Request PDF on ResearchGate | On Jan 1, , G. A. Stefanatos and others published Event related potentials: A methods handbook. Event-related potentials: A methods handbook Request Full-text Paper PDF In contrast, event-related potentials (ERPs) provide a real-time measure of the. The first comprehensive handbook to detail ERP methodology, covering experimental design, data analysis, and special applications. The study of event- related.

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1 Interpreting Event-Related Brain Potentials. 3. Leun J. Otten and Michael D. Rugg. 2 Ten Simple Rules for Designing ERP Experiments Steven J. Luck. Event‐Related Potentials: A Methods Handbook. Edited by Todd C Handy. A Bradford Book. Cambridge (Massachusetts): MIT Press. $ xi + p + 9 pl; ill. Event-Related Potentials: A Methods Handbook. edited by Todd C. Handy, pp., Bradford Book, , $ Over the past ten to fifteen.

However, many complex methodological challenges arise in applying this technique to clinical populations, and these challenges must be overcome for the ERP technique to live up to its potential. The goal of this paper is to describe some of the most salient challenges and provide effective strategies for dealing with them. Our own experience has been mainly in schizophrenia, but much of the information presented here applies to any clinical population. We focus our discussion on traditional approaches to ERPs, for which methods been refined over many decades.

Information about newer approaches, such as time-frequency analysis, can be found elsewhere 1 ; 2. We begin with a brief overview of the ERP technique, followed by a discussion of the challenges in designing experiments, practical considerations in recording and analysis, and issues in interpreting ERP effects. The present article is necessarily brief and focused, but broader reviews are available elsewhere 3 — In addition, we strongly recommend the ERP publication guidelines of the Society for Psychophysiological Research as a supplement to the recommendations in this paper ERPs arise from postsynaptic potentials in cortical pyramidal neurons, which produce opposite polarities on either side of the active tissue the specific polarity depending on whether the postsynaptic potential is excitatory or inhibitory; see 13 for a more detailed account.

If a large number of neurons on the order of thousands to millions are active together in time and spatially aligned, their electric fields summate, and the summed voltage can be recorded on the surface of the head.

Importantly, this means that not all brain activity can be measured with scalp-recorded EEG, and ordinarily ERPs do not directly reflect action potentials, interneuron activity, or subcortical activity although their influence on cortical PSPs may indirectly affect ERPs. ERPs are conducted through the brain, skull, and scalp virtually instantaneously at nearly the speed of light.

Therefore, scalp-recorded voltages reflect neural activity happening at exactly that point in time. This is what gives the ERP technique such excellent temporal resolution. Postsynaptic potentials last tens to hundreds of milliseconds, and may be occurring in dozens of areas of the brain at the same time. Because the potentials generated in a given region of the brain spread widely across the scalp, the voltages recorded at a given electrode site typically reflect activity from multiple brain areas discussed further below.

Note that the spreading of voltages in ERP recordings makes it generally difficult to localize ERPs to specific regions of the brain with confidence for more information on source localization, see 3 ; 14 — ERPs have several properties that make them especially useful for understanding key aspects of psychiatric disorders.

The fact that ERPs provide an instantaneous, continuous, millisecond-resolution measure of processing means that they can be used to isolate the dozens of individual sensory, cognitive, affective, and motor processes that occur between a stimulus and a response, making it possible to unpack the many different factors that contribute to overt behavior.

All of these processes are typically collapsed into a single time slice in functional magnetic resonance imaging fMRI and positron emission tomography PET experiments because of the sluggish nature of the hemodynamic response. Thus, ERPs are particularly useful for unpacking processes that occur rapidly over a period of 1—2 seconds, whereas fMRI and PET are useful for unpacking processes that operate on slower time scales or for which relationships with distinct neuroanatomical substrates are important to resolve or confirm.

In addition, many disorders are characterized by a change in the timing of one or more neural processes, and this can be measured much more readily with ERPs than with fMRI or PET.

Recent developments in equipment have also made it easier to record EEG in well-controlled environments outside the laboratory, such as clinics, schools, and hospitals. Moreover, although there are differences in waveshape, size, and timing of ERPs between individuals, ERPs tend to be highly stable within an individual.

