Connectomics Lesson Plan: EyeWire Edu

Background information

Connectomics is the study of connectomes, the comprehensive maps of neuronal projections and connections. In order to understand connectomes it is important to have a basic understanding of structural, physiological, and chemical neuroscience. Read the following posts for your understanding:

C Elegans Connectome
C Elegans Connectome

Anatomy of a Neuron

Introduction to Connectomics

Connectomics as a field has focused on the brain and retina, but it is important to note that the nervous system also consists of nerves and cell bodies in the spinal cord and throughout the body. In order to best understand how neurons wire together, students must understand the basic brain structure, the structure of a neuron, and how it functions.

 

Grades: 6-12

Time: 1 hour per lesson (3 hours)

For any questions, please post a new discussion to EyeWire’s Education Forum and for further material please see EyeWire Edu Recommended Teacher Resources.

Lesson One: Nervous System Anatomy

 The brain is divided up into structures. Often each structure has a specific job, such as the motor cortex coordinating movement. Sometimes the structures play diverse roles in a multitude of tasks, such as the prefrontal cortex in perception, decision making and complex problem solving. These structures are groups of brain cells that work together and are physically close to each other. If you need to familiarize yourself with brain structures, you can do the activity (featured below) thoroughly beforehand. You can dive straight into the activity or begin the lesson by going over simple neural anatomy, dividing the nervous system into eight parts:

Frontal Lobe- Decision making, planning, working memory

Parietal Lobe- Sensory and motor processing in the brain

Temporal Lobe- Long term memory, Auditory information, language comprehension

Occipital Lobe- Visual information

Cerebellum- The heavily ridged structure in the bottom back of the brain that controls balance and motor control.

Brainstem: Vital functions (respiratory and cardiovascular control), relay between the brain and body, alertness

Spinal Cord: Sensory and motor information organization from the body to the brain.

Peripheral Nervous System: Everything else. Sensory neurons, motor neurons, neurons in your internal organs.

  1. Activity: Let students play around with the FINR brain structure visualizer. The structures students will explore are connected to each other through large tracts of cell branches. These connections allow for communication and collaboration between the structures. Ask students to write down which parts of the brain they think may be connected, and what they think the brain can do because of each connection.
    Screen Shot 2015-02-24 at 1.51.26 PM

FINR hosts a 3D rotating brain and offers a few paragraphs about the function of a structure when you click on it. It also offers explanations of common brain injuries, highlighting the affected region.

 

FINR Takeaway Concept: The brain is made of many structures that are defined by their function. These structures must communicate with each other.

Image from: BrainCraft
Image from: BrainCraft

2. Video: To lead from brain structure into the next lesson, watch this BrainCraft Video(3m21s) about localization of function and development.

BrainCraft Takeaway Question:

  • What are the three main steps in early neural development? Answer: newly formed neurons develop, neurons migrate to location, neurons begin to develop connections between each other.

Lesson Two: Neuron Anatomy

The tracts that connect the structures in the brain are made up of fibers from many cells(amount variable between tracts, the largest is the corpus callosum at 200 million cells). These fibers are only part of a brain cell. A brain cell is better known as a neuron.

  1. By BruceBlaus (Own work) [CC-BY-3.0], via Wikimedia Commons
    By BruceBlaus (Own work) [CC-BY-3.0], via Wikimedia Commons
    A neuron has a large blob-like structure from which its branches emerge called a cell body. This is alternatively named the soma. The nucleus is here, so this is where the DNA is housed and this is also where most of the organelles are found, such as protein preparing golgi apparatuses and energy producing mitochondria. Mitochondria are also found down the length of neuron branches. This is a good time to bring your lesson back to biology.  The cell body has many long projections, and one of these projections is called the axons. Axons are usually longer because they are signal senders, and must travel to the cell they are sending a signal to. Axons are also sometimes physically distinguishable by the insulating sheaths (called myelin sheaths) that cover them to speed up electrical signal transmission. The cell body has many short branching projections, called dendrites, which are signal receivers. The point where a communication signal is transmitted from one cell to the next is called a synapse. The synapses are the connections and are thus the basis of connectomics and the brain working as a unit. The majority of synapses send the signal from one cell’s axon to another cell’s dendrite. Scientists used to think that projections stopped growing when an individual reached adulthood but discoveries are rapidly being made about adulthood neural plasticity. Neural plasticity is the ability to form new projections and connections in response to damage and shifting environments.
  2. Activity: http://eyewire.org
    1. When you create an account you are introduced to the game with a tutorial. Additional support is available if you don’t feel confident teaching the game after the in-game tutorial.
      1. Video Tutorial 1
      2. Written instructions
    2. Use this EyeWire Worksheet to allow student to navigate the game while learning about neuron structure, edit if you have any specifications for usernames/emails you wish students to use.

