02357nas a2200205   4500008004100000022001400041245007700055210006900132260001200201490000700213520170000220100002401920700003201944700002401976700002202000700002102022700001902043700002102062856006802083       2023                        eng d  a1662-453X00aCharacterization of High-Gamma Activity in Electrocorticographic signals0 aCharacterization of HighGamma Activity in Electrocorticographic   c08/20230 v173 aIntroduction: Electrocorticographic (ECoG) high-gamma activity (HGA) is a widely recognized and robust neural correlate of cognition and behavior. However, fundamental signal properties of HGA, such as the high-gamma frequency band or temporal dynamics of HGA, have never been systematically characterized. As a result, HGA estimators are often poorly adjusted, such that they miss valuable physiological information.

Methods: To address these issues, we conducted a thorough qualitative and quantitative characterization of HGA in ECoG signals. Our study is based on ECoG signals recorded from 18 epilepsy patients while performing motor control, listening, and visual perception tasks. In this study, we first categorize HGA into HGA types based on the cognitive/behavioral task. For each HGA type, we then systematically quantify three fundamental signal properties of HGA: the high-gamma frequency band, the HGA bandwidth, and the temporal dynamics of HGA.

Results: The high-gamma frequency band strongly varies across subjects and across cognitive/behavioral tasks. In addition, HGA time courses have lowpass character, with transients limited to 10 Hz. The task-related rise time and duration of these HGA time courses depend on the individual subject and cognitive/behavioral task. Task-related HGA amplitudes are comparable across the investigated tasks.

Discussion: This study is of high practical relevance because it provides a systematic basis for optimizing experiment design, ECoG acquisition and processing, and HGA estimation. Our results reveal previously unknown characteristics of HGA, the physiological principles of which need to be investigated in further studies.1 aGruenwald, Johannes1 aSieghartsleitner, Sebastian1 aKapeller, Christoph1 aScharinger, Josef1 aKamada, Kyousuke1 aBrunner, Peter1 aGuger, Christoph  uhttps://www.frontiersin.org/articles/10.3389/fnins.2023.1206120