Event-related potential

However, the field has increasingly moved to higher-density arrays of electrodes, made possible by new means of applying electrodes and the miniaturization of the hardware.

As a result, it is not uncommon for many investigators to record from 64, , or even electrodes.

The advantages to these larger arrays are multiple. First, the greater spatial sampling permits one to identify components that might have eluded capture with smaller arrays, where the inter-electrode distances were greater.

Similarly, greater spatial sampling permits one to distinguish one component from another based in part on scalp topography. A final benefit, that has little to do with science per se, is that some dense array systems are quick and easy to put on, such as the EGI electrode net.

As a result, this makes possible the ability to test, using many electrodes, infants or other difficult-to-test children. Topics that have received the most attention in ERP research include recognition memory, attention, working memory, executive functions, auditory and visual sensory processing, face processing, and language processing.

In this section, we review a selection of the processes that have been examined in developmental populations using ERPs, and some of the associated ERP components, with an emphasis on those that are most relevant for a developmental approach to studying psychiatric disorders. We also include a glossary of these and other ERP components in this section see Table 1. Components are typically labeled according to the polarity of the deflection i.

Alternatively, components are sometimes labeled based on the topography of the ERP waveform e. Finally, the names of other components are derived from their apparent functional significance e. An auditory sensory component relevant to developmental psychopathology research is the Mismatch Negativity MMN. The MMN is a negative-going component recorded from centro-frontal electrodes approximately ms following a rarely-presented auditory stimulus, reflecting an automatic change-detection response 6.

This early obligatory component is present from birth through adulthood 7 , is typically presented and analyzed as a difference wave i. The MMN reflects the earliest stage of obligatory auditory attention, and is generally believed to be the outcome of a mechanism that compares current auditory input to memory traces from previous auditory inputs and signals e. The MMN has already been utilized to examine low-level auditory sensory abilities in infants, children, and adults with a variety of medical and psychiatric disorders e.

Human faces provide critical signals for normal social and communicative interaction, and face processing and the neural and perceptual mechanisms that underlie it are directly or indirectly relevant for a wide variety of psychiatric disorders. The face-sensitive adult N component is a negative deflection recorded from electrodes over occipital-temporal cortex that peaks at approximately ms following the presentation of a picture of a face or object.

Decades of research indicate that the N exhibits larger amplitude and shorter latency responses to faces than to a variety of other stimuli In terms of its neural sources, converging evidence suggests that the N reflects specialized activity in several regions of the occipital and temporal lobes that are involved in face processing 18 , 20 , 21 , The N has been studied extensively as a marker for the specialized neural and perceptual mechanisms associated with the early stages of face processing, and recent evidence-suggests that the face-sensitive responding of the N may index a collection of specialized early-stage neural and perceptual mechanisms that are unique to the recognition and identification of faces as a salient and important visual stimulus 23 , 24 , 25 , Most notably, the results of several studies suggest that the large amplitude of the N component in response to faces compared with objects may reflect the extensive long-term experience we have with identifying and discriminating faces from one another 26 , There are considerable functional differences between the face-sensitivities of N responses in children and adults see 28 for review.

However, the N is observable in children as young as 4 years of age, and the electrophysiological processing of faces becomes adult-like during adolescence. Additionally, researchers have identified two infant ERP components, the N and the P, which may represent developmental precursors to the adult N Like the N, these components are recorded from electrodes over occipital-temporal cortex, and are sensitive to faces on a number of dimensions.

Specifically, the N has been observed to elicit larger amplitude responses to human faces relative to monkey faces or matched visual noise stimuli 30 , 31 , 32 , P latency is shorter for faces than for other objects 33 , and the N and P both exhibit face inversion effects with larger amplitude responding for upright compared with inverted faces 30 , We also recently found that the occipital-temporal P in infants and N in adults were similar in that they both exhibited larger amplitude responses to fear faces versus happy or neutral faces These findings complement previous research in which we showed that a later ERP component recorded from electrodes over frontal cortex Nc also exhibited increased amplitude responses to fearful versus happy faces 35 , 36 , We have also shown that the Nc component indexes familiarity in face processing, in that it is larger for familiar as compared to unfamiliar faces in the first year of life Furthermore, developmental changes observed in face-sensitive ERP components are believed to reflect the effects of experience in shaping the neural systems that underlie face processing.

