The manufacturer of the Geodesic Sensor Net is Electrical Geodesics, Inc (EGI). For contact information, please visit <a href="http://www.egi.com/company">http://www.egi.com/company</a>.

1. Preparing the Experimental Setup
<ol>
	<li>Prior to the participant's arrival at the lab, ensure that the Geodesic EEG System (GES) components and the experiment control computer and software (Net Station) are operating properly.</li>
	<li>Remove all unneeded and potentially distracting items from the experiment room.</li>
	<li>Set up the experiment room in accordance with the particular experimental paradigm being implemented. Here we use paradigms ranging from computer-based tasks administered via E-Prime presentation software to various parent-infant and experimenter-infant interaction paradigms.</li>
	<li>Ensure that the video cameras are charged and arrange the cameras at angles ideal for the current experimental setup.</li>
</ol>
2.	Exchanging Information
<ol>
	<li>Upon the participant's arrival at the lab, describe the Geodesic Sensor Net application protocol and explain the experiment. </li>
	<li>After ensuring that the participant has a good understanding of the experimental protocol, make sure that he or she (or his or her legal guardian) signs a consent form before proceeding with the experiment. </li>
	<li>For EEG studies, it is often useful to obtain from the participant certain information that may be expected to have an influence on the recorded electrical brain activity. For example, information about drowsiness, last meal, and last sleep might be of interest. In the Haley lab, such information is obtained by administering standardized questionnaires. To help the experiment proceed in a timely manner, it is advisable to have two experimenters present: one to administer the questionnaires, and one to carry out the HCGSN preparations detailed below.</li>
</ol>
3.	Preparing for HydroCel Geodesic Sensor Net Application
<ol>
	<li>Prepare the HydroCel Saline electrolyte solution of distilled water, potassium chloride, and baby shampoo, making sure to stir thoroughly until all of the potassium chloride is dissolved in the solution.</li>
	<li>Using a measuring tape, measure the circumference of the participant's head, recording the measurement in centimeters. </li>
	<li>Retrieve the appropriately sized HCGSN-i.e., the one that encompasses the range of head circumferences in which the participant's head circumference falls.</li>
	<li>Submerge the sensor end of the HCGSN in the electrolyte solution and allow it to soak for 5 minutes, being sure to keep the connector end away from all liquids. It is advisable to use a timer or stopwatch to guarantee accurate timing.</li>
	<li>Open the Net Station software on the control computer and begin an experimental control session to allow zero and gain measurements to be taken before connecting the HCGSN connector and collecting data.</li>
</ol>
4.	Applying the HydroCel Geodesic Sensor Net 
In order to allow for the valid and consistent analysis of collected EEG data, the net application procedure must be highly standardized. Such standardization is achieved by taking measurements of the participant's head (as described above) to ensure the accurate and consistent placement of electrodes from participant to participant. If optimal net positioning is not initially achieved, remove the net and reapply. 
<ol>
	<li>While waiting for the sensor net to finish soaking in the electrolyte solution, guide the participant into the experiment room and instruct him or her to sit on a chair. The chair should be without wheels to avoid unwanted movement during the sensor net application. In the case of an infant participant, have the infant's guardian sit on the chair with the infant sitting upright on his or her lap, holding the infant by the waist so that the infant's entire head is accessible and the infant remains still.</li>
	<li>Using a measuring tape and a china marker pencil, locate and mark the vertex by taking the following measurements: 
		<ol class="lalpha">
			<li>Ear to ear over the top of the head</li>
			<li>Nasion to inion over the top of the head</li>
		</ol>
	The vertex can be identified as the point at which these two measurements cross.</li>
