Simple Visual Discrimination Task Research Articles

Obstacle negotiation while dual-tasking in children with Developmental Coordination Disorder (DCD): An augmented-reality approach

BackgroundChildren with Developmental Coordination Disorder (DCD) exhibit deficits in predictive motor control, balance, and aspects of cognitive control, which are important for safely negotiating obstacles while walking. As concurrent performance of cognitive and motor tasks (dual-tasking) may exacerbate these deficits, we examined motor and cognitive dual-tasking differences between children with DCD and their typically developing (TD) peers during obstacle negotiation. Methods34 children aged 6–12 years (16 TD, 18 DCD) walked along a 12 m path, stepping over an obstacle (30 % or 50 % of leg length) at its mid-point. On dual-task trials, participants completed a simple or complex (cognitive) visual discrimination task presented via an augmented reality headset. Proportional dual-task costs (pDTCs) were measured on cognitive and gait outcomes over three phases: pre-obstacle, obstacle step-over, and post-obstacle. ResultsDuring the obstacle step-over phase, both groups increased their leading leg clearance when dual-tasking, while the DCD group had larger pDTC than TD for the high obstacle under simple stimulus conditions (viz simple-high combination). The complex cognitive task produced larger pDTCs than the simple one on leading leg clearance and post-obstacle gait variability. ConclusionsIn general, both DCD and TD groups showed similar pDTCs under complex conditions, while the specific deficit in DCD under the simple-high combination suggests a (default) compensatory strategy during step-over when attention is diverted to a secondary task. Competing cognitive and motor demands during obstacle negotiation present a potential safety risk for children.

Motor-induced oscillations in choice response performance.

Recently, numerous studies have revealed 4-12 Hz fluctuations of behavioral performance in a multitude of tasks. The majority has utilized stimuli near detection threshold and observed related fluctuations in hit-rates, attributing these to perceptual or attentional processes. As neural oscillations in the 8-20 Hz range also feature prominently in cortical motor areas, they might cause fluctuations in the ability to induce responses, independent of attentional capabilities. Additionally, different effectors (e.g., the left versus right hand) might be cyclically prioritized in an alternating fashion, similar to the attentional sampling of distinct locations, objects, or memory templates. Here, we investigated these questions via a behavioral dense-sampling approach. Twenty-six participants performed a simple visual discrimination task using highly salient stimuli. We varied the interval between each motor response and the subsequent target from 330 to 1040 ms, and analyzed performance as a function of this interval. Our data show significant fluctuations of both RTs and sensitivity between 12.5 and 25 Hz, but no evidence for an alternating prioritization of left- versus right-hand responses. While our results suggest an impact of motor-related signals on performance oscillations, they might additionally be influenced by perceptual processes earlier in the processing hierarchy. In summary, we demonstrate that behavioral oscillations generalize to situations involving highly salient stimuli, closer to everyday life. Moreover, our work adds to the literature by showing fluctuations at a high speed, which might be a consequence of both low task difficulty and the involvement of sensorimotor rhythms.

Modulation of Conflict Processing by Reappraisal: An Experimental Investigation.

Negative affect facilitates conflict processing. Here we sought to assess whether symmetrically, its downregulation by means of reappraisal could lower it. To this end, 105 participants performed the confound-minimized Stroop task eliciting negative affect that was followed by a simple reward-related visual discrimination task. Conflict processing was induced with the former task. Half of them (experimental group) were instructed to use this second task to downregulate negative affect arising from the Stroop task. The other half (control group) did not receive these appraisal-related instructions. Group comparisons showed that negative affect and the conflict effect were similar for these two groups. However, when we added and modeled the subjective ratings related to emotion regulation, we found that conflict processing significantly improved for participants who reported using reappraisal spontaneously, and this gain occurred irrespective of negative affect. These results suggest that reappraisal can influence conflict processing but this change does not depend on negative affect.

Evidence of cognitive specialization in an insect: proficiency is maintained across elemental and higher-order visual learning but not between sensory modalities in honey bees.

