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<meta content="Tandonnet, Christophe" name="eprints.creators_name" />
<meta content="Burle, B." name="eprints.creators_name" />
<meta content="Hasbroucq, T." name="eprints.creators_name" />
<meta content="Vidal, F." name="eprints.creators_name" />
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<meta content="Spatial enhancement of EEG traces by surface Laplacian estimation:
comparison between local and global methods" name="eprints.title" />
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<meta content="ERP; Scalp current density; Current source density; Source derivation; Clinical applications" name="eprints.keywords" />
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<meta content="Abstract
Objective: Surface Laplacian estimation enhances EEG spatial resolution. In this paper, we compare, on empirical grounds, two
computationally different estimations of the surface Laplacian.
Methods: Surface Laplacian was estimated from the same monopolar data set with both Hjorth’s method [local; Electroenceph Clin
Neurophysiol 39 (1975) 526] as modified by MacKay [Electroenceph Clin Neurophysiol 56 (1983) 696] and with spherical spline
interpolation [global; Electroenceph Clin Neurophysiol 72 (1989) 184].
Results: The grand averages computed with the two methods proved to be very similar but differed markedly from the monopolar ones.
The two different computations were highly correlated, presented low relative errors and allowed to evidence comparable experimental
effects.
Conclusions: These results suggest that Hjorth’s method and spherical spline interpolation convey similar topographic and chronometric
informations.
Significance: We provide empirical evidence that local and global methods of surface Laplacian estimation are equivalent to improve the
spatial resolution of EEG traces. Global methods allow to explore the scalp topography and local methods allow to spare time in electrode
setting that can be useful for studies on special populations (i.e. children, aged subjects) and for clinical purposes." name="eprints.abstract" />
<meta content="2005" name="eprints.date" />
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<meta content="Clinical Neurophysiology" name="eprints.publication" />
<meta content="116" name="eprints.volume" />
<meta content="18-24" name="eprints.pagerange" />
<meta content="10.1016/j.clinph.2004.07.021" name="eprints.id_number" />
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<meta content="1388-2457" name="eprints.issn" />
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<meta content="References
Babiloni F, Cincotti F, Carducci F, Rossini PM, Babiloni C. Spatial
enhancement of EEG data by surface Laplacian estimation: the use of
magnetic resonance imaging-based head models. Clin Neurophysiol
2001;112:724–7.
Gevins A, Leong H, Smith ME, Le J, Du R. Mapping cognitive brain
function with modern high-resolution electroencephalography. Trends
Neurosci 1995;18:429–36.
Gratton G, Coles MG, Sirevaag EJ, Eriksen CW, Donchin E. Pre- and
poststimulus activation of response channels: a psychophysiological
analysis. J Exp Psychol Hum Percept Perform 1988;14:331–44.
Hasbroucq T, Possamaı¨ C-A, Bonnet M, Vidal F. Effect of the irrelevant
location of the response signal on choice reaction time: an electromyographic
study in humans. Psychophysiology 1999;36:522–6.
He B, Lian J, Li G. High-resolution EEG: a new realistic geometry
spline Laplacian estimation technique. Clin Neurophysiol 2001;112:
845–52.
Hjorth B. An on-line transformation of EEG scalp potentials into orthogonal
source derivations. Electroenceph Clin Neurophysiol 1975;39:526–30.
Homan RW, Herman J, Purdy P. Cerebral location of international 10–20
system electrode placement. Electroenceph Clin Neurophysiol 1987;66:
376–82.
Law SK, Rohrbaugh JW, Adams CM, Eckardt MJ. Improving spatial and
temporal resolution in evoked EEG responses using surface Laplacians.
Electroenceph Clin Neurophysiol 1993;88:309–22.
MacKay DM. On-line source density computation with a minimum of
electrodes. Electroenceph Clin Neurophysiol 1983;56:696–8.
Nunez PL. Electric fields of the brain. New York: Oxford University Press;
1981.
Nunez PL. Neocortical dynamics and human EEG rhythms. New York:
Oxford University Press; 1995.
Nunez PL. Toward a quantitative description of large-scale neocortical
dynamic function and EEG. Behav Brain Sci 2000;23:371–437.
Nunez PL, Silberstein RB, Cadiush PJ, Wijesinghe J, Westdorp AF,
Srinivasan R. A theoretical and experimental study of high resolution
EEG based on surface Laplacians and cortical imaging. Electroenceph
Clin Neurophysiol 1994;90:40–57.
Pernier J, Perrin F, Bertrand O. Scalp current density fields: concept and
properties. Electroenceph Clin Neurophysiol 1988;69:385–9.
Perrin F, Pernier J, Bertrand O, Giard MH, Echallier JF. Mapping of scalp
potentials by surface spline interpolation. Electroenceph Clin Neurophysiol
1987a;66:75–81.
Perrin F, Bertrand O, Pernier J. Scalp Current density mapping: value and
estimation from potential data. IEEE Trans Biomed Eng 1987b;34:
283–8.
