This work was supported by NSF grant BCS0745880.

I. Introduction
In the field of Cognitive Neuroscience, functional magnetic resonance imaging (fMRI) has become the standard method of analysis. The popularity of fMRI stems in part from readily available data acquisition and analysis techniques in addition to easily interpretable results that highlight the brain regions associated with a given cognitive process. However, fMRI has poor temporal resolution and thus cannot track the rapid temporal dynamics of the functioning brain. If Cognitive Neuroscientists continue to primarily use fMRI, the resultant picture of brain function will be severely deficient. Event-related potentials (ERPs) are used much less frequently even though this method offers excellent temporal resolution. The purpose of the present article is to detail the key techniques involved in high density ERP data acquisition. It is hoped that this information will foster the increased use of ERPs in Cognitive Neuroscience.
II. General Equipment Setup 
ERP data are typically measured in a location with a low level of ambient electromagnetic field strength to minimize interference with the neural signal. To minimize such interference, ERPs are often measured in a shielded metal chamber (i.e., a Faraday cage) but it may be possible to find an unshielded location with an acceptable level of ambient field strength (1 mg or less, which can be measured using an electromagnetic field meter). Each electrode connects to an amplifier which in turn connects to a data acquisition computer. A separate computer is used for stimulus presentation. To minimize interference with the neural signal, only essential powered components should be housed inside the shielded chamber or near the recording location, such as the stimulus display and the response keyboard (for example, lamps can be used to assist in electrode application but should be powered off during recording). A video switch can be used to display either the data acquisition computer or the stimulus presentation computer on a single monitor. If a shielded chamber is used, all cables can run through a small conduit in the wall (that is a few inches in diameter) or a cracked door. Participants should be seated in a comfortable chair with arm rests and a back height that provides shoulder support to minimize neck muscle artifact, but allows access to posterior inferior electrodes for subsequent electrode impedance reduction. We use a shielded chamber (constructed by Global Partners in Shielding, Inc., Passaic, NJ) and a 128-channel Quik-Cap/SynAmps2 NeuroScan system (Compumedics USA, Charlotte, NC).
III. Cap Placement and Electrode Digitization
Electrodes are typically embedded in a spandex cap which significantly reduces application time. However, the relative electrode locations in a cap are fixed which eliminates the possibility of using standard electrode configurations, such as the 10-20 electrode system1 or a higher density variant such as the 10-5 electrode system2, that are precisely positioned on an individual participant basis. For presentation of the final results in a standard format, we position electrode Oz for each participant at the approximate location dictated by the 10-5 electrode system (and then label all of the electrodes according to their approximate 10-5 electrode system positions). When applying the cap, ensure it has left-right symmetry, with midline electrodes placed over the midline of the head, and that the most posterior-inferior electrodes are superior to the skull-neck boundary to avoid neck muscle artifact. While a chin strap will adequately maintain the cap in position, attaching the side straps to a custom made belt at waist level using velcro fasteners can improve lateral electrode contact with the head. Electrodes adjacent to the eyes can also be applied for subsequent removal of eye-movement or blink artifacts.
Although it is reasonable to assume that electrode placement is relatively consistent across participants, differences in head size and electrode cap placement will produce electrode location variability. To address such variability, electrode locations can be measured for each participant. We use a Polhemus FASTRAK digitizer (Colchester, VT) which includes a transmitter, three receivers which mount on the cap using velcro (to correct for participant motion), and a stylus for recording each electrode location (this hardware is compatible with Neuroscan's SCAN/3DSpaceDx software that we use for data acquisition). Regardless of which digitizer is used, it should be setup according to the specified guidelines, such as avoiding proximity to large metal objects and separating transmitter and receiver cables. The digitizer should be calibrated and tested for accuracy and should be moved, if necessary, to a different location until spatial localization is accurate.
IV. Reducing Electrode Impedances
After the electrode locations are digitized, the participant should sit comfortably in the recording chair. Some participants find it more comfortable when a folded hand towel is lightly tucked between their shoulders and the chair back. Then, the multi-electrode cap should be plugged into the amplifiers. The impedance of each electrode must be reduced such that it is below a predetermined threshold. This is done by injecting a conducting gel into each electrode opening, which will allow current to flow between the scalp and the overlying electrode. To eliminate the possibility of cross-participant contamination, a new sterile syringe and blunt tip needle must be used for each participant. It is notable that although 5 k&Omega;l is a standard impedance threshold, a somewhat higher threshold can be used if the ambient electromagnetic field strength is very low. We use the NeuroScan SCAN software to measure electrode impedance, which displays impedance level by color for all electrodes in real-time. There