WordNet

used as an intensive especially to indicate something unexpected; "even an idiot knows that"; "declined even to consider the idea"; "I dont have even a dollar!"
become even or more even; "even out the surface" (同)even out
make even or more even (同)even out
equal in degree or extent or amount; or equally matched or balanced; "even amounts of butter and sugar"; "on even terms"; "it was a fifty-fifty (or even) split"; "had a fifty-fifty (or even) chance"; "an even fight" (同)fifty-fifty
occurring at fixed intervals; "a regular beat"; "the even rhythm of his breathing" (同)regular
symmetrically arranged; "even features"; "regular features"; "a regular polygon" (同)regular
to a greater degree or extent; used with comparisons; "looked sick and felt even worse"; "an even (or still) more interesting problem"; "still another problem must be solved"; "a yet sadder tale" (同)yet, still
being level or straight or regular and without variation as e.g. in shape or texture; or being in the same plane or at the same height as something else (i.e. even with); "an even application of varnish"; "an even floor"; "the road was not very even"; "the picture is even with the window"
divisible by two
in spite of; notwithstanding; "even when he is sick, he works"; "even with his head start she caught up with him"
to the full extent; "loyal even unto death"
have or establish a relationship to; "She relates well to her peers"
be in a relationship with; "How are these two observations related?" (同)interrelate
give an account of; "The witness related the events"
a special set of circumstances; "in that event, the first possibility is excluded"; "it may rain in which case the picnic will be canceled" (同)case
a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
something that happens at a given place and time
existing in possibility; "a potential problem"; "possible uses of nuclear power" (同)possible
the inherent capacity for coming into being (同)potentiality, potency
the latter part of the day (the period of decreasing daylight from late afternoon until nightfall); "he enjoyed the evening light across the lake" (同)eve, even, eventide
a later concluding time period; "it was the evening of the Roman Empire"
the early part of night (from dinner until bedtime) spent in a special way; "an evening at the opera"

PrepTutorEJDIC

『平らな』,平たんな / 『同じ高さの』,同一平面の,平行の / (運動・動作・品質などが)『均一の』,規則的な,一様の,むらのない / (数・量などが)『同じの』,等しい,釣り合のとれた互角の / 『偶数の』 / 公平な,公正な(fair) / 平静な,穏やかな,落ち着いた(calm) / 貸借にない,清算済みの / 端数のない,ちょうどの,きっかりの / 《意味を強めて,不審や意外の念を含み》…『でさえも』,までも / 《比較級の前に用いて》『なおいっそう』,さらに(still,yet) / 《形容詞の前または後の用いて》(…と)すら言える;《古》《時を表す副詞の前に用いて》ちょうど / …‘を'平らにする,ならす / …‘を'釣り合わせる,平均させる《+『up』+『名』,+『名』+『up』》 / …‘の'変動をなくする,‘を'安定させる《+『out』+『名』,+『名』+『out』》
夕べ,晩
(…に)〈事件・事情など〉‘を'『物語る』《+『名』+『to』+『名』》 / (…と)…‘を'『関係させる』,結びつける《+『名』+『to(with)』+『名』》 / 〈物・事が〉(…に)関係がある,かかわる《+『to(with)』+『名(wh・節・句)』》 / (…に)〈人が〉なじむ,順応する《+『to』+『名』》
(特に重要な)『でき事』,事件;行事 / (スポーツの)『種目』;勝負,試合 / 《文》成り行き,結果
可能性のある,潜在的な / 可能性,潜在力 / 電位
『夕方』,夕刻,晩(日没から就寝時までの間) / 《文》末期,晩年 / 夜会,夕べ / 夕方の,夕暮れの

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/10/22 13:51:49」(JST)

wiki en

A waveform showing several ERP components, including the N100 and P300. Note that the ERP is plotted with negative voltages upward, a common, but not universal, practice in ERP research

An event-related potential (ERP) is the measured brain response that is the direct result of a specific sensory, cognitive, or motor event.^[1] More formally, it is any stereotyped electrophysiological response to a stimulus. The study of the brain in this way provides a noninvasive means of evaluating brain functioning in patients with cognitive diseases.