Individuals differing in their cognitive abilities and foraging strategies may confer a valuable benefit to their social groups as variability may help them to respond flexibly in scenarios with different resource availability. Individual learning proficiency may either be absolute or vary with the complexity or the nature of the problem considered. Determining whether learning ability correlates between tasks of different complexity or between sensory modalities is of high interest for research on brain modularity and task-dependent specialization of neural circuits. The honeybee Apis mellifera constitutes an attractive model to address this question because of its capacity to successfully learn a large range of tasks in various sensory domains. Here, we studied whether the performance of individual bees in a simple visual discrimination task (a discrimination between two visual shapes) is stable over time and correlates with their capacity to solve either a higher-order visual task (a conceptual discrimination based on spatial relationships between objects) or an elemental olfactory task (a discrimination between two odorants). We found that individual learning proficiency within a given task was maintained over time and that some individuals performed consistently better than others within the visual modality, thus showing consistent aptitude across visual tasks of different complexity. By contrast, performance in the elemental visual-learning task did not predict performance in the equivalent elemental olfactory task. Overall, our results suggest the existence of cognitive specialization within the hive, which may contribute to ecological social success.

The Acquisition of Culturally Patterned Attention Styles Under Active Inference.

This paper presents an active inference based simulation study of visual foraging. The goal of the simulation is to show the effect of the acquisition of culturally patterned attention styles on cognitive task performance, under active inference. We show how cultural artefacts like antique vase decorations drive cognitive functions such as perception, action and learning, as well as task performance in a simple visual discrimination task. We thus describe a new active inference based research pipeline that future work may employ to inquire on deep guiding principles determining the manner in which material culture drives human thought, by building and rebuilding our patterns of attention.

Mice with exonic RELN deletion identified from a patient with schizophrenia have impaired visual discrimination learning and reversal learning in touchscreen operant tasks

The Reelin gene (RELN) encodes a large extracellular protein, which has multiple roles in brain development and adult brain function. It activates a series of neuronal signal transduction pathways in the adult brain that function in synaptic plasticity, dendritic morphology, and cognitive function. To further investigate the roles of Reln in brain function, we generated a mouse line using the C57BL/6 J strain with the specific Reln deletion identified from a Japanese patient with schizophrenia (Reln-del mice). These mice exhibited abnormal sociality, but the pathophysiological significance of the Reln deletion for higher brain functions, such as learning and behavioral flexibility remains unclear. In this study, cognitive function in Reln-del mice was assessed using touchscreen-based visual discrimination (VD) and reversal learning (RL) tasks. Reln-del mice showed normal learning in the simple VD task, but the learning was delayed in the complex VD task as compared to their wild-type (WT) littermates. In the RL task, sessions were divided into early perseverative phase (sessions with <50% correct) and later learning phase (sessions with ≥50% correct). Reln-del mice showed normal perseveration but impaired relearning ability in both simple RL and complex RL task as compared to WT mice. These results suggest that Reln-del mice have impaired learning ability, but the behavioral flexibility is unaffected. Overall, the observed behavioral abnormalities in Reln-del mice suggest that this mouse model is a useful preclinical tool for investigating the neurobiological mechanism underlying cognitive impairments in schizophrenia and a therapeutic strategy.

Working memory and visual discrimination distraction tasks improve cold pressor pain tolerance in children.

Distraction is a well-established pain management technique for children experiencing acute pain, although the mechanisms underlying the effectiveness of distraction are not well understood. It has been postulated that engagement of executive functions, such as working memory, may be a critical factor in attenuating pain via distraction. To test this hypothesis, we compared a 1-back task requiring engagement of working memory with a simple visual discrimination task demanding focused attention, but lower cognitive load (0-back). Seventy-nine children (6-12 years old) underwent a baseline cold pressor trial followed by cold pressor trials in which they completed the visual discrimination and 1-back tasks in counterbalanced order. Executive functioning ability was assessed via the Wechsler Intelligence Scale for Children (5th Edition) working memory subscales and by parent report on the Behavior Rating Inventory of Executive Function, Second Edition (BRIEF®2). Children's pain tolerance improved in both the visual discrimination and 1-back conditions though a differential response to the 2 tasks was not observed. Age moderated the relation between executive functioning and response to distraction; older children with better executive functioning skills demonstrated greater improvements in both distraction interventions. Findings demonstrate the benefits of both visual discrimination and working memory distraction tasks for elementary-aged children experiencing acute pain. Further research is required in order to elucidate the role of executive functioning skills and cognitive load in enhancing distraction analgesia in children, with particular focus on determining optimal load and task difficulty in light of emerging executive functioning abilities in this age group. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

What happens to an individual visual working memory representation when it is interrupted?