	<li>Remove the sensor net from the electrolyte bucket and place it on a clean, dry towel. Gently pat the sensor net with the towel to remove excess electrolyte solution. </li>
	<li>Give the connector end of the HCGSN to the participant or to a second experimenter to hold during the net application.</li>
	<li>Pick up the HCGSN, putting both hands in the interior of the net. Hold the net such that your thumbs are pushed firmly (but gently) on either side of the central, most frontal electrode and your pinkie fingers are pushed firmly against the band connecting the most posterior row of electrodes. Be careful not to overstretch the net. Your remaining six fingers should be loose within the net to allow the center portion to fall limp.</li>
	<li>Crouch or kneel down so that you are at eye level with the participant.</li>
	<li>From back to front, pull the sensor net over the participant's head. It is often useful to have a second experimenter present when applying the sensor net on an infant participant, to distract the infant and minimize head movement.</li>
	<li>Using your fingertips, pull gently on the band of the net and adjust it so that the vertex electrode sits on the vertex point previously marked with the china marker pencil. Tighten the ear and chin straps. Inspect anatomical landmark locations and net symmetry to see whether the net is positioned correctly, and make the necessary adjustments.</li>
</ol>
5.	Measuring Electrode Impedances
EEG is measured as the potential difference (voltage) between the referenced site and the measured site. High impedance at the scalp-electrode interface causes a drop in measured voltage, attenuation of signal amplitude, and an increase in the presence of noise. While post-acquisition filtering in certain studies (e.g., conventional ERP studies) can get rid of this noise, high impedance generally compromises the fidelity of acquired EEG data. It is therefore important to make sure impedances are within the tolerable specifications before beginning to record EEG data. 
<ol>
	<li>Plug the connector end of the HCGSN into the interface cable and turn the lever to lock it in place. Turn on the camera.</li>
	<li>In the control room, open up a new session in Net Station, enter the participant's information, and click Begin Session. Because the video and dEEG signals are synched, a live video feed from the experiment room should appear on the screen.</li>
	<li>Select the Panels dropdown menu, open Impedance, and click the Measure button. A montage of the HCGSN sensor array will appear on the screen. Drag the window to the edge of the screen so that it opens up on the monitor in the experiment room.</li>
	<li>Using a disposable pipette, rake aside the participant's hair so that each electrode is seated directly on the participant's scalp.</li>
	<li>Refer to the Impedance Measurement window displaying the HCGSN montage on the monitor. Sensors that are not making good contact with the scalp will appear red. Make note of the electrode sensor numbers. Use the pipette and a small amount of the already prepared electrolyte solution to improve the impedance of these sensors. Electrodes on the montage will turn green as their impedance is improved.</li>
	<li>When impedances are satisfactory (i.e., when all electrodes on the montage are green), click the Save &amp; Close button on the Impedance Measurement window in the control room.</li>
	<li>In Net Station, open the Dense Waveform Display. Scroll through the waveforms and note any channels that are displaying high amplitude noise due to poor scalp contact.</li>
</ol>
6.	Taking Baseline Recordings
Before beginning the experimental paradigm, take some baseline dEEG recordings of the participant's resting electrical brain activity. Resting baseline recordings are important in continuous dEEG studies because there is a high degree of variability in electrical brain activity from participant to participant. As a result, most continuous dEEG studies must implement a within-subjects experimental design, analyzing the differences between each experimental condition and a pre-experiment baseline phase. For event-related EEG studies, a baseline phase may not be necessary.
