Dr. Erin Schuman, professor of biological sciences and researcher at the California Institute of Technology, explained the detailed neuroscience of memory as well as leading research on the topic in a lecture at UC Irvine. The lecture, titled “Learning, Memory and the Brain,” occurred Monday, Nov. 3 at the Beckman Center.
Schuman began her presentation with an explanation of the mechanical function of neurons, brain cells that send signals through the body, presenting a cross-section of a brain synapse, which is the point of communication for the neurons. She explained the importance of proteins in synaptic plasticity, a term referring to the ability of a synapse to change. This ability is vital to the formation of long-term memory.
“If you use medication to block protein synthesis in animals and put them in a learning environment, they can’t retain long-term memory,” Schuman said.
Although protein synthesis formation is known to be vital to the formation of memory, little is known of the exact mechanism necessary for memory retention or where protein synthesis occurs.
Schuman recounted how she has been able to attach miniscule fluorescent particles called quantum dots, or “Qdots,” to proteins in dendrites, the short branches that extend off the neuron cell body. Qdots allow the interaction and movement of proteins to be viewed as bright dots within the neuron.
“When I first looked at this I felt like an astronomer looking through a telescope at the stars,” Schuman said, showing the audience a video of protein movement in a neuron.
Scientists now know that the hippocampus is responsible for the storage of episodic memory, which include images and details of past events. Schuman went on to explain the development of theories linking brain function and memory retention through the famous case of an intractable epilepsy patient known as “HM.” After having both his hippocampi resected (partially excised) in order to relieve seizures, the patient became unable to generate any new long-term memories.
Schuman illustrated the importance of the hippocampus to memory by showing the audience videos of the Morris water maze, in which rats swim through a pool of water to locate a partially submerged platform. Healthy rats quickly remember the location of the platform relative to other objects in the room after being placed in the pool, while rats with damaged hippocampi have extreme difficulty finding the platform, even after several attempts.
For the purpose of studying memory formation in humans in her research, Schuman described the use of electrodes placed in the hippocampus of epilepsy patients, which measure brain activity.
“We present the subjects with a series of images and ask them sometime later if they’ve seen them,” Schuman said. “The neuron shows dramatic increase in firing when seeing old stimuli.”
However, her research indicates a frequent difference in what a neuron’s activity indicates and what a person reports.
“In 75 percent of trials, neurons got it right even when people got it wrong,” Schuman said.
Schuman expressed confidence that research in neuroscience may lead to breakthroughs in cognitive diseases, such as Alzheimer’s disease.
“I think some of these basic principles regarding protein synthesis are involved in neurodegeneration,” Schuman said.
The presentation was given as part of the annual Gerard lecture series, which was created in 1977 in honor of Ralph Gerard, a leading neuroscience researcher at UCI and a prominent figure in the field. Gerard was a co-founder of the Society of Neuroscience, an organization aimed at advancing the study of neuroscience.
“Ralph Gerard was conceptually rich and technically gifted, and [Schuman] captures both of those,” said Dr. Tom Carew, professor and chair in the Department of Neurobiology and Behavior, who invited Schuman to speak.