Task-specific sensory and motor preparatory activation revealed by contingent magnetic variation

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Details zur Publikation

Autorenliste: Maestu F
Verlag: Elsevier Science B.V., Amsterdam.
Jahr der Veröffentlichung: 2004
Bandnummer: 21
Heftnummer: 1
Erste Seite: 59
Letzte Seite: 68
Seitenumfang: 10
ISSN: 0926-6410
Sprachen: Englisch-Vereinigtes Königreich (EN-GB)


Beschreibung

The present report studied the magnetic counterpart (CMV) of the
auditory contingent negative variation (CNV). The ear where the target
auditory stimulus would be presented was cued with a visual central
arrow at a validity of 84%. The subject's behavioral response and the
magnetoencephalographic (MEG) and electroencephalographic (EEG) signals
were recorded. The central cue diminished reaction times (RTs) to the
auditory target in the valid conditions with respect to the invalid
conditions, indicating that the attentional manipulation was effective.
The averaged magnetic field power during the preparatory period was
significantly higher than baseline, suggesting the simultaneous presence
of a magnetic counterpart of the electric CNV-the CMV The field maps of
the CMV grand averages showed two different and well-established
periods: an early one with a magnetic field distribution that suggests a
central source, and a late one with a field topography comparable to a
low-intensity auditory-evoked field (M I). Single-dipole analysis of the
preparatory phase in the subject's magnetic resonance images (MRI)
demonstrated the presence of dipolar activity in the posterior cingulate
(PCC) and posterior parietal cortices (PPC), superior temporal gyrus
(STG) and motor cortices (MC). The lateralization of this activity
depended on the orientation of the central cue. These results suggest
that the action and perceptual-related areas needed to process the
expected subsequent imperative task are recruited during the preparatory
periods, influencing the behavioral RTs.


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