Channel Selection Methods for the P300 Speller

Total Page:16

File Type:pdf, Size:1020Kb

Channel Selection Methods for the P300 Speller G Model NSM 6874 1–10 ARTICLE IN PRESS Journal of Neuroscience Methods xxx (2014) xxx–xxx Contents lists available at ScienceDirect Journal of Neuroscience Methods jo urnal homepage: www.elsevier.com/locate/jneumeth 1 Clinical Neuroscience 2 Channel selection methods for the P300 Speller a,∗ b a b a 3 Q1 K.A. Colwell , D.B. Ryan , C.S. Throckmorton , E.W. Sellers , L.M. Collins a 4 Department of Electrical & Computer Engineering, Duke University, Durham, NC, USA b 5 Department of Psychology, East Tennessee State University, Johnson City, TN, USA 6 7 h i g h l i g h t s 8 • 9 Active electrode (“channel”) selection leads to higher average P300 Speller classification performance compared to a standard channel set of similar 10 size. • 11 Jumpwise regression is capable of selecting an effective electrode subset at runtime. • 12 Some experimental subjects see large gains in accuracy with channel selection. 13 2514 a r t i c l e i n f o a b s t r a c t 15 16 Article history: The P300 Speller brain–computer interface (BCI) allows a user to communicate without muscle activity 17 Received 11 October 2013 by reading electrical signals on the scalp via electroencephalogram. Modern BCI systems use multiple 18 Received in revised form 6 March 2014 electrodes (“channels”) to collect data, which has been shown to improve speller accuracy; however, 19 Accepted 10 April 2014 system cost and setup time can increase substantially with the number of channels in use, so it is in the 20 user’s interest to use a channel set of modest size. This constraint increases the importance of using an 21 Keywords: effective channel set, but current systems typically utilize the same channel montage for each user. We 22 Brain–computer interface examine the effect of active channel selection for individuals on speller performance, using generalized 23 P300 Speller standard feature-selection methods, and present a new channel selection method, termed jumpwise 24 Channel selection regression, that extends the Stepwise Linear Discriminant Analysis classifier. Simulating the selections of each method on real P300 Speller data, we obtain results demonstrating that active channel selection can improve speller accuracy for most users relative to a standard channel set, with particular benefit for users who experience low performance using the standard set. Of the methods tested, jumpwise regression offers accuracy gains similar to the best-performing feature-selection methods, and is robust enough for online use. © 2014 Published by Elsevier B.V. 26 1. Introduction remain in the experimental stage and are primarily used in a labo- 36 ratory environment (Vaughan et al., 2006). 37 27 Brain–computer interface (BCI) systems are designed to analyze One BCI that has been successfully deployed to users with ALS 38 28 real-time data associated with a human user’s brain activity and (Sellers and Donchin, 2006) is the P300 Speller, first developed 39 29 translate it into computer output. The clearest current motivation by Farwell and Donchin (1988). This system combines measure- 40 30 for BCI development is to extend a means for communication and ments of electroencephalogram (EEG) signals on the user’s scalp, a 41 31 control to people with neurological diseases, such as amyotrophic software signal processor, an online classifier, and presentation of 42 32 lateral sclerosis (ALS) or spinal-cord injury, who have lost motor stimuli that evoke a P300 event-related potential (ERP), in order to 43 33 ability (“locked-in” patients). However, state-of-the-art BCI sys- sequentially choose items from a list (e.g. the letters in a word, or 44 34 tems for such individuals are still expensive and limited in speed commands such as “Page Down” or “Escape”). 45 35 and accuracy, and setup for home use is nontrivial; most systems The original P300 Speller, as conceived by Farwell and Donchin, 46 employed only a single electrode (one “channel” of information). 47 The use of additional channels was discovered to improve clas- 48 ∗ sification performance, and most if not all modern P300 Speller 49 Corresponding author. systems include data from multiple recording sites (e.g. Krusienski 50 E-mail addresses: [email protected], [email protected] (K.A. Col- et al., 2006; Sellers and Donchin, 2006; Schalk et al., 2004). How- 51 well), [email protected] (D.B. Ryan), [email protected] (C.S. Throckmorton), [email protected] (E.W. Sellers), [email protected] (L.M. Collins). ever, larger channel sets require more complicated electrode caps 52 http://dx.doi.org/10.1016/j.jneumeth.2014.04.009 0165-0270/© 2014 Published by Elsevier B.V. Please cite this article in press as: Colwell KA, et al. Channel selection methods for the P300 Speller. J Neurosci Methods (2014), http://dx.doi.org/10.1016/j.jneumeth.2014.04.009 G Model NSM 6874 1–10 ARTICLE IN PRESS 2 K.A. Colwell et al. / Journal of Neuroscience Methods xxx (2014) xxx–xxx 53 and more amplifier channels, which can greatly increase the cost literature (e.g. Farwell and Donchin, 1988; Sellers and Donchin, 119 54 of a system: implementing a 32-channel system rather than an 8- 2006; Krusienski et al., 2008); however, the proposed methods 120 55 channel system can raise the system cost by tens of thousands of for channel selection could be used in conjunction with other 121 56 dollars. This cost can be prohibitive to home users. Further, each classifiers or could be similarly included into a classifier training 122 57 channel must be calibrated individually for proper placement and phase. 