are a number of techniques that can be speed up the impedance reduction process, which is the most time consuming aspect of ERP data acquisition. It is important to keep in mind that the aim is to restrict gel application between the scalp and the immediately overlying electrode. It is recommended that the dominant hand control the syringe and application of the gel while the non-dominant hand performs other functions. The syringe filled with conducting gel can rest against the head with no participant discomfort, but should never be pressed against the head. First, for a given electrode, it is often useful to make a few circles with the syringe while it rests against the head, to move the intervening hair. After this, while lightly pressing the electrode down with the non-dominant hand, a small amount of gel should be injected at the scalp and then the syringe should be pulled out while continuing to inject gel to make a gel bridge between the scalp and the electrode. Gel that protrudes from the electrode opening should be wiped off with a tissue and discarded. In some cases, conducting gel will connect adjacent electrodes such that impedances will be linked - this reduces spatial resolution but is usually of minor concern as there are a high number of electrodes. Gel should first be applied to the ground and reference electrodes, and if the first set of electrode impedances all remain high gel should be reapplied to these two electrodes. As gel usually becomes more conductive over time, one strategy is to inject gel in electrodes within a scalp quadrant (such as the right posterior scalp) until all impedances begin to decrease, inject gel in electrodes within the next quadrant until all impedances begin to decrease, and then cycle through the quadrants re-injecting gel into the highest impedance electrodes. It should be highlighted that the gel application process should never cause the participant discomfort, and it should made clear to the participant that they should verbalize any discomfort so the corresponding action can be stopped.
V. Data Recording
Before recording commences, participants should be encouraged to get into a comfortable position and relax, to minimize neck muscle artifact, and avoid head movements that might produce contact between posterior electrodes and the chair back. It should be stressed to the participant that during recording they should remain relatively still, as significant movement of the chair (which typically contains a metal frame) can create electromagnetic interference. Participants should then receive a response keyboard and all non-essential equipment near the participant, such as lights, should be removed or turned off. To allow for subsequent event-related analysis, the onset of each stimulus event must be signaled/triggered by the stimulus computer and received and stored along with the electrophysiological data. We send these trigger pulses at each stimulus onset through the parallel port via E-Prime programs (Psychology Software Tools, Inc., Pittsburgh, PA), that include custom InLine port initialization and trigger scripts that are freely available3, and the triggers are received and stored by the SCAN software. Port configuration pin-outs should be referenced to ensure valid trigger values are used. Of relevance, most amplifier high-pass filter settings are acceptable as the aim is simply to remove very low frequency components (such as DC) that are irrelevant to the transient neural response. In contrast, acceptable low-pass filter settings vary depending on the recording environment. In environments with very low ambient electromagnetic interference a low-pass filter with a very high frequency cutoff (such as 200 Hz) can be used, which minimizes distortion of the neural response that does contain higher frequencies. In environments with higher levels of interference, a lower frequency cutoff (such as 80 Hz) and a 60 Hz notch filter can be used such that the electrophysiological response is dominated by the neural signal. Note that filtering can also be conducted in software after the data is acquired, although filtering at the amplifier stage often produces less signal distortion.
VI. Cleaning the Cap
The multi-electrode cap must be thoroughly cleaned and disinfected immediately after data recording is complete. We begin by soaking the cap in warm water for 5-10 minutes and then rinsing each electrode with a running water stream to thoroughly remove all of the conducting gel. The blunt end of a wooden stick cotton swab can be used to clear the holes in the electrodes. Then we soak the cap in a soapy warm water bath (consisting of 4 quarts of water and 1-2 oz of Dial) for 30 minutes to ensure all the gel has been removed, followed by thorough rinsing with water. To avoid cross-participant contamination, the cap must be soaked for 15-30 minutes in an appropriate water/disinfectant mix (such as 4 parts of water to 1 part Envirocide) and then should be rinsed thoroughly with water. When hanging up the cap to dry, it should be placed symmetrically and without tension as it may retain some degree of its drying position, which if irregular can reduce the ease of subsequent impedance reduction.
VII. Analysis Overview
Data pre-processing4 consists of multiple steps including exclusion of electrodes that had poor or intermittent contact, removal of blink artifacts, baseline correction, and additional high-pass or low-pass filtering. Pre-processing is followed by event-related averaging, and spatial resolution can be improved by conducting ERP source localization5. We use the BESA analysis software (Gr&auml;felfing, Germany) for pre-processing, event-related averaging, and source localization (BESA regularly offers two-day analysis courses), with additional analysis conducted on exported event-related average files using custom scripts written in MATLAB (The MathWorks, Natick, MA).

