This work was performed in part at the high performance computing cluster (HPCC), which is supported by information and communication technology office (ICTO) of the University of Macau. This study was supported by MYRG2019-00082-FHS and MYRG 2018-00081-FHS grants from the University of Macau in Macau, and also funded by The Science and Technology Development Fund, Macau SAR (FDCT 0011/2018/A1 and FDCT 025/2015/A1).

Prior to the experimental tests, all participants signed informed consent documents. The protocol for the present study was approved by the Ethics Committee of the University of Macau.
1. Hardware and software setting for concurrent EEG and fNIRS recordings
<ol>
	<li>Construct a head cap for concurrent EEG-fNIRS recordings.
	<ol>
		<li>Select the appropriate cap size according to the head circumference of participants. In this study, use a medium-size cap since it is suitable for most adoles...

<ol>
	<li>Kennan, R. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+recording+of+event-related+auditory+oddball+response+using+transcranial+near+infrared+optical+topography+and+surface+EEG.">Simultaneous recording of event-related auditory oddball response using transcranial near infrared optical topography and surface EEG.</a> NeuroImage. 16 (3), 587-592 (2002).</li><li>Horovitz, S. G., Gore, J. 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Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concurrent+mapping+of+brain+activation+from+multiple+subjects+during+social+interaction+by+hyperscanning:+a+mini-review.">Concurrent mapping of brain activation from multiple subjects during social interaction by hyperscanning: a mini-review.</a> Quantitative Imaging in Medicine and Surgery. 8 (8), 819-837 (2018).</li><li>Scholkmann, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+on+continuous+wave+functional+near-infrared+spectroscopy+and+imaging+instrumentation+and+methodology.">A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology.</a> NeuroImage. 85, 6-27 (2014).</li><li>Wan, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neural+basis+of+the+hemodynamic+response+nonlinearity+in+human+primary+visual+cortex:+Implications+for+neurovascular+coupling+mechanism.">The neural basis of the hemodynamic response nonlinearity in human primary visual cortex: Implications for neurovascular coupling mechanism.</a> NeuroImage. 32 (2), 616-625 (2006).</li><li>Miller, E. 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K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+continuous+EEG-fNIRS+recording+of+temporal+lobe+seizures.">Non-invasive continuous EEG-fNIRS recording of temporal lobe seizures.</a> Epilepsy Research. 99 (1-2), 112-126 (2012).</li><li>Peng, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=fNIRS-EEG+study+of+focal+interictal+epileptiform+discharges.">fNIRS-EEG study of focal interictal epileptiform discharges.</a> Epilepsy Research. 108 (3), 491-505 (2014).</li><li>Liu, Y., Ayaz, H., Shewokis, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multisubject+"learning"+for+mental+workload+classification+using+concurrent+EEG,+fNIRS,+and+physiological+measures.">Multisubject "learning" for mental workload classification using concurrent EEG, fNIRS, and physiological measures.</a> Frontiers in Human Neuroscience. 11, (2017).</li><li>Aghajani, H., Garbey, M., Omurtag, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+mental+workload+with+EEG+fNIRS.">Measuring mental workload with EEG+fNIRS.</a> Frontiers in Human Neuroscience. 11, (2017).</li><li>Balconi, M., Vanutelli, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamic+(fNIRS)+and+EEG+(N200)+correlates+of+emotional+inter-species+interactions+modulated+by+visual+and+auditory+stimulation.">Hemodynamic (fNIRS) and EEG (N200) correlates of emotional inter-species interactions modulated by visual and auditory stimulation.</a> Scientific Reports. 6, (2016).</li><li>Donohue, S. E., Appelbaum, L. G., McKay, C. C., Woldorff, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neural+dynamics+of+stimulus+and+response+conflict+processing+as+a+function+of+response+complexity+and+task+demands.">The neural dynamics of stimulus and response conflict processing as a function of response complexity and task demands.</a> Neuropsychologia. 84, 14-28 (2016).</li><li>Liu, Y., Ayaz, H., Shewokis, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mental+workload+classification+with+concurrent+electroencephalography+and+functional+near-infrared+spectroscopy.">Mental workload classification with concurrent electroencephalography and functional near-infrared spectroscopy.</a> Brain-Computer Interfaces. 4 (3), 175-185 (2017).</li><li>Fazli, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+performance+by+a+hybrid+NIRS-EEG+brain+computer+interface.">Enhanced performance by a hybrid NIRS-EEG brain computer interface.</a> NeuroImage. 59 (1), 519-529 (2012).</li><li>Putze, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+fNIRS-EEG+based+classification+of+auditory+and+visual+perception+processes.">Hybrid fNIRS-EEG based classification of auditory and visual perception processes.</a> Frontiers in Neuroscience. 8, 373 (2014).</li><li>Horovitz, S. 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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+N200+and+P300:+Selected+studies+of+the+Event-Related+Potential.">Characterization of N200 and P300: Selected studies of the Event-Related Potential.</a> International Journal of Medical Sciences. 2 (4), 147-154 (2005).</li><li>Suzuki, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+the+superior+frontal+cortex+and+alpha+oscillation+in+a+flanker+task:+Simultaneous+recording+of+electroencephalogram+(EEG)+and+near+infrared+spectroscopy+(NIRS).">The relationship between the superior frontal cortex and alpha oscillation in a flanker task: Simultaneous recording of electroencephalogram (EEG) and near infrared spectroscopy (NIRS).</a> Neuroscience Research. 131, 30-35 (2018).</li><li>Keles, H. O., Barbour, R. 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The authors have nothing to disclose.&#8195;