<ol>
	<li>Leave the participant alone in the experiment room and instruct him or her to sit quietly and minimize movement. For infant participants, the parent/guardian should remain in the room with the infant sitting quietly in his or her lap. In the Haley lab, a movie titled Baby Mozart, an audio-visual combination of classical music and colourful moving designs, is played to ensure that infants remain calm and still. While an interactive baseline phase may not always be ideal, it can be used as a pre-baseline phase to calm the infant before taking baseline recordings.</li>
	<li>In Net Station, click the Record button to begin recording video and waveform data. On the Dense Waveform Display, event markers can be inserted to link behavioural events to electrical activity throughout the experiment. Insert a 'baseline' event marker on the waveform display. </li>
	<li>Record baseline for a standardized time period. In the Haley lab, the standard baseline phase lasts 2 minutes.</li>
</ol>
7.	Running the Experiment
In dEEG studies, it is essential to have at least two experimenters present throughout the study. One experimenter will be responsible for interacting with the participant and implementing the behavioural paradigm, while the second experimenter will monitor the Dense Waveform Display. 
<ol>
	<li>Implement the experimental paradigm.</li>
	<li>Monitor the Dense Waveform Display throughout the experiment to determine whether any channels are displaying increasing noise levels. Increasing noise may be reflective of increasing impedances. Acceptable impedance levels can be regained by using more electrolyte solution. This should be done at a break in the experimental protocol.</li>
</ol>
8.	Debriefing the Participant
<ol>
	<li>When the experiment is complete, carefully loosen and remove the HCGSN from the participant's head. Rinse, disinfect, and dry the net.</li>
	<li>Give the participant a towel with which to wipe off any excess electrolyte solution.</li>
	<li>Give the participant any remaining questionnaires that need to be completed.</li>
</ol>
9.	Analysis
The same EGI software used to acquire dEEG data is also used to analyze the data, allowing for a smooth and easy transition from data collection to data analysis. Because the HCGSN also picks up electrical noise originating from the environment, the data must first be filtered and cleaned before it can be analyzed. All of the necessary tools are included in Net Station.
<ol>
	<li>In Net Station, click on and open the Waveform Tools panel. Run the acquired data file through the filtering and artifact detection tools after setting the desired parameters. The artifact detection tool identifies spikes resulting from eye blinks or eye movements and detects bad channels. In many cases, additional hand-editing and artifact removal may be necessary (especially when working with infant populations, in which you cannot control eye blinks and movements).</li>
	<li>Segment the data so as to separate the different experimental conditions on the basis of the inserted event markers.</li>
	<li>Apply any desired analysis. In the Haley lab, frequency analysis is used to analyze how characteristic frequencies of brain activity varies between experimental conditions and between different brain regions. A decrease in wave power is potentially reflective of the increased activity of neurons in that region. </li>
</ol>
10.	Representative Data
<img src="/files/ftp_upload/2759/2759fig1.jpg" alt="Figure 1" /> 
Figure 1. Raw EEG waveforms showing the fluctuations in recorded voltage (&mu;v) across time (s), at a single electrode (electrode 30). The waveforms represent data collected during the first 1000ms of each of 3 experimental phases: baseline, demonstration, and immediate recall.
<img src="/files/ftp_upload/2759/2759fig2.jpg" alt="Figure 2" /> 
Figure 2. Raw data collected from the entire scalp (128-electrode montage) during three experimental phases (baseline, demonstration, immediate recall) of a participating infant. Data is presented as a topographical map and illustrates differences in surface-level brain electrical activity (&mu;v) across brain regions and experimental phase of the puppet task.

