Fast and slow parietal pathways mediate spatial attention

Abstract

Mechanisms of selective attention are vital for guiding human behavior. The parietal cortex has long been recognized as a neural substrate of spatial attention, but the unique role of distinct parietal subregions has remained unclear. Using single-pulse transcranial magnetic stimulation, we found that the angular gyrus of the right parietal cortex mediates spatial orienting during two distinct time periods after the onset of a behaviorally relevant event. The biphasic involvement of the angular gyrus suggests that both fast and slow visual pathways are necessary for orienting spatial attention.

Dorsal and Ventral Parietal Contributions to Spatial Orienting in the Human Brain

“…However, given the lack of time and event specificity provided by such offline TMS approaches, its impact on other task-associated processes (such as target detection, feature discrimination, or response selection) cannot be ruled out. More specific event-related TMS studies (delivering pulses around the time of target onset) have been applied to dissect out the underlying bases of visual detection or discrimination processes (Rushworth et al, 2001;Grosbras and Paus, 2002;Chambers et al, 2004), but they focused in target onset periods rather than on those specifically underlying cue-induced attentional orienting computations.…”

Parietal Stimulation Decouples Spatial and Feature-Based Attention

“…Our results suggest that the SMG may be an important input region to aIPS. If so, then the critical epoch of spatial selection in the SMG should precede that of the aIPS, which could be tested in future TMS studies using single-pulse (Chambers et al, 2004a) or twin-coil methods (Pascual-Leone and Walsh, 2001;Ellison et al, 2007). Interestingly, stimulation of the pIPS yielded no significant effects on spatial or feature-based selection, suggesting that pIPS is not singularly critical for either process.…”

The contribution of the right supra-marginal gyrus to sequence learning in eye movements

“…The dorsal network is crucial for the retrieval of goal relevant information and for the top-down control of attention (endogenous attention). The ventral network supports attention/memory in the encoding of behaviorally relevant or unexpected stimuli (exogenous attention) (Vandenberghe et al, 1996;Nobre et al, 1997;Corbetta, Kincade, Ollinger, McAvoy & Shulman, 2000;Cabeza, Ciaramelli, Olson & Moscovitch, 2008;Cabeza et al, 2012;Corbetta & Shulman, 2002;Chambers, Stokes & Mattingley, 2004a;Chambers, Payne, Stokes & Mattingley, 2004b;Morris, Chambers & Mattingley, 2007;Singh-Curry & Husain, 2009;Hu et al, 2009). A number of findings suggest that the rSMG does not fall comfortably within either of these functional streams.…”

“…Furthermore, TMS studies, whilst clearly demonstrating involvement of the AG in orienting/switching attention, fail to show any causal involvement of the SMG in attentional control mechanisms (Rushworth et al, 2001;Chambers et al, 2004b). However, the rSMG (Brodmann Area 40) does appear form part of a cortical network that is involved in orienting attention across both space and time (Coull & Nobre, 1998).…”