Attentional Sub-processes Research Articles

Efficacy of the Therapeutic Game "Trisquel" in the Treatment of Patients With Substance-Related Disorders Randomized Clinical Study.

Substance-related disorders (SRD) have been consistently associated with alterations both in cognitive and executive functions, which affect to patients’ quality of life. The main objective of this work was to test the beneficial cognitive effects on patients with SRD after the implementation of “Trisquel,” an intervention program in board game format. To check the effectiveness of Trisquel program, a group of people diagnosed with SRD was randomly assigned either to the experimental group or to the control group. The experimental group performed Trisquel structured sessions twice a week during 3 months, while the control group performed routinely conventional therapeutic activities with the same frequency and duration. Neuropsychological tests were done to both groups before and after the intervention. After the 3 months of intervention the experimental group showed the following statistically significant improvements for WAIS-III subtests: number key, symbol search, arithmetic, direct digits, inverse digits, total digits, letters-numbers in the processing speed index and in the working memory index. Regarding STROOP tests, statistically significant progress was observed in the phonetic fluency letter P, phonetic fluency letter M, phonetic fluency letter R subtests, word-reading and word-color subtests. The control group only obtained improvements for WAIS-III subtests of arithmetic, letters-numbers and in the working memory index. The results of this study confirm that “Trisquel” is an effective intervention program for people diagnosed with SRD, getting improvements in processing speed (psychomotor and reading), attentional subprocesses (focused and sustained) and executive functions (updating and inhibition).

Neural evidence for dynamic within-trial changes in allocation of visual attention

ABSTRACT In their article “Progress toward resolving the attentional capture debate”, Luck et al. (2021. Progress toward resolving the attentional capture debate. Visual Cognition, 29(1), 1–21.) aim at reconciling stimulus-driven, goal-driven and signal suppression accounts of visual attention. At the center of their model is a “control state” that determines activations on a priority map and thus under which circumstances a stimulus captures attention or can be suppressed. In this commentary I will outline neural evidence that suggests that various factors simultaneously affect the control state and that speak against a dichotomy of “attentional capture versus suppression.” For example, EEG studies using event-related potentials (ERPs) suggest that attention can be captured without suppression, that suppression can be applied reactively as a response to capture, and suppression can be proactively applied to prevent capture. ERP results furthermore suggest that different degrees of attentional enhancement and suppression are applied to stimuli and that attentional subprocesses are interdependent. This indicates that the priority map can change dynamically within a trial, and behavioral effects may be a snapshot of a specific distribution of resources on the priority map at a particular moment. I suggest that EEG measures can be used to quantify the relative contribution of attentional factors to determine attention deployment under those circumstances.

TVA-based modeling of short-term memory capacity, speed of processing and perceptual threshold in chronic stroke patients undergoing cognitive training: case-control differences, reliability, and associations with cognitive performance.

Attentional deficits following stroke are common and pervasive, and are important predictors for functional recovery. Attentional functions comprise a set of specific cognitive processes allowing to attend, filter and select among a continuous stream of stimuli. These mechanisms are fundamental for more complex cognitive functions such as learning, planning and cognitive control, all crucial for daily functioning. The distributed functional neuroanatomy of these processes is a likely explanation for the high prevalence of attentional impairments following stroke, and underscores the importance of a clinical implementation of computational approaches allowing for sensitive and specific modeling of attentional sub-processes. The Theory of Visual Attention (TVA) offers a theoretical, computational, neuronal and practical framework to assess the efficiency of visual selection performance and parallel processing of multiple objects. Here, in order to assess the sensitivity and reliability of TVA parameters reflecting short-term memory capacity (K), processing speed (C) and perceptual threshold (t0), we used a whole-report paradigm in a cross-sectional case-control comparison and across six repeated assessments over the course of a three-week computerized cognitive training (CCT) intervention in chronic stroke patients (> 6 months since hospital admission, NIHSS ≤ 7 at hospital discharge). Cross-sectional group comparisons documented lower short-term memory capacity, lower processing speed and higher perceptual threshold in patients (n = 70) compared to age-matched healthy controls (n = 140). Further, longitudinal analyses in stroke patients during the course of CCT (n = 54) revealed high reliability of the TVA parameters, and higher processing speed at baseline was associated with larger cognitive improvement after the intervention. The results support the feasibility, reliability and sensitivity of TVA-based assessment of attentional functions in chronic stroke patients.

