Rita Barakat
Center for Aphasia and Related Disorders (CARD)
University of California Berkeley
Wednesday, November 18th 2015
 The material covered in this presentation is a
summary of approximately one year’s worth
of an undergraduate Molecular Neurobiology
curriculum.
 If you have specific questions regarding the
details referenced in certain slides, I will be
more than happy to provide more
information!
 There are hundreds of different types of neurons, and it is estimated that
each neuron can form 1000 or more unique connections with other neurons,
creating the complex neural networks that we are able to visualize today.
 The way these connections relay information is binary, in that the electrical/
electrochemical signal transmitted is either excitatory (typically causing a
depolarization of the post-synaptic cell), or inhibitory (typically causing a
hyperpolarization of the post-synaptic cell).
 Below are some of the more “general”
classifications of these neuron cell types
(organized by morphology/ function):
◦ Horizontal Cells (A)
◦ Bipolar Cells (B)
◦ Multipolar Cells ( C)
◦ Stellate (Golgi Type II) Cells (D)
◦ Pyramidal Cells (E)
◦ Purkinje Cells (F)
◦ …AND MANY MORE!!
 Many visualization techniques have been developed for imaging neurons at the
single-cell resolution; below is a brief summary of some of these methods:
◦ Nissl Stain (ideal for visualizing the soma and distinguishing between cortical layers
in situ)
◦ Golgi Stain (ideal for visualizing single neuron morphology, a Potassium Dichromate-
based staining technique that is still relatively mysterious in terms of its staining
selectivity)
◦ Immunohistochemistry (ideal for staining neurons that express a specific receptor/
protein, utilizes the endogenous mechanism of antibody-antigen binding)
◦ Retrograde/ Anterograde/ Viral Tracing (involves the injection of a tracer molecule,
either a fluorophore or a dye, that will travel in the retrograde or anterograde
direction and stain the neurons that are connected within a particular circuit. The
viral transfection-version of this technique involves infecting a circuit with a virus,
such as the Rabies virus, that will allow for more precise visualization of the cells
connected in series)
◦ Two-photon Microscopy (a high-resolution imaging technique which involves the
ejection of two photons of equal magnitude but opposite sign wavelengths, such as
+/- 45 nm, which allow for a very narrow range of the receptive field to be
visualized)
◦ “Brainbow” (utilizes selective expression of fluorescent proteins that distinguishes the
soma, as well as some limited visualization of the axon extensions, of individual
neurons)
Molecular Neurobiology Overview Presentation
 For every neuron, there are on average ten glial cells assisting with various
physiological processes (acquiring nutrients, initiating an immune response,
myelination, etc.)
 There are five major Glial Cell types (the sixth type, known as the Radial Glial
Cell, is present primarily during development). Below is a summary of these
five types, their morphology, location and function:
1. Astrocytes (CNS): The most abundant glial cell, they are named for their star-shape.
They have been to shown to assist in providing neurons with nutrients/ oxygen.
2. Oligodendrocytes (CNS): The “myelinating” glial cell of the central-nervous system,
these cells are able to detect/ “decide” which axons should be myelinated, and wrap
around the axon to form a “process” that then signals for myelination.
3. Schwann Cells (PNS): Perform a similar/ same function to the Oligodendrocytes, but
on nerve fibers in the periphery. Unlike oligodendrocytes, these cells do not form a
process on the axon fiber, and need additional cell assistance to influence
myelination.
4. Ependymal Cells (CNS): These glial cells line the choroid plexus membrane in the
ventricles and produce CSF.
5. Microglia (CNS): The smallest and least abundant glial cell, they function as the
immune cells of the nervous system (initiate the immune/ inflammation response).
 While the majority of connections between neurons are formed between
axons and dendrites, the Axon fiber itself is essential in initiating and
propagating the electrochemical signal (the Action Potential) that ultimately
conveys information to downstream, “higher” brain regions.
 In Molecular Neurobiology and Biophysics, we think of the axon as being
analogous to a wire that would transmit electrical information in the form of
electron flow. Based on the principles of Ohm’s Law (V = IR), we can then
assign qualitative and quantitative values to different features of the axon
(such as the diameter, length, and degree of myelination).
 Particular synapses can be strengthened or weakened depending on the
frequency of firing from a pre-synaptic cell onto a post-synaptic cell. A high
firing frequency is associated with Short-Term Facilitation (STF), a
phenomenon that can last up to a few hours. A low firing frequency is
associated with Short-Term Depression (STD), which can decrease the
strength of a monosynaptic connection for a brief period of time.
 The primary difference between “short” vs. “long” term changes in synaptic
strength is the recruiting of proteins for transcription, which only occurs in
the cases of extreme high or extreme low frequency firing periods that
induce Long-Term Potentiation (LTP) or Long-Term Depression (LTD).
 A significant increase in the synaptic Calcium Ion concentration has been
linked to LTP, whereas a moderate increase has been linked to LTD.
“The cells that fire together wire together”!
 “Hebb’s Postulate” provides a pre-synaptic explanation for neural plasticity,
which applies primarily to small (mono- or di-synaptic) connections, that
explains the associative phenomenon between neural firing (see above
quote)
 A new classification for a form of Hebbian plasticity that relies on a close
temporal relationship between the pre-synaptic and post-synaptic firing is
referred to as “Spike-Timing Dependent Plasticity” (STDP).
 On a larger scale, synapses can encode relative strengths that ultimately
translate into meaningful information in the “higher” cortical areas. This pre-
and post-synaptic phenomenon is referred to as Homeostatic Plasticity, and
essentially involves the encoding of a “homeostatic” baseline strength of a
particular synapse that allows it to be distinguishable relative to neighboring
connections.
◦ Pre-Synaptic “Scaling”: A pre-synaptic neuron can modify its firing
magnitude/ frequency in order to control the strength of its relationship to
the post-synaptic neuron.
◦ Post-Synaptic “Modification”: The post-synaptic neuron cannot control the
magnitude/ frequency of the signal it will receive from the pre-synaptic
neuron, however, it can still maintain a relative synaptic strength based on
the degree of transmitter receptors are expressed on the cell membrane.
Molecular Neurobiology Overview Presentation
In thinking about Neuron/ Glial cell morphology and function in
a broader context:
• “How can we take advantage of the physiological properties of a unique
Neuron or Glial cell type in a potential therapeutic approach?”
 e.g.) The potential role of the oligodendrocytes in remyelinating spared neurons
post-lesion, and how exactly to trigger this process based on what is known about
oligodendrocyte activity in vivo.
In thinking about Plasticity (Hebbian vs. Homeostatic) in a
broader context:
• “How can we stimulate synaptic strengthening (LTP) in order to influence
the activity of a particular circuit?”
• e.g.) Providing electrical/ magnetic stimulation to a tract that has been damaged in
order to revive and rebuild the synaptic strength of the overall circuit
Combining the powers of Molecular Neurobiology and
Cognitive Neuropsychology! 