ERPs are measured with electroencephalography (EEG). The magnetoencephalography (MEG) equivalent of ERP is the ERF, or event-related field.^[2]

1 History
2 Calculation
3 ERP Components Nomenclature
4 Relative Advantages & Disadvantages
- 4.1 ERP vs Behavioral Measures
- 4.2 ERP vs Other Physiological Measures
  - 4.2.1 Invasiveness
  - 4.2.2 Spatial and Temporal Resolution
- 4.3 Cost
5 Clinical ERP
6 Research ERP
7 ERP Software and Training Resources
8 See also
9 Further reading
10 References

History

With the discovery of the electroencephalogram (EEG) in 1929, Hans Berger revealed that one could measure the electrical activity of the human brain by placing electrodes on the scalp and intensifying the signal. Changes in voltage can then be plotted over a period of time. He observed that the voltages could be influenced by external events that stimulated the senses. The EEG proved to be a useful source in recording brain activity over the ensuing decades. However, it tended to be very difficult to assess the highly specific neural process that are the focus of cognitive neuroscience because using pure EEG data made it difficult to isolate individual neurocognitive processes. Event-related potentials (ERPs) offered a more sophisticated method of extracting more specific sensory, cognitive, and motor events by using simple averaging techniques. In 1935-1936 Pauline and Hallowell Davis recorded the first known ERPs on awake humans and their findings were published a few years later, in 1939. Due to World War II not much research was conducted in the 1940s, but research focusing on sensory issues picked back up again in the 1950s. In 1964, research by Grey Walter and colleagues began the modern era of ERP component discoveries when they reported the first cognitive ERP component, called the contingent negative variation (CNV).^[3] Sutton, Braren, and Zubin (1965) made another advancement with the discovery of the P3 component.^[4] Over the next fifteen years, ERP component research became increasingly popular. The 1980s, with the introduction of inexpensive computers, opened up a new door for cognitive neuroscience research. Currently, ERP is one of the most widely used methods in cognitive neuroscience research to study the physiological correlates of sensory, perceptual and cognitive activity associated with processing information.^[5]

Calculation

ERPs can be reliably measured using electroencephalography (EEG), a procedure that measures electrical activity of the brain over time using electrodes placed on the scalp. The EEG reflects thousands of simultaneously ongoing brain processes. This means that the brain response to a single stimulus or event of interest is not usually visible in the EEG recording of a single trial. To see the brain's response to a stimulus, the experimenter must conduct many trials (100 or more) and average the results together, causing random brain activity to be averaged out and the relevant waveform to remain, called the ERP.^[6]

The random (background) brain activity together with other bio-signals (e.g., EOG, EMG, EKG) and electromagnetic interference (e.g., line noise, fluorescent lamps) constitute the noise contribution to the recorded ERP. This noise obscures the signal of interest, which is the sequence of underlying ERPs under study. From an engineering point of view it is possible to define the signal-to-noise ratio (SNR) of the recorded ERPs. The reason that averaging increases the SNR of the recorded ERPs (making them discernible and allowing for their interpretation) has a simple mathematical explanation provided that some simplifying assumptions are made. These assumptions are:

The signal of interest is made of a sequence of event-locked ERPs with invariable latency and shape
The noise can be approximated by a zero-mean Gaussian random process of variance which is uncorrelated between trials and not time-locked to the event (this assumption can be easily violated, for example in the case of a subject doing little tongue movements while mentally counting the targets in an oddball paradigm).

Having defined , the trial number, and , the time elapsed after the ^th event, each recorded trial can be written as where is the signal and is the noise (Note that, under the assumptions above, the signal does not depend on the specific trial while the noise does).

The average of trials is

.

The expected value of is (as hoped) the signal itself, .

Its variance is

.

For this reason the noise amplitude of the average of trials is times that of a single trial.