This study tested the hypothesis that even the simplest cognitive tasks require the storage of information in working memory (WM), distorting any information that was previously stored in WM. Experiment 1 tested this hypothesis by requiring observers to perform a simple letter discrimination task while they were holding a single orientation in WM. We predicted that performing the task on the interposed letter stimulus would cause the orientation memory to become less precise and more categorical compared to when the letter was absent or when it was present but could be ignored. This prediction was confirmed. Experiment 2 tested the modality specificity of this effect by replacing the visual letter discrimination task with an auditory pitch discrimination task. Unlike the interposed visual stimulus, the interposed auditory stimulus produced little or no disruption of WM, consistent with the use of modality-specific representations. Thus, performing a simple visual discrimination task, but not a simple auditory discrimination task, distorts information about a single feature being maintained in visual WM. We suggest that the interposed task eliminates information stored within the focus of attention, leaving behind a WM representation outside the focus of attention that is relatively imprecise and categorical.

Effects of absolute luminance and luminance contrast on visual discrimination in low mesopic environments.

Recent research revealed considerable decline in visual perception under low luminance conditions. However, systematic studies on how visual performance is affected by absolute luminance and luminance contrast under low mesopic conditions (<0.5cd/m2) is lacking. We examined performance in a simple visual discrimination task under low mesopic luminance conditions in three experiments in which we systematically varied base luminance and luminance contrast between stimulus and background. We further manipulated eccentricity of the stimuli because of known rods and cones gradients along the retina. We identified a "deficiency window" for performance as measured by d' when luminance was < 0.06cd/m2 and luminance contrast as measured by the luminance ratio between stimulus and background was below < 1.7. We further calculated performance-based luminance as well as contrast efficiency functions for reaction times (RTs). These power functions demonstrate the contrast asymptote needed to decrease RTs and how such a decrease can be achieved given various combinations of absolute luminance and luminance contrast manipulations. Increased eccentricity resulted in slower RTs indicative of longer scan distances. Our data provide initial insights to performance-based efficiency functions in low mesopic environments that are currently lacking and to the physical mechanisms being utilized for visual perception in these extreme environments.

Visual interference disrupts visual knowledge

Abstract We show that visual interference impairs people’s ability to make use of visual knowledge. These results provide strong evidence that making use of stored visual knowledge—long-term memory of what things look like—depends on perceptual mechanisms. In the first set of studies, we show that presenting visual noise patterns during or after hearing a verbal cue greatly reduces the effectiveness of the cue on a simple visual discrimination task. In the second experiment, participants were tasked with answering questions about visual features of familiar objects, e.g., verifying that tables have flat surfaces. Accuracy in answering visual, but not encyclopedic questions was reduced when viewing colorful noise patterns. This result is most parsimoniously explained by positing that judgments required activation of visual representations that were being interfered with when viewing irrelevant patterns. Although much of our conceptual knowledge may abstract away from perceptual details, knowledge of what things look like appears to be represented in a visual format.

