Neural Mechanisms for the Benefits of Stimulus-Driven Attention.

Stimulus-driven attention can improve working memory (WM) when drawn to behaviorally relevant information, but the neural mechanisms underlying this effect are unclear. The present study used functional magnetic resonance imaging (fMRI) to test competing hypotheses regarding the nature of the benefits of stimulus-driven attention to WM: that stimulus-driven attention benefits WM directly via salience detection, that stimulus-driven attention benefits WM incidentally via cognitive control mechanisms recruited to reduce interference from salient features, or that both mechanisms are co-involved in enhancing WM for salient information. To test these hypotheses, we observed activation in brain regions associated with cognitive control and salience detection. We found 2 cognitive control regions that were associated with enhanced memory for salient stimuli: a region in the right superior parietal lobule and a region in the right inferior frontal junction. No regions associated with salience detection were found to show this effect. These fMRI results support the hypothesis that benefits to WM from stimulus-driven attention occur primarily as a result of cognitive control and top-down factors rather than pure bottom-up aspects of stimulus-driven attention.

Logged In and Zoned Out.

Laptop computers are widely prevalent in university classrooms. Although laptops are a valuable tool, they offer access to a distracting temptation: the Internet. In the study reported here, we assessed the relationship between classroom performance and actual Internet usage for academic and nonacademic purposes. Students who were enrolled in an introductory psychology course logged into a proxy server that monitored their online activity during class. Past research relied on self-report, but the current methodology objectively measured time, frequency, and browsing history of participants' Internet usage. In addition, we assessed whether intelligence, motivation, and interest in course material could account for the relationship between Internet use and performance. Our results showed that nonacademic Internet use was common among students who brought laptops to class and was inversely related to class performance. This relationship was upheld after we accounted for motivation, interest, and intelligence. Class-related Internet use was not associated with a benefit to classroom performance.

Ventral fronto-parietal contributions to the disruption of visual working memory storage.

The ability to maintain information in visual working memory (VWM) in the presence of ongoing visual input allows for flexible goal-directed behavior. Previous evidence suggests that categorical overlap between visual distractors and the contents of VWM is associated with both the degree to which distractors disrupt VWM performance and activation among fronto-parietal regions of cortex. While within-category distractors have been shown to elicit a greater response in ventral fronto-parietal regions, to date, no study has linked distractor-evoked response of these regions to VWM performance costs. Here we examined the contributions of ventral fronto-parietal cortex to the disruption of VWM storage by manipulating memoranda-distractor similarity. Our results revealed that the degree of activation across cortex was graded in a manner suggesting that similarity between the contents of VWM and visual distractors influenced distractor processing. While abrupt visual onsets failed to engage ventral fronto-parietal regions during VWM maintenance, objects sharing categorical- (Related objects) and feature-overlap (Matched objects) with VWM elicited a significant response in the right TPJ and right AI. Of central relevance, the magnitude of activation in the right AI elicited by both types of distractor objects subsequently predicted costs to binding change detection accuracy. In addition, Related and Matched distractors differentially affected ventral-dorsal connectivity between the right AI and dorsal parietal regions, uniquely contributing to disruption of VWM storage. Together, our current results implicate activation of ventral fronto-parietal cortex in disruption of VWM storage, and disconnection between ventral frontal and dorsal parietal cortices as a mechanism to protect the contents of VWM.

The nature of working memory gating in Parkinson's disease: A multi-domain signal detection examination.

Distractions are ubiquitous; our brains are inundated with task-irrelevant information. Thus, to remember successfully, one must actively maintain relevant information and prevent distraction from entering working memory. Researchers suggest the basal ganglia-prefrontal pathways are vital to this process by acting as a working memory gate. Using Parkinson's disease as a model of frontostriatal functioning and with signal detection analyses, the present study aims to better characterize the contribution of frontostriatal pathways of this gating process and to determine how it operates across multiple domains. To achieve this, Parkinson's disease patients and healthy controls completed verbal and spatial working memory tasks consisting of three conditions: low-load without distraction; low-load with distraction; and high-load without distraction. Patients were tested both ON and OFF dopaminergic medication, allowing for assessment of the contribution of dorsal and ventral frontostriatal pathways. The results demonstrate that when medication is withheld, Parkinson's patients have a response bias to answer "NO" across all conditions and domains, supporting our hypothesis that the basal ganglia-prefrontal pathways allow or prevent updates of working memory. Contrastingly, medication status affects d' in the distraction condition but not in the high- or low-load conditions. We attribute this to stimulus valuation processes that were impaired by dopaminergic medication overdosing the ventral pathway. These findings are both consistent with the hypothesis that the working memory gate filters spatial and verbal information before it enters into the working memory system, adding support for the gate being a domain-general mechanism of the central executive.

