The Nervous System: Crash Course 1

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A happy neuron, presumably dopaminergic via Crash Course


We love neurons here at EyeWire and are always on the lookout for great resources that communicate how the brain works. Today I discovered an awesome video series from CrashCourse. It beautifully visualizes the nervous system and warrants a highlights reel here on the blog.

Central and Peripheral

Your nervous system is divided up into two areas:

central and peripheral nervous system
Central and Peripheral Nervous System via Crash Course


The Central Nervous System is the brain and spinal column. It’s divided up into many different regions and subregions, each with unique characteristics contributing to activity and cognition. It’s complicated and in the interest of a brief first article here, I’m writing up a separate highlights reel of Crash Course’s CNS video.

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Path to Central nervous system HQ: the brain. via Crash Course


The Peripheral Nervous System is subdivided by function. Your sensory system detects stimuli from parts of the body, for example, texture or temperature when you touch something. The motor system controls movement of muscles, with control originating from the brain and spinal column. It is subdivided into somatic or voluntary muscle movement and autonomic or involuntary movements such as those relating to heart beat, digestion, and pupil dilation. The Autonomic nervous system is further subdivided into Sympathetic, commonly described as “fight or flight” fast response, and Parasympathetic, a complementary system that encourages relaxation., crash course, nervous system
via Crash Course

Together, these systems integrate billions of signals per second to create the sensory and conceptual experience of being you.

Cells of the Nervous System

There are many types of cells in the nervous system. Both Central and Peripheral contain neurons and supporting cells called glia.  Cell types are differentiated by structure, function and genomic profile.

At EyeWire, we currently only map neurons. But there are at least as many non-neuron cells, called glia in the brain as neurons. Here’s a brief overview of them, all images thanks to Crash Course:

cute neurons schwann cells crash course cute neurons satellite cells crash course cute neurons oligodendrites cells crash course cute neurons ependymial cells crash course cute neurons microglial cells crash course cute neurons astrocytes cells crash course

glial cell types overview crash course, glial cells, crash course, eyewire, citizen science, neurons, neuroscience
Glial Recap by Crash Course




neuron by crash course, neuron
This neuron loves Crash Course as much as we do

We don’t know exactly how many types of neurons there are in the brain. Neuroscientists estimate that there are hundreds or even thousands of types and subtypes of neurons.

At EyeWire, we’ve been working to create the world’s most complete catalog of retinal neuron types. As we map cells, such as those found in the Countdown to Neuropia, we send 3D models to Seung Lab at Princeton University, where they are analyzed for connectivity. This has been a difficult challenge, which is why we’re building Museum.EyeWire, an upcoming online resource for the world’s research community that aims to create a global consensus of cell types, allowing us to properly model how functional connections allow circuits to perform complex information processing, such as detecting motion.

That’s all for this post. Up next in this series: Action Potentials and how neurons communicate. Let us know what you think of this post in chat at


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