Causal evidence for the role of the sensory visual cortex in visual short-term memory maintenance.

The role of the sensory visual cortex during visual short-term memory (VSTM) remains controversial. This controversy is possibly due to methodological issues in previous attempts to investigate the effects of transcranial magnetic stimulation (TMS) on VSTM. The aim of this study was to use TMS, while covering previous methodological deficits. Sixty-four young adults were recruited to participate in two experiments (Experiment 1: n = 36; Experiment 2: n = 28) using a VSTM orientation change-detection task under TMS. Monocular vision was ensured using red-blue goggles combined with red-blue stimuli. Double-pulse TMS was delivered at different times (Experiment 1: 0, 200 or 1000 ms; Experiment 2: 200, 1000 ms) during a 2 s maintenance phase, on one side of the occipital hemisphere. In Experiment 2, a sham TMS condition was introduced. Decreased detection sensitivity (d') in the ipsilateral occipital hemisphere to visual hemifield, and in the real TMS (compared with sham TMS) condition indicated inhibitory TMS effects, and thus, a causal involvement of the sensory visual cortex during early (200 ms) and late (1000 ms) maintenance in VSTM. These findings are aligned with sensory recruitment, which proposes that both perceptual and memory processes rely upon the same neural substrates in the sensory visual cortex. The methods used in this study were preregistered and had received in-principle acceptance on 6 June 2022 (Stage 1 protocol can be found in: https://doi.org/10.17605/OSF.IO/EMPDT).

Utilizing Co-Creative Principles to Develop an E-Learning Platform for Interprofessional Training on Tinnitus: The Erasmus+ Project Tin-TRAC.

Tinnitus treatment, diagnosis and management across Europe varies significantly. The lack of national clinical guidelines for tinnitus management in most European countries and the absence of a common language across all disciplines involved is reflected in the diversification of healthcare practices. Interprofessional Training for Tinnitus Researchers and Clinicians (Tin-TRAC) is an Erasmus+ project that aims to develop common educational ground in the form of an e-Learning platform, co-created by patients, researchers and clinicians, which is able to unify tinnitus diagnosis and treatment strategies across Europe. A pan-European thematic educational platform integrating the best practices and latest research achievements with regard to tinnitus diagnosis and management has the potential to act as a facilitator of the reduction of interdisciplinary and interregional practice diversification. A detailed analysis of the educational needs of clinicians and researchers across disciplines will be followed by the co-creative development of the curriculum. Reusable learning objects will incorporate the training contents and will be integrated in an open e-Learning platform. Tin-TRAC envisions that its output will answer the need to create a common language across the clinicians and researchers of different disciplines that are involved in tinnitus management, and reduce patients' prolonged suffering, non-adherence and endless referral trajectories.

Unequal allocation of overt and covert attention in Multiple Object Tracking.

In many real-life contexts, where objects are moving around, we are often required to allocate our attention unequally between targets or regions of different importance. However, typical multiple object tracking (MOT) tasks, primarily investigate equal attention allocation as the likelihood of each target being probed is the same. In two experiments, we investigated whether participants can allocate attention unequally across regions of the visual field, using a MOT task where two regions were probed with either a high and low or with equal priority. Experiment 1 showed that for high-priority regions, accuracy (for direction of heading judgments) improved, and participants had more frequent and longer fixations in that region compared with a low-priority region. Experiment 2 showed that eye movements were functional in that they slightly improved accuracy when participants could freely move their eyes compared with when they had to centrally fixate. Replicating Experiment 1, we found better tracking performance for high compared with low-priority regions, in both the free and fixed viewing conditions, but the benefit was greater for the free viewing condition. Although unequal attention allocation is possible without eye movements, eye movements seem to improve tracking ability, presumably by allowing participants to fixate more in the high-priority region and get a better, foveal view of the objects. These findings can help us better understand how observers in real-life settings (e.g., CCTV monitoring, driving) can use their limited attentional capacity to allocate their attention unequally in a demand-based manner across different tracking regions.

