June 23, 2008
Unlocking memory’s secrets
By CAROL CLark
Psychology theories took on a human face for Joe Manns when he volunteered at an Alzheimer’s center as an undergraduate student. For a few hours a week, he played simple games of cards and dominos with the patients, or just sat with them and asked how things were going.
“The most difficult part for me were the people in the middle of the downward slope of Alzheimer’s,” recalls Manns, assistant professor of psychology. “You’d be having a happy time that very quickly could result in tears. They might become a little confused during a card game and you could see it in their eyes, the realization that they were losing their memories.”
The experience helped convince Manns to make memory the focus of his career. “I saw how critical memory is to life — how big a role it plays in who you are,” he says. “And it’s a topic that scales well. You can study memory in terms of the cells in a dish, or from a cognitive perspective: Do our hopes and dreams affect what we recall?”
Manns’ research explores how the hippocampus supports declarative memory — facts that you can bring to consciousness and verbalize — such as what you ate for breakfast, or the name of your third-grade teacher.
“One of the big advances in neuroscience in recent years is the idea that there are multiple memory systems in the brain, and the hippocampus system is only one of them,” Manns says. “It’s not as if memory relies on any one place. It relies on the extreme interconnectedness of the brain.”
During a postdoctoral fellowship at Boston University, Manns led a research project that implanted micro-wires into the brains of laboratory rats, to monitor electrical activity in the hippocampus. The rats were then exposed to a series of tiny pots filled with different fragrant substances, such as oregano, basil, thyme, tarragon and cocoa powder. When the rats demonstrated that they could memorize the scents in a particular order they were rewarded with a Fruit Loop buried in a pot.
The results, which were published in the journal “Neuron,” suggested that the hippocampus supports the performance of this memory task by associating the odors with the context in which they were encountered.
Manns joined Emory in January, and is continuing to use electrophysiology to study the brains of rats engaged in recounting spatial and episodic cues. “It’s a process similar to you remembering where you parked your car each day,” he says, explaining that data gleaned from rats can help us understand how our own memories function.
“Emory has a particularly strong memory community,” Manns adds. “I can form collaborations here with scientists across the entire spread of research, from the psychological level of how memory emerges in infancy, to those studying the cellular and molecular aspects of memory.”