123 58 impedance before each spelling session, adding to setup time and Each channel of EEG data contributes a number of time-samples 124 59 user discomfort. As a result, clinically relevant systems are limited (features) for classification decisions; channel selection can be 125 60 to using a subset of all possible electrode locations. The selec- viewed as a feature selection problem, with the additional constraint 126 61 tion of these channel locations impacts system performance: one that only entire channels of features may be selected for inclusion 127 62 sensitivity analysis concluded that identifying an appropriate chan- or exclusion. Feature selection is commonly performed in machine 128 63 nel set for an individual was more important than factors such learning problems with high dimensionality (many features) under 129 64 as feature space, pre-processing hyperparameters, and classifier the assumption that it is possible to discard some features at a 130 65 choice (Krusienski et al., 2008). In addition to empirical demon- low cost (for example, if the features are irrelevant or redun- 131 66 strations of the benefit of channel selection (Schröder et al., 2005; dant). Feature selection reduces data storage and computational 132 67 Krusienski et al., 2008; Rakotomamonjy and Guigue, 2008; Cecotti requirements by discarding unnecessary dimensions, reduces clas- 133 68 et al., 2011), principled reasons for selecting channel sets on a sifier training time by training on less-complex data, and guards 134 69 per-subject basis include the difficulty of outpatient calibration against classifier over-fitting by reducing the effect of the “curse 135 70 of electrode caps by nonclinical aides (such that electrodes that of dimensionality.” (See Guyon and Elisseefi, 2003 for an excellent 136 71 might have been useful do not yield as much information), as well introduction to feature selection.) Methods for feature selection fall 137 72 as several neurological motivations, including variation in brain into two categories: wrapper methods, which determine feature 138 73 structure and response across subjects arising from their unique subsets’ value by measuring their performance with the chosen 139 74 cortical folds, and the plasticity of the brain over time, particu- classifier; and filter methods, which choose subsets of features inde- 140 75 larly as it adapts to a new system. Disease progression may also pendently of the classifier. Wrapper methods observe a “search 141 76 impact the optimal set of electrodes. Furthermore, BCI deployment space” of possible combinations of features, assigning each combi- 142 77 for home use has proven much more challenging than deployment nation a value based on the classifier’s performance; these methods 143 78 in the laboratory environment (Sellers and Donchin, 2006; Sellers are appealing for their empiricism and simplicity, but can suffer 144 79 et al., 2006; Kübler et al., 2001); it is possible that the subject- high computation requirements due to the need to repeatedly train 145 80 independent channel sets that are effective for healthy subjects and test the classifier (Guyon and Elisseefi, 2003). Filter methods 146 81 do not generalize to other populations. As a practical note, it is can be faster, but require a performance metric independent of 147 82 anticipated that in order for users to obtain both a performance classification performance. These categories remain when gener- 148 83 benefit from selecting channels from an extensive set and the cost alizing features to channels, and approaches from both categories 149 84 and setup savings of employing a system with a small subset of are explored here: a heuristic filter method, maximum signal-to- 150 85 those channels, a channel selection calibration session could first noise ratio selection (Max-SNR); the wrapper methods sequential 151 86 be conducted in a laboratory environment to determine the opti- forward selection (SFS) and k-forward, m-reverse (KFMR) selection; 152 87 mal subset, which would then be the only channels set up for and a new filter method, jumpwise selection (JS). The performance 153 88 home use. of each method is compared to baseline results obtained with the 154 89 Although channel selection has been investigated for other standard eight-channel montage determined in Krusienski et al.