<ol>
	<li>Willis, W. G., Weiler, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+substrates+of+childhood+attention-deficit+/+hyperactivity+disorder:+Electroencephalographic+and+Magnetic+Resonance+Imaging+evidence.">Neural substrates of childhood attention-deficit / hyperactivity disorder: Electroencephalographic and Magnetic Resonance Imaging evidence.</a> Developmental Neuropsychology. 27, 135-182 (2005).</li><li>Yang, L., Liu, Z., He, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG-fMRI+reciprocal+functional+neuroimaging.">EEG-fMRI reciprocal functional neuroimaging.</a> Clinical Neurophysiology. 121, 1240-1250 (2010).</li><li>Dale, M. P., Halgren, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatiotemperal+mapping+of+brain+activity+by+integration+of+multiple+imaging+modalities.+Current+Opinion+in+Neurobiology.">Spatiotemperal mapping of brain activity by integration of multiple imaging modalities. Current Opinion in Neurobiology.</a> 11, 202-208 (2001).</li><li>Sperli, F., Spinelli, L., Seeck, M., Kurian, M., Michel, C. M., Lantz, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+source+imaging+in+pediatric+epilepsy+surgery:+A+new+perspective+in+presurgical+workup.">EEG source imaging in pediatric epilepsy surgery: A new perspective in presurgical workup.</a> Epilepsia. 47, 1-10 (2006).</li><li>Holmes, M. D., Quiring, J., Tucker, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+that+juvenile+myoclonic+epilepsy+is+a+disorder+of+frontotemporal+corticothalamic+networks.">Evidence that juvenile myoclonic epilepsy is a disorder of frontotemporal corticothalamic networks.</a> NeuroImage. 49, 80-93 (2010).</li><li>Holmes, M. D., Tucker, D. M., Quiring, J. M., Hakimian, S., Miller, J. W., Ojemann, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparing+Noninvasive+dense+array+and+intracranial+electroencephalography+for+the+localization+of+seizures.">Comparing Noninvasive dense array and intracranial electroencephalography for the localization of seizures.</a> Neurosurgery. 66, 1-10 (2010).</li><li>Muthukumaraswamy, S. D., Johnson, B. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+rolandic+mu+rhythm+during+observation+of+a+precision+grip.">Changes in rolandic mu rhythm during observation of a precision grip.</a> Psychophysiology. 41, 152-156 (2004).</li><li>Muthukumaraswamy, S. D., Johnson, B. W., McNair, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mu+rhythm+modulation+during+observation+of+an+object-directed+grasp.">Mu rhythm modulation during observation of an object-directed grasp.</a> Cognitive Brain Research. 19, 195-201 (2004).</li><li>Arbel, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Error+processing+by+individuals+with+specific+language+impairment:+An+ERP+study.">Error processing by individuals with specific language impairment: An ERP study.</a> Dissertation Abstracts International: Section B: The Sciences and Engineering. 67, 3095-3095 (2006).</li><li>Lepage, J., Th&#233;oret, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+evidence+for+the+presence+of+an+action+observation-execution+matching+system+in+children.">EEG evidence for the presence of an action observation-execution matching system in children.</a> European Journal of Neuroscience. 23, 2505-2510 (2006).</li><li>Sokhadze, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Event-related+potential+study+of+novelty+processing+abnormalities+in+autism.">Event-related potential study of novelty processing abnormalities in autism.</a> Applied Psychphysiology and Biofeedback. 34, 37-51 (2009).</li><li>Nystr&#246;m, 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+infant+mirror+neuron+system+studied+with+high+density+EEG.">The infant mirror neuron system studied with high density EEG.</a> Social Neuroscience. Special Issue: The Mirror Neuron System. , 3-3 (2008).</li><li>Bernier, R., Dawson, G., Webb, S., Murias, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+mu+rhythm+and+imitation+impairments+in+individuals+with+autism+spectrum+disorder.">EEG mu rhythm and imitation impairments in individuals with autism spectrum disorder.</a> Brain and Cognition. 64, 228-237 (2007).</li><li>Brodbeck, V., Lascano, A. M., Spinelli, L., Seeck, M., Michel, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+EEG+source+imaging+of+epileptic+spikes+in+patients+with+large+brain+lesions.">Accuracy of EEG source imaging of epileptic spikes in patients with large brain lesions.</a> Clinical Neurophysiology. 120, 679-685 (2009).</li><li>Ramon, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Power+spectral+density+changes+and+language+lateralization+during+covert+object+naming+tasks+measured+with+high-density+EEG+recordings.">Power spectral density changes and language lateralization during covert object naming tasks measured with high-density EEG recordings.</a> Epilepsy and Behaviour. 14, 54-59 (2009).</li></ol>

