title: Plasticity of brain wave network interactions and evolution across physiologic states.
abstract: Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions representing dynamical communications within and between different brain areas in the frequency domain. We introduce the concept of time delay stability (TDS) to quantify coordinated bursts in the activity of brain waves, and we employ a system-wide Network Physiology integrative approach to probe the network of coordinated brain wave activations and its evolution across physiologic states. We find an association between network structure and physiologic states. We uncover a hierarchical reorganization in the brain wave networks in response to changes in physiologic state, indicating new aspects of neural plasticity at the integrated level. Globally, we find that the entire brain network undergoes a pronounced transition from low connectivity in Deep Sleep and REM to high connectivity in Light Sleep and Wake. In contrast, we find that locally, different brain areas exhibit different network dynamics of brain wave interactions to achieve differentiation in function during different sleep stages. Moreover, our analyses indicate that plasticity also emerges in frequency-specific networks, which represent interactions across brain locations mediated through a specific frequency band. Comparing frequency-specific networks within the same physiologic state we find very different degree of network connectivity and link strength, while at the same time each frequency-specific network is characterized by a different signature pattern of sleep-stage stratification, reflecting a remarkable flexibility in response to change in physiologic state. These new aspects of neural plasticity demonstrate that in addition to dominant brain waves, the network of brain wave interactions is a previously unrecognized hallmark of physiologic state and function.
authors.affiliation: Laboratory for Network Physiology, Department of Physics, Boston University Boston, MA, USA ; Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA.
authors.forename: Kang K L
authors.initials: KK
authors.lastname: Liu
authors.affiliation: Department of Physics, Bar-Ilan University Ramat Gan, Israel.
authors.forename: Ronny P
authors.initials: RP
authors.lastname: Bartsch
authors.affiliation: Laboratory for Network Physiology, Department of Physics, Boston University Boston, MA, USA ; Department of Mathematics, School of Science, Beijing Jiaotong University Beijing, China.
authors.forename: Aijing
authors.initials: A
authors.lastname: Lin
authors.affiliation: Dipartimento di Fisica e Chimica, Viale delle Scienze, University of Palermo Palermo, Italy ; Center for Network Science and Department of Economics, Central European University Budapest, Hungary.
authors.forename: Rosario N
authors.initials: RN
authors.lastname: Mantegna
authors.affiliation: Laboratory for Network Physiology, Department of Physics, Boston University Boston, MA, USA ; Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA ; Institute of Solid State Physics, Bulgarian Academy of Sciences Sofia, Bulgaria.
authors.forename: Plamen Ch
authors.initials: PCh
authors.lastname: Ivanov
mesh_terms: D000328:Adult; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D055815:Young Adult
keywords: brain wave interactions; network physiology; neural plasticity; sleep; time delay stability