Restricted and repetitive behaviors in autism spectrum disorders: the relationship of attention and motor deficits.

Restricted and repetitive behaviors (RRBs) are hallmark symptoms of autism spectrum disorders (ASDs); however, it has proven difficult to understand the mechanisms underlying these behaviors. One hypothesis suggests that RRBs are the result of a core deficit in attention. Alternatively, abnormalities of the motor system may constitute the central mechanism underlying RRBs, given motor deficits observed in ASDs. In this experiment, we investigated the etiology of RRBs and the relationship between attention and motor deficits. Movement impairments (a) may be indirectly related to attention deficits, (b) may result from a shared compromised process, or (c) may be independent. Twenty-two adolescents with ASD and 20 typically developing participants performed a spatial attention task. Movement impairments were assessed with a rhythmic tapping task. Attentional orienting and motor control were found to be related and supported the hypothesis that these impairments in ASD arise from a shared process. In contrast, measures of attention switching and motor control were found to be independent. Stereotyped behaviors, as assessed by parental ratings, were related more to the degree of motor impairment than to deficits of attention. These results suggest that both attentional orienting deficits and stereotyped RRBs are related to a compromised motor system.

Executive function in Parkinson's disease: contributions of the dorsal frontostriatal pathways to action and motivation.

Disruption of the dorsal frontostriatal pathways in Parkinson's disease (PD) is associated with impairments in motivation, as well as in executive function. The goal of this study was to investigate whether these impairments are related and, if so, whether the disruption of frontostriatal pathways compromises the ability to process the motivational aspects of feedback in such tasks. In Experiment 1, informative feedback improved the performance of young, healthy participants in a task-switching paradigm. This task-switching paradigm was then used in Experiment 2 to test whether feedback would improve the performance of 17 PD patients and age-matched controls. The PD group benefitted from feedback to the same degree as control participants; however, depression scores on the Beck Depression Inventory were significantly related to feedback usage, especially when response selection demands were high. Regardless of feedback, PD patients were more impaired when response demands were high than in an equally difficult condition with low action demands. These results suggest that response selection is a core impairment of insufficient dopamine to the dorsal frontal striatal pathways.

Gotcha: Working memory prioritization from automatic attentional biases.

Attention is an important resource for prioritizing information in working memory (WM), and it can be deployed both strategically and automatically. Most research investigating the relationship between WM and attention has focused on strategic efforts to deploy attentional resources toward remembering relevant information. However, such voluntary attentional control represents a mere subset of the attentional processes that select information to be encoded and maintained in WM (Theeuwes, Journal of Cognition, 1[1]: 29, 1-15, 2018). Here, we discuss three ways in which information becomes prioritized automatically in WM-physical salience, statistical learning, and reward learning. This review integrates findings from perception and working memory studies to propose a more sophisticated understanding of the relationship between attention and working memory.

Individual differences in attentional control predict working memory capacity in adults who stutter.

PURPOSE: Prior research has suggested that people who stutter exhibit differences in some working memory tasks, particularly when more phonologically complex stimuli are used. This study aimed to further specify working memory differences in adults who stutter by not only accounting for linguistic demands of the stimuli but also individual differences in attentional control and experimental influences, such as concomitant processing requirements. METHOD: This study included 40 adults who stutter and 42 adults who do not stutter who completed the Attention Network Test (ANT; Fan et al., 2002) and three complex span working memory tasks: the Operation Span (OSPAN), Rotation Span, and Symmetry Span (Draheim et al., 2018; Foster et al., 2015; Unsworth et al., 2005, 2009). All complex span tasks were dual-tasks and varied in linguistic content in task stimuli. RESULTS: Working memory capacities demonstrated by adults who stutter paralleled the hierarchy of linguistic content across the three complex span tasks, with statistically significant between-group differences in working memory capacity apparent in the task with the highest linguistic demand (i.e., OSPAN). Individual differences in attentional control in adults who stutter also significantly predicted working memory capacity on the OSPAN. DISCUSSION: Findings from this study extend existing working memory research in stuttering by showing that: (1) significant working memory differences are present between adults who stutter and adults who do not stutter even using relatively simple linguistic stimuli in dual-task working memory conditions; (2) adults who stutter with stronger executive control of attention demonstrate working memory capacity more comparable to adults who do not stutter on the OSPAN compared to adults who stutter with lower executive control of attention.

