Occipitotemporal alpha and theta dynamics support memory formation in the developing brain

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Qin Yin^1,2, Elizabeth L. Johnson³, Adam J. O. Dede³, Kurtis I. Auguste^4,5, Robert T. Knight⁶, Eishi Asano^1,7, Noa Ofen^1,2; ¹Wayne State University, Detroit, MI, ²University of Texas at Dallas, Dallas, TX, ³Northwestern University, Chicago, IL, ⁴University of California, San Francisco, CA, ⁵UCSF Benioff Children’s Hospital, Oakland and San Francisco, CA, ⁶University of California, Berkeley, CA, ⁷Children’s Hospital of Michigan, Detroit, MI

The medial temporal lobe (MTL) is crucial for episodic memory and receives inputs from the occipital cortex to form memories for visual stimuli. The oscillatory mechanisms underlying the occipital-MTL interaction in the developing brain are largely unknown. We analyzed intracranial EEG data from 131 occipital and 90 MTL electrodes in 31 pediatric patients (5.9-20.5 years) undergoing direct cortical monitoring for seizure management. Subjects studied pictures of scenes by responding indoor/outdoor during scene presentation in preparation for a memory recognition test. First, we characterized oscillations in the occipital cortex and MTL. Oscillation detection revealed that alpha dominates the occipital cortex [median(IQR), 8.48(4.98) Hz], and theta dominates MTL [median(IQR), 6.88(3.46) Hz]. We observed an age-related increase in MTL peak frequency. Second, we analyzed event-related phase-amplitude coupling (PAC) between detected oscillations and high-frequency activity (70-150 Hz), a mechanism posited to support information and mnemonic representation, as a function of recognition performance (subsequent hit vs. miss). We observed increased PAC on subsequent hit compared to miss trials in stimulus-locked and response-locked data in both regions. The occipital stimulus-locked PAC effects positively correlated with recognition accuracy. Third, we analyzed occipital-MTL phase synchrony, a mechanism of inter-regional interaction, with occipital and MTL peak frequencies separately. We observed increased phase synchrony on subsequent hit compared to miss trials in stimulus-locked and response-locked data in occipital and MTL peak frequencies. These results demonstrate the important role of neural oscillations in providing the functional infrastructure of memory in the developing brain by facilitating local processing and inter-regional interaction.

Topic Area: LONG-TERM MEMORY: Episodic