Differential Contribution of Right and Left Parietal Cortex to the Control of Spatial Attention: A Simultaneous EEG-rTMS Study

Abstract

We have recently shown that interference with repetitive transcranial magnetic stimulation (rTMS) of right posterior intraparietal sulcus (IPS) cortex during the allocation of spatial attention leads to abnormal desynchronization of anticipatory (pretarget) electroencephalographic alpha rhythms (8-12 Hz) in occipital-parietal cortex and the detection of subsequently presented visual targets (Capotosto et al. 2009). Since lesion data suggest that lesions of the right frontoparietal cortices produce more severe and long-lasting deficits of visual spatial attention than lesions of the left hemisphere, here, we used the mentioned rTMS-electroencephalographic procedure to test if the control of anticipatory alpha rhythms by IPS is asymmetrically organized in the 2 hemispheres. Results showed that interference with either left or right IPS during covert spatial attention equally disrupted the normally lateralized anticipatory modulation of occipital visual cortex, with stronger alpha desynchronization contralaterally to the attended visual field. In contrast, only interference with right IPS induced a paradoxical pretarget synchronization of alpha rhythms and bilateral deficits of target identification. These results suggest that the control of spatial topography of anticipatory alpha rhythms in occipital-parietal cortex is shared between left and right IPS cortex, but that right IPS uniquely contributes to a bilateral prestimulus activation of occipital visual cortex.

Magnetic stimulation of visual cortex impairs perceptual learning

“…Moreover, since several previous findings showed a behavioral impairment after IPS stimulation during attention tasks (Capotosto et al, 2009) (Capotosto et al, 2012a) , it is unlike that the present null result for IPS is due to its resiliency to TMS. Furthermore, it can be speculated that the TMS effects on the targeted visual areas should be extended only within the visual network since it exhibits high local efficiency (i.e.…”

“…The parameters are consistent with published safety guidelines for TMS stimulation (Rossi et al, 2009). Of note, previous studies have shown that such stimulation has effect for at least 2 sec, thus affecting target processing (Capotosto et al, 2009) (Capotosto et al, 2012a) (Capotosto et al, 2012b).…”

The hybrid model of attentional control: New insights into hemispheric asymmetries inferred from TMS research

“…As these studies have been reviewed recently (Taylor and Thut, 2012), we will not go into great detail here but will briefly mention the main findings. Most importantly, TMS over both frontal and parietal nodes of the dorsal network has an effect on the EEG responses in the context of attention tasks (Capotosto et al, 2009(Capotosto et al, , 2011(Capotosto et al, , 2012Sauseng et al, 2011;Taylor et al, 2007). Moreover, the typical changes in posterior alpha power that can be observed when attention is shifted towards one hemifield are often attenuated with TMS along with corresponding behavioral changes.…”

Dynamics of Alpha Control: Preparatory Suppression of Posterior Alpha Oscillations by Frontal Modulators Revealed with Combined EEG and Event-related Optical Signal

“…Hemodynamic activity in the Dorsal Attention Network (DAN; Corbetta and Shulman, 2002) is negatively correlated with electroencephalographic (EEG) alpha power (Laufs et al, 2003; Shadaghiani et al, 2010), whereas regions of the default mode network (DMN; Mo et al, 2012; Ben-Simon et al, 2008) and cingulo-opercular network (CON; Dosenbach et al, 2007; Laufs et al, 2003; Shadaghiani et al, 2010, 2012) have shown the opposite relationship. Correspondingly, repetitive transcranial magnetic stimulation (rTMS) of DAN's right inferior parietal sulcus (IPS) or right frontal eye fields (FEF) suppresses both posterior alpha desynchronization and the detection advantages normally accompanying shifts of spatial attention (Capotosto et al, 2012; Hamidi et al, 2009). …”