Poster A66, Saturday, March 24, 1:30–3:30 pm, Exhibit Hall C
A Synergistic Ecphory Account of Pupillary Old/New Effects During Episodic Memory Retrieval
Mingjian He1, Elena Festa1, William Heindel1; 1Brown University
Locus coeruleus-noradrenergic (LC-NA) activity has been associated with memory retrieval (Devauges & Sara, 1991). Pupillometry measures of LC-NA activity in humans have established a pupillary old/new effect in explicit recognition memory paradigms, with old stimuli eliciting greater pupil dilations than new stimuli during test (Vo et al. 2008). While this pupillary effect was first interpreted as reflecting cognitive effort (Papesh et al. 2012), recent findings alternatively support memory-trace strength (Otero et al. 2011) or attentional orienting (Mill et al. 2016) interpretations. The present study assessed the pupillary old/new effect in an explicit recognition task under two conditions manipulating overall memory performance, and investigated whether the pupillary effect generalizes to an implicit memory (stem-completion priming) task. A multiple regression modeling approach (Krishnamurthy et al. 2016) was employed to quantify pupillary responses independent of confounding factors across time points. Implicit memory results showed reduced rather than increased pupil dilation for successfully primed compared to unsuccessfully primed or new stem items (a reverse old/new effect). Explicit recognition results confirmed the standard old/new pupillary effect, and found a larger effect for correct than incorrect trials. Taken together, results suggest that the pupillary old/new effect does not reflect memory strength per se regardless of task demands, but rather reflects an interaction between memory strength and processes specific to explicit episodic memory retrieval. We propose that the pupillary old/new effect reflects synergistic ecphory (Tulving 1982), a theoretical framework that reconciles previous findings while also integrating neurobiological accounts of LC-NA modulation of memory retrieval (Sara 2000).
Topic Area: LONG-TERM MEMORY: Episodic