Differential influences of prism adaptation on reflexive and voluntary covert attention

Abstract

Recent research has demonstrated some beneficial effects in patients with neglect using rightward shifting prismatic lenses. Despite a great deal of research exploring this effect, we know very little about the cognitive mechanisms underlying prism adaptation in neglect. We examined the possibility that prism adaptation influences visual attention by having healthy participants complete either a reflexive or a voluntary covert visual attention cuing paradigm before and after adaptation to leftward, rightward, or sham (no shift) prisms. The results for reflexive orienting demonstrated that a subset of participants with large cuing effects before prism adaptation were faster to reorient attention away from an invalid cue on the side of space opposite the prismatic shift post adaptation. For voluntary orienting, left prisms increased the efficiency of voluntary attention in both left and right visual space in participants with a small cuing effect before prism adaptation. In contrast, right prisms decreased the efficiency of voluntary attention in both left and right space for participants with a large cuing effect before prism adaptation. No significant effects were observed in the sham prism groups. These results suggest that prism adaptation may exert a variety of influences on attentional orienting mechanisms.

Modulation of visual attention by prismatic adaptation

“…In normal subjects, rightward PA was shown to modulate differentially endogenous and exogenous generated shifts of attention (Striemer et al, 2006). Following rightward PA, exogenous reorienting of attention from invalid cues was faster for targets on the right side.…”

“…Striemer and colleagues investigated the effects of rightward and leftward PA on reflexive and voluntary reorienting of attention (Striemer et al, 2006). Following rightward PA, a subgroup of subjects, who had large cueing effects before PA, became faster at reorienting reflexively attention from invalid cues on the left to targets on the right side.…”

Studying the neural bases of prism adaptation using fMRI: A technical and design challenge

“…Such efforts could also be informed through research in healthy controls, in whom prism adaptation has been shown to produce changes in spatial cognition that resemble some of those that are shown by neglect patients (Bultitude & Woods, 2010;Loftus, Nicholls, Mattingley, & Bradshaw, 2008;Loftus, Vijayakumar, & Nicholls, 2009;Michel et al, 2003;Michel, Pisella, Prablanc, Rode, & Rossetti, 2007;Nicholls, Kamer, & Loftus, 2008). Mirroring the directionally-selective effects of prism adaptation in neglect patients, changes in spatial cognition in healthy controls almost exclusively follow adaptation to leftward-shifting prisms, although there have been isolated reports of such changes following adaptation to rightwardshifting prisms, too (Berberovic & Mattingley, 2003;Striemer, Sablatnig, & Danckert, 2006).…”

Leftward oculomotor prismatic training induces a rightward bias in normal subjects

“…When prisms are removed, they show a pointing error contralateral to prism deviation (the so-called aftereffect), which disappears after a few trials (Chapman et al 2010;Fortis et al 2011). This effect can be measured through different experimental tasks, such as open loop straight ahead pointing (SSA), visual straight ahead (VSA), line bisection, pre-bisected line length estimation (Colent et al 2000;Berberovic and Mattingley 2003;Girardi et al 2004;Schintu et al 2014), doublestep saccades tasks (Bultitude et al 2013), and computerized reaction-time tests of spatial attention (Striemer et al 2006). When initial prismatic deviation is directed leftwards, it is effective in transitorily inducing neglect-like behaviours in healthy participants (Michel et al 2003;Jacquin-Courtois et al 2013).…”