Neural Reinstatement Tracks Spread of Attention between Object Features in Working Memory

Abstract

Attention can be allocated in working memory (WM) to select and privilege relevant content. It is unclear whether attention selects individual features or whole objects in WM. Here, we used behavioral measures, eye-tracking and EEG to test the hypothesis that attention spreads between an object's features in WM. Twenty-six participants completed a WM task that asked them to recall the angle of one of two oriented, colored bars after a delay while EEG and eye-tracking data were collected. During the delay, an orthogonal “incidental task” cued the color of one item for a match/mismatch judgment. On congruent trials (50%), the cued item was probed for subsequent orientation recall; on incongruent trials (50%), the other memory item was probed. As predicted, selecting the color of an object in WM brought other features of the cued object into an attended state as revealed by EEG decoding, oscillatory α-power, gaze bias, and improved orientation recall performance. Together, the results show that attentional selection spreads between an object's features in WM, consistent with object-based attentional selection. Analyses of neural processing at recall revealed that the selected object was automatically compared with the probe, whether it was the target for recall or not. This provides a potential mechanism for the observed benefits of nonpredictive cueing in WM, where a selected item is prioritized for subsequent decision-making.

Cortico-ocular coupling in the service of episodic memory formation

“…vision, audition) 35 , independent of retinal input and present during full darkness 33 . Similar associations between gaze bias and alpha/beta power modulation have recently been reported in the context of working memory 36,45 . Together with the here reported results, these studies make a strong case that the association between gaze and alpha/beta activity reflects a fundamental functional organization linking visual cortical signals to oculomotor action.…”

“…Complementing such cognitive interpretations, a recent account of alpha/beta activity argues for a view closer to the biological implementation of the association between alpha/beta power modulations and oculomotor action 33 . Building on recent evidence demonstrating this close relationship in a variety of tasks [34][35][36] , the account postulates a fundamental and domain-general functional organization linking visual cortical signals to oculomotor action. The topographic modulation of alpha power (i.e.…”

“…The topographic modulation of alpha power (i.e. power reduction) was associated with consistent eye movements towards the contralateral visual hemifield 36-38 . We here set out to test the link between eye movements and alpha/beta activity in the context of episodic memory formation.…”

“…The topographic modulation of alpha power (i.e. power reduction) was associated with consistent eye movements towards the contralateral visual hemifield [36][37][38] .…”

Microsaccades transiently lateralise EEG alpha activity

“…Modulations in alpha activity have been implicated, for example, in visual anticipation ( Thut et al, 2006 , Worden et al, 2000 ), in visual working memory ( Foster et al, 2016 , Sauseng et al, 2009 , van Ede, 2018 ), and in spontaneous excitability fluctuations in visual brain areas ( Busch et al, 2009 , Romei et al, 2008 , van Dijk et al, 2008 ). Spatial modulations in alpha activity have further been linked to the oculomotor system ( Liu et al, 2022 , Pan et al, 2022 , Popov et al, 2022 , Popov et al, 2021 , Popov and Staudigl, 2022 , Printzlau et al, 2022 ), but studies so far have considered this link predominantly in task periods with clear spatial-attention demands. Here we fill this gap and report how spontaneous microsaccades – made in the absence of incentives to look elsewhere – are associated with transient lateralisation of EEG activity in the alpha frequency band according to microsaccade direction.…”