More Related Content

PPTX
What is different about activities on the two sides of the synapse?
PPTX
Neuron communication
PPTX
Synapse
PPTX
Synapse by sunita tiwale
PPTX
NYAI - Intersection of neuroscience and deep learning by Russell Hanson
PPT
Synapse1
PPTX
Physiology of Synapse II Synapse types II Functional Elements of Synapse II ...
PPTX
Synapses akriti
What is different about activities on the two sides of the synapse?
Neuron communication
Synapse
Synapse by sunita tiwale
NYAI - Intersection of neuroscience and deep learning by Russell Hanson
Synapse1
Physiology of Synapse II Synapse types II Functional Elements of Synapse II ...
Synapses akriti

What's hot (19)

PPT
Chapter 02: Genetics & Behavior
PPTX
Nervous system 3; Synapses and Neurotransmitters
PPTX
Synapses
PPTX
Synapic transmission
PDF
EPSP and IPSP
PPTX
Chemical and electrical synapse
PPT
NERVE PHYSIOLOGY- CLASSIFICATION & PROPERTIES OF NERVE FIBERS
PPTX
Synapse
PPTX
The brain and energy
PPT
Neuron Structure
PPTX
Synaptic Transmission
PDF
Popularising_Abstract_Giulia_Gatta
PPTX
Synaptic transmission
PPTX
NEURAL TRANSMISSION ppt
DOCX
Basic structure of neuron
PPT
Long term potentiation
PPT
Signal transmission at synapse
PPT
Chapter12 neuraltissuemarieb
Chapter 02: Genetics & Behavior
Nervous system 3; Synapses and Neurotransmitters
Synapses
Synapic transmission
EPSP and IPSP
Chemical and electrical synapse
NERVE PHYSIOLOGY- CLASSIFICATION & PROPERTIES OF NERVE FIBERS
Synapse
The brain and energy
Neuron Structure
Synaptic Transmission
Popularising_Abstract_Giulia_Gatta
Synaptic transmission
NEURAL TRANSMISSION ppt
Basic structure of neuron
Long term potentiation
Signal transmission at synapse
Chapter12 neuraltissuemarieb
Ad

Similar to Molecular Neurobiology Overview Presentation (20)