Control preference persists with age.

The opportunity to exert control in one's environment is desirable, and individuals are willing to seek out control, even at a financial cost. Additionally, control-related activation of reward regions in the brain and the positive affect associated with the opportunity to exert control suggest that control is rewarding. The present study explores whether there are age-related differences in the preference for control. Older and younger adults chose whether to maintain control and play a guessing game themselves or to cede this control to the computer. Maintaining and ceding control were associated with different amounts of monetary reward that could be banked upon a successful guess. This required participants to weigh the value associated with control compared to monetary rewards. We found that older adults preferred control and traded monetary reward for control, similar to younger adults. The results suggest that the preference for exerting control may be preserved across age. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Left TPJ activity in verbal working memory: implications for storage- and sensory-specific models of short term memory.

Patients with damage to the left temporoparietal junction (TPJ) have a low verbal span without concomitant deficits in speech perception. This pattern of cognitive impairment is taken as evidence for a dedicated phonological buffer that plays little role in perception (storage-specific account). In contrast, other research suggests that items are maintained and perceived in the same regions (sensory-specific account). In an fMRI study, we demonstrate that the left TPJ does not respond in a way predicted of a phonological buffer; that is, activity in this region is not sustained during encoding or maintenance. Instead, a region in the superior temporal gyrus that has been associated with both speech perception and production demonstrated the expected profile of a store: it was more active in the verbal condition than the object condition and was active during both encoding and maintenance. These results support the sensory-specific account of short term memory rather than the storage-specific account. Based on the pattern of activity in the left TPJ, we suggest that the impairment of verbal working memory observed in patients with TPJ damage may be due to diminished attentional processes rather than reduced storage capacity.

Is it worth it? The costs and benefits of bringing a laptop to a university class.

Students often bring laptops to university classes, however, they do not limit their laptop use to class-related activity. Off-task laptop use occurs frequently in university classrooms and this use negatively impacts learning. The present study addresses whether potential benefits of class-related laptop use might mitigate the costs of off-task laptop activity. We used tracking software to monitor both class-related and off-task laptop use by undergraduate students enrolled in an introductory psychology course, and we observed how types of laptop use related to course performance. We found a positive correlation between class-related use and exam scores that was driven by viewing lecture slides during class. We also found a negative correlation between off-task laptop use and exam scores, but class-related activities did not predict an increase in off-task use. Thus, for students who constrain their laptop use to class-related activity, the benefits outweigh the costs. While a laptop may be beneficial for some, it is unclear which students are able to constrain themselves to class-related activities and whether the benefits of class-related laptop use obtained by slide viewing could be achieved by other means. Thus, students and educators should carefully consider the costs and benefits of laptop use in the classroom.

Persistent guidance of attention in visual statistical learning.

When repeatedly selected features have predictive value, an observer can learn to prioritize them. However, relatively little is known about the mechanisms underlying this persistent statistical learning. In two experiments, we investigated the boundary conditions of statistical learning. Each task included a training phase where targets appeared more frequently in one of two target colors, followed by a test phase where targets appeared equally in both colors. A posttest survey probed awareness of target color probability differences. Experiment 1 tested whether statistical learning requires the predictive feature to be inherently bound to the target. Participants searched for a horizontal or vertical line among diagonal distractors and reported its length (long or short). In the bound condition, targets and distractors were colored, whereas targets were presented in white font and surrounded by colored boxes in the unbound condition. Experiment 2 tested whether reducing task difficulty by simplifying the judgment (horizontal or vertical) would eliminate statistical learning. The results suggested that statistical learning is robust to manipulations of binding, but is attenuated when task difficulty is reduced. Finally, we found evidence that explicit awareness may contribute to statistical learning, but its effects are small and require large sample sizes for adequate detection. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Attention induces surround suppression in visual working memory.

