Abstracts

Rationale: Stereo-electroencephalogram (sEEG) recordings in the patients with refractory epilepsy has both high spatial and temporal resolution and high signal-to-noise ratio not only in epileptic foci localization but also in cognitive function mapping. In everyday life, humans are always flooded with multifarious sounds concurrently. A key component of this effective extraction process is auditory attention, which allocates both perceptual and cognitive resources on the processing of a target sound. However, what brain areas mediate auditory attention and how these brain regions interacted during auditory attention processing are still unclear. This study aimed to study the relevant brain networks of auditory attention using sEEG approach in young adult epileptic patients. Methods: Six patients underwent sEEG monitoring as a part of the preoperative evaluation of intractable neocortical epilepsy at Sanbo Brain Hospital, Capital Medical University participated in this study. All the participants claimed that they did not have a history of hearing impairment and had no difficulty in hearing. Under the attention condition, the task of each patient was to identify a target syllable from background noises while under the non-attention condition, a visual distraction task was introduced. All the experimental procedures were approved by the Ethics Committee of the Sanbo Hospital of Capital Medical University. Results: As stereo-EEG provided a unique opportunity for directly obtaining electrophysiological activities in the human cortex during awake and task-relevant status, the results revealed that both auditory cortex (peak latency = 54 milliseconds) and superior temporal gyrus (peak latency = 140 milliseconds) were enhanced when patients paid attention to the target sound (t-tests, both p < 0.05). Granger causality analyses revealed that auditory cortex and superior temporal gyrus dynamically interacted during the whole auditory attention task.  Conclusions: Using the ‘golden standard’ sEEG approach, the results not only established the framework of auditory attention in human brain functional mapping, but also develop a new paradigm for the clinical preoperative evaluation and localization of the auditory attention function. Funding: This work was supported by the National Natural Science Foundation of China (81671285), the China Postdoctoral Science Foundation (2016M601066), the Capital Health Research and Development of Special (2016-1-8012), Beijing Municipal Science & Technology Commission (Z161100000516230, Z161100002616016).