Wide amplitude noise (such as eye blinks or movement artifacts) are often several orders of magnitude larger than the underlying ERPs. Therefore, trials containing such artifacts should be removed before averaging. Artifact rejection can be performed manually by visual inspection or using an automated procedure based on predefined fixed thresholds (limiting the maximum EEG amplitude or slope) or on time-varying thresholds derived from the statistics of the set of trials.^[7]

ERP Components Nomenclature

ERP waveforms consist of a series of positive and negative voltage deflections, which are related to a set of underlying components'^[8] '. Though some ERP components are referred to with acronyms (e.g., contingent negative variation - CNV, error-related negativity - ERN, early left anterior negativity - ELAN, closure positive shift - CPS), most components are referred to by a letter (N/P) indicating polarity (negative/positive), followed by a number indicating either the latency in milliseconds or the component's ordinal position in the waveform. For instance, a negative-going peak that is the first substantial peak in the waveform and often occurs about 100 milliseconds after a stimulus is presented is often called the N100 (indicating its latency is 100 ms after the stimulus and that it is negative) or N1 (indicating that it is the first peak and is negative); it is often followed by a positive peak, usually called the P200 or P2. The stated latencies for ERP components are often quite variable. For example, the P300 component may exhibit a peak anywhere between 250ms - 700ms.^[9]

While evoked potentials reflect the processing of the physical stimulus, event-related potentials are caused by the "higher" processes, that might involve memory, expectation, attention, or changes in the mental state, among others.

Relative Advantages & Disadvantages

ERP vs Behavioral Measures

Compared with behavioral procedures, ERPs provide a continuous measure of processing between a stimulus and a response, making it possible to determine which stage(s) are being affected by a specific experimental manipulation. Another advantage over behavioral measures is that they can provide a measure of processing of stimuli even when there is no behavioral change. However, because of the significantly small size of an ERP, it usually takes a large sample size to accurately measure it correctly.^[10]

ERP vs Other Physiological Measures

Invasiveness

Unlike microelectrodes which require an electrode to be inserted into the brain and PET scans that expose humans to radiation, ERPs use EEG, a non-invasive procedure.

Spatial and Temporal Resolution

ERPs provide excellent temporal resolution of 1 ms or better. The spatial resolution of an ERP, however, is currently undefined making it impossible to definitively localize ERPs. This provides the ERP with a major disadvantage over hemodynamic measures (fMRI and PET) which have a spatial resolution in the millimeter range. The fact that ERPs cannot easily be localized makes it extremely difficult to isolate a single ERP component from the overall ERP component.^[11]

Cost

ERP research is much cheaper to do than other imaging techniques such as fMRI and PET. This is because purchasing and maintaining an EEG system is less expensive than the other systems.

Clinical ERP

Physicians and neurologists will sometimes use a flashing visual checkerboard stimulus to test for any damage or trauma in the visual system. In a healthy person, this stimulus will elicit a strong response over the primary visual cortex located in the occipital lobe, in the back of the brain.

ERP component abnormalities in clinical research have been shown in neurological conditions such as:

dementia^[12]
Parkinson's disease^[13]
multiple sclerosis^[14]
head injuries^[15]
stroke^[16]
Obsessive-Compulsive Disorder^[17]

Research ERP

ERPs are used extensively in neuroscience, cognitive psychology, cognitive science, and psycho-physiological research. Experimental psychologists and neuroscientists have discovered many different stimuli that elicit reliable ERPs from participants. The timing of these responses is thought to provide a measure of the timing of the brain's communication or timing of information processing. For example, in the checkerboard paradigm described above, healthy participants' first response of the visual cortex is around 50-70 ms. This would seem to indicate that this is the amount of time it takes for the transduced visual stimulus to reach the cortex after light first enters the eye. Alternatively, the P300 response occurs at around 300ms in the oddball paradigm, for example, regardless of the type of stimulus presented: visual, tactile, auditory, olfactory, gustatory, etc. Because of this general invariance with regard to stimulus type, the P300 component is understood to reflect a higher cognitive response to unexpected and/or cognitively salient stimuli.