Attentional Processes in Children With Attentional Problems or Reading Difficulties as Revealed Using Brain Event-Related Potentials and Their Source Localization.

Visual attention-related processes include three functional sub-processes: alerting, orienting, and inhibition. We examined these sub-processes using reaction times, event-related potentials (ERPs), and their neuronal source activations during the Attention Network Test (ANT) in control children, attentional problems (AP) children, and reading difficulties (RD) children. During the ANT, electroencephalography was measured using 128 electrodes on three groups of Finnish sixth-graders aged 12–13 years (control = 77; AP = 15; RD = 23). Participants were asked to detect the direction of a middle target fish within a group of five fish. The target stimulus was either preceded by a cue (center, double, or spatial), or without a cue, to manipulate the alerting and orienting sub-processes of attention. The direction of the target fish was either congruent or incongruent in relation to the flanker fish, thereby manipulating the inhibition sub-processes of attention. Reaction time performance showed no differences between groups in alerting, orienting, and inhibition effects. The group differences in ERPs were only found at the source level. Neuronal source analysis in the AP children revealed a larger alerting effect (double-cued vs. non-cued target stimuli) than control and RD children in the left occipital lobe. Control children showed a smaller orienting effect (spatially cued vs. center-cued target stimuli) in the left occipital lobe than AP and RD children. No group differences were found for the neuronal sources related to the inhibition effect. The neuronal activity differences related to sub-processes of attention in the AP and RD groups suggest different underlying mechanisms for attentional and reading problems.

The spatial orienting of the focus of attention in working memory makes use of inhibition: Evidence by hemispheric asymmetries in posterior alpha oscillations

Retroactive cuing of information after encoding improves working memory performance. However, there is an ongoing debate on the contribution of target enhancement vs. distractor inhibition attentional sub-processes to this behavioral benefit. We investigated the electrophysiological correlates of retroactive attentional orienting by means of oscillatory EEG parameters. In order to disentangle excitatory and inhibitory attentional processes, the to-be-memorized information was presented in a way that posterior hemispheric asymmetries in oscillatory power could be unambiguously linked to lateral target vs. distractor processing. We found an increase of posterior alpha power (8–14 Hz) contralateral to the position of non-cued working memory content and a decrease of alpha power contralateral to cued positions. These effects were insensitive to the number of cued or non-cued items, supporting their relation to the spatial orienting of attention. Importantly, only the alpha power increase contralateral to non-cued positions differed reliably from the asymmetry in a neutral control condition, highlighting the importance of an inhibitory mechanism for the retroactive focusing of attention. Furthermore, the alpha power asymmetries relative to the positions of cued and non-cued items predicted the individual susceptibility to interference by irrelevant information during working memory retrieval. These findings indicate that the retroactive orienting of the focus of attention can bias the mental representations of non-spatial stimulus features stored in working memory and thereby promote a target-oriented retrieval process.

The effect of mild acute psychological stress on attention processing: an ERP study.

We aimed to investigate the effect of mild acute psychological stress on attention processing by adopting a consecutive task paradigm. In each trial, a probe stimulus (left or right arrow) was presented immediately after a mental arithmetic task (psychological stressor). Participants were asked to estimate whether the product of a multiplication term was above 10 or not, either with (stress block) or without (control block) time pressure and social-evaluative threat. When the probe was presented, participants were asked to judge the direction of the arrows. Increased subjective stress and negative affect were found for the stress versus control trials. For the probe task, reaction times were faster in the stress block than in the control block. Event-related potentials locked to the arrows revealed that (a) fronto-central N1 was enhanced in the stress block compared to the control block. This finding might indicate that stress amplified processes of early perception and that vigilance and sensory intake were augmented. (b) fronto-central N2 was enhanced in the stress block compared to the control block. This finding might reflect increased effort to control selective attention in completing the probe task. (c) less positive P3 was evoked in the stress block than in the control block. This finding potentially reflects the fact that fewer attentional resources were engaged in processing the probe, or that the activity associated with the process of response evaluation was decreased. In sum, mild acute psychological stress exerts a dissociable effect on the neural subprocesses of attention.

