Poster C49, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Competitive and independent encoding of episodic versus procedural memory
Sungshin Kim1, Joel Voss; 1Medical Social Sciences, Feinberg School of Medicine
Episodic memory and procedural memory have different operational characteristics and depend on distinct neural systems. Nonetheless, many findings suggest that they compete for limited resources in that procedural learning harms consolidation of newly encoded episodic memories, and vice versa. However, little is known regarding the dynamics of their interactions during learning. We developed a novel paradigm involving interleaved motor adaptation learning and object-location association learning in order to identify interactions between these learning types and corresponding fMRI correlates. Immediately prior to object-location learning trials, subjects learned offsets of reaching movements via visual feedback, which was selectively presented on a subset of trials in order to vary procedural learning. In 15 subjects, subsequent memory performance was significantly reduced for object-location associations for trials with feedback versus trials without feedback, but only for trials early in the course of procedural learning. In later stages of procedural learning when reaching accuracy had plateaued, memory was comparable for feedback and no-feedback trials. These findings suggest that procedural learning and episodic learning are competitive, particularly when demands are greatest during the early stages of procedural learning (i.e., the fast component), whereas procedural and episodic learning are independent at later stages (i.e., the slow component). fMRI correlates of the competition versus independent operation of procedural and episodic learning obtained using this task will be discussed.
Topic Area: EXECUTIVE PROCESSES: Working memory