No conflicts of interest declared.

The Hydrocel Geodesic Sensor Net from EGI constitutes a non-invasive and easy-to-apply method of obtaining dEEG data from both adult and infant participants. This technology combines high temporal and spatial resolution with an increased opportunity for mobility, making it ideal for use in complex behavioural paradigms to investigate cognitive activities that may be reflected only in subtle changes in electrical activity. Given increasing interest in investigating the development of infant cognition and the relative scarcity of brain imaging techniques suitable for use in the infant population, the use of the HCGSN is likely to increase, leading us to a deeper understanding of infant cognition.

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.

Watch this Scientific Journal Video about Investigating Social Cognition in Infants and Adults Using Dense Array Electroencephalography dEEG at JoVE.com

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.

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 ...

investigating-social-cognition-infants-adults-using-dense-array

Research

JoVE Journal

Neuroscience

17.7K 조회수.  University Toronto Scarborough. 조밀한 배열 electroencephalography은 유아와 성인의 사회적인지 기능을 연구하기 위해 점점 사용되고 있습니다. 여기 우리는 유아와 어른의 뇌파 공부를위한 기존의 방법론에 큰 개선을 나타냅니다 설립 방법론을 제시한다.

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

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in rodents have shown a direct link between testosterone and aggressive behavior1 and folk wisdom adapts these findings to humans, suggesting that testosterone induces antisocial, egoistic or even aggressive behavior2. However, many researchers doubt a direct testosterone-aggression link in humans, arguing instead that testosterone is primarily involved in status-related behavior3,4. As a high status can also be achieved by aggressive and antisocial means it can be difficult to distinguish between anti-social and status seeking behavior.
We therefore set up an experimental environment, in which status can only be achieved by prosocial means. In a double-blind and placebo-controlled experiment, we administered a single sublingual dose of 0.5 mg of testosterone (with a hydroxypropyl-&beta;-cyclodextrin carrier) to 121 women and investigated their social interaction behavior in an economic bargaining paradigm. Real monetary incentives are at stake in this paradigm; every player A receives a certain amount of money and has to make an offer to another player B on how to share the money. If B accepts, she gets what was offered and player A keeps the rest. If B refuses the offer, nobody gets anything. A status seeking player A is expected to avoid being rejected by behaving in a prosocial way, i.e. by making higher offers.
The results show that if expectations about the hormone are controlled for, testosterone administration leads to a significant increase in fair bargaining offers compared to placebo. The role of expectations is reflected in the fact that subjects who report that they believe to have received testosterone make lower offers than those who say they believe that they were treated with a placebo. These findings suggest that the experimental economics approach is sensitive for detecting neurobiological effects as subtle as those achieved by administration of hormones. Moreover, the findings point towards the importance of both psychosocial as well as neuroendocrine factors in determining the influence of testosterone on human social behavior.

The procedure described in this protocol shows that testosterone administration and folk beliefs about testosterone may be associated with directly opposed social behaviors.

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in ...

Electrophysiological Measurements and Analysis of Nociception in Human Infants

Pain is an unpleasant sensory and emotional experience. Since infants cannot verbally report their experiences, current methods of pain assessment are based on behavioural and physiological body reactions, such as crying, body movements or changes in facial expression. While these measures demonstrate that infants mount a response following noxious stimulation, they are limited: they are based on activation of subcortical somatic and autonomic motor pathways that may not be reliably linked to central sensory processing in the brain. Knowledge of how the central nervous system responds to noxious events could provide an insight to how nociceptive information and pain is processed in newborns.
The heel lancing procedure used to extract blood from hospitalised infants offers a unique opportunity to study pain in infancy. In this video we describe how electroencephalography (EEG) and electromyography (EMG) time-locked to this procedure can be used to investigate nociceptive activity in the brain and spinal cord.
This integrative approach to the measurement of infant pain has the potential to pave the way for an effective and sensitive clinical measurement tool.

