Dynamic Plasticity in the Medial Temporal Lobe: An Update

Summary

Date: 
April 1, 2014 - 1:00pm
Location: 
NW 243
About the Speaker
Name: 
Wendy Suzuki (NYU)

A major goal of our lab is to use behavioral neurophysiological approaches to understand the neural basis of episodic memory, or memory for the events of our lives.  Our strategy has been to subdivide episodic memory into its component parts.  We have mainly focused on two key aspects of episodic memory:  1) the ability to form new associations on-line (i.e., new associative learning) and 2) memory for temporal order (i.e., what come first, second or third).  In this talk, I will describe our latest findings addressing these two forms of memory.  Our previous studies showed that about 18% of recorded hippocampal cells signaled new associative learning.  In a new study, we show that an even larger proportion of the hippocampal neurons are engaged in new associative learning and that individual hippocampal cells can participate in highly flexible and differential ways at various time points during the trial. In other studies, we showed a strong timing signal in the hippocampus as subjects performed a temporal order memory test.  In a second update, I’ll described experiments in which we examined whether timing signals in the hippocampus were present in other tasks that do not explicitly require memory for temporal order.  We not only found strong timing signals during an object-place associative learning task, but many hippocampal cells signaled the conjunction of timing with other context-rich task information.  These findings, taken together illustrate the wide range and striking flexibility of hippocampal responses.