The influence of attentional biases on multiple working memory precision parameters for children and adults.

Working memory (WM) improves dramatically during childhood but what drives this improvement is not well understood. One influential account thus far has proposed a simple increase in storage capacity. However, recent findings have shown that multiple factors, such as differences in the ability to use attention to enhance the maintenance of internal representations, as well as changes in WM precision, also interact in influencing age-related differences in WM capacity. We aimed to examine whether and how the developing ability to orient attention retrospectively to internal representations influences WM precision. To do so, we employed a paradigm that combined the continuous-recall WM task with the partial-cueing report task. Specifically, 7-year-olds and young adults were asked to reproduce the colour of a probe item in a colour wheel. The initial memory array, which included the probe item, could be followed by a spatial cue that directed participants' attention to a location in the memory array (a 'retro-cue'). Results showed that attentional biases engendered by retro-cues facilitated overall precision compared to uncued baseline performance, for both age groups, although to a smaller degree in 7-year-olds compared to adults. Importantly, investigation of modelling parameters suggested that children demonstrate lower representational quality of items in WM but that spatial attentional cues improve overall precision by increasing the probability of target storage, maintenance and recall, and by reducing misbinding errors as well as random guessing, not by changing representational quality. These results add significantly to our knowledge on the relation between retrospective attention and WM development.

Feature binding in short-term memory and long-term learning.

In everyday experience, we encounter visual feature combinations. Some combinations are learned to support object recognition, and some are arbitrary and rapidly changing, so are retained briefly to complete ongoing tasks before being updated or forgotten. However, the boundary conditions between temporary retention of fleeting feature combinations and learning of feature bindings are unclear. Logie, Brockmole, and Vandenbroucke demonstrated that 60 repetitions of the same feature bindings for change detection resulted in no learning, but clear learning occurred with cued recall of the feature names. We extended those studies in two new experiments with the same array of colour-shape-location combinations repeated for 120 trials. In Experiment 1, change detection was well above chance from Trial 1, but improved only after 40 to 60 trials for participants who subsequently reported becoming aware of the repetition, and after 100 to 120 trials for participants reporting no awareness. Performance improved rapidly in Experiment 2 when participants reconstructed the array by selecting individual features from sets of colours, shapes, and locations. All participants subsequently reported becoming aware of the repetition. We conclude that change detection involves a visual cache memory that functions from the first trial, and retains feature bindings only for the duration of a trial. In addition, a weak residual episodic memory trace accumulates slowly across repetitions, eventually resulting in learning. Reconstructing feature combinations generates a much stronger episodic memory trace from trial to trial, and so learning is faster with performance supported both by the limited capacity visual cache and learning of the array.

Learning What to Attend to: From the Lab to the Classroom.

Research in adult cognitive neuroscience addresses the bidirectional relationship between attentional selection and prior knowledge gained from learning and experience. This research area is ready for integration with developmental cognitive neuroscience, in particular with educational neuroscience. We review one aspect of this research area, learning what to attend to, to propose a path of integration from highly controlled experiments based on developmental and adult cognitive theories to inform cognitive interventions for learners across the lifespan. In particular, we review the research program that we have developed over the last few years, describe the constraints that we have faced in integrating adult and developmental paradigms, and delineate suggested next steps to inform educational neuroscience in more applied ways. Our proposed path of integration transitions from basic to applied research, while also suggesting that input from education could inform new basic research avenues that may more likely yield outcomes meaningful for education.

Towards an integrative model of visual short-term memory maintenance: Evidence from the effects of attentional control, load, decay, and their interactions in childhood.