Recommended publications
  • Part II: Auditory Evoked Potentials, P300 Response and Contingent Negative Variation in Social Drinkers
    Article NIMHANS Journal Social Drinking - Part II: Auditory Evoked Potentials, P300 Response and Contingent Negative Variation in Social Drinkers Volume: 14 Issue: 01 January 1996 Page: 23-30 Chitra Andrade &, C R Mukundan Reprints request , - Department of Clinical Psychology, National Institute of Mental Health & Neuro Sciences, Bangalore 560 029, India Abstract The study aimed to determine if any neurophysiological evidence supporting cognitive changes exist in social drinkers. The sample comprised of 44 male social drinkers and 22 teetotallers matched for age and education. Details of drinking habits were elicited through interviews of the subjects. The experiments consisted of tests for late Auditory Evoked Potentials (AEP), Auditory P300 and Contingent Negative Variation (CNV). EEG was recorded from the Fz and Cz electrode sites of the 10-20 International electrode placement system. The two groups were compared on the mean amplitudes and latencies of P1-N1-P2 components of the AEP, the P300 and the early and late components of the CNV. Results showed that the two groups did not differ significantly on both the amplitude and latency measures of the various components, indicating that there is no electrophysiological evidence of change in cognitive processing or brain dysfunction in social drinkers. Key words - Social drinking, Event related potentials, AEP, P 300, CNV Event Related Potential (ERP) responses have been reported to be sensitive to several aspects of alcohol use, including acute intoxication, withdrawal, tolerance, alcohol related chronic brain dysfunction, in utero exposure, social consumptions and familial risk for alcoholism [1], [2], [3], [4], [5]. There have been very few studies in social drinkers (SDs) using ERP measures and the results have been equivocal.
    [Show full text]
  • Spectral Components of the P300 Speller Response in Electrocorticography
    Proceedings of the 5th International FrA1.4 IEEE EMBS Conference on Neural Engineering Cancun, Mexico, April 27 - May 1, 2011 Spectral Components of the P300 Speller Response in Electrocorticography Dean J. Krusienski, SeniorMember, IEEE , and Jerry. J. Shih Abstract —Recent studies have demonstrated that the P300 and showed predictable time courses in the delta, theta, and Speller can be used to reliably control a brain-computer alpha bands. With the increased spatial resolution and interface via scalp-recorded electroencephalography (EEG) and spectral bandwidth afforded by ECoG, and the recent intracranial electrocorticography (ECoG). However, the exact association of gamma band features with a wide variety of reasons why some disabled individuals are unable to cortical processes [7][23][32], an examination of the spectral successfully use the P300 Speller remain unknown. The characteristics of the P300 Speller response using ECoG is superior bandwidth and spatial resolution of ECoG compared justified. This paper provides a preliminary spatio-temporal to EEG may provide more insight into the nature of the responses evoked by the P300 Speller. This study examines the analysis of the P300 Speller responses in the conventional spatio-temporal progression of the P300 Speller response in delta, theta, alpha, beta, low-gamma, and high-gamma bands. ECoG for six conventional frequency bands. II. METHODOLOGY I. INTRODUCTION A. Subjects BRAIN -COMPUTER INTERFACE (BCI) is a device that Six subjects with medically intractable epilepsy who Auses brain signals to provide a non-muscular underwent Phase 2 evaluation for epilepsy surgery with communication channel [34], particularly for individuals with temporary placement of intracranial grid or strip electrode severe neuromuscular disabilities.
