Naslov
Attentional modulation of the earliest visual neuromagnetic responses

Autori
Sušac, Ana ; Bubić, Andreja ; Josef Golubić, Sanja ; Huonker, Ralph ; Goetz, Theresa ; Haueisen, Jens ; Supek, Selma

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
BIOMAG 2012, Book of Abstracts / Tallon-Baudry, Catherine ; Bertrand, Oliver - Pariz, 2012, 276-277

Skup
18th International Conference on Biomagnetism

Mjesto i datum
Pariz, Francuska, 23.08.2012. - 30.08.2012

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
C1 (earliest visual response); V1 (primary visual cortex); attentional modulation; MEG
(C1 (earliest visual responce); V1 (primary visual cortex); attentional modulation; MEG)

Sažetak
Recent EEG studies have shown attentional effect on the earliest C1 component (50-100 ms). There is, however, only one MEG study that reported very early attentional effects at the cortical level, in the V1, using a distributed source model. In this study, we used multiple current dipoles to model the earliest neuromagnetic responses in attended and non-attended conditions. Two types of top-down cuing were employed: trial-by-trial cuing with unpredictable attended location and sustained cuing with attention to a specific location during the whole block. The evoked visual responses were measured on 14 subjects using Elekta Neuromag 306- channel MEG system at the Biomagnetic Center in Jena. Standard stimulus was a Gabor patch presented in the upper left and lower right parafoveal locations for a duration of 100 ms. Target stimulus (P = 0.2) consisted of the standard Gabor pattern with a ring of reduced luminance. The task of the participants was to respond to targets presented at the cued location. In the control condition, participants had to respond to targets presented at both locations. MEG data were analyzed using the MRIVIEW Calibrated Start Spatio-Temporal (CSST) multi-start inverse procedure for spatio-temporal source localization. Up to three sources were identified during the first 100 ms post-stimulus. Our preliminary results indicated differences in the dynamics of the occipital sources identified for the same stimulus when it was attended and non-attended during 70-100 ms. Both types of cueing caused attentional modulation. The results of our multi-dipole source localization analysis provide new evidence that even the earliest cortical visual neuromagnetic responses are modulated by attention.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Temeljne medicinske znanosti

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