<ol>
	<li>Jasper, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ten-twenty+electrode+system+of+the+International+Federation.">The ten-twenty electrode system of the International Federation.</a> Electroencephalogr. Clin. Neurophysiol. 10, 371-375 (1958).</li><li>Oostenveld, R., Praamstra, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+five+percent+electrode+system+for+high-resolution+EEG+and+ERP+measurements.">The five percent electrode system for high-resolution EEG and ERP measurements.</a> Clin. Neurophysiol. 112, 713-719 (2001).</li><li>Slotnick, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+retinotopic+reactivation+during+spatial+memory.">Rapid retinotopic reactivation during spatial memory.</a> Brain Res. 1268, 97-111 (2009).</li><li>Slotnick, S. D., Handy, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Source+localization+of+ERP+generators.+In+Event-Related+Potentials:+A+Methods+Handbook.">Source localization of ERP generators. In Event-Related Potentials: A Methods Handbook.</a> , 149-166 (2004).</li></ol>

No conflicts of interest declared.

high density event-related potential  data acquisition in cognitive neuroscience

Functional magnetic resonance imaging (fMRI) is currently the standard method of evaluating brain function in the field of Cognitive Neuroscience, in part because fMRI data acquisition and analysis techniques are readily available. Because fMRI has excellent spatial resolution but poor temporal resolution, this method can only be used to identify the spatial location of brain activity associated with a given cognitive process (and reveals virtually nothing about the time course of brain activity). By contrast, event-related potential (ERP) recording, a method that is used much less frequently than fMRI, has excellent temporal resolution and thus can track rapid temporal modulations in neural activity. Unfortunately, ERPs are under utilized in Cognitive Neuroscience because data acquisition techniques are not readily available and low density ERP recording has poor spatial resolution. In an effort to foster the increased use of ERPs in Cognitive Neuroscience, the present article details key techniques involved in high density ERP data acquisition. Critically, high density ERPs offer the promise of excellent temporal resolution and good spatial resolution (or excellent spatial resolution if coupled with fMRI), which is necessary to capture the spatial-temporal dynamics of human brain function.

Watch this Scientific Journal Video about High Density Event-related Potential  Data Acquisition in Cognitive Neuroscience at JoVE.com

High Density Event-related Potential  Data Acquisition in Cognitive Neuroscience

Event-related potential (ERP) recording is under utilized in Cognitive Neuroscience because data acquisition techniques are not readily available and this method often has poor spatial resolution. To foster the increased use of ERPs in Cognitive Neuroscience, the present article details key techniques involved in high density ERP data acquisition.

Functional magnetic resonance imaging (fMRI) is currently the standard method of evaluating brain function in the field of Cognitive Neuroscience, in part ...

high-density-event-related-potential-data-acquisition-cognitive

Nanyang Technological University

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12.5K Views.  Boston College. Event-related potential (ERP) recording is under utilized in Cognitive Neuroscience because data acquisition techniques are not readily available and this method often has poor spatial resolution. To foster the increased use of ERPs in Cognitive Neuroscience, the present article details key techniques involved in high density ERP data acquisition.