    [Show full text]
  • Rapid P300 Brain-Computer Interface Communication with a Head-Mounted Display
    ORIGINAL RESEARCH published: 05 June 2015 doi: 10.3389/fnins.2015.00207 Rapid P300 brain-computer interface communication with a head-mounted display Ivo Käthner 1*, Andrea Kübler 1 and Sebastian Halder 1, 2 1 Institute of Psychology, University of Würzburg, Würzburg, Germany, 2 Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan Visual ERP (P300) based brain-computer interfaces (BCIs) allow for fast and reliable spelling and are intended as a muscle-independent communication channel for people with severe paralysis. However, they require the presentation of visual stimuli in the field of view of the user. A head-mounted display could allow convenient presentation of visual stimuli in situations, where mounting a conventional monitor might be difficult or not feasible (e.g., at a patient’s bedside). To explore if similar accuracies can be achieved with a virtual reality (VR) headset compared to a conventional flat screen monitor, we conducted an experiment with 18 healthy participants. We also evaluated it with a person in the locked-in state (LIS) to verify that usage of the headset is possible for Edited by: Emanuel Donchin, a severely paralyzed person. Healthy participants performed online spelling with three University of South Florida, USA different display methods. In one condition a 5 × 5 letter matrix was presented on a Reviewed by: conventional 22 inch TFT monitor. Two configurations of the VR headset were tested. In Fabien Lotte, the first (glasses A), the same 5×5 matrix filled the field of view of the user. In the second INRIA (National Institute for Computer Science and Control), France (glasses B), single letters of the matrix filled the field of view of the user.
    [Show full text]
  • Stimulus Frequency and Masking As Determinants of P300 Latency in Event-Related Potentials from Auditory Stimuli *
    Biological Psycho&v 21 (1985) 309-318 309 North-Holland STIMULUS FREQUENCY AND MASKING AS DETERMINANTS OF P300 LATENCY IN EVENT-RELATED POTENTIALS FROM AUDITORY STIMULI * John POLICH Department of Neurology, California College of Medicine, University of California, Irvine, CA 92717, U.S.A. Lawrence HOWARD School of Social Sciences, University of California, Irvine, CA 92717, U.S.A Arnold STARR Department of Neurology, California College of Medicine, University of Californra, twine, CA 92717, U.S.A. Accepted for publication 8 May 1985 The effects of target tone frequency, presence of a masking stimulus. and subject sex on the auditory ERP were studied with an ‘oddball’ paradigm. P300 latency became shorter (about 15 msec) as the difference between the standard (1000 Hz) and target tone frequency increased (1500, 2000, 4000 Hz) but became longer (about 10 msec) with the presence of a white noise masking stimulus. Similar results were obtained for both the P3a and P3b subcomponents of the P300 potential. No significant differences between the adult male and female subjects were observed. The role of stimulus parameters in applied testing situations is discussed. 1. Introduction The P300 component of the event-related brain potential (ERP) is a large (5-15 luv), positive-going waveform that occurs with a modal latency of about 300 msec in normal young adults. Although the neurophysiology underlying the P300 is still being explored (Halgren, Squires, Wilson, Rohrbaugh, Bab and Crandall, 1980; Okada, Kaufman and Williamson, 1983), the cognitive events associated with its generation have received considerable attention (Donchin, 1981; Donchin, Ritter and McCallum, 1978; Pritchard, 1981).
    [Show full text]
  • Electrocorticographic (Ecog) Correlates of Human Arm Movements
    Exp Brain Res DOI 10.1007/s00221-012-3226-1 RESEARCH ARTICLE Electrocorticographic (ECoG) correlates of human arm movements Nicholas R. Anderson • Tim Blakely • Gerwin Schalk • Eric C. Leuthardt • Daniel W. Moran Received: 23 November 2011 / Accepted: 8 August 2012 Ó Springer-Verlag 2012 Abstract Invasive and non-invasive brain–computer kinematics are encoded. In non-human primates, the rela- interface (BCI) studies have long focused on the motor tionships among these kinematics have been more carefully cortex for kinematic control of artificial devices. Most of documented, and we sought to begin elucidating that these studies have used single-neuron recordings or elec- relationship in humans using ECoG. The largest modula- troencephalography (EEG). Electrocorticography (ECoG) tion in ECoG activity for direction, speed, and velocity is a relatively new recording modality in BCI research that representation was found in the primary motor cortex. We has primarily been built on successes in EEG recordings. also found consistent cosine tuning across both tasks, to We built on prior experiments related to single-neuron hand direction and velocity in the high gamma band recording and quantitatively compare the extent to which (70–160 Hz). Thus, the results of this study clarify the different brain regions reflect kinematic tuning parameters neural substrates involved in encoding aspects of motor of hand speed, direction, and velocity in both a reaching preparation and execution and confirm the important role and tracing task in humans. Hand and arm movement of the motor cortex in BCI applications. experiments using ECoG have shown positive results before, but the tasks were not designed to tease out which Keywords Electrocorticography Á Subdural electroencephalography Á Motor cortex Á Brain–computer interfaces Á Arm tuning Á Cosine tuning N.