Perrin F, Pernier J, Bertrand O, Echallier JF. Spherical splines for scalp
potential and current density mapping. Electroenceph Clin Neurophysiol
1989;72:184–7 (Corrigenda Electroenceph Clin Neurophysiol,
1990 (76) 565–566).
Srebro R. Localization of visually evolved cortical activity in humans.
J Physiol 1985;360:233–46.
Steinmetz H, Fu¨ rst G, Meyer BU. Craniocerebral topography within the
international 10–20 system. Electroenceph Clin Neurophysiol 1989;72:
499–506.
Tandonnet C, Burle B, Vidal F, Hasbroucq T. The influence of time
preparation on motor processes assessed by surface Laplacian
estimation. Clin Neurophysiol 2003;114:2376–84.
Vidal F, Grapperon J, Bonnet M, Hasbroucq T. The nature of unilateral
motor commands in between-hand choice tasks as revealed by surface
Laplacian estimation. Psychophysiology 2003;40:796–805." name="eprints.referencetext" />
<meta content="Tandonnet, Christophe and Burle, B. and Hasbroucq, T. and Vidal, F. (2005) Spatial enhancement of EEG traces by surface Laplacian estimation: comparison between local and global methods. Clinical Neurophysiology, 116 . pp. 18-24. ISSN 1388-2457" name="eprints.citation" />
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comparison between local and global methods" name="DC.title" />
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<meta content="Hasbroucq, T." name="DC.creator" />
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<meta content="Abstract
Objective: Surface Laplacian estimation enhances EEG spatial resolution. In this paper, we compare, on empirical grounds, two
computationally different estimations of the surface Laplacian.
Methods: Surface Laplacian was estimated from the same monopolar data set with both Hjorth’s method [local; Electroenceph Clin
Neurophysiol 39 (1975) 526] as modified by MacKay [Electroenceph Clin Neurophysiol 56 (1983) 696] and with spherical spline
interpolation [global; Electroenceph Clin Neurophysiol 72 (1989) 184].
Results: The grand averages computed with the two methods proved to be very similar but differed markedly from the monopolar ones.
The two different computations were highly correlated, presented low relative errors and allowed to evidence comparable experimental
effects.
Conclusions: These results suggest that Hjorth’s method and spherical spline interpolation convey similar topographic and chronometric
informations.
Significance: We provide empirical evidence that local and global methods of surface Laplacian estimation are equivalent to improve the
spatial resolution of EEG traces. Global methods allow to explore the scalp topography and local methods allow to spare time in electrode
setting that can be useful for studies on special populations (i.e. children, aged subjects) and for clinical purposes." name="DC.description" />
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<h1 class="ep_tm_pagetitle">Spatial enhancement of EEG traces by surface Laplacian estimation: comparison between local and global methods</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Tandonnet, Christophe</span> and <span class="person_name">Burle, B.</span> and <span class="person_name">Hasbroucq, T.</span> and <span class="person_name">Vidal, F.</span> (2005) <xhtml:em>Spatial enhancement of EEG traces by surface Laplacian estimation: comparison between local and global methods.</xhtml:em> Clinical Neurophysiology, 116 . pp. 18-24. ISSN 1388-2457</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2153/1/Tandonnet%2CBurle%2CHasbroucq%2CVidal_Cli.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2153/1/Tandonnet%2CBurle%2CHasbroucq%2CVidal_Cli.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />296Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input accept-charset="utf-8" value="2696" name="docid" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1016/j.clinph.2004.07.021">http://dx.doi.org/10.1016/j.clinph.2004.07.021</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Abstract
Objective: Surface Laplacian estimation enhances EEG spatial resolution. In this paper, we compare, on empirical grounds, two
computationally different estimations of the surface Laplacian.
Methods: Surface Laplacian was estimated from the same monopolar data set with both Hjorth’s method [local; Electroenceph Clin
Neurophysiol 39 (1975) 526] as modified by MacKay [Electroenceph Clin Neurophysiol 56 (1983) 696] and with spherical spline
interpolation [global; Electroenceph Clin Neurophysiol 72 (1989) 184].
Results: The grand averages computed with the two methods proved to be very similar but differed markedly from the monopolar ones.
The two different computations were highly correlated, presented low relative errors and allowed to evidence comparable experimental
effects.
Conclusions: These results suggest that Hjorth’s method and spherical spline interpolation convey similar topographic and chronometric
informations.
Significance: We provide empirical evidence that local and global methods of surface Laplacian estimation are equivalent to improve the
spatial resolution of EEG traces. Global methods allow to explore the scalp topography and local methods allow to spare time in electrode
setting that can be useful for studies on special populations (i.e. children, aged subjects) and for clinical purposes.</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">The definitive version is available at http://www.sciencedirect.com/
</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">ERP; Scalp current density; Current source density; Source derivation; Clinical applications</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/210000.html">210000 Science - General</a><br /><a href="http://eprints.utas.edu.au/view/subjects/380100.html">380000 Behavioural and Cognitive Sciences > 380100 Psychology</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2153</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Scholarly Publications Librarian</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">10 Oct 2007 14:45</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2153;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2153">item control page</a></p>
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