Video: High Density Event-related Potential  Data Acquisition in Cognitive Neuroscience

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Whereas behavioral data inform us about the patients' performance, ERPs allow us to record discrete changes in brain activity. Further, ERPs can give us insight into the onset, duration, and interaction of independent cognitive processes associated with memory retrieval. In patient populations, these types of studies are used to examine which aspects of memory are impaired and which remain relatively intact compared to a control population. The methodology for collecting ERP data from a vulnerable patient population while these participants perform a recognition memory task is reviewed. This protocol includes participant preparation, quality assurance, data acquisition, and data analysis. In addition to basic setup and acquisition, we will also demonstrate localization techniques to obtain greater spatial resolution and source localization using high-density (128 channel) electrode arrays.

The methodology for collecting high-density event-related potential data while patients with Alzheimer's disease perform a recognition memory task is reviewed. This protocol will include subject preparation, quality assurance, data acquisition, and data analysis.

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic ...

Medicine

Investigating the Effects of Antipsychotics and Schizotypy on the N400 Using Event-Related Potentials and Semantic Categorization

Within the field of cognitive neuroscience, functional magnetic resonance imaging (fMRI) is a popular method of visualizing brain function. This is in part because of its excellent spatial resolution, which allows researchers to identify brain areas associated with specific cognitive processes. However, in the quest to localize brain functions, it is relevant to note that many cognitive, sensory, and motor processes have temporal distinctions that are imperative to capture, an aspect that is left unfulfilled by fMRI&#8217;s suboptimal temporal resolution. To better understand cognitive processes, it is thus advantageous to utilize event-related potential (ERP) recording as a method of gathering information about the brain. Some of its advantages include its fantastic temporal resolution, which gives researchers the ability to follow the activity of the brain down to the millisecond. It also directly indexes both excitatory and inhibitory post-synaptic potentials by which most brain computations are performed. This sits in contrast to fMRI, which captures an index of metabolic activity. Further, the non-invasive ERP method does not require a contrast condition: raw ERPs can be examined for just one experimental condition, a distinction from fMRI where control conditions must be subtracted from the experimental condition, leading to uncertainty in associating observations with experimental or contrast conditions. While it is limited by its poor spatial and subcortical activity resolution, ERP recordings&#8217; utility, relative cost-effectiveness, and associated advantages offer strong rationale for its use in cognitive neuroscience to track rapid temporal changes in neural activity. In an effort to foster increase in its use as a research imaging method, and to ensure proper and accurate data collection, the present article will outline &#8211; in the framework of a paradigm using semantic categorization to examine the effects of antipsychotics and schizotypy on the N400 &#8211; the procedure and key aspects associated with ERP data acquisition.

Using event-related EEG potentials (ERPs), we investigate the effects of antipsychotic medications on abnormal semantic brain activations in healthy individuals with schizotypal traits. We use ERPs to track distinct changes in brain activity, shedding insight into the cognitive processes associated with semantic categorization.

Within the field of cognitive neuroscience, functional magnetic resonance imaging (fMRI) is a popular method of visualizing brain function. This is in ...

Behavior

Infant Auditory Processing and Event-related Brain Oscillations

Rapid auditory processing and acoustic change detection abilities play a critical role in allowing human infants to efficiently process the fine spectral and temporal changes that are characteristic of human language. These abilities lay the foundation for effective language acquisition; allowing infants to hone in on the sounds of their native language. Invasive procedures in animals and scalp-recorded potentials from human adults suggest that simultaneous, rhythmic activity (oscillations) between and within brain regions are fundamental to sensory development; determining the resolution with which incoming stimuli are parsed. At this time, little is known about oscillatory dynamics in human infant development. However, animal neurophysiology and adult EEG data provide the basis for a strong hypothesis that rapid auditory processing in infants is mediated by oscillatory synchrony in discrete frequency bands. In order to investigate this, 128-channel, high-density EEG responses of 4-month old infants to frequency change in tone pairs, presented in two rate conditions (Rapid: 70 msec ISI and Control: 300 msec ISI) were examined. To determine the frequency band and magnitude of activity, auditory evoked response averages were first co-registered with age-appropriate brain templates. Next, the principal components of the response were identified and localized using a two-dipole model of brain activity. Single-trial analysis of oscillatory power showed a robust index of frequency change processing in bursts of Theta band (3 - 8 Hz) activity in both right and left auditory cortices, with left activation more prominent in the Rapid condition. These methods have produced data that are not only some of the first reported evoked oscillations analyses in infants, but are also, importantly, the product of a well-established method of recording and analyzing clean, meticulously collected, infant EEG and ERPs. In this article, we describe our method for infant EEG net application, recording, dynamic brain response analysis, and representative results.

