Development of this paradigm was supported by the Therapeutic Cognitive Neuroscience Fund and the Benjamin and Adith Miller Family Endowment on Aging, Alzheimer's, and Autism Research.

All methods described here were approved by the Institutional Review Board of Johns Hopkins University, where the original study6 was performed.
1.Creating Stimuli
<ol>
	<li>Create an initial list of concrete nouns from which prime-target pairs will be made.
	<ol>
		<li>From a selected corpus such as Subtlex19, select approximately 500 concrete nouns and obtain variables of interest (e.g., frequency, length, concretene...

<ol>
	<li>Tager-Flusberg, H., Paul, R., Lord, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Language+and+communication+in+autism.">Language and communication in autism.</a> Handbook of Autism and Pervasive Developmental Disorders. , 335-364 (2005).</li><li>Kamio, Y., Robins, D., Kelley, E., Swainson, B., Fein, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atypical+Lexical/Semantic+Processing+in+High-Functioning+Autism+Spectrum+Disorders+without+Early+Language+Delay.">Atypical Lexical/Semantic Processing in High-Functioning Autism Spectrum Disorders without Early Language Delay.</a> Journal of Autism and Developmental Disorders. 37, 1116-1122 (2007).</li><li>McCleery, J. P., Ceponiene, R., Burner, K. M., Townsend, J., Kinnear, M., Schreibman, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+correlates+of+verbal+and+nonverbal+semantic+integration+in+children+with+autism+spectrum+disorders.">Neural correlates of verbal and nonverbal semantic integration in children with autism spectrum disorders.</a> Journal of Child Psychology and Psychiatry. 51 (3), 277-286 (2010).</li><li>Dunn, M. A., Gaughan, H., Kreuzer, J., Kurtzberg, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiologic+correlates+of+semantic+classification+in+autistic+and+normal+children.">Electrophysiologic correlates of semantic classification in autistic and normal children.</a> Developmental Neuropsychology. 16 (1), 79-99 (1999).</li><li>Kamio, Y., Toichi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+access+to+semantics+in+autism:+is+pictorial+access+superior+to+verbal+access?.">Dual access to semantics in autism: is pictorial access superior to verbal access?.</a> Journal of Child Psychology and Psychiatry. 41 (7), 859-867 (2000).</li><li>Coderre, E. L., Chernenok, M., Gordon, B., Ledoux, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Linguistic+and+Non-Linguistic+Semantic+Processing+in+Individuals+with+Autism+Spectrum+Disorders:+An+ERP+Study.">Linguistic and Non-Linguistic Semantic Processing in Individuals with Autism Spectrum Disorders: An ERP Study.</a> Journal of Autism and Developmental Disorders. 47 (3), 795-812 (2017).</li><li>Neely, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semantic+priming+effects+in+vidual+word+recognition:+A+selective+review+of+current+findings+and+theories.">Semantic priming effects in vidual word recognition: A selective review of current findings and theories.</a> Basic processes in reading: Visual word recognition. 11, 264-336 (1991).</li><li>McNamara, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Semantic priming: Perspectives from memory and word recognition. , (2005).</li><li>McPherson, W. B., Holcomb, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+electrophysiological+investigation+of+semantic+priming+with+pictures+of+real+objects.">An electrophysiological investigation of semantic priming with pictures of real objects.</a> Psychophysiology. 36, 53-65 (1999).</li><li>Kutas, M., Federmeier, K. 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F., Phillips, C., Poeppel, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cortical+network+for+semantics:+(de)constructing+the+N400.">A cortical network for semantics: (de)constructing the N400.</a> Nature Reviews Neuroscience. 9 (12), 920-933 (2008).</li><li>Brouwer, H., Fitz, H., Hoeks, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Getting+real+about+Semantic+Illusions:+Rethinking+the+functional+role+of+the+P600+in+language+comprehension.">Getting real about Semantic Illusions: Rethinking the functional role of the P600 in language comprehension.</a> Brain Research. 1446, 127-143 (2012).</li><li>Barrett, S. E., Rugg, 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=Event-Related+Potentials+and+the+Semantic+Matching+of+Pictures.">Event-Related Potentials and the Semantic Matching of Pictures.</a> Brain and Cognition. , 201-212 (1990).