A MEG analysis of the P300 in visual discrimination tasks.
Electroencephalogr Clin Neurophysiol
; 108(1): 45-56, 1998 Jan.
Article
em En
| MEDLINE
| ID: mdl-9474061
ABSTRACT
Based on recent research that indicated that P300 scalp topography varies as a function of task and/or information to be processed, this study examined scalp-recorded magnetic fields correlated with the P300 by means of whole-head magnetoencephalography. Subjects performed two discrimination tasks, in which targets, defined on either object or spatial characteristics of the same visual stimuli, had to be discriminated. Based on the across-subject root mean square (RMS) functions a sequence of 4 components could be identified in both tasks, N1m, P3m, and two later components, which, based on their estimated neuronal sources, were classified as representing motor processes during and following the manual responses to target stimuli. Reliable between-task differences in source localization were obtained for the P3m component, but not for the other components. Inferior-medial sources were found for the P3m evoked by both spatial and object targets, with these sources being located about 3.5 cm more anterior for object targets. These results suggest that different neuronal sources, possibly located in subcortical regions in the vicinity of the thalamus, contribute to the P3m evoked by target stimuli defined by either object or spatial stimulus characteristics.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Percepção Visual
/
Potenciais Evocados P300
/
Discriminação Psicológica
/
Potenciais Evocados Visuais
Tipo de estudo:
Prognostic_studies
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Electroencephalogr Clin Neurophysiol
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Alemanha