High-density electroencephalography (dEEG) is being used increasingly to study brain development and plasticity in the early years of life. Here we present an application of sophisticated analysis techniques that builds on traditional EEG recording to understand the oscillatory dynamics of rapid auditory processing in the infant brain.

Rapid auditory processing and acoustic change detection abilities play a critical role in allowing human infants to efficiently process the fine spectral ...

Investigating Social Cognition in Infants and Adults Using Dense Array Electroencephalography (dEEG)

Dense array electroencephalography (dEEG), which provides a non-invasive window for measuring brain activity and a temporal resolution unsurpassed by any other current brain imaging technology1,2, is being used increasingly in the study of social cognitive functioning in infants and adults. While dEEG is enabling researchers to examine brain activity patterns with unprecedented levels of sensitivity, conventional EEG recording systems continue to face certain limitations, including 1) poor spatial resolution and source localization3,4,2) the physical discomfort for test subjects of enduring the individual application of numerous electrodes to the surface of the scalp, and 3) the complexity for researchers of learning to use multiple software packages to collect and process data. Here we present an overview of an established methodology that represents a significant improvement on conventional methodologies for studying EEG in infants and adults. Although several analytical software techniques can be used to establish indirect indices of source localization to improve the spatial resolution of dEEG, the HydroCel Geodesic Sensor Net (HCGSN) by Electrical Geodesics, Inc. (EGI), a dense sensory array that maintains equal distances among adjacent recording electrodes on all surfaces of the scalp, further enhances spatial resolution4,5,6 compared to standard dEEG systems. The sponge-based HCGSN can be applied rapidly and without scalp abrasion, making it ideal for use with adults7,8, children9,10,11, and infants12, in both research and clinical4,5,6,13,14,15 settings. This feature allows for considerable cost and time savings by decreasing the average net application time compared to other dEEG systems. Moreover, the HCGSN includes unified, seamless software applications for all phases of data, greatly simplifying the collection, processing, and analysis of dEEG data.
The HCGSN features a low-profile electrode pedestal, which, when filled with electrolyte solution, creates a sealed microenvironment and an electrode-scalp interface. In all Geodesic dEEG systems, EEG sensors detect changes in voltage originating from the participant's scalp, along with a small amount of electrical noise originating from the room environment. Electrical signals from all sensors of the Geodesic sensor net are received simultaneously by the amplifier, where they are automatically processed, packaged, and sent to the data-acquisition computer (DAC). Once received by the DAC, scalp electrical activity can be isolated from artifacts for analysis using the filtering and artifact detection tools included in the EGI software. Typically, the HCGSN can be used continuously for only up to two hours because the electrolyte solution dries out over time, gradually decreasing the quality of the scalp-electrode interface.
In the Parent-Infant Research Lab at the University of Toronto, we are using dEEG to study social cognitive processes including memory, emotion, goals, intentionality, anticipation, and executive functioning in both adult and infant participants.

Investigating Social Cognition in Infants and Adults Using Dense Array Electroencephalography dEEG

Dense array electroencephalography is being used increasingly to study social cognitive functions in infants and adults. Here we present an established methodology that represents a significant improvement on conventional methodologies for studying EEG in infants and adults.

Dense array electroencephalography (dEEG), which provides a non-invasive window for measuring brain activity and a temporal resolution unsurpassed by any ...

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy

When considering human neuroimaging data, an appreciation of signal variability represents a fundamental innovation in the way we think about brain signal. Typically, researchers represent the brain's response as the mean across repeated experimental trials and disregard signal fluctuations over time as "noise". However, it is becoming clear that brain signal variability conveys meaningful functional information about neural network dynamics. This article describes the novel method of multiscale entropy (MSE) for quantifying brain signal variability. MSE may be particularly informative of neural network dynamics because it shows timescale dependence and sensitivity to linear and nonlinear dynamics in the data.

Neuroimaging researchers typically consider the brain's response as the mean activity across repeated experimental trials and disregard signal variability over time as "noise". However, it is becoming clear that there is signal in that noise. This article describes the novel method of multiscale entropy for quantifying brain signal variability in the time domain.