Controversy currently exists regarding whether visual working memory (VWM) maintains sensory or non-sensory representations. Here, we tested the nature of VWM representations by leveraging a perceptual surround suppression effect when an item is attended. Participants performed a delayed-estimation task in which they memorized an array of six colors. A cue indicated which location was most likely probed. In separate experiments, we manipulated external attention (via a precue) or internal attention (via a retrocue). Both types of attention elicited a surround suppression effect, such that memory performance showed a Mexican-hat profile as a function of cue-probe offsets. Given the sensory origin of the surround suppression effect, our results thus provide compelling evidence that VWM maintenance relies on sensory mechanisms.

Shifting set about task switching: behavioral and neural evidence for distinct forms of cognitive flexibility.

Task switching is an important aspect of cognitive control and understanding its underlying mechanisms is the focus of considerable research. In this paper, we contrast two different kinds of task switching paradigms and provide evidence that different cognitive mechanisms underlie switching behavior depending on whether the switch is between sets of rules (rule switch) or sets of features presented simultaneously (perceptual switch). In two experiments, we demonstrate that behavioral effects (Experiment 1) and neural recruitment (Experiment 2) vary with the type of switch performed. While perceptual switch costs occurred when the alternative feature set was physically present, rule switch costs were observed even in their absence. Rule switching was also characterized by larger target repetition effects and by greater engagement of the dorsolateral prefrontal cortex. In contrast, perceptual switching was associated with greater recruitment of the parietal cortex. These results provide strong evidence for multiple forms of switching and suggest the limitations of generalizing results across shift types.

Using FMRI to test models of complex cognition.

This article investigates the potential of fMRI to test assumptions about different components in models of complex cognitive tasks. If the components of a model can be associated with specific brain regions, one can make predictions for the temporal course of the BOLD response in these regions. An event-locked procedure is described for dealing with temporal variability and bringing model runs and individual data trials into alignment. Statistical methods for testing the model are described that deal with the scan-to-scan correlations in the errors of measurement of the BOLD signal. This approach is illustrated using a "sacrificial" ACT-R model that involves mapping 6 modules onto 6 brain regions in an experiment from Ravizza, Anderson, and Carter (in press) concerned with equation solving. The model's visual encoding predicted the BOLD response in the fusiform gyrus, its controlled retrieval predicted the BOLD response in the lateral inferior prefrontal cortex, and its subgoal setting predicted the BOLD response in the anterior cingulate cortex. On the other hand, its motor programming failed to predict anticipatory activation in the motor cortex, its representational changes failed to predicted the pattern of activity in the posterior parietal cortex, and its procedural component failed to predict an initial spike in caudate. The results illustrate the power of such data to direct the development of a theory of complex problem solving, both at the level of a specific task model as well as at the level of the cognitive architecture.

Cerebellar damage produces selective deficits in verbal working memory.

The cerebellum is often active in imaging studies of verbal working memory, consistent with a putative role in articulatory rehearsal. While patients with cerebellar damage occasionally exhibit a mild impairment on standard neuropsychological tests of working memory, these tests are not diagnostic for exploring these processes in detail. The current study was designed to determine whether damage to the cerebellum is associated with impairments on a range of verbal working memory tasks, and if so, under what circumstances. Moreover, we assessed the hypothesis that these impairments are related to impaired rehearsal mechanisms. Patients with damage to the cerebellum (n = 15) exhibited a selective deficit in verbal working memory: spatial forward and backward spans were normal, but forward and backward verbal spans were lower than controls. While the differences were significant, digit spans were relatively preserved, especially in comparison to the dramatic reductions typically observed in classic 'short-term memory' patients with perisylvian brain damage. The patients tended to be more impaired on a verbal version compared to a spatial version of a working memory task with a long delay and this impairment was correlated with overall symptom and dysarthria severity. These results are consistent with a contribution of the cerebellum to rehearsal and suggest that inclusion of a delay before recall is especially detrimental in individuals with cerebellar damage. However, when we examined markers of rehearsal (i.e. word-length and articulatory suppression effects) in an immediate serial recall task, we found that qualitative aspects of the patients' rehearsal strategies were unaffected. We propose that the cerebellum may contribute to verbal working memory during the initial phonological encoding and/or by strengthening memory traces rather than by fundamentally subserving covert articulatory rehearsal.

