Guide to Playing Mozak
Getting to Know a Neuron
- Getting to Know the Project
- Getting to Know a Neuron
- Getting to Know an Image Stack
- Noise vs. Signal
- Types of Neurons — Spiny/Aspiny
- Tracing Faint Branches
- Creating a Fully Connected Structure
- Creating Axon and Dendrite Traces
Let us start with the basics about neurons. The main compartment of a neuron is its soma. The soma contains a cell’s nucleus and many other organelles controlling the cell’s basic functions. Here are some images to help you identify the soma:
You will notice that there are many long, skinny processes exiting the soma. We call these processes neurites. However, we more commonly separate them into two groups: dendrites or axons.
Most neurons have multiple dendrites exiting the soma. The function of a dendrite is to receive the chemical signal from the axons of thousands of other neurons. Dendrites tend to travel directly away from the soma and branch a few times before ending. For the cells posted on Mozak, dendrites are usually thick, well-labeled and easy to trace. Here is an example to help you identify the dendrites:
To show you the axon, we are going to have to zoom in. This is because the axon is thin and intermittently labeled. Each neuron has only one axon, and it may exit the soma or it may exit a dendrite very close to the soma. The function of an axon is to transmit the signal of a neuron to all the neurons it synapses with. Unlike most dendrites, an axon can take a very complex path, branching, twisting and turning in all directions. An axon can also travel long distances to synapse with neurons in other areas of the brain or body. Luckily, we are only reconstructing the local axon within a few hundred microns of the soma (for now)! Here is an example image to help you identify axon. In this example the axon exits the soma (can you find where?):
You will notice that the axon is hard to identify in the image above. This is because the example is a 2D image. When you trace in Mozak, the axon will be easier to follow because we provide a 3D image stack of each neuron.