What is memory? What are the brain processes that allow us to learn and retain everything from tying a shoe, learning a song or riding a bike?
Dr. Eric Kandel wants to know. Kandel, the world’s foremost memory researcher, author of a first year neuroscience textbook, Nobel Laureate and 1987 Gairdner awardee, gave a talk on Friday about his research and the new exciting possibilities in tackling the memory problem.
Kandel’s interest in science followed an unorthodox path. Born in Vienna, he immigrated to New York in 1939 at the age of 9, and took an undergraduate degree in history and literature at Harvard in 1952.
“There was little in my early life to indicate that an interest in biology would become the passion of my academic career,” he once wrote.
His early years in Nazi Vienna left an indelible mark, and questions of memory and human motivation lead him to psychoanalysis. And so, on a whim, he took a single chemistry course in the summer of 1951 and entered NYU medical school in 1952 intent on being a psychoanalyst.
But seeing the emerging possibilities of molecular biology he would eventually abandon psychoanalysis professionally to work full-time as a researcher.
Kandel stressed that his research in memory storage is one part of a larger project: the synthesis of biology and cognitive psychology into a new, profound understanding of the mind. Memory storage, said Kandel, offers a point where a unification might occur, and used the talk to “outline the possibility of a new science of the mind, a molecular biology of cognition.”
The event opened with a presentation of Kandel’s research in the 1970s and 1980s on the giant marine slug Aplysia, an organism ideal for study because of its simple nervous system. Kandel looked at the withdrawal action of the animals gills after application of a shock, like the unconscious reflex of touching a hot iron and withdrawing your hand. Withdrawal becomes more acute as the number and strength of the shocks increase. He wished to understand the neural circuitry behind this simple behaviour.
Kandel was able to recreate this behavior by growing in culture the two neurons of the circuit. Shocks were mimicked by applying the chemical seratonin, which is released when the gill is stimulated, to one of the neurons. By applying seratonin below and above the threshold level required to make the gills withdraw, Kandel was able to decipher the molecular steps responsible for converting short-term memory to long-term memory. He found that long-term memory requires the production of new proteins to create new nerve connections; short-term memory requires no new proteins and produces no new connections.
“It is the growth of connections that is the self-maintained form of memory storage,” he said.
This radical reductionism differed strikingly from the behaviorist vogue of the 1950s. It offered, for the first time, a look inside the actual workings of the brain, rather than treating it as a “black-box.”
Kandel’s latest research has looked at conscious, spatial learning in mice. It is known that new arrangements of neurons called “brain-maps” are made when mice enter new surroundings. Scientists can even predict where a mouse is in shocked environments depending on which cells are activated.
Kandel researched whether the biochemistry of memory he had found was responsible for the creation and maintenance of the map. It turns out that the signal pathway responsible for protein synthesis of memory as well as attention is necessary for the stabilization of these maps.
It is not known, however, how that attention translates biologically. Based on his own research, Kandel speculates that the recruitment of dopamine, a well-known brain chemical, is largely responsible for the persistence of attentive behaviour.
Despite this uncertainty, Kandel is optimistic. “What is clear…is that molecular biology is going beyond its initial confines. It’s now in a position to take advantage of the enormous synthesis between disciplines in neuroscience, and begin to address the more complex problems of perception, thought and action on the molecular level.”
Eric Kandel is University Professor of Physiology and Psychiatry at the Center for Neurobiology and Behavior of the Columbia University College of Physicians and Surgeons.