PPTX
Unit 1 Nervous System.pptx by Nutan Kamble
PPTX
Structure & function of nerve tissue.pptx
PPT
Lect. 9 nervous tissues
DOC
Nervous tissue study_questions
PPTX
Excitable Tissue: NERVE PHYSIOLOGY.pptx
PDF
Neuronas y neuroglias
PDF
Excitable tissues nerve
PPTX
Unit one -The Nervous system presentation
PPTX
Nervous System
PDF
Ns3 Review Of The Organization Of The Nervous System
PPTX
PDF
neurons-1hhdbbbsjndjnnbbdjndnnndj30501.pdf
PPTX
Nervous system Sem 2.pptx (Organization of nervous system, neuron, neuroglia,)
PPTX
Nervous system Sem 2.pptx (Brain structure) )
PPT
Excitable tissues nerve
PPT
4. Nervous system ppt..ppt which important
PPTX
HAP 1 anatomy physiology and pathophysio
PPTX
Nervous System 1 (63).pptx
PPT
Johny's Anatomy & Physiology Part 2
PPTX
Neurophysiology description in human body
Unit 1 Nervous System.pptx by Nutan Kamble
Structure & function of nerve tissue.pptx
Lect. 9 nervous tissues
Nervous tissue study_questions
Excitable Tissue: NERVE PHYSIOLOGY.pptx
Neuronas y neuroglias
Excitable tissues nerve
Unit one -The Nervous system presentation
Nervous System
Ns3 Review Of The Organization Of The Nervous System
neurons-1hhdbbbsjndjnnbbdjndnnndj30501.pdf
Nervous system Sem 2.pptx (Organization of nervous system, neuron, neuroglia,)
Nervous system Sem 2.pptx (Brain structure) )
Excitable tissues nerve
4. Nervous system ppt..ppt which important
HAP 1 anatomy physiology and pathophysio
Nervous System 1 (63).pptx
Johny's Anatomy & Physiology Part 2
Neurophysiology description in human body
Ad