In this protocol, combined EEG and fNIRS recordings were performed to examine the brain activation patterns involving an event-related Flanker paradigm by recording the neural signals of the whole brain and concurrent hemodynamic responses of the prefrontal cortex. The ERP results showed that N200 at Fz was able to significantly distinguish the congruent and incongruent conditions (P=0.037). Meanwhile, the HbO signals in SFC (channels 21) also exhibited a significant difference between the congruent and incongruent condi...

This study aims to develop a working protocol to reveal the neural activation pattern underlying the Flanker task by using fused EEG and fNIRS neuroimaging techniques. Interestingly, the concurrent fNIRS-EEG recordings allow for the inspection of the relationship between the hemodynamic signals in the prefrontal cortex and various event-related potential (ERP) components of the whole brain associated with the Flanker task.
The integration of various noninvasive neuroimaging modalities including functional near-infrared spectroscopy (fNIRS), electroencephalography (EEG), and functional magnetic resonance imaging (fMRI) is essential to improve the understanding of where and when information processing is taking place in the brain1,2,3. Additionally, there is the potential to combine fNIRS and EEG to examine the relationship between local neural activity and subsequent changes in hemodynamic responses, in which EEG and fNIRS can be complementary in revealing the neural mechanism of human brain cognitive function. fNIRS is a vascular-based functional neuroimaging technique that relies on the hemodynamic responses to infer brain activation. fNIRS measures the relative oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) concentration changes in the cerebral cortex, which plays an important role in the study of cognitive processing3,4,5,6,7. According to the neurovascular and neurometabolic coupling mechanism8, the change of local neural activity associated with cognitive processing is generally accompanied by subsequent alterations in the local blood flow and blood oxygen with a delay of 4-7 seconds. It is shown that the neurovascular coupling is likely a power transducer, which integrates the fast dynamics of neural activity into the vascular input of slow hemodynamics9. Specifically, fNIRS is mostly used for inspecting the neurovascular activity in the frontal lobe, especially the prefrontal cortex that is responsible for high cognitive functions, such as executive functions10,11,12, reasoning and planning13, decision making14, and social cognition and moral judgment15. However, the hemodynamic responses measured by fNIRS only indirectly capture the neural activity with a low temporal resolution, whereas EEG can offer temporally fine and direct measures of neural activities. Consequently, the combination of EEG and fNIRS recording can identify more features and reveal more information associated with the functioning of the brain.
More importantly, the multi-modal acquisition of EEG and fNIRS signals has been conducted to inspect the brain activation underlying various cognitive tasks16,17,18,19,20,21,22 or brain-computer interface23,24. In particular, concurrent ERP (event-related potential) and fNIRS recordings were carried out based on the event-related auditory oddball paradigm1, in which fNIRS can identify the hemodynamic changes in the frontotemporal cortex several seconds after the appearance of P300 component. Horovitz et al. also demonstrated the simultaneous measurements of fNIRS signals and the P300 component during a semantic processing task25. Interestingly, previous studies based on simultaneous EEG and fNIRS recordings showed that P300 during oddball stimuli exhibited a significant correlation with fNIRS signals26. It was discovered that the multi-modal measures have the potential to reveal the comprehensive cognitive neural mechanism based on the event-related paradigm26. Besides the oddball task, the Flanker task associated with ERP component N200 is also an important paradigm, which can be used for the investigation of cognitive ability detection and evaluation with healthy controls and patients with various disorders. Specifically, N200 was a negative component that peaks 200-350 ms from the anterior cingulated cortex frontal27 and superior temporal cortex28. Although previous studies examined the relationship between the superior frontal cortex and alpha oscillation in the Flanker task29, the correlation between the N200 amplitude and the hemodynamic responses during the Flanker task has not been explored.
