-called vegetative functions)
Long tracts
How do thought, emotion and behavior
arise from this?
• Overview of brain anatomy & systems
– Localization/networks
– Scale in the nervous system
– Sensorimotor systems
• How our brains interact with the external world (loops)
– States ‘of mind’ (and body)
• Specific functional systems
– Memory & emotion
• How our brains use previous experience to modify behavior
• Vision & attention; language
•Animals & humans: anatomy, physiology, & behavior
•Tract tracing
•Single unit recordings
•Behavioral studies; pharmacology
•Patients with focal brain lesions
•Behavioral studies & post-mortem anatomy
•Structural imaging: In vivo structure/function
correlations
•Neuroimaging/brain mapping
•Functional neuroimaging
Phrenology (Gall, early 1800s)
1.The brain is the organ of the mind.
2. The mind is composed of multiple distinct, innate
faculties.
3. Because they are distinct, each faculty must have a
separate seat or "organ" in the brain.
1860s
1909
2005
 Protect by surrounding and buffering
 Speed transmission by forming myelin sheaths
Visual system
Visual system
Visual system
Visual system
Visual system
Visual system
1909
2005
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major brain systems subserving
cognition and behavior
Left perisylvian language network
Parieto-frontal network for spatial attention
Occipitotemporal network for object/face recognition
Medial temporal/limbic network for learning & memory
Prefrontal network for attention & comportment
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From Mesulam MM, Brain, 1998
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1) Tubular organization of central nervous
system
2) Columnar/longitudinal organization of spinal
and cranial nerve nuclei
3) Complex C-shaped organization of cerebral
cortex and deep structures
Tubular organization of central nervous
system
• Columnar/longitudinal organization of spinal
and cranial nerve nuclei
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Nuclei: locations of
neuron cell bodies w/in
the central nervous
system
Ganglia: locations of
neuron cell bodies in
the periphery
Tracts: locations of
axons w/in the central
nervous system
Nerves: locations of
axons in the periphery
Dorsal surface
Dorsal
root
Gray matter
White matter
Ventral surface
Ventral
root
Spinal nerve
NTA 1-4
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1) Tubular organization of central nervous
system
• 2) Columnar/longitudinal organization of spinal and
cranial nerve nuclei
• 3) Complex C-shaped organization of cerebral cortex
and nuclei and structures located beneath cortex
– Lateral ventricle
– Basal ganglia
– Hippocampal formation & Fornix
•Portion of the dorsal ectoderm becomes
committed to become the nervous system:
Neural plate
Neural
plate
Neural
groove
Neural
tube
White matter
Gray matter
Ectoderm
Neural tube wall:
neurons & glia of CNS
Neural tube cavity:
ventricular system
Neural crest: PNS
neurons, etc
NTA 3-1
Brain vesicles:
Rostral
Forebrain
Midbrain
Neural Tube Development
Hindbrain
Spinal cord
Caudal
Rostral neural tube forms the
brain
Caudal neural tube forms
the spinal cord
Cephalic
flexure
NTA 3-2
3-vesicle stage
5-vesicle stage
Forebrain
Cerebral
hemisphere
Midbrain
Diencephalon
Hindbrain
Midbrain
Pons &
Cerebellum
Medulla
Lateral
ventricle
3rd
ventricle
Cerebral
aqueduct
4th
ventricle
Spinal cord
Central
canal
Cephalic
flexure
NTA 3-2
…by the 5 vesicle stage, all 7 major
brain divisions are present
The cephalic flexure persists into maturity
Cephalic
flexure
NTA 1-13
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Segmentation
• Nuclear organization:
columnar
Alar plate
Sulcus
limitans
Dorsal horn
Central
canal
Basal plate
Ventral horn
Dorsal horn
Central
canal
Ventral horn
NTA 3-7
Dorsal horn
Dorsal
root
Ventral
root
Ventral horn
Similarities between SC and
brain stem development
•Sulcus limitans separates sensory and
motor nuclei
•Nuclei have columnar shape
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Key differences
1) central canal enlargement motor medial
and sensory lateral
2) migration away from ventricle
3) >> sensory and motor
Alar plate and
migrating
neuroblasts
Basal plate
NTA 3-8
4th Vent
Alar plate
Striated/branchio.
Striated/somite
Autonomic.
Vestibular/auditory.
Somatic sensory.
Sulcus limitans
Basal plate
Taste/viscerosensory
Inferior olivary
nucleus
Alar plate
Basal plate
NTA 3-9
4th Vent Alar plate
Striated/branchio.
Striated/somite
Vestibular/auditory.
Somatic sensory.
Taste/viscerosensory
Basal plate
Sulcus limitans
Autonomic.
Pontine nuclei
Alar plate
NTA 3-10
Basal plate
Cerebral aq.
Alar plate
Somatic sensory.
Autonomic.
Sulcus limitans
Basal plate
Sub. nigra
Striated/somite
Red
nucleus
More like spinal
Cord b/c fewer
nuclear classes
and cerebral aqueduct
Basal plate
NTA 3-11
Similarities between forebrain and
hindbrain/spinal development
•Tubular
Key differences
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1) CH more complex than BS/SC
2) Cortical gyri more complex anatomy than nuclei
3) Subcortical nuclei are C-shaped
◦ Confusing: structure in two places on image
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Thalamus
◦ Gateway to cortex
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Hypothalamus
◦ Control of endocrine and
bodily functions
◦ Circadian rhythms
◦ Etc.
NTA 3-14
Parietal
Occipital
Frontal
Temporal
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Cerebral cortex (NTA 3-15)
Lateral ventricles (NTA 3-16)
Striatum (NTA 3-16)
Hippocampal formation and fornix
(NTA 3-17)
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7 Major components of the central nervous system &
Ventricles
All present from ~ 1st prenatal month
• Longitudinal organization of SC and BS nuclei
– Columns
– Anatomical and functional divisions
• C-shape organization of cerebral hemisphere
structures and diencephalic
– Cerebral cortex
– Lateral ventricle
– Striatum
– Hippocampal formation and fornix