    [Show full text]
  • Considerations in Source Estimation of the P3
    Source estimation Halgren E. Considerations in Source Estimation of the P3. In: Ikeda I, Inoue Y, eds. Event-related Potentials in Patients with Epilepsy: from Current State to Future Prospects. Paris: John Libbey Eurotext 2008: 71-87. Considerations in Source Estimation of the P3 Eric Halgren, Ph.D. Multimodal Imaging Laboratory Departments of Radiology, Neurosciences and Psychiatry, University of California at San Diego Abstract It is not possible to localize the cerebral structures that generate the P3 from non-invasive recordings. In addition to inherent ambiguities in source localization, many generators that are active during the P3 do not propagate to the scalp and thus would remain invisible to even perfect inverse solutions. Furthermore, scalp recordings are not directly informative with regard to underlying neural processes. In theory, fMRI could help distinguish between alternative P3 generators, but in practice, its utility may be limited. Recordings directly within the brain are limited by incomplete sampling and possible pathology. However, they are the only unambiguous means to demonstrate local generation of potentials which overlap in time with the scalp P3 and possess similar cognitive correlates. Decreases in scalp P3 after brain lesions suggest which structures might contribute directly to the scalp P3, but post-lesion decreases can also be due to disruption of antecedent calculations. Despite these considerations, and remaining dissociations, there is increasing convergence in the distribution of generator structures inferred from different methods. However, bringing the P3s and the cognitive states that they embody into mechanistic neuroscience requires going beyond the localization of generating structures to identifying generating synapses, channels and circuits.
    [Show full text]
  • Working Memory Load for Faces Modulates P300, N170, and N250r
    Working Memory Load for Faces Modulates P300, N170, and N250r Helen M. Morgan, Christoph Klein, Stephan G. Boehm, Kimron L. Shapiro, and David E. J. Linden Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/20/6/989/1759555/jocn.2008.20072.pdf by guest on 18 May 2021 Abstract & We used event-related potential (ERP) methodology to ex- was also found to modulate other ERPs. The amplitude of the amine neural activity associated with visual working memory N170 elicited by the target face decreased with load, and this (WM) for faces. There were two main goals. First, to extend N170 decrease leveled off at load 2, reflecting the behavioral WM previous findings of P300 load modulation to WM for faces. capacity of around two faces. In addition, the N250r, observed as Second, to examine whether N170 and N250r are also influ- an ERP difference for target faces that were present in the encod- enced by WM load. Between one and four unfamiliar faces were ing array relative to target faces that were absent, was also reduced simultaneously presented for memory encoding. After a 1-sec for higher WM loads. These findings extend previous work by delay, a target face appeared, and participants had to judge showing that P300 modulation by WM load also occurs for faces. whether this face was part of the previous face array. P300 Furthermore, we show, for the first time, that WM load affects the amplitude decreased as WM load increased, and this P300 sup- N250r and the early visual N170 component. This suggests that pression was observed at both encoding and retrieval.