Molecular Neurobiology Overview Presentation

  • 1. Rita Barakat Center for Aphasia and Related Disorders (CARD) University of California Berkeley Wednesday, November 18th 2015
  • 2.  The material covered in this presentation is a summary of approximately one year’s worth of an undergraduate Molecular Neurobiology curriculum.  If you have specific questions regarding the details referenced in certain slides, I will be more than happy to provide more information!
  • 3.  There are hundreds of different types of neurons, and it is estimated that each neuron can form 1000 or more unique connections with other neurons, creating the complex neural networks that we are able to visualize today.  The way these connections relay information is binary, in that the electrical/ electrochemical signal transmitted is either excitatory (typically causing a depolarization of the post-synaptic cell), or inhibitory (typically causing a hyperpolarization of the post-synaptic cell).  Below are some of the more “general” classifications of these neuron cell types (organized by morphology/ function): ◦ Horizontal Cells (A) ◦ Bipolar Cells (B) ◦ Multipolar Cells ( C) ◦ Stellate (Golgi Type II) Cells (D) ◦ Pyramidal Cells (E) ◦ Purkinje Cells (F) ◦ …AND MANY MORE!!
  • 4.  Many visualization techniques have been developed for imaging neurons at the single-cell resolution; below is a brief summary of some of these methods: ◦ Nissl Stain (ideal for visualizing the soma and distinguishing between cortical layers in situ) ◦ Golgi Stain (ideal for visualizing single neuron morphology, a Potassium Dichromate- based staining technique that is still relatively mysterious in terms of its staining selectivity) ◦ Immunohistochemistry (ideal for staining neurons that express a specific receptor/ protein, utilizes the endogenous mechanism of antibody-antigen binding) ◦ Retrograde/ Anterograde/ Viral Tracing (involves the injection of a tracer molecule, either a fluorophore or a dye, that will travel in the retrograde or anterograde direction and stain the neurons that are connected within a particular circuit. The viral transfection-version of this technique involves infecting a circuit with a virus, such as the Rabies virus, that will allow for more precise visualization of the cells connected in series) ◦ Two-photon Microscopy (a high-resolution imaging technique which involves the ejection of two photons of equal magnitude but opposite sign wavelengths, such as +/- 45 nm, which allow for a very narrow range of the receptive field to be visualized) ◦ “Brainbow” (utilizes selective expression of fluorescent proteins that distinguishes the soma, as well as some limited visualization of the axon extensions, of individual neurons)
  • 6.  For every neuron, there are on average ten glial cells assisting with various physiological processes (acquiring nutrients, initiating an immune response, myelination, etc.)  There are five major Glial Cell types (the sixth type, known as the Radial Glial Cell, is present primarily during development). Below is a summary of these five types, their morphology, location and function: 1. Astrocytes (CNS): The most abundant glial cell, they are named for their star-shape. They have been to shown to assist in providing neurons with nutrients/ oxygen. 2. Oligodendrocytes (CNS): The “myelinating” glial cell of the central-nervous system, these cells are able to detect/ “decide” which axons should be myelinated, and wrap around the axon to form a “process” that then signals for myelination. 3. Schwann Cells (PNS): Perform a similar/ same function to the Oligodendrocytes, but on nerve fibers in the periphery. Unlike oligodendrocytes, these cells do not form a process on the axon fiber, and need additional cell assistance to influence myelination. 4. Ependymal Cells (CNS): These glial cells line the choroid plexus membrane in the ventricles and produce CSF. 5. Microglia (CNS): The smallest and least abundant glial cell, they function as the immune cells of the nervous system (initiate the immune/ inflammation response).
  • 7.  While the majority of connections between neurons are formed between axons and dendrites, the Axon fiber itself is essential in initiating and propagating the electrochemical signal (the Action Potential) that ultimately conveys information to downstream, “higher” brain regions.  In Molecular Neurobiology and Biophysics, we think of the axon as being analogous to a wire that would transmit electrical information in the form of electron flow. Based on the principles of Ohm’s Law (V = IR), we can then assign qualitative and quantitative values to different features of the axon (such as the diameter, length, and degree of myelination).
  • 8.  Particular synapses can be strengthened or weakened depending on the frequency of firing from a pre-synaptic cell onto a post-synaptic cell. A high firing frequency is associated with Short-Term Facilitation (STF), a phenomenon that can last up to a few hours. A low firing frequency is associated with Short-Term Depression (STD), which can decrease the strength of a monosynaptic connection for a brief period of time.  The primary difference between “short” vs. “long” term changes in synaptic strength is the recruiting of proteins for transcription, which only occurs in the cases of extreme high or extreme low frequency firing periods that induce Long-Term Potentiation (LTP) or Long-Term Depression (LTD).  A significant increase in the synaptic Calcium Ion concentration has been linked to LTP, whereas a moderate increase has been linked to LTD.
  • 9. “The cells that fire together wire together”!  “Hebb’s Postulate” provides a pre-synaptic explanation for neural plasticity, which applies primarily to small (mono- or di-synaptic) connections, that explains the associative phenomenon between neural firing (see above quote)  A new classification for a form of Hebbian plasticity that relies on a close temporal relationship between the pre-synaptic and post-synaptic firing is referred to as “Spike-Timing Dependent Plasticity” (STDP).
  • 10.  On a larger scale, synapses can encode relative strengths that ultimately translate into meaningful information in the “higher” cortical areas. This pre- and post-synaptic phenomenon is referred to as Homeostatic Plasticity, and essentially involves the encoding of a “homeostatic” baseline strength of a particular synapse that allows it to be distinguishable relative to neighboring connections. ◦ Pre-Synaptic “Scaling”: A pre-synaptic neuron can modify its firing magnitude/ frequency in order to control the strength of its relationship to the post-synaptic neuron. ◦ Post-Synaptic “Modification”: The post-synaptic neuron cannot control the magnitude/ frequency of the signal it will receive from the pre-synaptic neuron, however, it can still maintain a relative synaptic strength based on the degree of transmitter receptors are expressed on the cell membrane.
  • 12. In thinking about Neuron/ Glial cell morphology and function in a broader context: • “How can we take advantage of the physiological properties of a unique Neuron or Glial cell type in a potential therapeutic approach?”  e.g.) The potential role of the oligodendrocytes in remyelinating spared neurons post-lesion, and how exactly to trigger this process based on what is known about oligodendrocyte activity in vivo. In thinking about Plasticity (Hebbian vs. Homeostatic) in a broader context: • “How can we stimulate synaptic strengthening (LTP) in order to influence the activity of a particular circuit?” • e.g.) Providing electrical/ magnetic stimulation to a tract that has been damaged in order to revive and rebuild the synaptic strength of the overall circuit Combining the powers of Molecular Neurobiology and Cognitive Neuropsychology! 

Editor's Notes

  • #3: <SUMMARIZING A YEAR’S WORTH OF UNDERGRADUATE COURSE MATERIAL IN <10 SLIDES!!!>
  • #4: NOT ON SLIDE, BUT TALK ABOUT: Electrical vs. Chemical Synapses (differences and similarities) Golgi vs. Ramon y Cajal (“Reticular Theory” vs. The Neuron Doctrine) The shape of the soma and function (Pyramidal Cells, Principal (aka Golgi Type I) Cells, Spiny and Smooth Stellate Cells)
  • #9: Discuss the mechanics of STF and STD: Rapid firing can lead to rapid recruiting and depletion of synaptic vesicles, which means that there will be a firing delay as the vesicles must be recycled Rapid firing also leads to Ca2+ accumulation around the synaptic vesicle release proteins, which will stimulate an increase in overall transmitter release
  • #10: BE PREPARED TO EXPLAIN FIGURE (Synaptic Tagging and Capture Hypothesis, first tested in C. Elegans!)