EEG decoding reveals task-dependent recoding of sensory information in working memory

• Published in: NeuroImage (Orlando, Fla.) Vol. 297; p. 120710
• Main Authors: Bae, Gi-Yeul, Chen, Kuo-Wei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.08.2024; Elsevier Limited; Elsevier
• Subjects: Attention; Attention task; Brain mapping; College students; Color; Color decoding; EEG; EEG decoding; Experiments; Hypotheses; Memory; Mental task performance; Recoding; Sensory evaluation; Sensory recruitment; Working memory; Sensory recruitment; EEG decoding; Working memory; Recoding; Color decoding
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2024.120710

•Spatial patterns of EEG signals reflect stimulus-specific sensory information.•Working memory recodes the sensory information into action-oriented response format depending on task contexts.•The recoding process occurs within a half second from the sensory encoding.•The recoding process enables precise maintenance of stimulus information in working memory, leading to enhanced task performance. Working memory (WM) supports future behavior by retaining perceptual information obtained in the recent past. The present study tested the hypothesis that WM recodes sensory information in a format that better supports behavioral goals. We recorded EEG while participants performed color delayed-estimation tasks where the colorwheel for the response was either randomly rotated or held fixed across trials. Accordingly, observers had to remember the exact colors in the Rotation condition, whereas they could prepare for a response based on the fixed mapping between the colors and their corresponding locations on the colorwheel in the No-Rotation condition. Results showed that the color reports were faster and more precise in the No-Rotation condition even when exactly the same set of colors were tested in both conditions. To investigate how the color information was maintained in the brain, we decoded the color using a multivariate EEG classification method. The decoding was limited to the stimulus encoding period in the Rotation condition, whereas it continued to be significant during the maintenance period in the No-Rotation condition, indicating that the color information was actively maintained in the condition. Follow-up analyses suggested that the prolonged decoding was not merely driven by the covert shift of attention but rather by the recoding of sensory information into an action-oriented response format. Together, these results provide converging evidence that WM flexibly recodes sensory information depending on the specific task context to optimize subsequent behavioral performance.