Lesson Three: Neuron Communication

Synapse, eyewire, neuron synapse, synapse brain, brain, neuroscience
A Synapse

Neurons communicate at synapses as mentioned above. When enough ions flow through the neuronal membrane the neuron will send an electric signal, called an action potential, down the length of its dendrites. The change in ion flow works like a light switch without a dimmer; there is a “threshold” if you will. If just one too few ions that cross the membrane, there is no action potential. If more than enough ions cross the membrane, the action potential is there, but no stronger than usual. When the action potential gets to a synapse, the neuron will communicate. Neurotransmitters, or signal chemicals, are released into the tiny space in between the neurons where they almost touch. The sending and receiving neurons in a synapse will never switch jobs. These neurotransmitters will bind with receptors, which in turn will tell the signal receiving cell to do something, such as send an action potential itself.

Activity: The interactive neural circuit builder from BrainU. Students drag and drop neurons on their screen, connecting them and watching them fire.This would be a good time to implement discussion of physics, chemistry or computer science

  1. Look, one at a time, at each neuron. What is required to make it fire, and how is it’s own firing pattern unique?
  2. Try organizing the neurons so the muscle twitches faster or slower. You can add neurons to make this work.

Additional Advanced Activity:

Neural structures and connections reflect of the real world around us. Pick a stimulus in the environment and design a neural circuit that could theoretically process this stimulus by breaking it up into parts. You can do this first by leading the class in an example, and then you can have students do this in small groups.

  1. Pick a simple stimulus. This can be based on memory, one of the five basic senses, emotion, associations, movement or something you think of yourself.
  2. Try to divide this stimulus into the smallest parts you can think of. Colors are part of light spectrums, objects are made up of parts, motion is combines spatial change and progression of time, and emotion is a result of associations and memory.
  3. Think about how neurons compare, contrast, order, and rank the little parts of the world to make sense of it. They look for patterns.
  4. Draw a formation of hypothetical neurons, or if you have access to crafts, use little styrofoam balls as cell bodies, colored pipe cleaners as projections, and connect them by winding them together

Ways to provide assistance:

  • Work as a class or in larger groups
  • Give students the stimuli, and allow them to do steps 2-4.
    • Stimuli Ideas:  Seeing shapes, seeing faces, touching something bumpy, sadness, happiness, remembering a name when you see a face, catching a ball when you see/realize it’s flying at you, a sight-impaired person reading braille.

Example based on EyeWire Nature paper: The neural circuit that perceives motion must interpret time and space stimuli, processing the place of an object across the dimension of time. So if the object is moving from the left visual field to the right, there may be columns of neurons that fire as the object appears in front of them, and a neuron that senses time-delay between neuronal firing. (in the nature paper we were looking at movement up-down as opposed to left-right)

Another example: Grazing your fingers across something bumpy results in sensation appearing and disappearing quickly as the raised parts of the surface brush against the skin. It also involves feeling your fingers jump a little in space every time they hit a raised part of the surface. Sensation neurons will fire with brief time delays as they touch nothing. The neurons that feel where you are in space will fire in reaction to your fingers jumping.

Note

If you would like to become more comfortable with neuroscience information, view pages such as BrainFacts and Neuroscience for Kids: Explore. Students frequently ask questions about concussions, and frequently ask questions that are way out there. Remind students there is still much about neuroscience that that is undiscovered, but that they could help study in the future. The students should leave with more questions and curiosity than they came in with.

Again, for any questions, please post a new discussion to EyeWire’s Education Forum and for further material please see EyeWire Edu Recommended Teacher Resources.

 

Educational Standards

This lesson plan was made adhering to the Next Generation Science Standards on Structure and Function for High Schoolers, though it is approachable for middle school students.