Introduction to Neuroanatomy

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Introduction to Neuroanatomy

• Structure-function relationships
• Localization of function in the CNS
• Non-invasive brain imaging
• CAT structure, low resolution
• MRI structure, high resolution
• PET function, low resolution
• fMRI function, high resolution

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Dual approach to learning neuroanatomy

• Functional anatomy
• Neural structures that serve particular
  functions e.g., pain path from skin to cortex
  for perception
• Regional anatomy
• Localization of structures in particular brain
  regions

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Lecture objectives

• Overview of brain structures to demystify
  anatomical content in Neural Science lectures
• Survey brain structure-function relations to
  provide background for first labs

First half of lecture

• Quick review of basic CNS organization
• Use development to understand principles of
  structural organization of CNS

Second half Functional localization
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Introduction to Neuroanatomy IRegional Anatomy
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CNS Organizational Principles

• 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

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Brief Overview of Mature CNS Neuroanatomy

• Tubular organization of central nervous system

• Columnar/longitudinal organization of spinal and
  cranial nerve nuclei

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SC
Dorsal surface
Dorsalroot
Ventralroot
Gray matter White matter
Spinal nerve
Ventral surface
NTA 1-4
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Brief Overview of Mature CNS Neuroanatomy

• 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

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Neural Induction

• Portion of the dorsal ectoderm becomes
  committed to become the nervous system
• Neural plate

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Ectoderm
Neuralplate
Neuralgroove
Neuraltube
NTA 3-1
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NT development
Brain vesicles
Rostral
Forebrain
Midbrain
Neural Tube Development
Hindbrain
Rostral neural tube forms the brain Caudal
neural tube forms the spinal cord
Spinal cord
Caudal
Cephalicflexure
NTA 3-2
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3 5 ves stages
3-vesicle stage
5-vesicle stage
Cerebralhemisphere
Lateralventricle
Forebrain
Midbrain
Diencephalon
Midbrain
3rdventricle
Hindbrain
Pons Cerebellum
Cerebral aqueduct
Medulla
4thventricle
Spinal cord
Centralcanal
Cephalicflexure
by the 5 vesicle stage, all 7 major brain
divisions are present
NTA 3-2
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MidsagBrain
The cephalic flexure persists into maturity
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axes
NTA 1-13
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Spinal cord brain stem have a similar
developmental plan

• Segmentation

• Nuclear organization columnar

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SC dev
Dorsal horn
Alar plate
Sulcuslimitans
Central canal
Basal plate
Ventral horn
Dorsal horn
Central canal
Ventral horn
NTA 3-7
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Dorsal horn
Dorsalroot
Ventralroot
Ventral horn
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Similarities between SC and brain stem
development
Sulcus limitans separates sensory and motor
nuclei Nuclei have columnar shape

• Key differences
• 1) central canal enlargement motor medial and
  sensory lateral
• 2) migration away from ventricle
• 3) gtgt sensory and motor

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BS dev
Alar plate andmigrating neuroblasts
Basal plate
NTA 3-8
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Medulla development
4th Vent
Alar plate
Basal plate
Sulcus limitans
Inferior olivarynucleus
NTA 3-9
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Pons development
4th Vent
Striated/branchio.
Alar plate
Striated/somite
Vestibular/auditory.
Somatic sensory.
Taste/viscerosensory
Autonomic.
Basal plate
Pontine nuclei
Sulcus limitans
Alar plate
Basal plate
NTA 3-10
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Midbrain development
Cerebral aq.
Alar plate
Somatic sensory.
Autonomic.
Striated/somite
Red nucleus
Basal plate
Sub. nigra
Sulcus limitans
More like spinal Cord b/c fewer nuclear
classesand cerebral aqueduct
Basal plate
NTA 3-11
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Similarities between forebrain and
hindbrain/spinal development
Tubular

• Key differences
• 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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Diencephalon

• Thalamus
• Gateway to cortex
• Hypothalamus
• Control of endocrine and bodily functions
• Circadian rhythms
• Etc.

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CH dev
NTA 3-14
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Cerebral Cortex Development
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Forebrain Development C-shaped Structures

• 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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Summary

• 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