Individual attentional selection capacities are reflected in interhemispheric connectivity of the parietal cortex

Modelling psychophysical data using the Theory of Visual Attention (TVA) allows for a quantification of attentional sub-processes, such as the resolution of competition amongst multiple stimuli by top-down control signals for target selection (TVA-parameter α). This fMRI study investigated the neural correlates of α by comparing activity differences and changes of effective connectivity between conditions where a target was accompanied by a distractor or by a second target. Twenty-five participants performed a partial report task inside the MRI scanner. The left angular gyrus (ANG), medial frontal, and posterior cingulate cortex showed higher activity when a target was accompanied by a distractor as opposed to a second target. The reverse contrast yielded activation of a bilateral fronto-parietal network, the anterior insula, anterior cingulate cortex, and left inferior occipital gyrus. A psychophysiological interaction analysis revealed that the connectivity between left ANG and the left and right supramarginal gyrus (SMG), left anterior insula, and right putamen was enhanced in the target-distractor condition in participants with worse attentional top-down control. Dynamic causal modelling suggested that the connection from left ANG to right SMG during distractor presence was modulated by α. Our data show that interindividual differences in attentional processing are reflected in changes of effective connectivity without significant differences in activation strength of network nodes.

Unraveling the sub-processes of selective attention: insights from dynamic modeling and continuous behavior.

Selective attention biases information processing toward stimuli that are relevant for achieving our goals. However, the nature of this bias is under debate: Does it solely rely on the amplification of goal-relevant information or is there a need for additional inhibitory processes that selectively suppress currently distracting information? Here, we explored the processes underlying selective attention with a dynamic, modeling-based approach that focuses on the continuous evolution of behavior over time. We present two dynamic neural field models incorporating the diverging theoretical assumptions. Simulations with both models showed that they make similar predictions with regard to response times but differ markedly with regard to their continuous behavior. Human data observed via mouse tracking as a continuous measure of performance revealed evidence for the model solely based on amplification but no indication of persisting selective distracter inhibition.

Lowered performance in working memory and attentional sub‐processes are most prominent in multi‐domain amnestic mild cognitive impairment subtypes

Research suggests that working memory and attention deficits may be present in mild cognitive impairment (MCI). However, the functional status of these domains within revised MCI subtypes remains unclear, particularly because previous studies have examined these cognitive domains with the same tests that were used to classify MCI subtypes. The aim of this study was to examine working memory and attention function in MCI subtypes on a battery of neuropsychological tests that were distinct from those used to classify MCI subtypes A total of 122 adults aged 60-90 years were classified at baseline as amnestic MCI, non-amnestic MCI, and multi-domain amnestic (a-MCI+). The attentional and working memory capacity of participants was examined using a battery of tests distinct from those used to classify MCI at screening. The a-MCI+ group demonstrated the poorest performance on all working memory tasks and specific sub-processes of attention. The non-amnestic MCI group had lowered performance on visual span and complex sustained attention only. There was no evidence of either attentional or working memory impairment in the amnestic MCI participants. When MCI cohorts are assessed on measures distinct from those used at classification, a-MCI+ subjects had the most compromised working memory and attention function. These results support previous findings that suggest a-MCI+ more closely resembles early stage Alzheimer's disease and those with a-MCI+ may be at increased rate of future cognitive decline compared to those with other MCI subtypes.

Dynamic upper and lower visual field preferences within the human dorsal frontoparietal attention network

Both in nonhuman primates and in humans, behavioral differences between the upper and lower visual field have been identified in distinct subprocesses of attention. Advantages of the lower field have been explained by its higher spatial resolution; those of the upper field by its higher efficiency in attentional shifting. The physiological basis of visual field asymmetries within in the frontoparietal attention network (FPN) remains unclear. This study investigates the physiological correlates of upper and lower field preferences within the FPN using event-related functional magnetic resonance imaging. The paradigm separated two attentional subprocesses during a visual search task. Whether in the upper or lower field, the attention of subjects was first directed at stationary locations (spatial orienting) and then shifted between locations to search for a target (visual search) in easy or difficult search displays. Depending on the task phase (spatial orienting vs. easy visual search), upper and lower visual field preferences in the FPN changed. The analysis revealed a lower field preference during stationary spatial orienting and an upper field preference during visual search. We conclude that also higher areas represent upper and lower visual field asymmetries depending on distinct subcomponents of visuospatial attentional processing.