The assessment and treatment of pain in infants is difficult because infants cannot verbally report their experience. In this video we describe quantitative electrophysiological methods and analysis techniques that can be used to measure the response to noxious events from the infant nervous system.

Pain is an unpleasant sensory and emotional experience. Since infants cannot verbally report their experiences, current methods of pain assessment are ...

Super-resolution Imaging of Neuronal Dense-core Vesicles

Detection of fluorescence provides the foundation for many widely utilized and rapidly advancing microscopy techniques employed in modern biological and medical applications. Strengths of fluorescence include its sensitivity, specificity, and compatibility with live imaging. Unfortunately, conventional forms of fluorescence microscopy suffer from one major weakness, diffraction-limited resolution in the imaging plane, which hampers studies of structures with dimensions smaller than ~250 nm. Recently, this limitation has been overcome with the introduction of super-resolution fluorescence microscopy techniques, such as photoactivated localization microscopy (PALM). Unlike its conventional counterparts, PALM can produce images with a lateral resolution of tens of nanometers. It is thus now possible to use fluorescence, with its myriad strengths, to elucidate a spectrum of previously inaccessible attributes of cellular structure and organization.
Unfortunately, PALM is not trivial to implement, and successful strategies often must be tailored to the type of system under study. In this article, we show how to implement single-color PALM studies of vesicular structures in fixed, cultured neurons. PALM is ideally suited to the study of vesicles, which have dimensions that typically range from ~50-250 nm. Key steps in our approach include labeling neurons with photoconvertible (green to red) chimeras of vesicle cargo, collecting sparsely sampled raw images with a super-resolution microscopy system, and processing the raw images to produce a high-resolution PALM image. We also demonstrate the efficacy of our approach by presenting exceptionally well-resolved images of dense-core vesicles (DCVs) in cultured hippocampal neurons, which refute the hypothesis that extrasynaptic trafficking of DCVs is mediated largely by DCV clusters.

We describe how to implement photoactivated localization microscopy (PALM)-based studies of vesicles in fixed, cultured neurons. Key components of our protocol include labeling vesicles with photoconvertible chimeras, collecting sparsely sampled raw images with a super-resolution microscopy system, and processing the raw images to produce a super-resolution image.

Detection of fluorescence provides the foundation for many widely utilized and rapidly advancing microscopy techniques employed in modern biological and ...

Investigating the Function of Deep Cortical and Subcortical Structures Using Stereotactic Electroencephalography: Lessons from the Anterior Cingulate Cortex

Stereotactic Electroencephalography (SEEG) is a technique used to localize seizure foci in patients with medically intractable epilepsy. This procedure involves the chronic placement of multiple depth electrodes into regions of the brain typically inaccessible via subdural grid electrode placement. SEEG thus provides a unique opportunity to investigate brain function. In this paper we demonstrate how SEEG can be used to investigate the role of the dorsal anterior cingulate cortex (dACC) in cognitive control. We include a description of the SEEG procedure, demonstrating the surgical placement of the electrodes. We describe the components and process required to record local field potential (LFP) data from consenting subjects while they are engaged in a behavioral task. In the example provided, subjects play a cognitive interference task, and we demonstrate how signals are recorded and analyzed from electrodes in the dorsal anterior cingulate cortex, an area intimately involved in decision-making. We conclude with further suggestions of ways in which this method can be used for investigating human cognitive processes.

Stereotactic Electroencephalography (SEEG) is an operative technique used in epilepsy surgery to help localize seizure foci. It also affords a unique opportunity to investigate brain function. Here we describe how SEEG can be used to investigate cognitive processes in human subjects.

Stereotactic Electroencephalography (SEEG) is a technique used to localize seizure foci in patients with medically intractable epilepsy. This procedure ...