</li><li>Hamm, J. P., Johnson, B. W., Kirk, I. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+N300+and+N400+ERPs+to+picture+stimuli+in+congruent+and+incongruent+contexts.">Comparison of the N300 and N400 ERPs to picture stimuli in congruent and incongruent contexts.</a> Clinical Neurophysiology. 212, 1339-1350 (2002).</li><li>Ganis, G., Kutas, M., Sereno, M. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+search+for+&amp;#34;common+sense&amp;#34;:+an+electrophysiological+study+of+the+comprehension+of+words+and+pictures+in+reading.">The search for &amp;#34;common sense&amp;#34;: an electrophysiological study of the comprehension of words and pictures in reading.</a> Journal of Cognitive Neuroscience. 8 (2), 89-106 (1996).</li><li>Nigam, A., Hoffman, J. E., Simons, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N400+to+Semantically+Anomalous+Pictures+and+Words.">N400 to Semantically Anomalous Pictures and Words.</a> Journal of Cognitive Neuroscience. 4 (1), 15-22 (1992).</li><li>Coltheart, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+MRC+psycholinguistic+database.">The MRC psycholinguistic database.</a> Quarterly Journal of Experimental Psychology. 33A, 497-505 (1981).</li><li>Brysbaert, M., New, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moving+beyond+Kucera+and+Francis:+A+critical+evaluation+of+current+word+frequency+norms+and+the+introduction+of+a+new+and+improved+word+frequency+measure+for+American+English.">Moving beyond Kucera and Francis: A critical evaluation of current word frequency norms and the introduction of a new and improved word frequency measure for American English.</a> Behavior Research Methods. 41 (4), 977-990 (2009).</li><li>Davies, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Corpus of Contemporary American English: 450 million words, 1990-present. , (2009).</li><li>Zuccolotto, A. P., Roush, R. E., Eschman, A., Schneider, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> E-Prime 2.0 Getting Started Guide. , (2012).</li><li>Duncan, C. C., 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=Event-related+potentials+in+clinical+research:+Guidelines+for+eliciting,+recording,+and+quantifying+mismatch+negativity,+P300,+and+N400.">Event-related potentials in clinical research: Guidelines for eliciting, recording, and quantifying mismatch negativity, P300, and N400.</a> Clinical Neurophysiology. 120 (11), 1883-1908 (2009).</li><li>Tools, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> E-Prime Extensions for Net Station 2.0 User Manual. , (2014).</li><li>Electrical Geodesics Inc. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Net Station 5 User Manual. , (2017).</li><li>Tanner, D., Morgan-Short, K., Luck, S. 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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Is+&amp;#34;Blank&amp;#34;+a+suitable+neutral+prime+for+event-related+potential+experiments?.">Is &amp;#34;Blank&amp;#34; a suitable neutral prime for event-related potential experiments?.</a> Brain and Language. 97, 91-101 (2006).</li><li>Franklin, M. S., Dien, J., Neely, J. H., Huber, E., Waterson, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semantic+priming+modulates+the+N400,+N300,+and+N400RP.">Semantic priming modulates the N400, N300, and N400RP.</a> Clinical Neurophysiology. 118 (5), 1053-1068 (2007).</li><li>Luck, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> An Introduction to the Event-Related Potential Technique. , (2005).</li><li>Groppe, D. M., Urbach, T. P., Kutas, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+univariate+analysis+of+event-related+brain+potentials/fields+I:+A+critical+tutorial+review.">Mass univariate analysis of event-related brain potentials/fields I: A critical tutorial review.</a> Psychophysiology. 48, 1711-1725 (2011).</li><li>Tanner, D., Van Hell, 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=ERPs+reveal+individual+differences+in+morphosyntactic+processing.">ERPs reveal individual differences in morphosyntactic processing.</a> Neuropsychologia. 56, 289-301 (2014).</li><li>D'Arcy, R. C. N., 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=Electrophysiological+assessment+of+language+function+following+stroke.">Electrophysiological assessment of language function following stroke.</a> Clinical Neurophysiology. 114 (4), 662-672 (2003).</li><li>P&#233;rez Vel&#225;zquez, J. L., Gal&#225;n, R. 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The author has nothing to disclose.