Due to the consistency of the P300 response to novel stimuli, a brain-computer interface can be constructed which relies on it. By arranging many signals in a grid, randomly flashing the rows of the grid as in the previous paradigm, and observing the P300 responses of a subject staring at the grid, the subject may communicate which stimulus he is looking at, and thus slowly "type" words.^[18]

Other ERPs used frequently in research, especially neurolinguistics research, include the ELAN, the N400, and the P600/SPS.

ERP Software and Training Resources

EEGLAB Toolbox- A freely available, open source, Matlab toolbox for processing and analyzing EEG data
ERPLAB Toolbox- A freely available, open source, Matlab toolbox for processing and analyzing ERP data
The ERP Boot Camp- A series of training workshops for ERP researchers

References

^ Luck, Steven J. (2005). An Introduction to the Event-Related Potential Technique. The MIT Press. ISBN 0-262-12277-4.
^ Brown, Colin M; Peter Hagoort (1999). "The cognitive neuroscience of language". In Colin M. Brown and Peter Hagoort. The Neurocognition of Language. New York: Oxford University Press. p. 6.
^ Walter, W.G; Cooper, R.; Aldridge, V.J.; McCallum, W.C.; Winter, A.L. (1964). "Contingent Negative Variation: an electric sign of sensorimotor association and expectancy in the human brain". Nature 203 (4943): 380–384.
^ Sutton, S., Braren, M., Zubin, J., & John, E.R. (1965). Evoked-Potential Correlates of Stimulus Uncertainty. Science, 150, 1187-1188
^ Handy, T. C. (2005). Event Related Potentials: A Methods Handbook. Cambridge, MA: Bradford/MIT Press.
^ Coles, Michael G.H.; Michael D. Rugg (1996). "Event-related brain potentials: an introduction". Electrophysiology of Mind. Oxford Scholarship Online Monographs. pp. 1–27. http://l3d.cs.colorado.edu/~ctg/classes/lib/cogsci/Rugg-ColesChp1.pdf.
^ "ERP_REJECT, rejection of outlier trials from ERP studies". Matlab File Exchange. http://www.mathworks.com/matlabcentral/fileexchange/33207. Retrieved December 30, 2011.
^ Luck, S.J., and Kappenman, E.S., ed. (2012). The Oxford Handbook of Event-Related Potential Components. Oxford University Press. pp. 664. ISBN 9780195374148. http://www.oup.com/us/catalog/general/subject/Psychology/CognitivePsychology/?view=usa&ci=9780195374148.
^ For discussion of ERP component naming conventions see Luck, Steven (2005), An Introduction to the Event-Related Potential Technique, MIT Press, pp. 10-11.
^ Luck, Steven (2005). An Introduction to the Event-Related Potential Technique. MIT Press, pp. 21-23.
^ Luck, Steven (2005). An Introduction to the Event-Related Potential Technique. Massachusetts Institute of Technology: MIT Press. pp. 25–26. ISBN 0-262-62196-7.
^ Boutros, N., et al. (1995). Evoked potentials in subjects at risk for Alzheimer's disease. Psychiatry Res, 57, (1), 57-63.
^ Prabhakar, S., Syal, P. and Srivastava, T. (2000). P300 in newly diagnosed nondementing Parkinson's disease: effect of dopaminergic drugs. Neurol India, 48, (3), 239- 242.
^ Boose, M. A. and Cranford, J. L. (1996). Auditory event-related potentials in multiple sclerosis. Am J Otol, 17, (1), 165-170.
^ Duncan, C. C., Kosmidis, M. H. and Mirsky, A. F. (2003). Event-related potential assessment of information processing after closed head injury. Psychophysiology, 40, (1), 45-59.
^ D'Arcy, R. C., et al. (2003). Electrophysiological assessment of language function following stroke. Clin Neurophysiol, 114, (4), 662-672.
^ Hanna, G.L., Carrasco, M., Harbin, S.M., Nienhuis, J.K., LaRosa, C.E., Chen, P., Fitzgerald, K.D., Gehring, W.J. (2012). Error-Related Negativity and Tic History in Pediatric Obsessive-Compulsive Disorder. Child Adolescent Psychiatry, 51, (9), 902-910.
^ Farwell, L.A.; Donchin E. (1988). "Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potentials". Electroencephalogr Clin Neurophysiol. 70 (6): 510–23. doi:10.1016/0013-4694(88)90149-6. PMID 2461285. http://www.ncbi.nlm.nih.gov/pubmed/2461285. Retrieved 5 December 2011.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 神経伝導検査の概要 overview of nerve conduction studies
2. 低酸素性虚血性脳障害：評価および予後 hypoxic ischemic brain injury evaluation and prognosis
3. 小児における夢遊およびその他の錯眠 sleepwalking and other parasomnias in children
4. 乳房肉腫：治療 breast sarcoma treatment
5. 分娩時の妊婦の気道管理 airway management of pregnant women at delivery

