Nonspatial Cueing of Tactile STM Causes Shift of Spatial Attention

Abstract

The focus of attention can be flexibly altered in mnemonic representations of past sensory events. We investigated the neural mechanisms of selection in tactile STM by applying vibrotactile sample stimuli of different intensities to both hands, followed by a symmetrically shaped visual retro-cue. The retro-cue indicated whether the weak or strong sample was relevant for subsequent comparison with a single tactile test stimulus. Locations of tactile stimuli were randomized, and the required response did not depend upon the spatial relation between cued sample and test stimulus. Selection between spatially segregated items in tactile STM was mirrored in lateralized activity following visual retro-cues (N2pc) and influenced encoding of task-irrelevant tactile probe stimuli (N140). Our findings support four major conclusions. First, retrospective selection results in transient shifts of spatial attention. Second, retrospective selection is functionally dissociable from attention-based rehearsal of locations. Third, selection mechanisms are linked across processing stages, as attention shifts in STM influence encoding of sensory signals. Fourth, selection in tactile STM recruits attentional control mechanisms that are, at least partially, supramodal.

Intermodal Attention Shifts in Multimodal Working Memory

“…This shows that attention can modulate the activation of specific representations, even after they have been encoded into visual WM. Analogous attentional modulations have also been found for representations in tactile WM (Katus, Müller, & Eimer, 2015;Katus, Andersen, & Müller, 2012).…”

“…EEG studies have shown that retrocues signaling the locations of task-relevant WM content guide spatial selection within unimodal tactile (Katus, Müller, et al, 2015) or visual WM representations (Myers et al, 2015;Kuo et al, 2012;Griffin & Nobre, 2003). Spatially selective modulations of WM content have not only been observed with spatial retrocues but also after the retrospective cueing of nonspatial stimulus attributes (i.e., stimulus intensity in tactile studies: Katus et al, 2012; color or shape in visual studies: Eimer & Kiss, 2010;Kuo et al, 2009); such effects indicate the selection of feature or object information, which is stored in cortical maps that are organized in a spatially specific manner (somatotopic vs. retinotopic for tactile vs. visual WM). There is also evidence that the retrospective cueing and subsequent attentional selection of object categories in WM leads to goal-dependent adjustments in the activation states of WM representations in distinct category-selective visual brain areas.…”

Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

“…We mimicked the condition of sustained attention to long-lasting sensory input by applying continuous stimuli at a certain frequency [4-7]. In EEG, such frequency-tagged stimuli elicit the steady state evoked potential (SSEP), an oscillatory response of the same frequency as the applied driving stimulus that can easily be analyzed in the frequency domain [8].…”

Shifts of Spatial Attention in Visual and Tactile Working Memory are Controlled by Independent Modality-Specific Mechanisms

“…Electrophysiological studies of WM have provided additional evidence for links between WM maintenance and space-based attentional control processes. Spatial location appears to be represented in an obligatory fashion in visual WM, even when it is task-irrelevant (Foster et al 2017;Kuo et al 2009;Katus, Andersen, Müller 2012).…”