Therefore, studying the development of face-related ERP components in psychiatric populations is an especially promising area of current and future research. Mnemonic and attentional ERPs are relevant for the study of psychiatric disorders in at least two respects. Therefore, the use of ERPs can shed light on the nature and timing of the neural abnormalities that underlie them, as well as their developmental course.

Second, ERPs that reflect memory or attention have proven to be invaluable tools for exploring new ground in a variety of cognitive domains in both typical and atypical development e.

The Nc component observed in infants and children is one of the most studied developmental ERP components. This negative deflection is recorded from electrodes over frontal cortex, exclusively to visual stimuli, and is involved in both memory and attention. As noted earlier, the Nc has also been observed to be of larger amplitude in response to fearful versus happy facial expressions Based on these and other data, it has been suggested that the Nc may specifically index the allocation of attentional resources to interesting or salient stimuli 39 , 42 , In addition to the role it may play in indexing attentional mechanisms, there is evidence that the Nc component also indexes mnemonic mechanisms, either directly or indirectly.

For example, several studies have shown that the Nc distinguishes mother's face from a stranger's face across several ages, even when the two stimuli are presented with equal probability 38 , 33 , 44 , 45 , but see also Furthermore, in studies of memory for actions performed with objects in 9- and month old infants, the latency of the Nc was found to be longer for pictures of the familiar action sequences versus unfamiliar action sequences.

Critically, the magnitude of the latency difference between the familiar and unfamiliar stimuli predicted behavioral performance in the memory test one month later, suggesting that the Nc was modulated by mnemonic mechanisms 47 , 48 , The role of mnemonic mechanisms in modulating the Nc component has also received support from research using a cross-modal recognition memory paradigm in typically developing infants e.

The specific roles of attention versus memory in modulating the Nc component under various circumstances remains a topic of debate see 53 for discussion. However, the results of a recent source modeling study may provide a basis for resolving this debate in the future.

Specifically, these data suggest the possibility that there may actually be two major generators that underlie the Nc component, which differentially index mnemonic and attentional mechanisms. One of the sources identified in this study was a prefrontal source that was active earlier and influenced by stimulus familiarization, and the other was a frontal pole source that was active later and not influenced by stimulus familiarization These findings suggest the distinct possibility that the scalp-recorded Nc may reflect two somewhat distinct processes, which may be more clearly distinguishable from one another with future research.

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These components appear to be more distinctly involved in mnemonic versus attentional processing Specifically, the PSW is believed to reflect the updating of memory representations for partially encoded stimuli, and evidence suggests it may reflect activity in temporal lobe regions involved in memory 54 , see also The NSW has been interpreted to reflect the detection of novelty, and evidence suggests it may be generated by regions of the frontal cortex Below we sample broadly from just two such areas: Zeanah, Fox, and Nelson have charted the development of three groups of children in Romania: Two ERP manipulations were performed.

Because there were no group differences in responding to the 4 emotions, the data were collapsed across emotion to highlight the amplitude differences between the groups.

ERPs recorded from institutionalized children, children living in foster care having previously experienced institutionalization, and never institutionalized children at 42 months of age to happy, fear, anger, and sad faces. As discussed in the text, the children living in foster care show ERP amplitudes that are at the midpoint between institutionalized and never institutionalized children, suggesting improvement over time.

As noted in the text, the groups showed a differential response to these faces; for purposes of this figure, however, we have collapsed across stimulus to reveal the differences in ERP amplitudes across the two groups. ERPs recorded from institutionalized children, children living in foster care having previously experienced institutionalization, and never institutionalized children at 42 months of age, to pictures of their caregiver's face and the face of a stranger.

Again, as with Figure 3 , we have collapsed over stimulus to reveal the group differences in ERP amplitudes. As was the case with the facial emotion manipulation see Figure 2 , the ERPs of the foster care group are beginning to normalize. Over and above reduced ERP amplitudes, two additional observations are worth noting.

