Module 1 Neuroanatomy

Describe characteristics of thick cytoskeleton filaments.

~15nm, myosin fibrils

Describe characteristics of intermediate cytoskeleton filaments.

~>11nm, neurofilaments; insoluble and very durable

What is the cytoskeleton protein that might serve as a recently identified biomarker for Alzheimer's disease?

neurofilament light chain (NFL)

Describe spiny neurons.

Spiny neurons have dendritic spines. This means that there is increased surface area for synaptic connections.

Describe aspiny neurons.

Aspiny neurons do not have dendritic spines. This means that there is decreased surface area for synaptic connections.

If something is considered an excitatory synapse, where is it located?

head of dendritic spine

If something is considered an inhibitory synapse, where is it located?

contact occurs at shaft or neck of the spine

What human disease is associated with a decrease in dendritic spine density?

Alzheimer's

What are the two types of axons?

myelinated and unmyelinated

What microtubule associated "motor" protein is responsible for fast anterograde axonal transport? What does this mean?

kinesin --> this means that information will travel away from the cell body

What microtubule associated "motor" protein is responsible for fast retrograde axonal transport? What does this mean?

dysrein --> means that information will travel towards the cell body

What material is transported by fast rates of axonal transport?

neurotransmitter vesicles

What material is transported by intermediate rates of axonal transport?

mitochondria, myosin protein

What material is transported by slow rates of axonal transport?

microfilaments, neurofilaments

What are the four major types of synapses? Describe them.

axo-dendritic: axon to dendrite which is the most common

axo-axonic: axon to axon

dendro-dendritic: dendrite to dendrite, not as common

axo-somatic: axon to cell body

What are the features to Gray's type I synapse?

asymmetrical, ~30nm, round and large, excitatory

What are the features to Gray's type II synapse?

symmetrical, ~20nm, oval, flattened, pleomorphic, inhibitory

What is the relative location of the perineuronal net?

interposed between a network of glial cell processes and nerve cell surfaces; network on OUTSIDE of cell

What is one function of chondroitin sulfate proteoglycan in the adult CNS?

makes extracellular matrix; if this is present, there will be no sprouting of new axons

What is the beneficial effect of chrondroitinase?

degrades CSPG, which will now allow for extensive sprouting of neurons

CNS receives what type of information?

sensory information

CNS sends out what type of information?

motor information

Why did scientists experience difficulty when first trying to microscopically examine brain tissue in the 1800s?

nervous tissue was difficult to see due to stains not being good enough and limitations in seeing things

Who were the two neuroscientists who shared the Nobel Prize in 1906?

Golgi and Cajal

Which Nobel Prize winner proposed the reticular theory? Describe it.

Golgi proposed the reticular theory, and this theory proposed that neurons created an interwoven framework where neurons were all connected

Which Nobel Prize winner proposed the neuron theory? Describe it.

Cajal proposed the neuron theory, and this theory proposed that neurons were not interwoven, and instead were individual. They touched, but weren't continuous.

Function of the cell body

houses nucleus, nucleolus, organelles

Function of the dendrite

receives information from a pre-synaptic neuron

Function of axon

transmits action potentials along its length to post-synaptic neurons

Multipolar neuron features

has multiple processes that extend from the cell body; more common for motor neurons

Bipolar neuron features

has two processes that extend from the cell body; more common for sensory neurons found in the retina

Unipolar neuron features

has only one process that extends from the cell body; more common for sensory neurons

What chemicals were used for Golgi staining?

potassium bichromate and stain with a silver nitrate

What is the utility for the Golgi stain?

even though we have millions of neurons side by side, this is random and not specific. It will show a neuron and we won't be able to choose what neuron we are looking at. The neighboring neurons have no affinity for the stain, so only one lights up at random.

What neurodevelopmental disorder shows morphological changes of Golgi-stained cortical neurons?

Williams syndrome

Why would scientists want to "single-label" individual neurons?

This is able to show fine details of neurons. This is for individual and selected neurons.

Why would scientists want to "dual-label" individual neurons?

This is to see if specific neurons have a response to a specific neurotransmitter.

Why would scientists want to employ the technique of immunocytochemistry?

To see if there is a specific antibody present. It will change color if there is some of this antibody present. Able to visualize exact location and abundance of specific proteins or molecules.

What is the expression of muscarinic cholinergic receptors in a rat brain (where are they highest)?

They are highest in the striatum of the rat brain, and we know this because when they performed immunocytochemistry on the brain, the darkest part of the brain was the striatum, which indicates that there was a high density of these receptors here.

What is the color change to gray matter of brain and/or spinal cord tissue when soaked in copper sulfate?

turns blue compared to white matter

What is the color change to white matter of brain and/or spinal cord tissue when soaked in silver nitrate?

turns an intense black

What is the specific descending (motor) tract that degenerates in ALS and subsequently becomes devoid of myelin in the spinal cord?

degeneration occurs at the lateral column of the spinal cord due to scarring. It will be filled with glial cells, so no myelin will be present here.

What is the internal reticular apparatus? Describe its function.

Golgi apparatus. It functions to modify newly formed proteins and sort them based on function.

What are Nissl bodies? Describe their function.

Rough endoplasmic reticulum. Functions to decode messages that allow for assembly of new proteins.

What is a unique characteristic of how Nissl bodies are distributed in a neuron?

they are not found in the axon hillock of a neuron

What are some physical features to microtubules?

cylindrical, hollow, 25nm wide, made of tubulin globin monomers

What are functions of microtubules?

transport material throughout cell, anchor organelles in position, structural stability

What are the three microtubule associated proteins? And where are they found?

MAP1 - axon, glia, dendrite

MAP2 - only found in dendrites

tau - primarily found in axons

What microtubule associated protein forms neurofibrillary tangles in Alzheimer's disease?

tau

What drug is used to reveal the presence of neurofibrillary tangles in the brain of someone with Alzheimer's?

flortaucipin

What is another neurodegenerative disease with neurofibrillary tangles detected in the living person's brain?

CTE (or other brain traumas)

Describe characteristics of thin cytoskeleton filaments.

~7nm, microfilaments, 2 actin filaments twisted together, anchor cell membrane to cytoskeleton

What human disease is associated with an increase in dendritic spine density?

drug addiction

What technique was used to increase spine density in striatal neurons in a mouse model of Parkinson's disease"

exercise with a treadmill

What is a toxic material from a bacterial infection that can be transported retrogradely in an axon and also retrogradely transferred trans-synaptically?

tetanus

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