By Jonny Lupsha, Wondrium Staff Writer
Scientists have trained rats to drive little cars to find food, The University of Richmond reported. Not only are the rats capable of operating the miniature vehicles, but they also seem to enjoy it. Rodents’ abilities to learn may be greater than previously thought.
According to The University of Richmond website, the rats’ success in operating the vehicles depended in part on their environment. “Rats housed in a complex, enriched environment (i.e., environment with interesting objects to interact with) learned the driving task, but rats housed in standard laboratory cages had problems learning the task,” Professor Kelly Lambert said. This lends to the theory that enriching environments assist the brain in learning new tasks and behaviors. Neuroplasticity—the brain’s ability to learn—seems to be far higher in rodents than once believed.
Neuroplasticity refers to how the brain learns, unlearns, and re-learns behaviors. Of course, there are behaviors we learn to how to do and there are functions of the brain that we do inherently, which are automatic.
“We divide wiring functions of the human brain into three categories,” said Dr. John Medina, Affiliate Professor of Bioengineering at the University of Washington School of Medicine.
The first category is called “experience-independent wiring,” he said. These neural circuits perform tasks like regulating our heartbeats and keeping our lungs working. They’re called “experience-independent” because they don’t need to be taught.
Second is “experience-dependent circuitry.” According to Dr. Medina, things that require learning, such as speaking a second language, are governed by our experience-dependent circuitry. They depend on experience to make their way into our grey matter.
The final category of how our brains are wired is called “experience-expectant wiring,” which is like a hybrid of the first two categories. “Here, the brain is internally hardwired to expect some kind of external input, some kind of experience,” Dr. Medina said. “Then it finishes its hard-wiring. The clearest example of experience-expectant wiring is vision.”
“The visual system is not fully developed at birth. It requires photic exposure—literally light getting into the eyes after birth—to finish wiring.”
How We Learn, Unlearn, and Adapt
According to Dr. Medina, neuroscientist Don Hebb is responsible for our understanding of neurons in the brain and how the brain learns behaviors, unlearns them, and also re-learns behaviors in place of earlier learned behaviors.
“He said that when two neurons synaptically connected to each other fire repeatedly, molecular alterations occur in both,” Dr. Medina said. “As a result, their relationship strengthens. The two are now electrically connected more strongly than they were before the repetitions happened.”
However, this can happen between more than two neurons, leading to an entire cluster of neurons that fire together to initiate a thought or behavior pattern. Conversely, when two neurons fail to ignite together, the connection between them dies off and we unlearn a behavior or thought.
Taking this example to its logical conclusion, the connections between our neurons can change over time and we can learn new behaviors to replace old ones. If you’ve only met someone once and have forgotten their name, but you see them regularly, you may associate their face with what you think their name is. The neuron associated with their face may fire with the neuron associated with that name.
However, if you call them that name and they correct you, those two neurons won’t fire together as much anymore. Instead, the neuron that holds their face in your memory may fire together with a new neuron—that of their actual name. This happens all the time as we adapt to new behaviors. We unlearn one thing and replace it with another in a kind of subconscious trial and error.
And if you’re a rat behind the wheel of an automobile, your neurons may be wiring, firing, and rewiring like fireworks on the Fourth of July.
Dr. John J. Medina contributed to this article. Dr. Medina is an Affiliate Professor of Bioengineering at the University of Washington School of Medicine. He holds a Ph.D. in Molecular Biology from Washington State University. In 2004, he was appointed to the rank of Affiliated Scholar at the National Academy of Engineering.