Prestimulus dynamics blend with the stimulus in neural variability quenching
Annemarie Wolff,
Liang Chen,
Shankar Tumati,
Mehrshad Golesorkhi,
Javier Gomez-Pilar,
Jie Hu,
Shize Jiang,
Ying Mao,
André Longtin,
Georg Northoff
Affiliations
Annemarie Wolff
University of Ottawa Institute of Mental Health Research, Ottawa, Canada; Corresponding authors.
Liang Chen
Department of Neurological Surgery, Huashan Hospital, Fudan University, Wulumuqi Middle Rd, Shanghai, China; Corresponding authors.
Shankar Tumati
University of Ottawa Institute of Mental Health Research, Ottawa, Canada
Mehrshad Golesorkhi
School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Canada
Javier Gomez-Pilar
Biomedical Engineering Group, Higher Technical School of Telecommunications Engineering, University of Valladolid, Valladolid, Spain; Centro de Investigación Biomédica en Red—Bioingeniería, Biomateriales y Nanomedicina, (CIBER-BBN), Spain
Jie Hu
Department of Neurological Surgery, Huashan Hospital, Fudan University, Wulumuqi Middle Rd, Shanghai, China
Shize Jiang
Department of Neurological Surgery, Huashan Hospital, Fudan University, Wulumuqi Middle Rd, Shanghai, China
Ying Mao
Department of Neurological Surgery, Huashan Hospital, Fudan University, Wulumuqi Middle Rd, Shanghai, China
André Longtin
Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada; Physics Department, University of Ottawa, Ottawa, Canada
Georg Northoff
University of Ottawa Institute of Mental Health Research, Ottawa, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
Neural responses to the same stimulus show significant variability over trials, with this variability typically reduced (quenched) after a stimulus is presented. This trial-to-trial variability (TTV) has been much studied, however how this neural variability quenching is influenced by the ongoing dynamics of the prestimulus period is unknown. Utilizing a human intracranial stereo-electroencephalography (sEEG) data set, we investigate how prestimulus dynamics, as operationalized by standard deviation (SD), shapes poststimulus activity through trial-to-trial variability (TTV). We first observed greater poststimulus variability quenching in those real trials exhibiting high prestimulus variability as observed in all frequency bands. Next, we found that the relative effect of the stimulus was higher in the later (300-600ms) than the earlier (0-300ms) poststimulus period. Lastly, we replicate our findings in a separate EEG dataset and extend them by finding that trials with high prestimulus variability in the theta and alpha bands had faster reaction times. Together, our results demonstrate that stimulus-related activity, including its variability, is a blend of two factors: 1) the effects of the external stimulus itself, and 2) the effects of the ongoing dynamics spilling over from the prestimulus period - the state at stimulus onset - with the second dwarfing the influence of the first.
