Dear colleague:
I thought that you might be interested in this colloquium scheduled for October. Please bring it to the attention of colleagues of yours.
Thanks very much,
Murray Singer
Murray Singer, Professor
Department of Psychology
University of Manitoba
Winnipeg, Manitoba
Canada R3T 2N2
Ph: 204-474-8486
murray.singer@umanitoba.ca
Title: The Representation of Episodic Memory in Single Neurons of the Human Hippocampus
Time and place: Thurs, Oct. 17, 2013, 3 PM (snacks at 2:30); Department of Psychology, University of Manitoba, P412 Duff Roblin
The hippocampus is known to play a fundamental role in declarative memory, but it is not known how mnemonic information is coded by the activity of individual hippocampal neurons. Three coding schemes have been considered: a localist coding scheme (i.e., "grandmother" cells), a fully distributed coding scheme, and a sparse distributed coding scheme. Sparse distributed coding has long been hypothesized to be the most efficient way for hippocampal neurons to rapidly encode pattern-separated episodic memories without overwriting previously stored information. We measured the activity of hippocampal neurons in 9 epilepsy patients undergoing intracranial monitoring as they completed a recognition memory test. Single-unit activity was higher in response to targets (previously studied words) compared to foils (novel words). This effect occurred because, for each neuron, only a few targets elicited a strong response, as uniquely predicted by the longstanding theory that episodic memory is supported by a sparse distributed neural code.
John Wixted is an acclaimed leader in research concerning the basic character of human memory, applications such as eyewitness memory, and the brain mechanisms of memory function. He regularly offers groundbreaking advances by challenging and often refuting existing theory and analysis. In this regard, he recently discovered that people's recollection of learning contexts makes a continuous contribution to memory performance, in contrast with the previously-held all-or-none view. Likewise, he has collaboratively provided evidence that a contemporary view of the role of the hippocampus in recognition-memory appreciably oversimplifies the true state of affairs.
Dr. Wixted achieves these advances by means of strikingly insightful, simple, and elegant experimental design. In his investigations of the continuous versus discrete nature of contextual recollection, he examined the distributions of people's ratings of their recollective experiences on scales such as 1-20 or 1-100. This approach, which oddly had escaped other investigators, clarified the memory processes under scrutiny.
Dr. Wixted has an outstanding capacity to make his material accessible and fascinating to the listening audience, almost regardless of the inherent interest value of the lecture topic. He simplifies complex issues and may even leave the audience feeling sorry that the talk is over.
Dr. Wixted's contributions have earned him many recognitions and awards during his career. He served as editor of the Psychonomic Bulletin & Review from 1998 to 2002. He is a Fellow of the prestigious Society of Experimental Psychologists. In 2011, that organization awarded him the Howard Crosby Warren Medal, previously conferred on individuals including Karl Lashley and B. F. Skinner.