In this protocol, a home-made EEG/fNIRS patch based on standard EEG cap was utilized for the concurrent EEG and fNIRS recordings. The arrangements of optodes/electrodes with support were achieved through the placement of fNIRS optodes fused into the EEG cap. The simultaneous EEG and fNIRS data acquisitions were carried out with the same stimuli tasks generated by E-prime software. We hypothesize that ERP components associated with the Flanker task can exhibit a significant correlation with the hemodynamic responses in the prefrontal cortex. Meanwhile, the combined ERP and fNIRS recordings can extract multiple signal indicators to identify the brain activation patterns with enhanced accuracy. To test the hypothesis, the fNIRS setup and EEG machine were integrated to reveal the complex neural cognition mechanism corresponding to the event-related Flanker task.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EEG cap</td>
			<td style="width:104px;">EASYCAP GmbH</td>
			<td style="width:119px;">-</td>
			<td style="width:167px;">-</td>
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			<td height="21" style="height:21px;width:216px;">EEG system</td>
			<td style="width:104px;">BioSemi</td>
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			<td>-</td>
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			<td height="21" style="height:21px;width:216px;">fNIRS system</td>
			<td style="width:104px;">TechEn</td>
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			<td>CW6 System</td>
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conducting concurrent electroencephalography and functional near-infrared spectroscopy recordings with a flanker task

Concurrent EEG and fNIRS recordings offer an excellent opportunity to gain a full understanding of the neural mechanism of cognitive processing by inspecting the relationship between the neural and hemodynamic signals. EEG is an electrophysiological technology that can measure the rapid neuronal activity of the cortex, whereas fNIRS relies on the hemodynamic responses to infer brain activation. The combination of EEG and fNIRS neuroimaging techniques can identify more features and reveal more information associated with the functioning of the brain. In this protocol, fused EEG-fNIRS measurements were performed for concurrent recordings of evoked-electrical potentials and hemodynamic responses during a Flanker task. In addition, the critical steps for setting up the hardware and software system as well as the procedures for data acquisition and analysis were provided and discussed in detail. It is expected that the present protocol can pave a new avenue for improving the understanding of the neural mechanisms underlying various cognitive processes by using the EEG and fNIRS signals.

Figure 2 shows the HbO signals for all channels while Figure 3 displays the ERPs at Fz and FCz for the two conditions of the Flanker task. Figure 4 illustrated the Pearson correlation analysis results showed that the fNIRS signals in SFC exhibited a significant correlation with the ERP N200 component at Fz for the incongruent condition (P&#60;0.05). However, this is not the case for the congruent condit...

Watch this Scientific Journal Video about Conducting Concurrent Electroencephalography and Functional Near-Infrared Spectroscopy Recordings with a Flanker Task at JoVE.com

Conducting Concurrent Electroencephalography and Functional Near-Infrared Spectroscopy Recordings with a Flanker Task

The present protocol describes how to perform concurrent EEG and fNIRS recordings and how to inspect the relationship between the EEG and fNIRS data.&#160;

Concurrent EEG and fNIRS recordings offer an excellent opportunity to gain a full understanding of the neural mechanism of cognitive processing by ...