Studying Brain Function in Children Using Magnetoencephalography

Magnetoencephalography (MEG) is a non-invasive neuroimaging technique which directly measures magnetic fields produced by the electrical activity of the human brain. MEG is quiet and less likely to induce claustrophobia compared with magnetic resonance imaging (MRI). It is therefore a promising tool for investigating brain function in young children. However, analysis of MEG data from pediatric populations is often complicated by head movement artefacts which arise as a consequence of the requirement for a spatially-fixed sensor array that is not affixed to the child's head. Minimizing head movements during MEG sessions can be particularly challenging as young children are often unable to remain still during experimental tasks. The protocol presented here aims to reduce head movement artefacts during pediatric MEG scanning. Prior to visiting the MEG laboratory, families are provided with resources that explain the MEG system and the experimental procedures in simple, accessible language. An MEG familiarization session is conducted during which children are acquainted with both the researchers and the MEG procedures. They are then trained to keep their head still whilst lying inside an MEG simulator. To help children feel at ease in the novel MEG environment, all of the procedures are explained through the narrative of a space mission. To minimize head movement due to restlessness, children are trained and assessed using fun and engaging experimental paradigms. In addition, children's residual head movement artefacts are compensated for during the data acquisition session using a real-time head movement tracking system. Implementing these child-friendly procedures is important for improving data quality, minimizing participant attrition rates in longitudinal studies, and ensuring that families have a positive research experience.

This article introduces a child-friendly research protocol designed to improve data quality by reducing head movement during pediatric magnetoencephalography (MEG). We familiarize families with the MEG environment, train children to remain still using an MEG simulator, and correct for residual head movement artefacts using a real-time head movement detection system.

Magnetoencephalography (MEG) is a non-invasive neuroimaging technique which directly measures magnetic fields produced by the electrical activity of the ...

Post-Movie Subliminal Measurement (PMSM), for Investigating Implicit Social Bias

New knowledge is continuously gained from a social environment that can influence how people respond to each other. Such responses often occur implicitly, at a subliminal perceptual level, and related brain mechanisms can be experimentally isolated by presenting the stimuli quickly. Subliminal presentation of faces that belong to different ethnicity groups, races, or gender has been shown to be successful in investigating social implicit responses. However, many implicit responses are based on knowledge previously gained about the faces (e.g., sexual orientation, political views, and socioeconomic status) and not solely on physical appearance. Here, a novel method called post-movie subliminal measurement (PMSM) is presented. When watching a socially engaging movie, a spectator gains knowledge about the protagonist and becomes familiar with his/her identity and world views. When the face of the protagonist is presented subliminally after the movie, it evokes an implicit neural response depending on what is learned about the protagonist. With a vast number of movies available, each depicting a variety of people with different identities, the PMSM method enables investigation of the brain&#39;s complex implicit biases in a manner that resembles real-life social perceptions.

Post-Movie Subliminal Measurement PMSM, for Investigating Implicit Social Bias

This protocol describes the use of movies to investigate brain mechanisms underlying implicit social biases during functional magnetic resonance imaging. When the face of a protagonist is presented after a movie subliminally, it evokes an implicit response based on knowledge of the protagonist gained during the movie.

New knowledge is continuously gained from a social environment that can influence how people respond to each other. Such responses often occur implicitly, ...

Culture of Neurospheres Derived from the Neurogenic Niches in Adult Prairie Voles

Neurospheres are primary cell aggregates that comprise neural stem cells and progenitor cells. These 3D structures are an excellent tool to determine the differentiation and proliferation potential of neural stem cells, as well as to generate cell lines than can be assayed over time. Also, neurospheres can create a niche (in vitro) that allows the modeling of the dynamic changing environment, such as varying growth factors, hormones, neurotransmitters, among others. Microtus ochrogaster (prairie vole) is a unique model for understanding the neurobiological basis of socio-sexual behaviors and social cognition. However, the cellular mechanisms involved in these behaviors are not well known. The protocol aims to obtain neural progenitor cells from the neurogenic niches of the adult prairie vole, which are cultured under non-adherent conditions, to generate neurospheres. The size and number of neurospheres depend on the region (subventricular zone or dentate gyrus) and sex of the prairie vole. This method is a remarkable tool to study sex-dependent differences in neurogenic niches in vitro and the neuroplasticity changes associated with social behaviors such as pair bonding and biparental care. Also, cognitive conditions that entail deficits in social interactions (autism spectrum disorders and schizophrenia) could be examined.

