Repetition Priming and Repetition Suppression: A Case for Enhanced Efficiency Through Neural Synchronization

Abstract

Stimulus repetition in identification tasks leads to improved behavioral performance ("repetition priming") but attenuated neural responses ("repetition suppression") throughout task-engaged cortical regions. While it's clear that this pervasive brain-behavior relationship reflects some form of improved processing efficiency, the exact form that it takes remains elusive. In this Discussion Paper, we review four different theoretical proposals that have the potential to link repetition suppression and priming, with a particular focus on a proposal that stimulus repetition affects improved efficiency through enhanced neural synchronization. We argue that despite exciting recent work on the role of neural synchronization in cognitive processes such as attention and perception, similar studies in the domain of learning and memory - and priming, in particular - have been lacking. We emphasize the need for new studies with adequate spatiotemporal resolution, formulate several novel predictions, and discuss our ongoing efforts to disentangle the current proposals.

Figure 1. Theories that explain repetition priming in the face of repetition suppression

Graphical depictions of the theories discussed in the text are shown for (A) Facilitation, (B) Sharpening, (C) Synchrony, and (D) Bayesian Explaining Away. Hypothetical Novel and Repeated conditions are shown with black and red curves, respectively. In D, suppressive feedback from higher levels to lower levels in the network structure is highlighted with the use of thick black lines, and the earlier separation of novel and repeated conditions in higher levels relative to lower levels is indicated with vertical dashed lines in the activity plots to the right.