Poster E48, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
Encoding induced alpha EEG activity tracks changes in working memory manipulations
Joel Robitaille1, Stephen M. Emrich1; 1Brock University
Previous fMRI studies have been able to decode features of an item held in working memory (Harrison & Tong, 2009) and track the changes applied to these features (Albers et al., 2012) from the activity detected within the visual cortex. More recently, Foster et al. (2016) were able to reconstruct orientation selectivity profiles from induced alpha-band (8 – 12 Hz) oscillations of electroencephalographic (EEG) data, enabling the identification of the contents held in visual memory. In an attempt to extend these findings this study examined whether the induced alpha activity, which has been shown to mediate the representation of orientations held in visual working memory, can be used to track an imagery manipulation of these representation via a mental rotation. A forward encoding model was applied to EEG activity recorded while participants were holding the orientation of a line in working memory and then applied a 60° mental rotation to the presented stimulus. The results replicate previous findings, revealing that induced posterior alpha-band activity contains sufficient information that allows for the identification of the representation maintained in working memory. Furthermore, the reconstruction of orientation selectivity profiles revealed reliable changes in the mental representation during the imagery manipulation suggesting a de-selection of the orientation presented at the beginning of the experiment.
Topic Area: EXECUTIVE PROCESSES: Working memory