Is filtering difficulty the basis of attentional deficits in schizophrenia?

The distractibility that schizophrenia patients display may be the result of a deficiency in filtering out irrelevant information. The aim of the current study was to assess whether patients with schizophrenia exhibit greater difficulty when task-irrelevant features change compared to healthy participants. Thirteen medicated outpatients with a diagnosis of schizophrenia and thirteen age- and parental education-matched controls performed a target selection task in which the task-relevant letter or the task-irrelevant features of color, and/or location repeated or switched. Participants were required to respond by pressing the appropriate key associated with the target letter. These patients with schizophrenia were slower when the task-relevant target letter switched than when it repeated. In contrast, schizophrenia patients performed similarly to controls when task-irrelevant information changed. Thus, we found no evidence that patients with schizophrenia were impaired in inhibiting irrelevant perceptual features. In contrast, changes in task-relevant features were problematic for patients relative to control participants. These results suggest that medicated outpatients who are mild to moderately symptomatic do not exhibit global impairments of feature processing. Instead, impairments are restricted to situations when task-relevant features vary. The current findings also suggest that when a course of action is not implied by an irrelevant feature, outpatients' behavior is not modulated by extraneous visual information any more than in healthy controls.

Where to start? Bottom-up attention improves working memory by determining encoding order.

The present study aimed to characterize the mechanism by which working memory is enhanced for items that capture attention because of their novelty or saliency-that is, via bottom-up attention. The first experiment replicated previous research by corroborating that bottom-up attention directed to an item is sufficient for enhancing working memory and, moreover, generalized the effect to the domain of verbal working memory. The subsequent 3 experiments sought to determine how bottom-up attention affects working memory. We considered 2 hypotheses: (1) Bottom-up attention enhances the encoded representation of the stimulus, similar to how voluntary attention functions, or (2) It affects the order of encoding by shifting priority onto the attended stimulus. By manipulating how stimuli were presented (simultaneous/sequential display) and whether the cue predicted the tested items, we found evidence that bottom-up attention improves working memory performance via the order of encoding hypothesis. This finding was observed across change detection and free recall paradigms. In contrast, voluntary attention improved working memory regardless of encoding order and showed greater effects on working memory. We conclude that when multiple information sources compete, bottom-up attention prioritizes the location at which encoding should begin. When encoding order is set, bottom-up attention has little or no benefit to working memory. (PsycINFO Database Record

Right parietal contributions to verbal working memory: spatial or executive?

The left inferior parietal cortex has been claimed to be the site of the verbal short-term store, yet imaging studies report activity of a homologous right-hemisphere region in verbal working memory tasks as well. In spite of its prevalent activity, right parietal contributions to verbal working memory are poorly understood. To clarify its role in verbal working memory performance, we tested a patient with a lesion in the right parietal lobe on verbal and spatial versions of the N-back task. The patient was impaired in all the spatial conditions regardless of load (0-, 1-, and 2-back), whereas in the verbal N-back he was impaired only in the conditions with a memory demand (1- and 2-back). Given that we had presented stimuli at multiple locations in the verbal N-back, however, it remained possible that the lesion impaired spatial representation rather than verbal working memory per se. With central stimulus presentation, his performance dramatically improved indicating that his difficulty with the N-back task was largely due to his poor visuospatial abilities.

Reduced phonological similarity effects in patients with damage to the cerebellum.

Ten cerebellar patients were compared to 10 control subjects on a verbal working memory task in which the phonological similarity of the words to be remembered and their modality of presentation were manipulated. Cerebellar patients demonstrated a reduction of the phonological similarity effect relative to controls. Further, this reduction did not depend systematically upon the presentation modality. These results first document that qualitative differences in verbal working memory may be observed following cerebellar damage, indicating altered cognitive processing, even though behavioral output as measured by the digit span may be within normal limits. However, the results also present problems for the hypothesis that the cerebellar role is specifically associated with articulatory rehearsal as conceptualized in the Baddeley-Hitch model of working memory.