During the course of each day, the brain is constantly responding to and processing external stimuli as we listen to people and music, read books and watch movies, eat and smell food, and are touched by and touch our loved ones. Along with that activity, however, the brain also undertakes complex computations that are more or less independent of outside stimuli, such as when generating emotional responses, pondering questions or planning future activities.
For the first time, it now is possible for researchers to peer into those internal processes in a rodent brain. Eva Pastalkova, a post-doctoral researcher at the Center for Molecular and Behavioral Neuroscience at Rutgers University, Newark and her advisor, Professor György Buzsaki, have developed a method for studying internally generated brain activity in rats.
For this and her other groundbreaking research, Pastalkova was selected as one of two national recipients of the 2009 Peter and Patricia Gruber International Research Award for Young Scientists sponsored by the Society of Neuroscience. The award recognizes prominent young scientists who have demonstrated international collaboration in advancing the field of neuroscience. Along with the award, the society presented her with a $25,000 grant to support her research.
A native of the Czech Republic, Pastalkova notes that as a member of Buzaski's lab she is part of a diverse research team, consisting of 20 people who in total speak 12 languages.
She also has been selected as one of 12 finalists for the 2009 New York Academy of Sciences Blavatnik Awards for Young Scientists, honoring the most noteworthy young scientists and engineers from the tri-state region. Finalists will be announced in mid-November.
"What I find fascinating is that the brain has a life of its own, " says Pastalkova. "Now that we can begin to study internally generated activity, we can, hopefully, gain a better understanding of the mechanism that generates it."
In her experiments, Pastalkova trained rats to run through a maze in the shape of an infinity symbol. The rats were rewarded for alternately running through the left and right loop of the maze. Between each run, each rat was forced to run on a running wheel for 20 seconds. With electrodes inserted into the brain of the rat,Pastalkova was able to examine the activity of neurons in the hippocampus, a brain structure necessary for memory formation. What she found was that when the rats were on the running wheel and all external stimuli were stationary (because the position of the animal was not changing), neurons were activated in a pattern similar to the onewhen the animal was moving through the maze. In fact, based on the pattern of neural activity, Pastalkova could tell whether the rat was about to run through the left or right arm of the maze.
"While the rat is running on the wheel, there are no cues in the external environment to cause any change in brain activity," notes Pastalkova. "Yet during that time when there were no varying external stimuli, the brain activity looked as if the animal were running a virtual course."
The process, she says, might be similar to the internal brain processes that take place while someone is exercising on a treadmill and tuning out the immediate environment to reflect on the day's events or a problem that needs to be solved.
"What the research seems to say is that there are complex thought processes generated by the brain itself," says Pastalkova. "For example, my dad, who was an applied chemist, knew that when solving a problem he needed to feed his brain with data and then let his brain rest so it could solve the problem."
In other major research, Pastalkova was part of the team at SUNY Downstate Medical Center in Brooklyn that identified the molecule, PKMzeta, that plays a central role in maintaining memories, recognized as a major advancement in the field of neuroscience. When the activity of the protein PKMzeta was blocked in the rat hippocampus, long-term memories were erased. This work also demonstrated that the mechanisms that maintain long-term memory potentiation, or long-lasting connections between neurons, are the same mechanisms that sustain spatial memory in rats, a finding that was hailed by Science as one of 10 major breakthroughs in 2006.
In January 2010, Pastalkova will be starting her own lab at the Janelia Farm Research Center in Virginia, a center of the Howard Hughes Medical Institute. To learn more about her research, visit http://osiris.rutgers.edu/~eva and http://www.hhmi.org/research/fellows/pastalkova.html.