Chronic cannabis users exhibit altered alpha and beta oscillations serving numerical working memory processing

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Peihan J. Huang¹ (jenny.huang@boystown.org), Jake J. Son¹, Jason A. John¹, Lucy K. Horne¹, Seth D. Springer¹, Mikki Schantell¹, Yasra Arif¹, Madelyn P. Willett¹, Hallie J. Johnson¹, Elizabeth Heinrichs-Graham¹, Tony W. Wilson¹; ¹Boys Town National Research Hospital

Cannabis is one of the most widely used psychoactive substances in the United States and research has shown that cannabis use impacts several cognitive domains, including inhibitory control, attention, and memory. However, despite such widespread use, the mechanisms underlying these effects remain poorly understood. In this study, we investigated the neural dynamics serving working memory processing in chronic cannabis users and nonusers using high-density magnetoencephalography (MEG) and a novel numerical working memory task. Briefly, MEG data were collected from 39 participants while performing a numerical working memory paradigm, whereby participants were asked to either maintain a group of visually presented numbers or to rearrange the numbers in ascending order. Significant oscillatory neural responses were imaged separately for each condition using a beamforming approach and subjected to whole-brain repeated-measures ANOVAs. Across both conditions, we found that cannabis users exhibited significantly weaker alpha oscillations in superior parietal, occipital, and other regions during encoding relative to nonusers. Interestingly, during the maintenance phase, there was a group-by-condition interaction effect in the right inferior frontal gyrus, left prefrontal, parietal, and other regions, such that cannabis users exhibited stronger alpha and beta oscillatory responses during the manipulate relative to maintain condition, while no such differences were found in nonusers. Finally, oscillatory response strength in the prefrontal cortices predicted accuracy in the nonusers, but not in cannabis users. In conclusion, our results provide evidence for altered neural oscillatory activity across a broad network of regions serving numerical working memory processes in chronic cannabis users relative to nonusers.

Topic Area: EXECUTIVE PROCESSES: Working memory