A dual mechanism underlying retroactive shifts of auditory spatial attention: dissociating target- and distractor-related modulations of alpha lateralization

Abstract

Attention can be allocated to mental representations to select information from working memory. to date, it remains ambiguous whether such retroactive shifts of attention involve the inhibition of irrelevant information or the prioritization of relevant information. investigating asymmetries in posterior alpha-band oscillations during an auditory retroactive cueing task, we aimed at differentiating those mechanisms. Participants were cued to attend two out of three sounds in an upcoming sound array. importantly, the resulting working memory representation contained one laterally and one centrally presented item. A centrally presented retro-cue then indicated the lateral, the central, or both items as further relevant for the task (comparing the cued item(s) to a memory probe). time-frequency analysis revealed opposing patterns of alpha lateralization depending on target eccentricity: A contralateral decrease in alpha power in target lateral trials indicated the involvement of target prioritization. A contralateral increase in alpha power when the central item remained relevant (distractor lateral trials) suggested the de-prioritization of irrelevant information. no lateralization was observed when both items remained relevant, supporting the notion that auditory alpha lateralization is restricted to situations in which spatial information is task-relevant. Altogether, the data demonstrate that retroactive attentional deployment involves excitatory and inhibitory control mechanisms. In everyday life, we frequently rely on selective attention in order to focus on information that is relevant while ignoring behaviorally irrelevant sensory input. Without such an attentional filter, we would be overwhelmed by the sheer abundance of sensory information. Analogously, selective attention can operate on working memory contents that are no longer physically present in the environment. Such retroactive shifts of attention are critical in order to adapt to changing task demands and allow for an efficient allocation of limited mental storage resources. The deployment of covert spatial attention to one side in mnemonic (or perceptual) space has been linked to spatially-specific modulations of alpha oscillations 1-3. Typically, there is a relative decrease in alpha power over posterior scalp sites contralateral to the attended location, while alpha power increases contralateral to the unattended location. Based on the gating-by-inhibition framework by Jensen and Mazaheri 4 , low alpha power has been proposed to reflect a state of high excitability in the respective neural areas, whereas high alpha power reflects the functional inhibition of task-irrelevant regions. Analogously, two mechanisms could underlie the selection of information from working memory: shifting attention within working memory may either facilitate or strengthen the relevant information, or, on the other hand, the no longer relevant contents may be inhibited and thereby dropped from the focus of attention within working memory. Although many studies investig...

Equivalent current dipole sources of neurofeedback training-induced alpha activity through temporal/spectral analytic techniques

“…In the present study, participants learned to self-regulate alpha activity by shifting internal (mental imagery) and external attention (feedback) during training. Such shift produces comparable signatures of alpha activity modulations [33]. Alpha activity increases reflect internal attention of mental imagery [34].…”

Attentional Modulations of Alpha Power Are Sensitive to the Task-relevance of Auditory Spatial Information

“…Specifically, the difference between contralateral and ipsilateral alpha power at a cluster of posterior electrodes, comprising PO7/8, P7/8, P3/4, and PO3/4, was calculated separately for each condition and each subject. The selection of electrodes was based on previous studies of post-stimulus, posterior alpha lateralization (Klatt, Getzmann, Begau, & Schneider, 2019; Schneider, Göddertz, Haase, Hickey, & Wascher, 2019), except that P5/P6 were not part of the present electrode setup and thus, electrodes P3/4 were included in the electrode cluster instead. Given that post-stimulus alpha power asymmetries have been shown to appear as a relatively long-lasting, sustained effect (Klatt et al, 2018a), the mean contralateral-minus-ipsilateral differences in power were extracted in a broad 400 ms-time window, ranging from 546 to 961 ms following sound array onset 1 .…”

“… 2 Please note that the approach to compute alpha power for the decoding analysis (i.e., Hilbert transform) differs from the methods used for the univariate analyses of alpha power (i.e., Morlet wavelet convolution). For the univariate analyses, we wanted to keep the approach consistent with and comparable to our previous manuscripts (Begau, Klatt, Wascher, Schneider, & Getzmann, 2021; Klatt et al, 2019, 2018a); for the decoding analysis, we adopted the analysis approach from Bae and Luck (2018) and thus, applied a Filter Hilbert transformation. However, conducting the univariate analyses of alpha power using a Hilbert transform approach, essentially reproduces all results.…”

Age influences audiovisual speech processing in multi-talker scenarios – Evidence from cortical oscillations

“…While frontocentral theta represents divided attention, which is necessary for the simultaneous processing of both auditory and visual input, alpha oscillations – especially over parieto-occipital scalp sites – seem to play an important role in selective attention, such as the focusing on relevant and suppression of irrelevant auditory information (Klatt et al, 2020; Schneider et al, 2021; Wöstmann et al, 2016). Specifically, a posterior alpha power increase can be found when irrelevant working memory contents are suppressed (Klatt et al, 2020). Increased probability for alpha oscillations occurring with the presentation of audiovisual stimuli relative to auditory-only stimuli is interpreted as a higher need for focused attention in the maintenance of audiovisual stimuli (Fingelkurts et al, 2007).…”

“…Furthermore, Keller and colleagues (2017) discussed the role of alpha and theta oscillations in multisensory attention. While frontocentral theta represents divided attention, which is necessary for the simultaneous processing of both auditory and visual input, alpha oscillations – especially over parieto-occipital scalp sites – seem to play an important role in selective attention, such as the focusing on relevant and suppression of irrelevant auditory information (Klatt et al, 2020; Schneider et al, 2021; Wöstmann et al, 2016). Specifically, a posterior alpha power increase can be found when irrelevant working memory contents are suppressed (Klatt et al, 2020).…”