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Electrocortical Correlates of Reading Disability Subtypes
Published in Kees P. van den Bos, Linda S. Siegel, Dirk J. Bakker, David L. Share, Current Directions in Dyslexia Research, 2020
The functioning of the brain can be measured in an indirect and in a more direct way. In the indirect way stimulus material is presented in the visual, auditory or tactile modality and speed and accuracy of manual or vocal responses are measured. On the basis of experimental changes in stimulus conditions and the subsequent changes in accuracy and speed of performance, one has to infer either normal or defective functioning of different brain areas. A method which enables a more direct measurement of brain functioning, and which provides the opportunity to monitor brain activity during processing, is the recording of Event-Related Potentials (ERPs). ERPs represent electrical responses of the brain that are time-locked to the processing of stimulus information. It is assumed that amplitudes and latencies of the different peaks or components in the ERP waveform reflect brain activity associated with, e.g., perceptual analysis, cognitive processing and response preparation and execution. Another important advantage of this technique is that information is gathered from a number of brain areas simultaneously, which provides the possibility of localizing the source of possible dysfunctions. Therefore, ERPs represent a powerful tool in assessing the role of left and right hemispheric mechanisms in different stages of the normal, as well as, the disturbed reading process.
Review of the Human Brain and EEG Signals
Published in Teodiano Freire Bastos-Filho, Introduction to Non-Invasive EEG-Based Brain–Computer Interfaces for Assistive Technologies, 2020
Alessandro Botti Benevides, Alan Silva da Paz Floriano, Mario Sarcinelli-Filho, Teodiano Freire Bastos-Filho
The EEG signals are composed of basic components of spontaneous potentials, which may be present throughout the range of frequencies of the EEG signal and are not produced by sensory stimulation. ERP is the change of the EEG potential in response to a particular event. ERP has much lower amplitude than the spontaneous activity, so that it cannot be recognized in the raw EEG. Therefore, average techniques are commonly employed for detecting the ERP. In the average technique, the ERP is considered to occur with an approximately constant delay in relation to the event, and the spontaneous activity is modeled as an additive random noise (Figure 1.29a) [37]. The EEG recordings obtained by repeating the same experiment or trial, under the same conditions, are called epochs, and as the number of epochs, N, used in the calculation of the average increases, the time-locked activity increases and the spontaneous activity decreases, and thus, the ERP can be observed.
Electrical Brain Stimulation to Treat Neurological Disorders
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
Derivatives of the EEG technique include Evoked Potentials (EP), which involves averaging the EEG activity time-locked to the presentation of a stimulus of some sort (visual, somatosensory, or auditory). Event-Related Potentials (ERPs) refer to averaged EEG responses that are time-locked to more complex processing of stimuli; this technique is used in cognitive science, cognitive psychology, and psychophysiological research.
Imitation of Touching Dangerous Animals Triggers Motor Inhibition in a Primed Target Grasping-Categorization Task
Published in Journal of Motor Behavior, 2023
Peng Liu, Jiali Zheng, Jiaxin Wang, Chunyuan Wang, Yongchun Wang, Leyun Lin, Yonghui Wang
Subsequent event-related potential (ERP) studies have examined the neural mechanism of the motor interference effect by using tool or animal pictures as target stimuli and combining a motor priming paradigm with either a Go/NoGo task (Cao & Liu, 2021; Liu, 2018; Liu et al., 2017) or a shape discrimination task (Cao et al., 2020). The studies focused on two ERP components: frontal N2 and parietal P3. In studies using dangerous stimuli, a more positive P3 component has been suggested to reflect a process that recruits more cognitive resources to process dangerous versus neutral stimuli (Decety et al., 2010; Kaestner & Polich, 2011). In contrast, a more negative N2 component is thought to reflect enhanced motor inhibition processing (Folstein & van Petten, 2008; Huster et al., 2013). Liu and colleagues proposed two hypotheses: (1) dangerous objects could induce aversion and inhibit prepared responses, leading to longer RTs and more negative N2 amplitudes in the dangerous condition than in the neutral condition (Anelli et al., 2013; Coello et al., 2012; Yiend & Mathews, 2001); or (2) dangerous objects could require more cognitive resources to process dangerous details, resulting in longer RTs and more positive P3 amplitudes in the dangerous condition. Their results supported the second hypothesis: the behavioral motor interference effect was accompanied by a significant difference in P3 amplitudes (but not N2 amplitudes) between the dangerous and neutral conditions, suggesting that it may result from the recruitment of more cognitive resources to process dangerous details.
Neural Correlates of Visual Attention and Short-Term Memory in Children with Reading Difficulty
Published in Developmental Neuropsychology, 2023
Alexis F. Koffman, Erica Flaten, Amy S. Desroches, Richard S. Kruk
Visual attention and visual memory difficulties can disrupt word decoding in children, particularly in parsing words and establishing solid representations of correct letter orders in words (Bosse, Tainturier, & Valdois, 2007; Liu, Liu, Pan, & Xu, 2018). In the current study, visual attention and short-term memory of children with reading difficulty and typical readers were examined using event-related potentials (ERPs). Given the high temporal resolution and specificity of ERP waveform data, these provide an important perspective on behavioral findings showing attention and memory anomalies in children with reading difficulty. ERPs are useful for clarifying reading-ability and age differences because they show neural activity as it unfolds, and because ERP components are linked to distinct aspects of perceptual/attentional and cognitive processing. The N1 and N2pc components reflect alerting and attentional orienting in selective visual attention (SVA), respectively, and these have been evoked in child participants in response to attentional tasks (Couperus & Quirk, 2015; Santhana Gopalan et al., 2020; Santhana Gopalan, Loberg, Hämäläinen, & Leppänen, 2019). The sustained posterior contralateral negativity (SPCN) component reflects visual short-term memory (VSTM) load; studies with children show that this ERP component is a valid marker of visual memory at young ages (Astle et al., 2014; Shimi, Nobre, & Scerif, 2015).
Detection of amyotrophic lateral sclerosis disease from event-related potentials using variational mode decomposition method
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Fırat Orhanbulucu, Fatma Latifoğlu
The ERP signals used in the study were created as a result of taking the average of the EEG signals of the target stimuli. The amplitude and latency values of the (Sutton et al. 1965; Duncan et al. 2009; Wilaiprasitporn and Yagi 2015); P300 wave, which is frequently used in the studies and stated as the most remarkable component of the ERP signal, were obtained. These properties, which are also included in the studies as MF, are obtained from the time domain of the ERP signal. The P300 or P3 positive amplitude value is measured in microvolts (µV), where the P300 waveform peaks generally between 280–600 milliseconds (ms) after the stimulus is delivered. The P300 latency value, measured in ms, is the time between the stimulus onset and the point where the P300 wave reaches its maximum amplitude point (Duncan et al. 2009; Güven 2019). In Figure 4, the ERP signals obtained from the Oz and Cz channel from the ALS patient and healthy individuals belonging to the sample participants are given.