Poster Session B, Sunday, March 24, 8:00 – 10:00 am, Pacific Concourse
Neural mechanisms of age-related decline in episodic memory precision
Saana Korkki1, Franziska Richter2, Jon Simons1; 1University of Cambridge, UK, 2University of Leiden, Netherlands
Episodic memory declines with older age, but the neurocognitive mechanisms of this decline remain debated. Recent work has highlighted reduced precision of retrieved memories as one factor contributing to age-related memory loss, however the neural underpinnings of this deficit are yet to be characterised. In the current functional magnetic resonance imaging study, healthy young and older participants encoded stimuli displays that consisted of one object overlaid on a scene background. The location and colour of the objects at encoding were randomly selected from circular feature spaces (0-360 degrees), and at retrieval, participants reconstructed either the location or the colour of each object using a continuous response dial. Computational modelling of retrieval errors allowed for detailed assessment of memory fidelity. Behaviourally, we observed age-related decreases in retrieval precision across the two feature conditions. At the neural level, retrieval-related activity in a network that involved regions such as the angular gyrus and the hippocampus tracked memory precision in both age groups. However, at encoding, we observed a diminished relationship between activity in visual regions and subsequent memory precision in the older group. Furthermore, encoding activity in the lateral prefrontal cortex was a significant predictor of memory precision in the younger group only. Together, the results implicate functional differences at encoding as contributing to the age-related deficit in episodic memory precision.
Topic Area: LONG-TERM MEMORY: Development & aging