Over the past decades there has been a surge of research aiming to shed light on the nature of capacity limits to visual short-term memory (VSTM). However, an integrative account of this evidence is currently missing. We argue that investigating parameters constraining VSTM in childhood suggests a novel integrative model of VSTM maintenance, and that this in turn informs mechanisms of VSTM maintenance in adulthood. Over 3 experiments with 7-year-olds and young adults (total N=206), we provide evidence for multiple cognitive processes interacting to constrain VSTM performance. While age-related increases in storage capacity are undisputable, we replicate the finding that attentional processes control what information will be encoded and maintained in VSTM in the face of increased competition. Therefore, a central process to the current model is attentional refreshment, a mechanism that it is thought to reactivate and strengthen the signal of the visual representations. Critically, here we also show that attentional influences on VSTM are further constrained by additional factors, traditionally studied to the exclusion of each other, such as memory load and temporal decay. We propose that these processes work synergistically in an elegant manner to capture the adult-end state, whereas their less refined efficiency and modulations in childhood account for the smaller VSTM capacity that 7-year-olds demonstrate compared to older individuals. We conclude that going beyond the investigation of single cognitive mechanisms, to their interactions, holds the promise to understand both developing and fully developed maintenance in VSTM.

Modeling the Effects of Perceptual Load: Saliency, Competitive Interactions, and Top-Down Biases.

A computational model of visual selective attention has been implemented to account for experimental findings on the Perceptual Load Theory (PLT) of attention. The model was designed based on existing neurophysiological findings on attentional processes with the objective to offer an explicit and biologically plausible formulation of PLT. Simulation results verified that the proposed model is capable of capturing the basic pattern of results that support the PLT as well as findings that are considered contradictory to the theory. Importantly, the model is able to reproduce the behavioral results from a dilution experiment, providing thus a way to reconcile PLT with the competing Dilution account. Overall, the model presents a novel account for explaining PLT effects on the basis of the low-level competitive interactions among neurons that represent visual input and the top-down signals that modulate neural activity. The implications of the model concerning the debate on the locus of selective attention as well as the origins of distractor interference in visual displays of varying load are discussed.

ERP markers of target selection discriminate children with high vs. low working memory capacity.

Selective attention enables enhancing a subset out of multiple competing items to maximize the capacity of our limited visual working memory (VWM) system. Multiple behavioral and electrophysiological studies have revealed the cognitive and neural mechanisms supporting adults' selective attention of visual percepts for encoding in VWM. However, research on children is more limited. What are the neural mechanisms involved in children's selection of incoming percepts in service of VWM? Do these differ from the ones subserving adults' selection? Ten-year-olds and adults used a spatial arrow cue to select a colored item for later recognition from an array of four colored items. The temporal dynamics of selection were investigated through EEG signals locked to the onset of the memory array. Both children and adults elicited significantly more negative activity over posterior scalp locations contralateral to the item to-be-selected for encoding (N2pc). However, this activity was elicited later and for longer in children compared to adults. Furthermore, although children as a group did not elicit a significant N2pc during the time-window in which N2pc was elicited in adults, the magnitude of N2pc during the "adult time-window" related to their behavioral performance during the later recognition phase of the task. This in turn highlights how children's neural activity subserving attention during encoding relates to better subsequent VWM performance. Significant differences were observed when children were divided into groups of high vs. low VWM capacity as a function of cueing benefit. Children with large cue benefits in VWM capacity elicited an adult-like contralateral negativity following attentional selection of the to-be-encoded item, whereas children with low VWM capacity did not. These results corroborate the close coupling between selective attention and VWM from childhood and elucidate further the attentional mechanisms constraining VWM performance in children.

The interplay of spatial attentional biases and mental codes in VSTM: Developmentally informed hypotheses.

