High-frequency Broadband Activity Increases during Memory Encoding and Retrieval in the Posterior Cingulate Cortex of Children and Adolescents

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Joseph P. Kelly¹ (josephkelly1@northwestern.edu), Adam J. O. Dede¹, Samantha M. Gray¹, Qin Yin², Parisa Vahidi², Eishi Asano^2,3, Olivia Kim McManus⁴, Shifteh Sattar⁴, Jack J. Lin⁵, Ammar Shaikhouni⁶, Peter Brunner⁷, Jarod L. Roland^7,8, Kurtis I. Auguste⁹, Joyce Y. Wu^1,10, Sandi K. Lam^1,10, Jeffrey S. Raskin^1,10, Robert T. Knight¹¹, Noa Ofen², Elizabeth L. Johnson¹; ¹Northwestern University Feinberg School of Medicine, ²Wayne State University, and University of Texas at Dallas, ³Children’s Hospital of Michigan, ⁴University of California, San Diego, and UCSD Rady Children’s Hospital, ⁵University of California, Davis, ⁶Ohio State University, and Nationwide Children’s Hospital, ⁷Washington University in St. Louis, ⁸St. Louis Children’s Hospital, ⁹University of California, San Francisco, and UCSF Benioff Children’s Hospital, ¹⁰Ann & Robert H. Lurie Children’s Hospital of Chicago, ¹¹University of California, Berkeley

Posterior cingulate cortex (PCC) is a central node in the posterior medial network supporting episodic memory. Intracranial EEG (iEEG) studies of PCC show that high-frequency broadband activity (HFA, 70-150 Hz), a robust signature of local population spiking, increases during memory encoding and retrieval. It is unknown whether these same HFA dynamics support memory in the PCC of children and adolescents, and whether age-related variability in these functional dynamics corresponds with age-related variability in memory performance and PCC structure. Here, we analyze iEEG data recorded from 25 neurosurgical epilepsy patients aged 5-30 years (11 females) performing an old/new scene recognition task. Trial-by-trial iEEG data from the study (encoding) and test (retrieval) phases of the task were analyzed as a function of retrieval success (remembered “hit” trials vs. forgotten “miss” trials). Initial results show that HFA increases for hits vs. misses at both encoding and retrieval, but at different times. Successful encoding was associated with an HFA increase from 300ms pre-stimulus to stimulus onset, while successful retrieval was associated with an HFA increase from stimulus onset to 300ms post-stimulus. These findings suggest that the same HFA increases observed at encoding and retrieval in adults also support memory in children and adolescents, while also adding temporal specificity to the effect. Data collection is ongoing. Further analysis will formally test these effects using mixed-effects linear models with cluster-based correction for multiple comparisons in the time domain. We will also test whether these effects increase with age and correspond with age-related reductions in PCC thickness.

Topic Area: LONG-TERM MEMORY: Development & aging