RT Journal Article
SR Electronic
T1 Multiscale Aspects of Generation of High-Gamma Activity during Seizures in Human Neocortex
JF eneuro
JO eneuro
FD Society for Neuroscience
SP ENEURO.0141-15.2016
DO 10.1523/ENEURO.0141-15.2016
VO 3
IS 2
A1 Tahra L. Eissa
A1 Andrew K. Tryba
A1 Charles J. Marcuccilli
A1 Faiza Ben-Mabrouk
A1 Elliot H. Smith
A1 Sean M. Lew
A1 Robert R. Goodman
A1 Guy M. McKhann, Jr
A1 David M. Frim
A1 Lorenzo L. Pesce
A1 Michael H. Kohrman
A1 Ronald G. Emerson
A1 Catherine A. Schevon
A1 Wim van Drongelen
YR 2016
UL http://www.eneuro.org/content/3/2/ENEURO.0141-15.2016.abstract
AB High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. However, the effects of the spatiotemporal dynamics of seizure on HG power generation are not well understood. Here, we studied HG generation and propagation, using a three-step, multiscale signal analysis and modeling approach. First, we analyzed concurrent neuronal and microscopic network HG activity in neocortical slices from seven intractable epilepsy patients. We found HG activity in these networks, especially when neurons displayed paroxysmal depolarization shifts and network activity was highly synchronized. Second, we examined HG activity acquired with microelectrode arrays recorded during human seizures (n = 8). We confirmed the presence of synchronized HG power across microelectrode records and the macroscale, both specifically associated with the core region of the seizure. Third, we used volume conduction-based modeling to relate HG activity and network synchrony at different network scales. We showed that local HG oscillations require high levels of synchrony to cross scales, and that this requirement is met at the microscopic scale, but not within macroscopic networks. Instead, we present evidence that HG power at the macroscale may result from harmonics of ongoing seizure activity. Ictal HG power marks the seizure core, but the generating mechanism can differ across spatial scales.