Neurons and neurotransmitters. The bigger picture?

[Pithikos]

I am trying to learn about neuroscience on my own but every book I have picked up goes so much into details for every single thing that I tend to miss the bigger picture. I have some questions that I can't seem to find answers on, mainly about how neurons work. Keep in mind that I have a computer science background and my best topics are not chemistry or biology.

From what I understand neurons communicate with each other by each one releasing some chemical substance called neurotransmitter. This goes like a domino, one releasing its chemical into the next neuron, next neuron releasing the same type of chemical in the next one and so on. This is how neurons communicate with each other. This raises some questions in my mind though.

My questions:

1. Can there be various types of neurotransmitters released from neuron A to neuron B at the same time? Or is it strictly one neurotransmitter per transmission so to say?
   
2. Is there a specific type of receptor for every type of neurotransmitter in every neuron? Or is there one receptor in a neuron that can pick any type of neurotransmitter?
3. What exactly is the main purpose of a neuron? To store information? To process it? (How?)
4. If a neurotransmitter (say dopamine) is released from neuron A to neuron B, is the same substance (dopamine) be released from neuron B to neuron C? Is it also going to be the exact same quantity?
5. How exactly is information transmitted between neurons since only a specific type of substance is transmitted? Do neurotransmitters somehow carry information?

For me all this is very confusing! Would appreciate some pointers

 

[maajdl]

You will have a good overview by reading these wiki articles below, without focusing too much on the details:

http://en.wikipedia.org/wiki/Neurotransmitter
http://en.wikipedia.org/wiki/Axon
http://en.wikipedia.org/wiki/Action_potentials

The network of axons, is what makes memory.
It is not rigid, but changes according to our experience, and builds up our memory in this way.

 

[Pythagorean]

I am trying to learn about neuroscience on my own but every book I have picked up goes so much into details for every single thing that I tend to miss the bigger picture. I have some questions that I can't seem to find answers on, mainly about how neurons work. Keep in mind that I have a computer science background and my best topics are not chemistry or biology.

From what I understand neurons communicate with each other by each one releasing some chemical substance called neurotransmitter. This goes like a domino, one releasing its chemical into the next neuron, next neuron releasing the same type of chemical in the next one and so on. This is how neurons communicate with each other. This raises some questions in my mind though.

My questions:

1. Can there be various types of neurotransmitters released from neuron A to neuron B at the same time? Or is it strictly one neurotransmitter per transmission so to say?
   
2. Is there a specific type of receptor for every type of neurotransmitter in every neuron? Or is there one receptor in a neuron that can pick any type of neurotransmitter?
3. What exactly is the main purpose of a neuron? To store information? To process it? (How?)
4. If a neurotransmitter (say dopamine) is released from neuron A to neuron B, is the same substance (dopamine) be released from neuron B to neuron C? Is it also going to be the exact same quantity?
5. How exactly is information transmitted between neurons since only a specific type of substance is transmitted? Do neurotransmitters somehow carry information?

For me all this is very confusing! Would appreciate some pointers

1. When talking about classical neurotransmitters, I think for the most part, it's one neurotransmitter per neuron. But the modern view of neurotransmitters allows a lot more chemicals and makes the answer more complicated. For example, NO functions as a neurotransmitter.

2. There are neurotransmitters that can accept more than one chemical, and some that even require a co-agonist (a second ligand to activate). One example is NMDA receptors. They're known for requiring glutamate, but they also must have glycine or D-serine present as a co-agonist to activate. It has been found that astrocytes can provide the co-agonist.

3. It depends on what you mean by information. In a general sense, a single neuron does store information, but it's the connection between neurons that is best known for storing information most closely related to memories. A single neuron stores information about its excitability and genetic processes underlying it that also play a role.

4. No. A GABAergic neuron can synapse onto a glutamate neuron. Serotonin neurons project from the brainstem to other neurons outside the brianstem, but those neurons are not serotonin neurons.

5. All the neurotransmitter does is act as a key to the lock (the receptor). Once the receptor is opened, it's a matter of ion charge balance between the inside and outside of the cell, and the permeability of the receptor. Some receptors only let calcium through, so when they are activated, they will redistribute charges across the neuronal membrane based on the electrochemical properties of calcium in the cell.