Dynamic Spatial Coding within the Dorsal Frontoparietal Network during a Visual Search Task

To what extent are the left and right visual hemifields spatially coded in the dorsal frontoparietal attention network? In many experiments with neglect patients, the left hemisphere shows a contralateral hemifield preference, whereas the right hemisphere represents both hemifields. This pattern of spatial coding is often used to explain the right-hemispheric dominance of lesions causing hemispatial neglect. However, pathophysiological mechanisms of hemispatial neglect are controversial because recent experiments on healthy subjects produced conflicting results regarding the spatial coding of visual hemifields. We used an fMRI paradigm that allowed us to distinguish two attentional subprocesses during a visual search task. Either within the left or right hemifield subjects first attended to stationary locations (spatial orienting) and then shifted their attentional focus to search for a target line. Dynamic changes in spatial coding of the left and right hemifields were observed within subregions of the dorsal front-parietal network: During stationary spatial orienting, we found the well-known spatial pattern described above, with a bilateral hemifield representation in the right hemisphere and a contralateral preference in the left hemisphere. However, during search, the right hemisphere had a contralateral preference and the left hemisphere equally represented both hemifields. This finding leads to novel perspectives regarding models of visuospatial attention and hemispatial neglect.

The theory of the whole-brain-work

The theory of the whole-brain-work basically explains the oscillatory dynamics of the human and nonhuman brain during cognitive processing. The theory is based on principles according to which brain functions are represented by the oscillatory activity. Oscillatory activity in a given frequency band performs multiple functions since they vary on a number of response parameters. There is selective cooperation in the stimulated brain; this produces super-binding between neural populations and super-synergy in the whole brain. The concept of super-synergy thus includes super-binding and, additionally, entropy and the role of EEG-oscillations as control parameters in brain's responsiveness. In super-synergy, spatial integration occurs through the selective cooperation of brain structures. Temporal integration occurs in line with the principle of superposition of oscillations in which the comparative polarity and phase angle are critical for forming the function-specific configurations. Extension of the theory of whole-brain-work to cognitive processing proposes that there is a constant reciprocal activation within the subprocesses of attention, perception learning and remembering and this leads to an APLR-alliance. In such a context, all brain functions are inseparable, for instance, from memory function and, in turn, memory states have no exact boundaries along the time space; memory states thus evolve in the APLR-alliance. The theory claims that the reentry and the dynamic behavior of oscillations during the reciprocal activation in APLR-alliance are among the causal factors for brain dynamics and for cognition.

The functional neuroanatomy of visual conjunction search: a parametric fMRI study

Visual conjunction search is proposed to be a multicomponent process which involves scaling and successive shifts of attention in space as well as object identification. Here, we first mapped brain areas sustaining the proposed attentional subprocesses and then tested whether their activity was modulated by search load, i.e., the number of shifts, as predicted by serial search models. Search load was manipulated indirectly by precueing a varying number of locations at which relevant objects were shown. Multiple subregions within the intraparietal sulcus (IPS) and the prefrontal cortex were activated after cueing. Activity in the right posterior IPS was modulated by the distance of attention shifts and in the left posterior IPS by “zooming out” to cover a large region of the visual field. More anterior subregions of the left IPS responded to object identification irrespective of the need for serial scanning. Corresponding regions in the right IPS were modulated parametrically with respect to search load, along with the right temporoparietal junction. These results support a functional segregation of subregions of the IPS. The posterior regions participate in large-scale shifts and scaling of the attentional focus and the anterior regions in object identification and rapid serial shifts during search. The sustained activation in the frontal eye fields after cueing suggests a role in maintaining attention in the periphery. Together with the findings in early visual areas from this experiment (Müller et al., 2003) the current observations are best accounted for by hybrid models of visual conjunction search, where parallel processing in visual and temporoparietal regions and serial scanning controlled by the right IPS cooperate.

Model Similarity Effects on Motor Performance

This experiment extended previous findings on whether model characteristics affect attentional subprocesses and mediate performance changes in an observational learning setting. College women (N = 75) were randomly assigned to groups in a 2 x 2 (Cueing by Model Similarity) factorial design or to a no-model control group. To assess attentional differences, subjects were cued either prior to or subsequent to a demonstration as to model characteristics, and model similarity was manipulated by having subjects view a similar or dissimilar model. All subjects saw the same videotaped demonstration, only their perceptions of model characteristics were manipulated. Subjects performed 20 performance trials in Phase 1 with outcome knowledge of results (KR) and, after a 1-rnin rest period, were given 10 more performance trials without KR in Phase 2. The results from Phase 1 indicated that subjects performed better after watching a model they perceived to be similar than after one they perceived as dissimilar. Phase 2 data indicated that all subjects were performing similarly in terms of outcome scores but that the control group was using a different strategy than the demonstration groups. The investigation found support for performance differences dependent on model characteristics and pointed to the need to examine more than outcome scores when assessing observational learning effects.