The aim of this study was to develop a working protocol to reveal the neuro activation pattern, underline the flanker task by using fused EEG and fNIRS neuro imaging technique. The simultaneous fNIRS EEG recordings allow for the inspection of the relationship between the of prefrontal cortex and different events related to the potential components of the whole brain. fNIRS in the cerebral cortex which pretty important law in study of cognitive processing.We know that fNIRS is mostly used for inspecting the neurovascular activity in the frontal lobe. is related to high brain cognitive functions. However the haemodynamic response meted by fNIRS can only read the activities with low temporal resolution but EEG can offer temporary find and direct measurement of neuro activities.The combination of EEG and fNIRS recordings is able to identify more features and reveal more information relate with the brain functions. In this study, you use the EEG fNIRS techniques were used for simultaneous recordings of ERP components and haemodynamic response with a flanker task. It's rational to assume that ERP components associate with the flanker task can exhibit significant correlation with the haemodynamic response.To tether this assumption, the fNIRS set up and the EEG machine were integrated together to reveal the complex neuro cognition metism corresponding to the event with flanker task. Prior to the experiment test, all participants signed informed consent documents. The study was approved by the ethics committee of the University of Macau.Number one, hardware and software setting for concurrent EEG and fNIRS recordings. Construct a feasible head cap for concurrent EEG and fNIRS recordings. Select the right cap size according to the head circumference of participants.In this study, a medium-sized cap is used since it's suitable for most adolescent or adult participants. Draw the layout according to the experiment design in the literature. Dig 22 holes inside the EEG cap for holding fNIRS optodes in line with a specifically out frontal cortex.Place 21 or 71 EEG electrodes along the surface of the EEG cap according to the 10-20 international system and mount the grates for the optodes. Set the distance between each source detector pair as three centimeters and then fix the optodes. In each the blue optodes are detectors while the red ones are laser sources.Setting the EEG and fNIRS port in the software. Set the parallel port, example H378 in this study for the EEG system. Set the serial ports, example 600 in this study for the fNIRS system.The port type and number should be modified regarding various EEG and fNIRS setups. Please contact the manufacturers for more information. Preparation before the experiment.Warm up the fNIRS system with lasers. Switch it on for 30 minutes. Set all necessary operation permitters for the fNIRS measurement system.Should the setup, including the EEG and fNIRS measurement systems to participant. Measure and mark the CZ point according to the 10-20 international system. Identify the electrode position of CZ at half of the distance between the and half of the distance between the left and right interorbital indentations.Place the front part of the cap along the participants forehead first and then pull down the back session of the cap towards the neck. Validation the positions. Note, it is highly recommended that EEG electrodes should be firstly set and subsequently the nearest optodes.If EEG conductive gel covers the holes for the placement of nearest optodes it should be clean to prevent the contamination of optodes. Preparation for the EEG recordings. Fill conductive gel by inserting a blunt needle through the holes of EEG electrode grate.Place all electrodes into the EEG electrodes grid according to the levels. Open the EEG software and inspect the signal quality of the electrodes. Readjust electrodes by refilling conductive gel if the signal quality could not meet the requirements.Preparation for the fNIRS recordings. Caution do not expose participants eyes to laser beam of the source directly. Place the optical fibers along the holder arms attached to the fNIRS measurement system and additional holder.Make sure that the fibers are neat and tidy. Insert the optical source and detectors into the holes according to the layout. Test the signal quality.If a channel does not have a high level signal to noise ratio. Example, if the channel is marked in yellow gently swap participant hair surrounding the optical probes to ensure that nothing exists between the optical probe and skull. If step 2.8.3 cannot improve the signal quality turn up the signal intensity.If there is too much signal. Example if the channel is marked in red, turn down the signal intensity. Run the experiment.Start