COGNITIVE
SCIENCE
107A
Neuroanatomy:
Basic Principles
Jaime A. Pineda, Ph.D.
Neurons
“The mysterious butterflies of the soul, the
beating of whose wings may some day –
who knows? clarify the secret o...
Neurons
• Functional units of
communication
• About 1011
(100 billion)
cells in the brain
• Independent units (Neuron
Doct...
Dendrites
Cell body or
perikaryon
Axon
Variety of Multipolar Neurons
Differ in genes expressed,
chemicals, shape,
arborization, connectivity
patterns…
Structure ...
INPUT (convergence)
INTEGRATION
OUTPUT
Cajal formulated Law of Dynamic Polarization
Dendrites generally receive synaptic i...
Cell Body
Nucleus (DNAmRNA)
Endoplasmic reticulum
(smooth proteins,
rough  lipids/steroids)
Golgi apparatus
Cytoskeleto...
Spines
Dendrites may be spiny or aspiny
30,000 – 40,000 spines on the largest pyramidal neurons
Increase receptive surface...
Cytoskeleton
• Formed by 3 types of
proteins
– Microtubules
(tubulins)
– Microfilaments (actins)
– Intermediate filaments
...
Protein conformation governed by quantum
effects – Roger Penrose and Stuart Hameroff
Quantum states believed to be too sen...
Myelination
• Insulates axon
• Speeds up conduction
without increasing
diameter of axon
• Saves energy
Synapses
Asymmetric: excitatory (Type2) Symmetric: inhibitory (Type1)
Pre- and post synapse
Organization of pyramidal cells
in cortex
Layers of distinct cells; radially
organized.
Layers allow for separation of inp...
Neuroglial Cells
• Physical and metabolic support
• 90% of cells in brain
• Four types in CNS
– Astrocytes (maintenance/su...
Glial Functions
• Astrocytes
• Constitute 20-50% of the volume in most brain areas
• Originate from radial glial cells – m...
Oligodendrocytes/Schwann cells
Einstein’s Brain
Greater number of
neuroglia
Larger inferior parietal
cortex
Principles of Brain Organization
• Subdivided into 3 primary
and 5 secondary regions
– Forebrain
• Telencephalon (endbrain...
Principles (cont.)
• Brain contains an
interconnected system
of ventricles
Interventricular foramen
Choroid Plexus
• Each ventricle contains
choroid plexus
• 60-80% of CSF comes from
CP; rest from extrachoroidal
sources
• ...
Functions of CSF
Brain contains a protective covering
Principles (cont.)
Hydrocephalus
Principles (cont.)
• Brain is composed of two
hemispheres connected by
a set of fibers (corpus
callosum)
• 200-250 million...
Topography of CC
splenium
genu
truncus
rostrum
isthmus
Principles (cont.)
• Cortex is subdivided
into four major
external lobes (plus
the internal limbic
lobe)
Limbic lobe
Found only in the medial view of the brain.
Its major responsibilities include olfaction and emotions
Principles (cont.)
• Cortex is subdivided into areas of
specialized function
Principles (cont.)
• Some areas of cortex
(primarily sensory
and motor areas) are
topographically
mapped.
V1 (retinotopic)...
Principles of Neuronal Circuitry
• Long hierarchical neuronal connections (macrocircuits)
– Sensory/motor pathways
– Point...
October 5 - Neuroanatomy
October 5 - Neuroanatomy
October 5 - Neuroanatomy
October 5 - Neuroanatomy
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October 5 - Neuroanatomy

  1. 1. COGNITIVE SCIENCE 107A Neuroanatomy: Basic Principles Jaime A. Pineda, Ph.D.