The present paper has reported critical steps in developing a semantic priming ERP paradigm with picture and word stimuli for exploring semantic processing deficits in individuals with ASD. Major steps include creating the stimuli, programming the task, and performing EEG testing and analyses. The most time-consuming part of this procedure is likely to be the creation of stimuli, as this requires careful matching both between and within stimulus pairs, conditions, and modalities on variables such as length, frequency, an...

Researchers in cognitive psychology have long been interested in how people understand the meaning of language. Language processing involves a sequence of steps of increasing complexity, from letter and word recognition, to semantic processing, to syntactic parsing. Semantic processing refers to accessing the meaning of a stimulus, be it a word, picture, or sound. Following early steps of initial word recognition, access of a word&#39;s meaning, or semantics, is a crucial step in language processing. Semantic integration refers to the process of integrating the meaning of stimuli to understand their relationships, and is crucial for higher-level language processing such as understanding sentences. Not only does the meaning of each word in a sentence need to be accessed, but the meanings of each individual word need to be integrated to form a coherent understanding of sentence meaning, or &#34;gist&#34;.
Individuals with autism spectrum disorder (ASD) often have significant deficits in language comprehension1. There is some evidence suggesting that these difficulties stem from deficits in semantic processing and integration2,3,4. However, other studies have suggested that individuals with ASD do not show semantic processing deficits when materials are presented in non-linguistic (e.g., visual or auditory) modalities3,5,6. Such findings suggest that semantic processing deficits in ASD may be restricted to linguistic (i.e., written or spoken) modalities. As such, approaches that contrast different modalities may provide insight into the extent to which semantic processing deficits are domain-specific or indicative of a pervasive processing style. The purpose of this paper is to describe a methodology for comparing semantic processing between different modalities using a semantic priming task during concurrent electrophysiological recording.
The semantic priming paradigm has a long history in research investigating how semantic processing influences lower-level word recognition7,8. In traditional semantic priming tasks, a prime word is presented (e.g., cat) followed by a target word that is either semantically related (e.g., dog) or unrelated (e.g., book) to the prime. Such a task is often done in the context of a lexical decision task, such that participants are asked to determine whether the target word is a real word or not. Other paradigms may have participants perform a semantic categorization task on the target word, or judge whether the two stimuli are related or not. Regardless of the specific task, decades of evidence have established that reaction times (RTs) are faster to target words that are semantically related to the prime compared to those that are unrelated.
This &#34;semantic priming effect&#34; has been attributed to a number of mechanisms in theoretical accounts7,8. One is that the priming effect is due to automatic spreading activation through the semantic network, such that the retrieval of the prime word&#39;s meaning activates the meaning of other semantically related words, including the target word. This then reduces the time needed for semantic activation of the target word. A second theoretical mechanism is that of expectancy, which posits that upon seeing the prime word, participants generate an expected set of potential targets. Target words that are included in this set are then recognized more quickly. Finally, others have postulated the existence of a post-lexical mechanism of semantic matching, which establishes the existence of a semantic relationship between the prime and target word. Regardless of the specific mechanism underlying the effect, semantic priming can be a useful index of semantic processing and integration. This paradigm is also not limited to lexical stimuli, and can also be used to investigate semantic priming of non-language stimuli like pictures9 as well as cross-modal semantic priming (e.g., between words and pictures)3.
Semantic priming effects have been well-studied in the psycholinguistic literature, and have been investigated with regards to the type of prime-target relations, the timing of prime and target presentation, and many other manipulations8. The electrophysiological correlates of this effect have also been well-characterized10. Electroencephalography (EEG) is a method of recording neural activity via changes in electrical activity measured at the scalp. EEG is a useful choice of methodology for a semantic priming paradigm because it has very good temporal resolution (on the order of milliseconds, ms) and can thereby provide subtle differences in semantic processing between conditions or groups even in the absence of behavioral effects or responses.
Event-related potentials (ERPs) are time-locked changes in the EEG that arise in response to a specific stimulus or behavior. Depending on the timing and polarity of the response, different components of the ERP are reflective of different aspects of cognitive processing. The N400 component is a well-established marker of semantic processing and semantic integration11,12 (although several other interpretations exist10,13). The N400 amplitude is reduced when semantic integration is easier (such as when the prime and target in a semantic priming paradigm are semantically related) compared to when semantic integration is more difficult (such as when two words are unrelated). Importantly, the amplitude difference between related and unrelated conditions (i.e., the &#34;N400 effect&#34;) is not specific to language. N400 effects are also observed in non-language modalities, such as in response to pairs of semantically-related and unrelated pictures or environmental sounds14,15,16,17. The N400 is thus a useful ERP component for the purposes of the current paradigm because it can be used as a modality-independent estimate of semantic processing and integration abilities.
Individuals with ASD show reduced or absent semantic priming effects and N400 effects in response to language stimuli2,3,4, suggesting impairments in semantic processing. Such effects have been found in response to visuo-semantic and audio-semantic stimuli3,5,6, lending support to the claim that semantic processing is selectively impaired for language stimuli. However, most previous studies comparing modalities have used cross-modal priming, such that the prime-target pair contains a lexical stimulus. Given the proposal that individuals with ASD have deficits in semantic processing of language stimuli, such cross-modal stimuli may have affected results. To truly investigate whether semantic processing of language is selectively impaired in individuals with ASD, within-modality pairs of lexical and non-lexical stimuli must be used. In a recent study, Coderre et al.6 provided the first direct comparison of within-modality word and picture semantic priming to investigate semantic processing deficits in adults (ages 18-68) with ASD. Participants with ASD and typically-developing (TD) participants viewed pairs of pictures and words and were asked to judge whether the stimuli were related or not. During this semantic priming task, their brain activity was recorded using EEG. By comparing N400 effects between groups and modalities, this paradigm provided insight into the nature of semantic processing in individuals with ASD.
The purpose of this paper is to describe the semantic priming ERP methodology employed by Coderre et al.6. Although this paradigm was initially implemented to study semantic processing in adults with ASD, it may prove useful for any experimenters wishing to explore the neural correlates of lexico-semantic and visuo-semantic processing, either in TD individuals or in specific clinical populations.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="126">
			<td height="126" style="height:126px;width:216px;">EEG system</td>
			<td style="width:71px;">Electrical Geodesics, Inc. (EGI)</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Geodesic EEG system (GES) 400 system: Net Amps 400 amplifier, NetStation 5.3, 128-channel HydroCel Geodesic Sensor nets</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">Potassium chloride</td>
			<td style="width:71px;">Electrical Geodesics, Inc. (EGI)</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">Plastic bucket</td>
			<td style="width:71px;">Electrical Geodesics, Inc. (EGI)</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">EGI provides a plastic bucket for mixing electrolyte but any clean container can be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Baby shampoo</td>
			<td style="width:71px;">Johnson&#39;s</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">GNU Image Manipulation Program (GIMP)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
	</tbody>
</table>