the experiment when the signals are stable with excellent signal to noise ratio and participants are familiar with the experiment instructions. After the experiment, save and export the data off the EEG fNIRS. Remove EEG electrodes and fNIRS optical probes carefully.Measurement of three dimensional, 3D MNI coordinates of fNIRS optodes with 3D digitizer. Let participants sit in a chair and wear the glasses with a sensor. Open the digitizer software on the computer.Ensure that the 3D digitizer system is in connection with the computer through an appropriate com port. Load the layout of optodes set in file. Move the 3D digitizer styles accord the key positions.NZ, LZ, left ear, right ear, CZ along the screen and press the button on the stylus. Localize optical source and detectors. Export the 3D coordinates file.Data analysis. fNIRS data analysis. Process the 3D MNI coordinates file by using the registration option in fNIRS SPM with MetLife 2019.Select stand alone special registration with 3D digitize. Choose the previously, save it others and origin text file.Registration. Pre-process fNIRS signals with Homer2 software according to the following steps.The application of the modified Motion artifact correction. Then pass filtering 0.015 hertz to 0.2 hertz. Normalize a more dynamic signal amplitude by dividing the average values.Generate the fNIRS data for each channel basing on a 3D digitized information. Select the channels that has a registration probability of 100%or more in SFC according to the regression calculation of the fNIRS SPM for further analysis. Export the peak values of HbO.EEG data processing. Load the raw EEG data folder into the EEG lab by using the plugins. Choose the BOC plugin for BDF file in this study.Note, please choose suitable plugin according to the EEG data file format. Set the channel location information for EEG lab. Load the corresponding location file of the cap.We reference in electrodes in ERP lab which is one plugin of EEG lab. Choose the channels, place it in the mass storage as referenced electrodes. Extract EEG data based on the event and bin files in the ERP lab.Filter the EEG data segment in the ERP lab by using the IIR filter. By filtering the low frequencies with a cutoff of 30 Hertz and by filtering the high frequencies with a curve of 0.1 Hertz. Remove ocular EEG artifacts within Bendon component analysis in EEG lab.Reject EEG data segment with amplitude values exceeding the range from positive 100 to the negative 100 microvolt at any channel in ERP lab. the EEG data segment in ERP lab. Note, these are the generally used data analysis method and the software for pre-processing EEG and fNIRS data.There are numerous processing software and methods available. Correlation calculation. Generate the relationship between fNIRS and EEG recordings with Pearson correlation analysis.Representative results. fNIRS headset placement and channels configuration. The digitized optodes layout are converted into the MNI coordinate system and overlapped along the brain cortex.HbO signal for all channels associated with the flanker task. The pink curves denoting congruent condition while the green ones indicate the congruent condition. ERP signal for FZ and FCZ electrodes.The black curves define the incongruent condition while the red ones denote the congruent condition. Correlation between the ERP N200 and fNIRS signal along the SFC for the incongruent condition. In summary combine the EEG and fNIRS neuro imaging was performed to map the brain activation involved flanked by recording the neuro signals of whole brain and haemodynamic response of the prefrontal cortex.We successfully acquired the EEG and fNIRS data with a flanker task. Our finding showed that the fNIRS haemodynamic response and ERP N200 components are significantly correlated which exhibit different perspective of cognitive mechanism associated with the flanker task. Our multimodal neuro imaging results support a essential roles of combined the EEG and fNIRS technique in contributing to brain which paves a new avenue for improving the understanding of neuro mechanism of different cognitive processing.

conducting-concurrent-electroencephalography-functional-near-infrared

Research

JoVE Journal

Neuroscience

7.5K visualizações.  University of Macau. O objetivo deste estudo foi desenvolver um protocolo de trabalho para revelar o padrão de ativação neurológica, sublinhar a tarefa flanker usando a técnica de imagem neurofísica fundida EEG e fNIRS. As gravações simultâneas de EEG fNIRS permitem a inspeção da relação entre o córtex pré-frontal e diferentes eventos relacionados aos componentes potenciais de todo o cérebro. fNIRS no córtex cerebral que é uma lei muito importante no estudo do processamento cognitivo.Sabe...