Naslov
Temporal dynamics of visual-evoked neuromagnetic sources: Effects of stimulus parameters and selective attention

Autori
Aine, Cheryl J. ; Supek, Selma ; George, John S.

Izvornik
International journal of neuroscience (0020-7454) 80 (1995); 79-104

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
magnetoencephalography ; selective visual attention ; early attention effects ; V1 ; spatio-temporal source localization ; cortical feedback connections

Sažetak
Results are reviewed from several neuromagnetic studies which characterize the temporal dynamics of neural sources contributing to the visual evoked response and effects of attention on these sources. Different types of pattern-onset stimuli (<2°) were presented sequentially to a number of field locations in the right visual field. Multiple dipole models were applied to a sequence of instantaneous field distributions constructed at 10 ms intervals. Best- fitting source parameters were superimposed on Magnetic Resonance images (MRI) of each subject to identify the anatomical structure(s) giving rise to the surface patterns. At least three sources, presumably corresponding to different visual areas, were routinely identified from 80-150 ms following the onset of visual stimulation. This observation was consistent across subjects and studies. The temporal sequence and strength of activation of these sources, however, were dependent upon the specific stimulus parameters used to evoke the response (e.g., eccentricity) and on the relevance of the stimulus to the subject. In addition, our results provide evidence for the recurrence of activity in striate and extrastriate regions, following the initial cycle of responses.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA