Selective attention to sound features mediates cross-modal activation of visual cortices

Abstract

Contemporary schemas of brain organization now include multisensory processes both in low-level cortices as well as at early stages of stimulus processing. Evidence has also accumulated showing that unisensory stimulus processing can result in cross-modal effects. For example, task-irrelevant and lateralized sounds can activate visual cortices; a phenomenon referred to as the auditory-evoked contralateral occipital positivity (ACOP). Some claim this is an example of automatic attentional capture in visual cortices. Other results, however, indicate that context may play a determinant role. Here, we investigated whether selective attention to spatial features of sounds is a determining factor in eliciting the ACOP. We recorded high-density auditory evoked potentials (AEPs) while participants selectively attended and discriminated sounds according to four possible stimulus attributes: location, pitch, speaker identity or syllable. Sound acoustics were held constant, and their location was always equiprobable (50% left, 50% right). The only manipulation was to which sound dimension participants attended. We analysed the AEP data from healthy participants within an electrical neuroimaging framework. The presence of sound-elicited activations of visual cortices depended on the to-be-discriminated, goal-based dimension. The ACOP was elicited only when participants were required to discriminate sound location, but not when they attended to any of the non-spatial features. These results provide a further indication that the ACOP is not automatic. Moreover, our findings showcase the interplay between task-relevance and spatial (un)predictability in determining the presence of the cross-modal activation of visual cortices.

Crossmodal spatial distraction across the lifespan

“…Our results also confirmed the capability of our exogenous manipulation since performance in the visual search task was better when the pre-cue was spatially aligned with the target (cued condition) than when it was neutral, which, in turn, elicited better performance than when the pre-cue was spatially misaligned with the target (uncued condition), irrespective of the age of the participants. These findings extend the notion that peripheral cues can "grab" -under the appropriate circumstances -spatial attention resources even under concurrent engagement of voluntary attention (Hillyard et al, 2016;Retsa, et al, 2020;Schreij, Owens, & Theeuwes, 2008; see also Santangelo & Spence, 2008), further clarifying the time course of this effect. Our results revealed a decrease of search performance as a function of decreasing SOA: the shorter the SOA, the harder participants found it to filter out the task-irrelevant auditory exogenous stimulus, irrespectively of the trial type and the participants' age.…”

“…For example, the presentation of a task-irrelevant sound from a particular spatial location may exogenously attract attention to that region of space, thereby: (i) facilitating the processing of relevant visual stimuli appearing in the same area, and also (ii) interfering with the selection of relevant visual stimuli located elsewhere (this phenomenon is known as crossmodal exogenous distraction; see McDonald, Teder-Sälejärvi, Di Russo, & Hillyard, 2003;McDonald & Ward, 2000;Spence & Driver, 2004;Spence & Soto-Faraco, 2020;Störmer, 2019;Van der Stoep, Nijboer, Van der Stigchel, & Spence, 2015). Indeed, even task-irrelevant sounds have been shown to activate the contralateral visual cortex, by eliciting an Auditory-evoked Contralateral Occipital Positivity (ACOP; Retsa, Matusz, Schnupp, & Murray, 2020), in line with the notion that visuospatial exogenous attention is enhanced at the location of the auditory stimulus (Hillyard, Störmer, Feng, Martinez, & McDonald, 2016). A critical factor determining whether exogenous stimuli have facilitatory and/or interfering effects is the temporal interval between the appearance of the task-irrelevant stimulus (i.e., the exogenous "cue"), and the task-relevant target.…”

Towards understanding how we pay attention in naturalistic visual search settings

“…Indeed, goal-based control gauges knowledge to facilitate visual, auditory and multisensory processing (e.g. Summerfield et al, 2008; Iordanescu et al, 2008; Matusz et al, 2016; Retsa et al, 2018, 2020). However, several questions remain.…”