First, regarding emotion recognition, the institutionalized group performed very similarly to the never institutionalized group; that is, the NC was largest to fearful faces than other faces.


Thus, it appears that institutionalization has no effect on discriminating facial expressions of emotion for elaboration, see 60 , Second, there were rather dramatic group differences between institutionalized vs.

Therefore, institutionalization does appear to have an impact on the neural systems involved in facial recognition for discussion, see Moulson, Westerlund and Nelson, in press, 60 , Overall, these findings illustrate how ERPs have been used to study the neural correlates of different dimensions of face processing among children experiencing early psychosocial deprivation.

Similar investigations have been conducted on children experiencing maltreatment, although space limitations prevent us from discussing this work 62 , 63 , 64 , and see also Researchers using ERPs have revealed abnormalities in the early stages of face processing in autism see 66 for review.

For example, McPartland and colleagues found that adolescents and adults with autism exhibited slower than normal peak N responses to faces but normal latency responses to objects relative to typically developing controls The latter finding suggests a reduced reliance on holistic processing mechanisms for face processing. These results also suggest a reduced degree, or reduced depth, of holistic processing in individuals with autism.

In an effort to determine whether the broader autism phenotype is associated with abnormalities in early stage face processing, Dawson and colleagues studied ERPs to upright and inverted faces and objects in parents of children with autism and control participants They found that N responses were faster to faces than to objects in the control group, but not in the parents of children with autism.

They also found that control participants exhibited right-stronger-than-left responses to the faces but the parents of children with autism did not. These data reflect early stage face processing abnormalities that are consistent with those observed in individuals diagnosed with autism and, therefore, indicate that abnormalities in the neural circuitry involved in early stages of face processing may be a functional trait marker for genetic risk for autism. Several other studies conducted by Dawson and colleagues have shed light on the nature of face processing impairments in young children with autism 73 , 74 , In one study, Dawson, Carver, and colleagues examined the neural correlates of familiar and unfamiliar face and object processing in 3- to 4-year old children with autism spectrum disorders ASD , children with developmental delays DD , and typically developing children TD The P recorded from electrodes over occipital-temporal cortex, and the Nc recorded from frontal and midline electrodes.

Unlike these TD children, 3- to 4-year old ASD children did not show differentiation of familiar and unfamiliar faces in either of these ERP components.

Like the TD children, however, they did show differential responses to familiar and unfamiliar objects in both the P and Nc components. Control children with DD in this study did not show differential P or Nc responses to familiar and unfamiliar faces or to familiar and unfamiliar objects. These results suggest that autism is associated with face-specific recognition memory impairment early in life.

In a follow-up study Dawson, Webb, and colleagues examined facial emotion processing in young children with autism In this study, they found that typically developing children exhibited larger amplitude responses in the N and NSW components to a face posed in a fearful expression compared with a face posed in a neutral expression, whereas the children with ASD did not.

Furthermore, the latency of the N component in response to the fear face was associated with better performance on naturalistic experimental assessments of diagnostic social behaviors i. These data provide evidence for abnormal processing of facial expressions of emotion at both the perceptual and early cognitive stages of processing, and further suggest that these abnormalities are meaningfully related to impaired social functioning in these children.

In , Webb, Dawson, and colleagues examined early stage face versus object processing in 3- to 4-year old children with autism To do so, they re-analyzed the ERP data collected in the study of familiar and unfamiliar face and object processing 74 described above , collapsing the data across familiarity.

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Statistical analysis of the face-sensitive N component revealed abnormal patterns of face and object processing in the ASD children relative to children in the two control groups.

Specifically, comparisons of N latencies revealed a significant interaction whereby TD children processed faces faster than objects, but ASD children processed objects faster than faces. However, the relationship between stimulus type and subject group was different between the ASD children object latencies shorter than faces and DD children equal latency responses to faces and objects.

The ASD children also exhibited a reduced amplitude response to the object stimulus relative to both groups of control children. Because effects of familiarity on the N were not examined, it is possible that the observed effects were driven by an interaction among familiarity, stimulus type, and the subject groups. However, these data provide preliminary evidence to suggest that early stage face versus object processing is abnormal in young children with autism, and further suggest that these abnormalities may be characterized by differences in both object and face processing in these children relative to controls.

