PSYC 304 Lecture Notes - Lecture 3: Horseradish Peroxidase, Peripheral Neuropathy, Peripheral Nervous System
Tuesday, September 20th, 2016
- What are the important components of a neuron?
- Early Neuroscience; Neuron Doctrine
- How do we study the nervous system?
- What is a synapse???
- Gross Neuroanatomy - CNS and PNS
❖ THE NERVOUS SYSTEM IS COMPOSED OF CELLS
➢ Neurons, or nerve cells, are the most important part of the nervous system.
■ There are around 100-150 billion of them; different phenotypes/functions.
■ When he says neurons, it is a CLASS. Example, with dogs, there are
different types of dogs. Neurons, are the same!!!
➢ Glial cells (plural - glia; “glue”): Provide support for neurons; do so much more.
■ 100-150 billion; different phenotypes/functions.
■ They don’t produce electrical signals.
➢ … Back to neurons!!!
■ Look at slides for a diagram. A good one :):):):)
■ Dendrites, are where the synapses are formed.
➢ Camillo Golgi: Invented in the “riazione nera” - black reaction product
■ Results in the deposition of a dark reaction product in the dendrites,
soma, and axon… basically outlines entire neuron!
■ Look at slides for photo of it
■ Also look up more on him
➢ Santiago Ramon y Cajal: Prodigious neuroscientist; suggested neurons were
separate…
❖ NEURON DOCTRINE → States that:
➢ The Neuron is the basic functional and structural unit of the brain
➢ Neurons are not continuous: Info is transmitted from cell to cell, across synapses.
➢ Neurons are made of 3 parts: dendrite, soma, and axon.
➢ Info flows from dendrite, to soma, then down the axon.
❖ INTRANEURONAL STRUCTURES
➢ Look at slide ( 4/17 AND 5/17) of crazy scary diagram… wtf???????? Is
that?????
❖ TECHNIQUES TO VISUALIZE NEURONS
➢ Golgi Stains: fill the whole cell, including details, but only stain a small
proportion of neurons. Fluorescent molecule injections give a similar result.
➢ Nissl Stains: outline all cell bodies b/c the dyes are attracted to RNA, which
encircles the nucleus.
➢ Techniques to study Neurons:
■ Autoradiography: Shows the distribution of radioactive chemicals in
tissues.
■ Immunocytochemistry: can detect a protein in tissue.
find more resources at oneclass.com
find more resources at oneclass.com
● Antibody production… ⇒ utilizes body’s immune response to
produce “antibody’s” directed against protein of interest.
● Y u no pay attention.. Look it up :p
● Look up mice and drugz
● Parts of brain activated from drug administration: PFC, Neocortex,
Hippocampus...
➢ In Situ (In place) Hybridization: Uses complementary radioactive probes to find
neurons with a specific mRNA sequence.
■ A with T, C with G…
Thursday, September 22nd, 2016
● In Situ Hybridization cont’d.
○ Note: Autoradiography shows the distribution of radioactive chemicals in
tissues
■ Immunocytochemistry can detect a protein in tissue…
○ These techniques only show if a particular protein, or mRNA sequence are
located inside a cell.
Techniques to Visualize Neurons: Tract Tracing
- Tracing pathways in the brain:
● Anterograde labeling: uses radioactive molecules or viruses taken up by the
cell, which are then transported to the axon tips; virus then jumps the synapse to
the next cell.
○ When it jumps across the synapse, it kills itself. This is important b/c now
you can determine which group of neurons is connected to another
neuron, by the space of one synapse.
○ Look at slide: fill up the needle, inject into ventral tegmental area. Wait a
day, 2 days, a week… then you would see the virus transported down the
axons, jumps over the synaptic cleft, and reveals the ultimate location. In
this case, we know that the ventral tegmental area transports to a
LOT of areas.
● Retrograde labeling: uses horseradish peroxidase (HRP) - it is taken up in the
axon terminals, and transported to the cell bodies, then visualized thru chemical
reactions.
○ Interesting way to look at the connections, and also gives really nice
pictures and visualization of the cells.
○ Look at slide: Motor neuron (send axons directly to muscles to
contract muscles/move arm/leg...) So, you inject into the tissue, wait a
few days… then you see the horseradish peroxidase is taken up by the
cell, transported back to nucleus…
○ HRP gets kind of spread around. It is like a molecule. Goes wherever it
wants to go
find more resources at oneclass.com
find more resources at oneclass.com
● CLARITY: Clear, Lipid-exchanged, Acrylamide-hybridized Rigid,
Imagine/immunostaining compatible, Tissue hYdrogel
○ It removes the fat and everything stays in place. Now you can use your
techniques to look at the neurons.
○ Turns the brain “clear” by embedding the brain into a gel and then
removing the lipid layers.
○ Look at slide: Before, there is a mouse brain. It is white, because of all
the fat and stuff. Apply this technique, and then after a few days, the brain
is completely clear. In the After, you see through it, because the fat has
been removed.
NEURONAL PHENOTYPES: GENERALIZED BY POLARITY
● Neurons are classified by shape, size, or function:
○ Multipolar neurons - one axon, many dendrites - most common type
■ Take a lot of connections from other cells. They integrate a lot of
information.
■ Processing a lot of information, because a lot of dendrites.
○ Bipolar neurons - one axon, one dendrite
■ Tend to be small, one axon, one dendrite.
○ Unipolar neurons - single extension branches in 2 directions, forming a
receptive pole and an output zone.
■ Also tend to be small.
○ Look at slide for diagram of each type of neuron
● Variety in form of nerve cells… Slide has cool neurons
❖ NEURONS ARE SPECIALIZED FOR COMMUNICATION
➢ Large neurons:
■ Have more complex inputs and outputs; can handle more “information”
■ Cover greater distances
■ Convey information more rapidly.
❖ The nervous system is composed of cells
➢ Neurons vary in FUNCTION:
■ Motor neurons: stimulate muscles or glands; degenerate in ALS, SBMA
■ Sensory neurons: respond to environmental stimuli, such as light, odour,
or touch; sensory neuropathy
● Things like your eyes, things like your eyes receive information,
transforms it into electrical information… senses’ info transmitted
by sensory neurons, and processed in the appropriate regions of
the brain.
● Sensory neuropathy: a condition… *look up?
● What happens when you dive deep down into ocean, then
come up too quickly? There is a dangerous buildup of gasses in
your nervous system, and the reason you need to go up slowly is
so you can get rid of those gasses over time, and if you go too
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The nervous system is composed of cells. Neurons, or nerve cells, are the most important part of the nervous system. There are around 100-150 billion of them; different phenotypes/functions. When he says neurons, it is a class. Glial cells (plural - glia; glue ): provide support for neurons; do so much more. different types of dogs. Dendrites, are where the synapses are formed. Camillo golgi: invented in the riazione nera - black reaction product. Results in the deposition of a dark reaction product in the dendrites, soma, and axon basically outlines entire neuron! Look at slides for photo of it. Santiago ramon y cajal: prodigious neuroscientist; suggested neurons were separate . The neuron is the basic functional and structural unit of the brain. Neurons are not continuous: info is transmitted from cell to cell, across synapses. Neurons are made of 3 parts: dendrite, soma, and axon. Info flows from dendrite, to soma, then down the axon.
