Poster D40, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Sex and Developmental Differences in the Oscillatory Dynamics Serving Verbal Working Memory: a MEG Study
Christine M Embury1,2, Alex I Wiesman1, Amy L Proskovec1,2, Elizabeth Heinrichs-Graham1, Yu-Ping Wang3, Vince D Calhoun4,5, Julia M Stephen4, Tony W Wilson1,2; 1University of Nebraska Medical Center, Omaha, NE, 2University of Nebraska Omaha, Omaha, NE, 3Tulane University, New Orleans, LA, 4The Mind Research Network, Albuquerque, NM, 5University of New Mexico, Albuquerque, NM
Changes in the structure and function of the brain are evident throughout childhood and adolescence, shaping the development of executive functions like working memory (WM). Previous verbal WM studies in healthy adults have shown the importance of alpha oscillations in left occipito-temporal cortices during the encoding and subsequent maintenance of WM representations. In this study, we used magnetoencephalography (MEG) to examine such alpha oscillatory activity during a verbal WM task in 95 healthy youth (9-14 years-old) who were enrolled in the NSF-funded Developmental Chronnecto-Genomics project. The task consisted of a grid of six consonants that appeared for 2 s (encoding), followed by an empty grid for 3 s (maintenance), and then a probe letter (retrieval), when participants responded whether it was in the previous set. All MEG data were transformed into the time-frequency domain and imaged using a beamformer. We found significant alpha oscillations in the left supramarginal and superior temporal regions (p < 0.000001), which may reflect operations of the so-called phonological loop component of verbal WM, and in the left inferior frontal region (p < 0.000001) throughout the task. In addition, we observed the expected parieto-occipital alpha synchronization during maintenance, although the response was weaker and emerged later than generally reported in adult studies. Finally, behavioral performance improved with age, and we found sex differences with age in the recruitment of right inferior frontal cortex during encoding and in the parietal and occipital cortices during maintenance, which may reflect an altered developmental trajectory between male and female youth.
Topic Area: EXECUTIVE PROCESSES: Working memory