What cognitive processes influence how well we maintain information in visual short-term memory (VSTM)? We used a developmentally informed design to delve into the interplay of top-down spatial biases with the nature of the internal memory codes, motivated by documented changes for both factors over childhood. Seven-year-olds, 11-year-olds, and adults completed a VSTM task in which they decided whether a probe item had been present in a preceding memory array. Spatial cues guided participants' attention to the likely location of the to-be-probed item during maintenance. We manipulated the memoranda to contain either highly familiar items or unfamiliar abstract shapes. All participants benefited from cues during maintenance, although benefits were smaller for 7-year-olds than for older participants. Critically, attentional benefits interacted with the nature of the memoranda: Better VSTM maintenance was obtained for cued familiar items. Furthermore, attentional benefits for familiar items correlated with validated measures of visual, but not verbal, short-term and working memory span. These data demonstrate that, in addition to the efficiency with which top-down biases operate during maintenance, the available mental codes for to-be-remembered items influence VSTM and differentially so over childhood. Attentional biases during maintenance seem to operate more efficiently on mental representations that are more robust and can be retrieved more easily. More important, this interaction follows a quantitative development. The findings elucidate further the dynamic interplay between attentional control and VSTM across development.

Age group and individual differences in attentional orienting dissociate neural mechanisms of encoding and maintenance in visual STM.

Selective attention biases the encoding and maintenance of representations in visual STM (VSTM). However, precise attentional mechanisms gating encoding and maintenance in VSTM and across development remain less well understood. We recorded EEG while adults and 10-year-olds used cues to guide attention before encoding or while maintaining items in VSTM. Known neural markers of spatial orienting to incoming percepts, that is, Early Directing Attention Negativity, Anterior Directing Attention Negativity, and Late Directing Attention Positivity, were examined in the context of orienting within VSTM. Adults elicited a set of neural markers that were broadly similar in preparation for encoding and during maintenance. In contrast, in children these processes dissociated. Furthermore, in children, individual differences in the amplitude of neural markers of prospective orienting related to individual differences in VSTM capacity, suggesting that children with high capacity are more efficient at selecting information for encoding into VSTM. Finally, retrospective, but not prospective, orienting in both age groups elicited the well-known marker of visual search (N2pc), indicating the recruitment of additional neural circuits when orienting during maintenance. Developmental and individual differences differentiate seemingly similar processes of orienting to perceptually available representations and to representations held in VSTM.

Orienting attention within visual short-term memory: development and mechanisms.

How does developing attentional control operate within visual short-term memory (VSTM)? Seven-year-olds, 11-year-olds, and adults (total n = 205) were asked to report whether probe items were part of preceding visual arrays. In Experiment 1, central or peripheral cues oriented attention to the location of to-be-probed items either prior to encoding or during maintenance. Cues improved memory regardless of their position, but younger children benefited less from cues presented during maintenance, and these benefits related to VSTM span over and above basic memory in uncued trials. In Experiment 2, cues of low validity eliminated benefits, suggesting that even the youngest children use cues voluntarily, rather than automatically. These findings elucidate the close coupling between developing visuospatial attentional control and VSTM.

Memory load modulates graded changes in distracter filtering.

Our ability to maintain small amounts of information in mind is critical for successful performance on a wide range of tasks. However, it remains unclear exactly how this maintenance is achieved. One possibility is that it is brought about using mechanisms that overlap with those used for attentional control. That is, the same mechanisms that we use to regulate and optimize our sensory processing may be recruited when we maintain information in visual short-term memory (VSTM). We aimed to test this hypothesis by exploring how distracter filtering is modified by concurrent VSTM load. We presented participants with sequences of target items, the order and location of which had to be maintained in VSTM. We also presented distracter items alongside the targets, and these distracters were graded such that they could be either very similar or dissimilar to the targets. We analyzed scalp potentials using a novel multiple regression approach, which enabled us to explore the neural mechanisms by which the participants accommodated these variable distracters on a trial-to-trial basis. Critically, the effect of distracter filtering interacted with VSTM load; the same graded changes in perceptual similarity exerted effects of a different magnitude depending upon how many items participants were already maintaining in VSTM. These data provide compelling evidence that maintaining information in VSTM recruits an overlapping set of attentional control mechanisms that are otherwise used for distracter filtering.