a semantic priming event-related potential (erp) task to study lexico-semantic and visuo-semantic processing in autism spectrum disorder

Individuals with autism spectrum disorder (ASD) have characteristic deficits in understanding the meaning of language, or semantic processing. However, some evidence indicates that semantic processing of non-linguistic stimuli is intact, suggesting that semantic deficits may be language-specific. To appropriately characterize semantic processing deficits in individuals with ASD, comparison of within-modality linguistic (e.g., written words) and non-linguistic (e.g., pictures) stimuli is required. This paper describes such a methodology that makes use of a semantic priming paradigm during concurrent recording of electroencephalographic (EEG) data. EEG provides a dynamic measure of brain activity that is well-suited to characterize subtle differences in semantic processing that may not be observable at the behavioral level. The semantic priming paradigm presents a prime picture or word (e.g., dog) followed by a target picture or word that is either related (e.g., cat) or unrelated (e.g., pencil) to the prime. This paradigm can thus be used to evaluate semantic processing across different modalities, and to compare lexico-semantic and visuo-semantic processing abilities in individuals with ASD and how they might differ from TD individuals. The specific steps involved in creating the stimuli, performing the EEG testing, and analyzing the EEG data are discussed. Representative results illustrate how the N400 component of the event-related potential (ERP) is reduced following semantically-related prime-target pairs compared to unrelated pairs. Comparisons of the N400 between conditions, modalities, and groups can provide estimates of the success of semantic processing, and can thereby be used to characterize semantic deficits in individuals with ASD or other clinical populations.

If stimuli have been appropriately sorted into related and unrelated conditions, an N400 effect should be observed for both word and picture stimuli (Figure 2). This is identifiable as a greater negative amplitude in unrelated conditions compared to related conditions. For word stimuli, the effect should occur from 300&#8211;500 ms over central or centro-parietal scalp6,10. For picture stimuli, the ef...

Watch this Scientific Journal Video about A Semantic Priming Event-related Potential ERP Task to Study Lexico-semantic and Visuo-semantic Processing in Autism Spectrum Disorder at JoVE.com

A Semantic Priming Event-related Potential ERP Task to Study Lexico-semantic and Visuo-semantic Processing in Autism Spectrum Disorder

This paper describes a semantic priming ERP task using within-modality pairs of pictures and words to investigate semantic processing in individuals with autism spectrum disorder (ASD).

A Semantic Priming Event-related Potential (ERP) Task to Study Lexico-semantic and Visuo-semantic Processing in Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) have characteristic deficits in understanding the meaning of language, or semantic processing. However, ...