When considering human neuroimaging data, an appreciation of signal variability represents a fundamental innovation in the way we think about brain ...

High-density Electroencephalographic Acquisition in a Rodent Model Using Low-cost and Open-source Resources

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network connectivity, are applicable to an expanding variety of questions in neuroscience. Performing these kinds of analyses in a rodent model requires higher electrode density than traditional screw electrodes can accomplish. While higher-density electroencephalographic montages for rodents exist, they are of limited availability to most researchers, are not robust enough for repeated experiments over an extended period of time, or are limited to use in anesthetized rodents.1-3 A proposed low-cost method for constructing a durable, high-count, transcranial electrode array, consisting of bilaterally implantable headpieces is investigated as a means to perform advanced electroencephalogram analyses in mice or rats.

Procedures for headpiece fabrication and surgical implantation necessary to produce high signal to noise, low-impedance electroencephalographic and electromyographic signals are presented. While the methodology is useful in both rats and mice, this manuscript focuses on the more challenging implementation for the smaller mouse skull. Freely moving mice are only tethered to cables via a common adapter during recording. One version of this electrode system that includes 26 electroencephalographic channels and 4 electromyographic channels is described below.

Instructions for the low-cost construction and surgical implantation of a chronic transcranial high-density electroencephalographic montage into mice are provided. Signal recording, extraction, and processing techniques are also described.

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network ...

How to Find Effects of Stimulus Processing on Event Related Brain Potentials of Close Others when Hyperscanning Partners

The partners of each pair must be able to pass the McGill Friendship Questionnaire without communicating. Each partner is then seated in front of a screen in one of two adjacent rooms. These rooms are separated by a glass window through which participants communicate to maintain feelings of togetherness while being fitted with the EEG cap. After checking for adequate EEG signals, the glass is covered by a curtain to prevent visual communication. Then, partners must be silent but are instructed to try to feel in the presence of their partner during the entire experiment. Just before it starts, participants are told that each of them will be presented with one image at a time and that these images will occur at the same time for both of them on their own screen. They are also instructed that, for each trial, the simultaneous images will always be different. However, unbeknownst to them, trials are randomized: only half of them are consistent with this instruction and actually include two different images. These trials form the DSC, that is, the different-stimuli condition. The other half of the trials are inconsistent with the instruction. They include two identical images and form the ISC (identical-stimuli condition). After the experiment, participants are sorted into two groups: those who reported that they felt in the presence of their partner during the majority of the trials and those who reported they did not. The impact of the stimulus processing of the partner is found by subtracting the mean voltages of the ERPs of the ISC (inconsistent with the instructions) from the ERPs of the DSC (consistent with the instructions) in at least two time windows (TWs): firstly, in the 75 to 150 ms TW, where the absolute values of these subtractions are greater, especially at right frontal sites, in those who felt in the presence of their partner than in those who did not; secondly, in the LPP time window (i.e., from 650 to 950 ms post onset), where ERPs are significantly less positive in the DSC than in the ISC in those in whom the raw results of the early (75-150ms) subtractions are negative.

This protocol describes key steps involved in assessing the sensitivity of the brain of one person to the stimulus processing of a close other by selecting pairs of partners, recording their electroencephalogram (EEG) simultaneously and computing their event-related brain potentials (ERPs).

The partners of each pair must be able to pass the McGill Friendship Questionnaire without communicating. Each partner is then seated in front of a screen ...

Event Related Potentials (ERPs) and other EEG Based Methods for Extracting Biomarkers of Brain Dysfunction: Examples from Pediatric Attention Deficit/Hyperactivity Disorder (ADHD)

