Neural Dynamics of Visual Stream Interactions During Memory-Guided Actions Investigated by Intracranial EEG
Sofia Moraresku1,2 · Jiri Hammer3,4 · Vasileios Dimakopoulos5 · Michaela Kajsova3,4 · Radek Janca4 · Petr Jezdik4 · Adam Kalina3,4 · Petr Marusic3,4 · Kamil Vlcek1,3,41 Laboratory of Neurophysiology of Memory, Institute of Physiology, Czech Academy of Sciences, Prague, Czechia
2 Third Faculty of Medicine, Charles University, Prague, Czechia
3 Department of Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Member of the Epilepsy Research Centre Prague - EpiReC consortium, Prague, Czechia
4 Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Member of the Epilepsy Research Centre Prague - EpiReC Consortium, Prague, Czechia
5 Klinik für Neurochirurgie, Universitätsspital Zürich, Universität Zürich, Zurich, Switzerland
Abstract
The dorsal and ventral visual streams have been considered to play distinct roles in visual processing for action: the dorsal stream is assumed to support real-time actions, while the ventral stream facilitates memory-guided actions. However, recent evidence suggests a more integrated function of these streams. We investigated the neural dynamics and functional connectivity between them during memory-guided actions using intracranial EEG. We tracked neural activity in the inferior parietal lobule in the dorsal stream, and the ventral temporal cortex in the ventral stream as well as the hippocampus during a delayed action task involving object identity and location memory. We found increased alpha power in both streams during the delay, indicating their role in maintaining spatial visual information. In addition, we recorded increased alpha power in the hippocampus during the delay, but only when both object identity and location needed to be remembered. We also recorded an increase in theta band phase synchronization between the inferior parietal lobule and ventral temporal cortex and between the inferior parietal lobule and hippocampus during the encoding and delay. Granger causality analysis indicated dynamic and frequency-specific directional interactions among the inferior parietal lobule, ventral temporal cortex, and hippocampus that varied across task phases. Our study provides unique electrophysiological evidence for close interactions between dorsal and ventral streams, supporting an integrated processing model in which both streams contribute to memory-guided actions.
Keywords
Dorsal visual stream; Ventral visual stream; Memory-guided actions; Intracranial EEG; Phase-locking value; Granger causality analysis; Alpha oscillations; Theta oscillations
