Original Research ARTICLE
Simultaneous EEG-NIRS Measurement of the Inferior Parietal Lobule during a Reaching Task with Delayed Visual Feedback
- 1Rhythm-based Brain Information Processing Unit, RIKEN CBS-Toyota Collaboration Center, Japan
- 2Electrical Engineering Program, Graduate School of Science and Technology, Meiji University, Japan
- 3Department of Electronics and Bioinformatics, Graduate School of Science and Technology, Meiji University, Japan
We investigated whether the inferior parietal lobule (IPL) responds in real-time to multisensory inconsistency during movement. The IPL is thought to be involved in both the detection of inconsistencies in multisensory information obtained during movement and that obtained during self-other discrimination. However, because of the limited temporal resolution of conventional neuroimaging techniques, it is difficult to distinguish IPL activity during movement from that during self-other discrimination. We simultaneously conducted electroencephalography (EEG) and near-infrared spectroscopy (NIRS) with the goal of examining IPL activity with a high spatiotemporal resolution during single reaching movements. Under a visual feedback-delay condition, gamma event-related synchronization (γ-ERS), i.e., an increase in gamma (31–47 Hz) EEG power, occurred during reaching movements. This γ-ERS is considered to reflect processing of information about prediction errors. To integrate this temporal information with spatial information from the NIRS signals, we developed a new analysis technique that enabled estimation of the regions that show a hemodynamic response characterized by EEG fluctuation present in the visual feedback-delay condition. As a result, IPL activity was explained by γ-ERS specific to visual feedback delay during movements. Thus, we succeeded in demonstrating real-time activation of the IPL in response to multisensory inconsistency. However, we did not find any correlation between either IPL activity or γ-ERS with the sense of agency. Therefore, our results suggest that while the IPL is influenced by prediction error signals, it does not engage in direct processing underlying the conscious experience of making a movement, which is the foundation of self-other discrimination.
Keywords: Electroencephalography, near-infrared spectroscopy, simultaneous measurement, psychophysiological interaction, Event-related (de)synchronization, inferior parietal lobule, visual feedback delay
Received: 14 Dec 2018;
Accepted: 13 Aug 2019.
Copyright: © 2019 Zama, Takahashi and Shimada. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: PhD. Takuro Zama, RIKEN CBS-Toyota Collaboration Center, Rhythm-based Brain Information Processing Unit, Wako, Japan, firstname.lastname@example.org