Dynamic Cortical and Tractography Atlases of Proactive and Reactive Alpha and High-gamma Activities
Abstract number :
1.026
Submission category :
1. Basic Mechanisms / 1C. Electrophysiology/High frequency oscillations
Year :
2022
Submission ID :
2204123
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:23 AM
Authors :
Hiroya Ono, MD, PhD – Wayne State University; Masaki Sonoda, MD, PhD – Pediatrics – Wayne State University; Kazuki Sakakura, MD – Pediatrics – Wayne State University; Yu Kitazawa, MD, PhD – Pediatrics – Wayne State University; Takumi Mitsuhashi, MD, PhD – Pediatrics – Wayne State University; Ethan Firestone, MS – Physiology – Wayne State University; Aimee Luat, MD – Pediatrics – Children’s Hospital of Michigan; Neena Marupudi, MD – Neurosurgery – Children’s Hospital of Michigan; Sandeep Sood, MD – Neurosurgery – Children’s Hospital of Michigan; Eishi Asano, MD, PhD, MS – Pediatrics – Wayne State University
Rationale: Alpha waves, posterior-dominant rhythms at 8-12 Hz reactive to eye opening and closure, are among the most fundamental EEG findings in clinical practice and research since Hans Berger first documented them in the early 20th century. Yet, the exact network dynamics of alpha waves around eye movements remain determined. High-gamma activity at 70-110 Hz, also reactive to eye movements, is a summary measure of local cortical activation supporting sensorimotor or cognitive function at given moments. We aimed to build the first-ever atlases directly visualizing the network dynamics of eye movement-related alpha and high-gamma modulations at cortical and white matter levels.
Methods: We studied 28 patients (age: 5-20 years) who underwent intracranial EEG and electrooculography recordings. We measured alpha and high-gamma modulations at 2,170 electrode sites outside the seizure onset zone, interictal spike-generating areas, and MRI-visible structural lesions. Dynamic tractography animated the white matter streamlines connecting cortices modulated significantly and simultaneously beyond a chance level on a millisecond scale.
Results: Before eye closure onset, significant alpha augmentation occurred at the occipital-frontal cortices. After eye closure onset, alpha-based functional connectivity was strengthened, while high gamma-based connectivity was weakened extensively in the intrahemispheric and interhemispheric pathways involving the central visual areas. The inferior fronto-occipital fasciculus supported the strengthened functional connectivity between the occipital and frontal lobe regions, whereas the posterior corpus callosum supported the intrahemispheric functional connectivity between the occipital lobes. After eye opening offset, significant high gamma augmentation and alpha attenuation occurred at the occipital, fusiform, and inferior parietal cortices. High gamma-based functional connectivity was strengthened, whereas alpha-based connectivity was weakened in the posterior interhemispheric and intrahemispheric white matter pathways involving central and peripheral visual areas (Figure 1).
Conclusions: Proactive and reactive alpha waves rapidly involve extensive, distinct white matter networks, including the frontal lobe areas in addition to the low- and high-order visual areas. Coupling with high-gamma co-attenuation in shared brain circuitry supports the notion of an idling role of alpha augmentation during eye closure. The dynamic tractography atlases may improve the understanding of the significance of EEG alpha waves while assessing the functional integrity of the brain networks in clinical practice and the effects of eye movements on task-related brain network measures in cognitive neuroscience research.
Funding: NIH Grant NS064033
Basic Mechanisms