Neuropsychiatric diagnoses like ADHD are based on subjective methods like interviews, rating scales and observations. There is a need for more brain-based supplements. Stimulant medication is the most common treatment for ADHD. Clinically useful predictors of response have so far not been reported. The aim of this paper is to describe the EEG based methods we apply to extract potential biomarkers for brain dysfunction. Examples relate to biomarkers for pediatric ADHD, and prediction of medication response. The main emphasis is on Event Related Potentials (ERPs).
A nineteen channel EEG is recorded during a 3 min eyes-opened task, a 3 min eyes-closed task, and a 20 min cued visual GO/NOGO task (VCPT). ERPs are recorded during this task. The goal of the ERP protocol is to extract biomarkers of assumed brain dysfunctions that significantly differentiate between a patient group and healthy controls. The protocol includes recording during standard conditions and artifact correction. ERP waves can be used or transformed into latent components. The components of the patient group are compared with controls, empathizing components that, when compared, show relatively high effect sizes. Sub-groups of the patients are selected on the basis of the cluster analysis in the space of the components. Treatment procedure (such as medication, tDCS or neurofeedback protocol) can be applied and the changes in components related to treatment in the subgroups are observed, forming the basis for clinical recommendations.
The methods described were applied in a study of 87 pediatric ADHD patients. The index of medication response discriminated significantly between responders and non-responders with a large, and clinically meaningful effect size (d = 1.84). In an ongoing study comparing ADHD children with matched controls, several variables discriminate significantly between patients and controls. The global index will exceed d = .8. The EEG based methods described here could be clinically meaningful.

Event Related Potentials ERPs and other EEG Based Methods for Extracting Biomarkers of Brain Dysfunction: Examples from Pediatric Attention Deficit/Hyperactivity Disorder ADHD

EEG-methods are applied for extracting biomarkers of brain dysfunctions. The focus is on multi-channel event-related potentials (ERPs) recorded in a cued GO/NOGO task. Non-brain artifacts are corrected and ERPs are compared with the normative data. Examples relate to biomarkers for ADHD diagnosis and prediction of medication response.

Neuropsychiatric diagnoses like ADHD are based on subjective methods like interviews, rating scales and observations. There is a need for more brain-based ...

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI

Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), EEG-fMRI, combines the complementary properties of scalp EEG (good temporal resolution) and fMRI (good spatial resolution) to measure neuronal activity during an electrographic event, through hemodynamic responses known as blood-oxygen-level-dependent (BOLD) changes. It is a non-invasive research tool that is utilized in neuroscience research and is highly beneficial to the clinical community, especially for the management of neurological diseases, provided that proper equipment and protocols are administered during data acquisition. Although recording EEG-fMRI is apparently straightforward, the correct preparation, especially in placing and securing the electrodes, is not only important for safety but is also critical in ensuring the reliability and analyzability of the EEG data obtained. This is also the most experience-demanding part of the preparation. To address these issues, a straightforward protocol that ensures data quality was developed. This article provides a step-by-step guide for acquiring reliable EEG data during EEG-fMRI using this protocol that utilizes readily available medical products. The presented protocol can be adapted to different applications of EEG-fMRI in research and clinical settings, and may be beneficial to both inexperienced and expert operators.

This article provides a straightforward protocol for acquiring good quality electroencephalography (EEG) data during simultaneous EEG and functional magnetic resonance imaging by utilizing readily available medical products.

Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), EEG-fMRI, combines the complementary properties of scalp EEG ...

Recording Brain Activity with Ear-Electroencephalography

The c-grid (ear-electroencephalography, sold under the name cEEGrid) is an unobtrusive and comfortable electrode array that can be used for investigating brain activity after affixing around the ear. The c-grid is suitable for use outside of the laboratory for long durations, even for the whole day. Various cognitive processes can be studied using these grids, as shown by previous research, including research beyond the lab. To record high-quality ear-EEG data, careful preparation is necessary. In this protocol, we explain the steps needed for its successful implementation. First, how to test the functionality of the grid prior to a recording is shown. Second, a description is provided on how to prepare the participant and how to fit the c-grid, which is the most important step for recording high-quality data. Third, an outline is provided on how to connect the grids to an amplifier and how to check the signal quality. In this protocol, we list best practice recommendations and tips that make c-grid recordings successful. If researchers follow this protocol, they are comprehensively equipped for experimenting with the c-grid both in and beyond the lab.

Presented here is the procedure for using the c-grid (ear-electroencephalography, sold under the name cEEGrid) for recording brain activity in and beyond the lab for extended durations. This protocol describes how to set up these arrays and how to record brain activity using them.

The c-grid (ear-electroencephalography, sold under the name cEEGrid) is an unobtrusive and comfortable electrode array that can be used for investigating ...

High Density Event-related Potential Data Acquisition in Cognitive Neuroscience

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