Abstract Details

Harmonics as a Principle of Brain Function  Selen Atasoy (Center for Brain and Cognition, University of Oxford, Oxford, United Kingdom)   PL4

Harmonic patterns constitute a universal characteristic of natural phenomena, emerging in acoustics, optics, and electromagnetism as well as in biological processes such as morphogenesis. Recently, brain activity in awake, resting state is also shown to follow stable harmonic wave patterns emerging on the anatomical connectivity of the human brain [1]. Crucially, these harmonic modes of brain's structural connectivity, termed 'connectome harmonics', provide a new frequency-specific language to describe any pattern of brain activity [2]. In this talk, I will demonstrate how various different states of consciousness including wakefulness [1,2], meditation, psychedelic state [3,4] and anesthesia-induced loss of consciousness as well as vegetative and minimally conscious states can be uniquely characterized by their connectome-harmonic signatures. Furthermore, extending the fundamental principle of harmonic modes from the structural connectivity to functional connectivity of the human brain, I will illustrate how the harmonic modes of brain's communication structure underlie the orchestration of brain's functional organization [5]. These harmonic waves, referred to as 'functional harmonics', provide the frequency-ordered communication channels of the human brain. I will show that 47 brain activation patterns elicited by 7 different task categories in the Human Connectome Project task battery can be reconstructed from a very small subset of functional harmonics, suggesting a simple and universal account for the previously unknown relationship between task and resting state brain activity. Overall, the findings I will present in this talk suggest a new understanding of the fundamental principles underlying human brain function in terms the universal phenomenon of harmonic waves. [1] Atasoy, S., Donnelly, I., & Pearson, J. (2016). Human brain networks function in connectomespecific harmonic waves. Nature Communications, 7, 10340. http://doi.org/10.1038/ncomms10340 [2] Atasoy, S., and Deco, G., and Kringelbach, M. L., and Pearson, J. (2017) Harmonic brain modes: a unifying framework for linking space and time in brain dynamics (2017), The Neuroscientist, 1073858417728032. [3]Atasoy, S., Roseman, L., Kaelen, M., Kringelbach, M. L., Deco, G., & Carhart-Harris, R. L. (2017). Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire reorganization under LSD. Scientific Reports, 7(1), 1?18. https://doi.org/10.1038/s41598-017-17546-0 [4]Atasoy, S., Vohryzek, J., Deco, G., Carhart-harris, R. L., & Kringelbach, M. L. (2018). Common neural signatures of psychedelics: Frequency-specific energy changes and repertoire expansion revealed using connectome-harmonic decomposition, 242. [5 Glomb, K., Kringelbach, M. L., Deco, G., Hagmann, P., Pearson, J., Atasoy, S., Functional harmonics reveal multi-dimensional basis functions underlying cortical organization, under review, doi: https://doi.org/10.1101/699678