Neurocognitive bases for the functional role of gaze direction during episodic memory retrieval

Previous research has established that when engaged in episodic memory retrieval, people frequently look at locations associated with the sought-after memory trace, even if those locations no longer contain any information. While it has been further demonstrated that gaze positions showing compatibility between encoding and retrieval increase the likelihood of successful remembering (Johansson & Johansson, 2014), virtually nothing is known about the neurocognitive bases subserving this “looking at nothing” effect. The present study combined electroencephalography (EEG) and eye-tracking to investigate oscillatory brain activity for 30 participants who retrieved information from a previously encoded spatial arrangement of objects. Critically, participants were directed to fixate on a location of a blank screen, where the location was either congruent or incongruent with the original encoding location of the to-be-retrieved object. The results replicate previous findings, by showing superior episodic memory performance when looking at a congruent location, and further demonstrate that this facilitatory effect of gaze direction is associated with increased cortical desynchronization in the alpha/beta-band. Such desynchronization of oscillatory power in the alpha/beta band is considered to reflect successful encoding and retrieval of an episodes’ sensory information (e.g., Hanslmayr, Staresina, & Bowman, 2016). Gaze direction showing compatibility between encoding and retrieval would thus increase the specificity of neural reactivation and ultimately increase the likelihood of successful remembering. To our knowledge, this is the first causal evidence that gaze direction is functionally relevant for cortical reconstruction during episodic remembering.