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Titolo:
On the processing of spatial frequencies as revealed by evoked-potential sourer modeling
Autore:
Kenemans, JL; Baas, JMP; Mangun, GR; Lijffijt, M; Verbaten, MN;
Indirizzi:
Univ Utrecht, Rudolf Magnus Inst Neurosci, Fac Pharm, Dept Psychopharmacol, NL-3508 TB Utrecht, Netherlands Univ Utrecht Utrecht Netherlands NL-3508 TB 3508 TB Utrecht, Netherlands Duke Univ, Ctr Cognit Neurosci, Durham, NC USA Duke Univ Durham NC USADuke Univ, Ctr Cognit Neurosci, Durham, NC USA
Titolo Testata:
CLINICAL NEUROPHYSIOLOGY
fascicolo: 6, volume: 111, anno: 2000,
pagine: 1113 - 1123
SICI:
1388-2457(200006)111:6<1113:OTPOSF>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
SELECTIVE ATTENTION; CHECKERBOARD ONSET; VISUAL-STIMULI; LOCALIZATION; CHANNELS; NEURONS; IDENTIFICATION; ASYMMETRY; GRATINGS; SYSTEM;
Keywords:
evoked potential; spatial frequency; dipole-source analysis; occipital cortex;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Kenemans, JL Univ Utrecht, Rudolf Magnus Inst Neurosci, Fac Pharm, Dept Psychopharmacol, POB 80082, NL-3508 TB Utrecht, Netherlands Univ Utrecht POB 80082 Utrecht Netherlands NL-3508 TB rlands
Citazione:
J.L. Kenemans et al., "On the processing of spatial frequencies as revealed by evoked-potential sourer modeling", CLIN NEU, 111(6), 2000, pp. 1113-1123

Abstract

Objectives and methods: Visually evoked potentials (VEPs) are known to be sensitive to spatial frequency, especially in the time range between 50 and100 ms post-stimulus. In two experiments we localized the cortical activity elicited by stimuli of varying spatial frequency in scalp-recorded brain potentials, using multi-electrode recordings and dipole-source analysis. Results: Low spatial frequencies (<1 c/d) activated relatively lateral occipital areas, the orientation of the neural ensembles involved being predominantly perpendicular to the scalp surface. In contrast, high spatial frequencies (>4 c/d) induced activation of more medial occipital areas with the predominant orientation of the sources being much more parallel to the scalp surface. Furthermore, at about 100 ms latency the lateral-occipital response to low spatial frequencies was stronger in the right hemisphere; no such asymmetry was found for the responses to the high spatial frequencies. These findings were consistent across varying recording conditions, individual subjects, subject populations, stimulus characteristics (grating orientation, grating vs. checkerboard), and task conditions (active vs. passive). Conclusion: The results indicate that there are differences in sensitivityto specific spatial frequencies between primary and secondary visual areas, as well as between the right and the left hemispheres. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/04/20 alle ore 22:58:59