  2. 2. Neurons “The mysterious butterflies of the soul, the beating of whose wings may some day – who knows? clarify the secret of mental life.” Santiago Ramon y Cajal (Father of modern neuroscience)
  3. 3. Neurons • Functional units of communication • About 1011 (100 billion) cells in the brain • Independent units (Neuron Doctrine) • Bioelectrically driven (Functional polarity) • Categorized in terms of Function (sensory, motor); Location (cortical, spinal); NT (cholinergic); Shape (pyramidal, stellate)
  4. 4. Dendrites Cell body or perikaryon Axon
  5. 5. Variety of Multipolar Neurons Differ in genes expressed, chemicals, shape, arborization, connectivity patterns… Structure  function 104 connections per neuron 1015 total interconnections
  6. 6. INPUT (convergence) INTEGRATION OUTPUT Cajal formulated Law of Dynamic Polarization Dendrites generally receive synaptic input (i.e. are postsynaptic) and axons generally send synaptic output (i.e., are presynaptic) Dynamic polarization (processes of input, integration, output, distribution) maybe considered “neurocomputation.” However, DP is NOT independent of the neuroanatomy and can occur in both directions. DISTRIBUTION (divergence)
  7. 7. Cell Body Nucleus (DNAmRNA) Endoplasmic reticulum (smooth proteins, rough  lipids/steroids) Golgi apparatus Cytoskeleton (microtubules, microfilaments) Mitochondria  ATP
  8. 8. Spines Dendrites may be spiny or aspiny 30,000 – 40,000 spines on the largest pyramidal neurons Increase receptive surface They receive most of the excitatory input Undergo morphological changes; regulate synaptic transmission
  9. 9. Cytoskeleton • Formed by 3 types of proteins – Microtubules (tubulins) – Microfilaments (actins) – Intermediate filaments • Microtubules (> 10% of total brain protein): intracellular transport, determine cell morphology
  10. 10. Protein conformation governed by quantum effects – Roger Penrose and Stuart Hameroff Quantum states believed to be too sensitive and fragile to disruption by thermal energy (environmental decoherence) to affect the macroscopic nature of proteins and other macromolecular structures. Microtubule lattice – computational quantum machine? (Orchestrated Objective Reduction) noncomputability
  11. 11. Myelination • Insulates axon • Speeds up conduction without increasing diameter of axon • Saves energy
  12. 12. Synapses Asymmetric: excitatory (Type2) Symmetric: inhibitory (Type1) Pre- and post synapse
  13. 13. Organization of pyramidal cells in cortex Layers of distinct cells; radially organized. Layers allow for separation of inputs and outputs. Unique apical dendrite allows for distribution of information to/from other layers.
  14. 14. Neuroglial Cells • Physical and metabolic support • 90% of cells in brain • Four types in CNS – Astrocytes (maintenance/support) – Oligodendrocytes (myelin)* – Microglia (macrophages) – Ependymal (line ventricles) *Schwann cell is the major neuroglial cell in PNS
  15. 15. Glial Functions • Astrocytes • Constitute 20-50% of the volume in most brain areas • Originate from radial glial cells – migration/guidance • Source for CAMs (N-CAM, laminin, fibronectin), growth factors, and cytokines (signaling proteins involved in immune function) • Regulate neurotransmitter uptake/inactivation (contain ion channels) • Detoxification of CNS • Astrogliosis – response to infection/disorders • Microglia • 5-20% of total cells in the mouse brain • Mediators of immune response (macrophages) • Secrete cytokines and growth factors • Constantly moving and analyzing the CNS for damaged neurons, plaques, and infectious agents
  16. 16. Oligodendrocytes/Schwann cells
  17. 17. Einstein’s Brain Greater number of neuroglia Larger inferior parietal cortex
  18. 18. Principles of Brain Organization • Subdivided into 3 primary and 5 secondary regions – Forebrain • Telencephalon (endbrain) • Diencephalon (interbrain) – Midbrain • Mesencephalon – Hindbrain • Metencephalon • Myelencephalon Neural plate > neural tube
  19. 19. Principles (cont.) • Brain contains an interconnected system of ventricles Interventricular foramen
  20. 20. Choroid Plexus • Each ventricle contains choroid plexus • 60-80% of CSF comes from CP; rest from extrachoroidal sources • Total CSF=130-150 ml • Rate = 20 ml/hr Blood-Brain Barrier endothelial cells (lining of blood vessels) Ependymal cells (lining the ventricles) astrocytes restricts passage of substances from bloodstream
  21. 21. Functions of CSF
  22. 22. Brain contains a protective covering Principles (cont.)
  23. 23. Hydrocephalus
  24. 24. Principles (cont.) • Brain is composed of two hemispheres connected by a set of fibers (corpus callosum) • 200-250 million fibers • Monotremes and marsupials do not have a corpus callosum • Agenesis and split brain patients
  25. 25. Topography of CC splenium genu truncus rostrum isthmus
  26. 26. Principles (cont.) • Cortex is subdivided into four major external lobes (plus the internal limbic lobe)
  27. 27. Limbic lobe Found only in the medial view of the brain. Its major responsibilities include olfaction and emotions
  28. 28. Principles (cont.) • Cortex is subdivided into areas of specialized function
  29. 29. Principles (cont.) • Some areas of cortex (primarily sensory and motor areas) are topographically mapped. V1 (retinotopic) A1 (tonotopic) M1 (mototopic) S1 (somatotopic)
  30. 30. Principles of Neuronal Circuitry • Long hierarchical neuronal connections (macrocircuits) – Sensory/motor pathways – Point-to-point connections – Long axons (myelinated) • Local circuit (microcircuits) – Interneurons (unmyelinated) – Short axons • Single source divergent – Modulatory systems – Global reach (unmyelinated)

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