    [Show full text]
  • Psychophysiological Processing of Emotionaland Self-Referential
    Running head: PSYCHOPHYSIOLOGICAL PROCESSING IN SCHIZOPHRENIA 1 Psychophysiological Processing of Emotional and Self-Referential Information in Schizophrenia by Anita M. Calwas A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science With Honors in Brain, Behavior and Cognitive Science from the University of Michigan 2011 Advisors: Dr. Patricia Deldin and Ivy Tso PSYCHOPHYSIOLOGICAL PROCESSING IN SCHIZOPHRENIA 2 Abstract People with schizophrenia have problems with social functioning, and it may be related to deficits in processing social information. This study investigated how people with schizophrenia process eye gaze, a form of self-referential social information, and whether it is related to paranoia symptoms in schizophrenia. Twenty-one participants with schizophrenia and 26 healthy controls were shown facial stimuli that differed on three dimensions: eye gaze direction, head orientation, and emotion. The participants chose whether they thought the person was looking at them or away from them. Their accuracy, response time, and event-related potentials (ERPs) were recorded. Although participants with schizophrenia did not differ from controls in accuracy, they had a longer reaction time compared to controls. N170 amplitudes in schizophrenia participants were comparable to controls’, but were affected by eye gaze direction and facial emotion in an opposite direction than in controls. Patients had an overall reduction in the P300 amplitude compared to controls, and they failed to show enlarged P300 to fearful faces relative to neutral faces as controls did. However, these processes were not significantly correlated with paranoia symptoms. These findings suggest that schizophrenia is characterized by abnormal modulation by emotion and gaze direction in facial structure encoding and reduced mental resources for memory update for salient information when they process self-referential and emotional social information.
    [Show full text]
  • Multiple Mechanisms Link Prestimulus Neural Oscillations to Sensory Responses
    RESEARCH ARTICLE Multiple mechanisms link prestimulus neural oscillations to sensory responses Luca Iemi1,2,3*, Niko A Busch4,5, Annamaria Laudini6, Saskia Haegens1,7, Jason Samaha8, Arno Villringer2,6, Vadim V Nikulin2,3,9,10* 1Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York City, United States; 2Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 3Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russian Federation; 4Institute of Psychology, University of Mu¨ nster, Mu¨ nster, Germany; 5Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Mu¨ nster, Mu¨ nster, Germany; 6Berlin School of Mind and Brain, Humboldt- Universita¨ t zu Berlin, Berlin, Germany; 7Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 8Department of Psychology, University of California, Santa Cruz, Santa Cruz, United States; 9Department of Neurology, Charite´-Universita¨ tsmedizin Berlin, Berlin, Germany; 10Bernstein Center for Computational Neuroscience, Berlin, Germany Abstract Spontaneous fluctuations of neural activity may explain why sensory responses vary across repeated presentations of the same physical stimulus. To test this hypothesis, we recorded electroencephalography in humans during stimulation with identical visual stimuli and analyzed how prestimulus neural oscillations modulate different stages of sensory processing reflected by distinct components of the event-related potential (ERP). We found that strong prestimulus alpha- and beta-band power resulted in a suppression of early ERP components (C1 and N150) and in an *For correspondence: amplification of late components (after 0.4 s), even after controlling for fluctuations in 1/f aperiodic [email protected] (LI); signal and sleepiness.
    [Show full text]
  • Working Memory Load for Faces Modulates P300, N170, and N250r
    Working Memory Load for Faces Modulates P300, N170, and N250r Helen M. Morgan, Christoph Klein, Stephan G. Boehm, Kimron L. Shapiro, and David E. J. Linden Abstract & We used event-related potential (ERP) methodology to ex- was also found to modulate other ERPs. The amplitude of the amine neural activity associated with visual working memory N170 elicited by the target face decreased with load, and this (WM) for faces. There were two main goals. First, to extend N170 decrease leveled off at load 2, reflecting the behavioral WM previous findings of P300 load modulation to WM for faces. capacity of around two faces. In addition, the N250r, observed as Second, to examine whether N170 and N250r are also influ- an ERP difference for target faces that were present in the encod- enced by WM load. Between one and four unfamiliar faces were ing array relative to target faces that were absent, was also reduced simultaneously presented for memory encoding. After a 1-sec for higher WM loads. These findings extend previous work by delay, a target face appeared, and participants had to judge showing that P300 modulation by WM load also occurs for faces. whether this face was part of the previous face array. P300 Furthermore, we show, for the first time, that WM load affects the amplitude decreased as WM load increased, and this P300 sup- N250r and the early visual N170 component. This suggests that pression was observed at both encoding and retrieval. WM load higher visual areas play an important role in WM for faces. & INTRODUCTION Recent work suggests that visual WM capacity may also Working memory (WM) refers to the system of tempo- depend on the nature of object perception processes.