English Journal

A novel bioelectronic nose based on brain-machine interface using implanted electrode recording in vivo in olfactory bulb.

Dong Q, Du L, Zhuang L, Li R, Liu Q, Wang P.SourceBiosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, PR China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, PR China.
Biosensors & bioelectronics.Biosens Bioelectron.2013 Nov 15;49:263-9. doi: 10.1016/j.bios.2013.05.035. Epub 2013 May 29.
The mammalian olfactory system has merits of higher sensitivity, selectivity and faster response than current electronic nose system based on chemical sensor array. It is advanced and feasible to detect and discriminate odors by mammalian olfactory system. The purpose of this study is to develop a n
PMID 23774163

Heart cycle-related effects on event-related potentials, spectral power changes, and connectivity patterns in the human ECoG.

Kern M, Aertsen A, Schulze-Bonhage A, Ball T.SourceNeurobiology and Biophysics, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany; Epilepsy Center, University Medical Center Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany.
NeuroImage.Neuroimage.2013 Nov 1;81:178-90. doi: 10.1016/j.neuroimage.2013.05.042. Epub 2013 May 16.
The perception of one's own heartbeat is a fundamental interoceptive process that involves cortical and subcortical structures. Yet, the precise spatiotemporal neuronal activity patterns underlying the cortical information processing have remained largely elusive. Although the high temporal and spat
PMID 23684883

A novel approach to predict subjective pain perception from single-trial laser-evoked potentials.

Huang G, Xiao P, Hung YS, Iannetti GD, Zhang ZG, Hu L.SourceDepartment of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.
NeuroImage.Neuroimage.2013 Nov 1;81:283-93. doi: 10.1016/j.neuroimage.2013.05.017. Epub 2013 May 16.
Pain is a subjective first-person experience, and self-report is the gold standard for pain assessment in clinical practice. However, self-report of pain is not available in some vulnerable populations (e.g., patients with disorders of consciousness), which leads to an inadequate or suboptimal treat
PMID 23684861

Japanese Journal

Brain response to affective pictures in the chimpanzee.

Hirata Satoshi,Matsuda Goh,Ueno Ari,Fukushima Hirokata,Fuwa Koki,Sugama Keiko,Kusunoki Kiyo,Tomonaga Masaki,Hiraki Kazuo,Hasegawa Toshikazu
Scientific reports 3, 2013-02-26
… In the present study, we measured event-related brain potentials in a fully awake adult chimpanzee as she looked at affective and neutral pictures. … The results revealed a differential brain potential appearing 210 ms after presentation of an affective picture, a pattern similar to that in humans. …
NAID 120005242098

O-21 Modulation of somatosensory processing during dual tasks : an event-related potential study(The Proceedings of the 20th Annual Meetings of Japan Society of Exercise and Sports Physiology July 28・29,(Tsukuba))

KIDA Tetsuo,KANEDA Takeshi,NISHIHIRA Yoshiaki
Advances in exercise and sports physiology 18(4), 92, 2013-02-00
NAID 110009592336

P.L. Exercise and event-related potential(The Proceedings of the 20th Annual Meetings of Japan Society of Exercise and Sports Physiology July 28・29,(Tsukuba))