We established the conditions to culture neural progenitor cells from the subventricular zone and dentate gyrus of the adult brain of prairie voles, as a complementary in vitro study, to analyze the sex-dependent differences between neurogenic niches that could be part of functional plastic changes associated with social behaviors.

Neurospheres are primary cell aggregates that comprise neural stem cells and progenitor cells. These 3D structures are an excellent tool to determine the ...

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 ...

Optrode Array for Simultaneous Optogenetic Modulation and Electrical Neural Recording

During the last decade, optogenetics has become an essential tool for the investigation of neural signaling due to its unique capability of selective neural modulation or monitoring. As specific types of neuronal cells can be genetically modified to express opsin proteins, optogenetics enables optical stimulation or inhibition of the selected neurons. There have been several technological advances in the optical system for optogenetics. Recently, it was proposed to combine the optical waveguide for light delivery with electrophysiological recording to simultaneously monitor the neural responses to optogenetic stimulation or inhibition. In this study, an implantable optrode array (2x2 optical fibers) was developed with embedded multichannel electrodes. 
A light-emitting diode (LED) was employed as a light source, and a microfabricated microlens array was integrated to provide sufficient light power at the tip of the optical fibers. The optrode array system comprises the disposable part and the reusable part. The disposable part has optical fibers and electrodes, while the reusable part has the LED and electronic circuitry for light control and neural signal processing. The novel design of the implantable optrode array system is introduced in the accompanying video in addition to the procedure of the optrode implantation surgery, optogenetic light stimulation, and the electrophysiological neural recording. The results of in vivo experiments successfully showed time-locked neural spikes evoked by the light stimuli from hippocampal excitatory neurons of mice.

Here, we present the fabrication method of an optrode system with optical fibers for light delivery and an electrode array for neural recording. In vivo experiments with transgenic mice expressing channelrhodopsin-2 show the feasibility of the system for simultaneous optogenetic stimulation and electrophysiological recording.

During the last decade, optogenetics has become an essential tool for the investigation of neural signaling due to its unique capability of selective ...

Brain Mapping Using a Graphene Electrode Array

Cortical maps represent the spatial organization of location-dependent neural responses to sensorimotor stimuli in the cerebral cortex, enabling the prediction of physiologically relevant behaviors. Various methods, such as penetrating electrodes, electroencephalography, positron emission tomography, magnetoencephalography, and functional magnetic resonance imaging, have been used to obtain cortical maps. However, these methods are limited by poor spatiotemporal resolution, low signal-to-noise ratio (SNR), high costs, and non-biocompatibility or cause physical damage to the brain. This study proposes a graphene array-based somatosensory mapping method as a feature of electrocorticography that offers superior biocompatibility, high spatiotemporal resolution, desirable SNR, and minimized tissue damage, overcoming the drawbacks of previous methods. This study demonstrated the feasibility of a graphene electrode array for somatosensory mapping in rats. The presented protocol can be applied not only to the somatosensory cortex but also to other cortices such as the auditory, visual, and motor cortex, providing advanced technology for clinical implementation.

We present a graphene array-based brain mapping procedure to reduce the invasiveness and improve spatiotemporal resolution. Graphene array-based surface electrodes exhibit long-term biocompatibility, mechanical flexibility, and suitability for brain mapping in a convoluted brain. This protocol allows for constructing multiple forms of sensory maps simultaneously and sequentially.

Cortical maps represent the spatial organization of location-dependent neural responses to sensorimotor stimuli in the cerebral cortex, enabling the ...