The overall goal of this semantic priming ERP methodology is to compare semantic processing of linguistic and non-linguistic stimuli in the form of words and pictures, in individuals with autism spectrum disorders, compared to typically-developing individuals. This method can help answer key questions in the autism field, such as whether individuals with autism spectrum disorders have a global deficit in semantic processing that extends beyond language. The main advantage of this technique is that it uses electroencephalography, a technique of measuring brain activity that can pick up on very subtle differences in cognitive processing between groups.Demonstrating the procedure will be Emme O'Rourke, a research assistant in my lab. Measure the circumference of the participant's head, passing through the inion and nasion in order to select the appropriate sized EEG net. Begin by immersing the electroencephalography, or EEG electrodes, in electrolyte solution for five minutes.Instruct the participant to close their eyes, then place the net so it fits snugly against their head. Once all electrodes have been seated against the scalp, check impedances. Re-seat or re-wet any electrodes with impedances above 50 kilo-Ohms.Finally, instruct the participant to judge whether the stimuli on the screen are related or unrelated, by pressing a button on the keyboard. Tell them to wait to make their response until the second stimulus has disappeared from the screen, and the black cross has disappeared. Finally, have the participant complete the task.Begin by opening the EEG processing software. To filter the data, create a new filtering tool by selecting filtering in the create drop-down menu, and rename the tool. Then set the highpass filter to 0.1 Hertz, and the lowpass filter to 50 Hertz.Save the tool, then drag the original EEG recording file into the input files box at the top left in the window, and hit run. Next, to segment the data into trials, create a new segmentation tool, and name it appropriately. Under categories to create, hit the plus sign to create a new category, and rename it picture related.Drag the code icon into the create category based on criteria box, and set it as code is PIC1, to time lock to the presentation of stimulus 1. Drag the key code icon into the create category box, and set it as key code cell number is 1. Note, to include only correct trials, drag another key code icon into the create category box, and set it as key code eval is 1.Then, at the bottom of the window, set the segment length to extend segment 100 milliseconds before, and 2, 300 milliseconds after. Clone the category by hitting the clone button, and rename it picture unrelated. Set the code to PIC1, and the key code cell number to 2.Clone the category and rename it word related. Set the code to WRD1, and the key code cell number to 3. Then clone the category again, and rename it word unrelated.Set the code to WRD1 and the key code cell number to 4. Save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run. To perform artifact detection, create a new artifact detection tool, and name it.Under artifact detection settings, hit the plus sign at the bottom of the window to add a new setting. Select bad channels from the drop-down menu under operation. Leave all of the default settings.Add a new setting and add select eye blink from the operation drop-down menu, and leave all of the default settings. Then, add a new setting, and select eye movement from the operation drop-down menu, and leave all of the settings. Save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run.Open the resulting file in the review panel and scroll through every trial by hitting the arrow buttons under the categories menu on the right sidebar. Mark trials as good or bad by hitting the green or red circles, respectively. When done, close the file to save the results.Next, create a new bad bad channel replacement tool, and name it. Save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run. Perform single subject averaging to collapse over trials.Create a new averaging tool and name it appropriately. Under averaging settings, select handle source files together, and handle subjects separately. Then, save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run.Next, create a new montage operations tool, and name it appropriately. Select the appropriate net from the drop-down menu under list montages for sensor layout. Select average reference, and make sure the exclude bad channels from reference box is selected.Save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run. Finally, perform baseline correction using the first 100 milliseconds of the segment. Create a new baseline correction tool, and name it.Under baseline correction settings, click select baseline from portion of segment. Select baseline with respect to segment time equals zero, and baseline begins 100 milliseconds before time zero, and is 100 milliseconds long. Lastly, save the tool, then drag the most recent preprocessed file into the input files box at the top left of the window, and hit run.Here, representative ERP waveforms at electrode CZ show a larger amplitude to unrelated conditions compared to related conditions, at approximately 400 milliseconds. Further, these topographic plots show the unrelated/related difference, averaged over a window from 400 to 500 milliseconds. Clinical groups, such as individuals with ASD, may show a smaller N400 effect in response to words, which suggests difficulties with lexicosemantic processing.Once the stimuli are created and the task is ready, EEG testing and pre-processing takes approximately one and a half hours per participant. This technique provides a unique way for researchers in the field of autism to explore semantic processing across different modalities in individuals with autism spectrum disorder. Following this procedure, other methods, like functional magnetic resonance imaging, can be performed to answer additional questions, like the neural circuitry underlying lexicosemantic and visual-semantic processing in individuals with autism spectrum disorder.Don't forget that working with individuals with autism can sometimes be challenging, and that certain adaptations or amendments to testing may need to be done while performing the EEG procedure.

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Research

JoVE Journal

Behavior

10.4K visualizações.  University of Vermont. The overall goal of this semantic priming ERP methodology is to compare semantic processing of linguistic and non-linguistic stimuli in the form of words and pictures, in individuals with autism spectrum disorders, compared to typically-developing individuals. This method can help answer key questions in the autism field, such as whether individuals with autism spectrum disorders have a global deficit in semantic processing that extends beyond language. The main advantage of this technique is...