Making Memories

A High School neuroscience collaboration equips students to study memory processes
Canadian psychologist Donald Hebb wrote, “neurons that fire together, wire together.” Imagine I clap my hands and immediately a grasshopper leaps. You see this and determine that my clap caused the grasshopper to jump because of the relative timing of those two actions. However, had my clap occurred long before the leap, you would be less likely to conclude that I made it jump. Had my clap followed the leap, you would likely rule out that I caused the jump all together. The causal relationship is strengthened (learned) by the events being close together, in proper order, and occurring over a certain amount of time. Congratulations, you now understand the gist of spike-timing dependent plasticity.

This week, students in High School Neuroscience investigated spike-timing dependent plasticity using home-built neurorobots with principal investigator Dr. Christopher Harris. Harris is a neuroscientist and educator from Backyard Brains, an organization helping students visualize and experiment with neural activity using robots constructed affordably with off-the-shelf electronics. The educational programs are funded through a grant from the National Institutes of Health (NIH).

High School science teacher Bill Wallace and dean of students and science teacher Bobby Asher have partnered with Harris to design lessons that guide students through the research process. Harris explained that GDS students are the first ever to explore neurobiology with these exercises. “And certainly no one has done this work at the high school level,” he emphasized.

After introductions to the user interface with free-roaming robots during their initial exposure to the neurorobots, students continued their investigations in their second experiment by working to establish strong synaptic connections based on a conditioned response to red or green stimuli. The conditioned response in their neurorobots—much like Ivan Pavlov conditioned a dog to salivate at the sound of a bell—ultimately transferred to long-term memory with longer exposure to the stimuli (hence “spike-timing dependent”).

The robot brains used in this lesson are programmed to emit a sound when their cameras are exposed to the red stimulus (the students used red shirts, books, Legos, etc.) and is not unlike the unconditioned response of Pavlov’s dog first salivating when it sees/smells meat. The students worked to establish an association between the red stimulus and a green one in the robot’s neural pathway. They presented the two colors to the neurorobot simultaneously for progressively longer periods of time then tracked the time before the association decayed. Working from the assumption that time matters in the establishment of a correlation, students were asked to determine the threshold at which point an association has been conditioned sufficiently that it transfers to long-term memory. Simply, how much training is required before the robot will no longer forget?

“The lab is all about thinking as opposed to just getting the results,” explained Bill, himself a PhD molecular biologist and former NIH researcher. “What’s written in school textbooks or presented in lectures is based upon years of research that often began with a single experiment with results that were not immediately understood. We are helping students develop comfort with analyzing data that at first glance don’t make sense. Instead of only presenting what Eric Kandel discovered about memory from his work with sea slugs in our classroom lectures, students are developing a much deeper understanding of the work by exploring memory for themselves and then assimilating that into their understanding of how the brain works.”

Harris noted, “I like the way Bill is approaching this material as a research effort. The students are developing an important tolerance of uncertainty. We see the students engaged—not just managing to complete the exercise—but rather demonstrating interest and asking intelligent questions about the user interface and also about memory processes themselves.”

Of course, students encounter their fair share of obstacles, including a whole host of unaccounted for variables: a nearby classmate wearing a green shirt, varying shades of green presented, distance from the optical lens, and more. And yet, these challenges are critical to Bill’s stated goals for the neuroscience class. Students rolled with the stumbles, learning as much from each other as from the activity. They held each other accountable for both the logistics of the exercise and for explaining their thinking. Finally, and not to be overlooked, students really seemed to enjoy the process: the sound in the room was frequently punctuated by laughter even as focused engagement remained high.

Next time Harris returns, students will move on from memory to motivation.

Staff writer Danny Stock tells the stories of teaching, learning, competing, creating, and performing at Georgetown Day School. He is a former GDS second grade teacher and current parent.


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