    [Show full text]
  • P300 Hemispheric Amplitude Asymmetries from a Visual Oddball Task
    Psychophysiology, 32 (1995), 467-475. Cambridge University Press. Printed in the USA. Copyright @ 1995 Society for Psychophysiological Research P300 hemispheric amplitude asymmetries from a visual oddball task JOEL E. ALEXANDER,a BERNICE PORJESZ,b LANCE O. BAUER,c SAMUEL KUPERMAN,d SANDRA MORZORATI,e SEAN J. O'CONNOR,e JOHN ROHRBAUGH,f HENRI BEGLEITER,b ANDJOHN POLICH a a Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA, USA bDepartment of Psychiatry, State University of New York Health Sciences Center, Brooklyn, USA C Department of Psychiatry, University of Connecticut Health Center, Farmington, USA dDepartment of Psychiatry, University of Iowa, Iowa City, USA e Department of Psychiatry, Institute of Psychiatric Research, Indianapolis, IN, USA f Department of Psychiatry, Washington University, St. Louis, MO, USA Abstract The P3(OO)event-related potential (ERP) was elicited in 80 normal, right-handed male subjects using a simple visual discrimination task, with electroencephalographic (EEG) activity recorded at 19electrodes. P3 amplitude was larger over the right than over the left hemisphere electrode sites primarily at anteromediallocations (F3/4, C3/4) for target, novel, and standard stimuli. The NI, P2, and N2 components also demonstrated hemispheric asymme- tries. The strongest P3 hemispheric asymmetries for all stimuli were observed at anterior locations, suggesting a frontal right hemisphere localization for initial stimulus processing, although target stimuli produced larger P3 amplitudes at parietal
    [Show full text]
  • What Are Neural Oscillations?
    02 Brain Neurorehabil. 2021 Mar;14(1):e7 https://doi.org/10.12786/bn.2021.14.e7 pISSN 1976-8753·eISSN 2383-9910 Brain & NeuroRehabilitation Special Review Brain Oscillations and Their Implications for Neurorehabilitation Sungju Jee1,2,3 1Department of Rehabilitation Medicine, College of Medicine, Chungnam National University, Daejeon, Korea 2Daejeon Chungcheong Regional Medical Rehabilitation Center, Chungnam National University Hospital, Daejeon, Korea 3Daejeon Chungcheong Regional Cardiocerebrovascular Center, Chungnam National University Hospital, Daejeon, Korea Received: Oct 6, 2020 Revised: Feb 14, 2021 HIGHLIGHTS Accepted: Mar 5, 2021 • Neural oscillation is rhythmic or repetitive neural activity in the central nervous system. Correspondence to • With brain oscillation, we diagnose, prognosticate and treat the neurological disease. Sungju Jee Department of Rehabilitation Medicine, College of Medicine, Chungnam National University; Daejeon Chungcheong Regional Medical Rehabilitation Center and Daejeon Chungcheong Regional Cardiocerebrovascular Center, Chungnam National University Hospital, 282 Munhwa-ro, Jung-gu, Daejeon 35015, Korea. E-mail: [email protected] Copyright © 2021. Korean Society for Neurorehabilitation i 02 Brain Neurorehabil. 2021 Mar;14(1):e7 https://doi.org/10.12786/bn.2021.14.e7 pISSN 1976-8753·eISSN 2383-9910 Brain & NeuroRehabilitation Special Review Brain Oscillations and Their Implications for Neurorehabilitation Sungju Jee 1,2,3 1Department of Rehabilitation Medicine, College of Medicine, Chungnam National University, Daejeon, Korea 2Daejeon Chungcheong Regional Medical Rehabilitation Center, Chungnam National University Hospital, Daejeon, Korea 3Daejeon Chungcheong Regional Cardiocerebrovascular Center, Chungnam National University Hospital, Daejeon, Korea Received: Oct 6, 2020 Revised: Feb 14, 2021 ABSTRACT Accepted: Mar 5, 2021 Neural oscillation is rhythmic or repetitive neural activities, which can be observed at Correspondence to all levels of the central nervous system (CNS).
    [Show full text]