Our goal in writing this paper was to introduce the reader to the utility of recording ERPs in the context of studying both typical development as well as developmental psychopathology. There is a growing literature using this method with a variety of risk and impaired populations, including children with ADHD, children with histories of maltreatment, children experiencing prenatal drug exposure, children suffering from dyslexia and other learning and memory problems, and children on the autism spectrum and those at risk for developing autism.

The advantages ERPs hold over other neuroimaging tools include their ease in application, the fact that they can be used across the entire lifespan, their superb temporal resolution and their relative inexpense. Their disadvantages include relatively poor spatial resolution. What does the future hold? First, serious efforts are currently being implemented to improve the spatial resolution of ERPs by using higher density arrays of electrodes and in more sophisticated methods of source modeling.

Second, a number of laboratories are currently co-registering ERPs with other imaging modalities e. We contend that continued refinement of this method, combined with the development of other imaging tools e. Joseph P. McCleery, Harvard Medical School. National Center for Biotechnology Information , U.

Author manuscript; available in PMC Dec McCleery , Ph. Author information Copyright and License information Disclaimer. Copyright notice. See other articles in PMC that cite the published article.

Best Practices for Event-Related Potential Research in Clinical Populations

Abstract A variety of neuroimaging tools are now available for use in studying neurodevelopment. What is the Event-Related Potential? How does one collect ERPs? What processes have been investigated using ERPs? May also be observable in the visual domain. See also P3b. P3b Middle to late childhood onward Context updating relevant to memory storage Midline with parietal maximum, — ms Time-locked to a target stimulus in oddball paradigms.

See also P3a. See also ERN and N2 Contingent Negative Variation CNV Late childhood onward Stimulus evaluation, motor and cognitive preparation Fronto-Central, — ms Occurs between a warning stimulus and a stimulus requiring a response Open in a separate window. Face Processing Human faces provide critical signals for normal social and communicative interaction, and face processing and the neural and perceptual mechanisms that underlie it are directly or indirectly relevant for a wide variety of psychiatric disorders.

Memory and Attention Mnemonic and attentional ERPs are relevant for the study of psychiatric disorders in at least two respects. How have ERPs been used to study atypical development? Figure 1. Figure 2. Figure 3. Figure 4. Autism Researchers using ERPs have revealed abnormalities in the early stages of face processing in autism see 66 for review. Conclusions Our goal in writing this paper was to introduce the reader to the utility of recording ERPs in the context of studying both typical development as well as developmental psychopathology.

References 1. Johnson MH. Blackwell Publishing; Oxford, UK: Neuroscience and Cognitive Development: The Role of Experience and the Developing Brain. New York, NY: The Cognitive Neuroscience of Development.

Psychology Press; Nelson CA, Luciana M.

Handbook of Developmental Cognitive Neuroscience. Cambridge, MA: MIT Press; Early selective-attention effect on evoked potential reinterpreted.

Acta Psychol. Mismatch negativity--a unique measure of sensory processing in audition. Int J Neurosci. Intermodal selective attention.

Effects of attentional load on processing of auditory and visual stimuli in central space. Electroencephalogr Clin Neurophysiol. Event-related potentials and autonomic responses to a change in unattended auditory stimuli.

Adaptive modeling of the unattended acoustic environment reflected in the mismatch negativity event-related potential. Brain Res.Specifically, the refinement of existing tools e. However, the relationship between stimulus type and subject group was different between the ASD children object latencies shorter than faces and DD children equal latency responses to faces and objects. Although it is difficult to know with certainty how scalp-recorded voltage changes originate at the neural level, the following represents the best estimate based on our understanding of both biophysics and the properties of neural communication.

Event-related brain potentials during an extended visual recognition memory task depict delayed development of cerebral inhibitory processes among 6-month-old infants with Down syndrome.

Because it is a lumping technique, spatial PCA by itself is unlikely to produce components that are related to individual neural and psychological processes.

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