ASSESSMENT OF LEARNING AND MEMORY IN THE CVN MOUSE MODEL OF ALZHEIMER’S DISEASE IN AUTOMATED TOUCH SCREEN CHAMBERS

According to previously published data and internal model validation, the CVN mouse model of AD exhibits cognitive impairments in contextual fear conditioning, Barnes maze and radial arm water maze most prominently at 9–12 months of age. To determine if impaired learning can be detected at an earlier age, we evaluated their cognitive performance by using a touch screen operant platform (Horner et al., 2013), which is similar to computerized CANTAB testing widely used in clinical setting. Cohorts of 4–5-month old male CVN (APPSDI/NOS2 knockout) and associated wild type (WT) mice were obtained from Charles River (Sulzfeld, Germany). Following acclimatization, animals were introduced to a restricted diet throughout the study period. Testing was conducted in Bussey-Saksida mouse touch screen chambers (Campden Instruments, Loughborough, UK). Mice were trained to develop screen-touching behavior using a 5-stage pretraining algorithm. Thereafter, they were tested in their ability to visually discriminate alternative black and white “lines-grid” stimuli on the touch screen. In order to test cognitive flexibility, the task of reversal of the acquired visual discrimination was implemented by switching the contingencies used in the visual discrimination test. During pretraining, CVN mice and WT mice required similar number of sessions to achieve the pretraining criterion. Furthermore, the majority of mice successfully acquired visual discrimination within 20 days, again without significant differences in the number of sessions required to reach the discrimination criterion between CVN and WT mice. We found that CVN mice did not exhibit gross cognitive impairment at 5–6 months of age and could learn a simple visual discrimination task at a rate comparable to that of WT mice. This is in line with the lack of deficits previously reported in other cognitive assays at comparable ages. However, CVN mice did demonstrate a slower rate of reversal learning at these ages. Further exploration of this slowed reversal learning phenotype is planned using this highly translatable touch screen approach in order to identify deficits in other touch screen tasks at an early age, but also at later ages, when the AD-related phenotypes are more prominent in terms of brain pathology and behavioral readouts.

Normal Performance of Fmr1 Mice on a Touchscreen Delayed Nonmatching to Position Working Memory Task.

Fragile X syndrome is a neurodevelopmental disorder characterized by mild-to-severe cognitive deficits. The complete absence of Fmr1 and its protein product in the mouse model of fragile X (Fmr1 KO) provides construct validity. A major conundrum in the field is the remarkably normal performance of Fmr1 mice on cognitive tests in most reports. One explanation may be insufficiently challenging cognitive testing procedures. Here we developed a delayed nonmatching to position touchscreen task to test the hypothesis that paradigms placing demands on working memory would reveal robust and replicable cognitive deficits in the Fmr1 KO mouse. We first tested Fmr1 KO mice (Fmr1) and their wild-type (WT) littermates in a simple visual discrimination task, followed by assessment of reversal learning. We then tested Fmr1 and WT mice in a new touchscreen nonmatch to position task and subsequently challenged their working memory abilities by adding delays, representing a higher cognitive load. The performance by Fmr1 KO mice was equal to WTs on both touchscreen tasks. Last, we replicated previous reports of normal performance by Fmr1 mice on Morris water maze spatial navigation and reversal. These results indicate that, while the Fmr1 mouse model effectively recapitulates many molecular and cellular aspects of fragile X syndrome, the cognitive profile of Fmr1 mice generally does not recapitulate the primary cognitive deficits in the human syndrome, even when diverse and challenging tasks are imposed.

Motion discrimination in dementia with Lewy bodies and Alzheimer disease.

Visual processing abilities of patients with dementia with Lewy bodies (DLB) or Alzheimer disease (AD) dementia were assessed psychophysically using a simple horizontal motion discrimination task that engages the dorsal visual processing stream. Participants included patients with mild dementia with DLB, AD dementia or Parkinson disease (PD) with dementia (PDD), without dementia with PD, and normal controls. Participants indicated the left or right direction of coherently moving dots that were embedded within dynamic visual noise provided by randomly moving dots. The proportion of coherently moving dots was increased or decreased across trials to determine a threshold at which participants could correctly indicate their direction with greater than 80% accuracy. Motion discrimination thresholds of patients with DLB and PDD were comparable and significantly higher (i.e., worse) than those of patients with AD dementia. The thresholds of patients with AD dementia and patients with PD were normal. These results were confirmed in subgroups of patients with DLB/PDD and AD dementia with autopsy-confirmed disease. A motion discrimination threshold greater than 0.23 distinguished between DLB/PDD and AD dementia with 67% sensitivity and 85% specificity. Differential deficits in detecting direction of simple horizontal motion suggest that dorsal processing stream dysfunction is greater in DLB and PDD than in AD dementia. Therefore, impaired performance on simple visual motion discrimination tasks that specifically engage occipitoparietal brain regions suggests the presence of Lewy body pathology.

Sensory gain outperforms efficient readout mechanisms in predicting attention-related improvements in behavior.

Spatial attention has been postulated to facilitate perceptual processing via several different mechanisms. For instance, attention can amplify neural responses in sensory areas (sensory gain), mediate neural variability (noise modulation), or alter the manner in which sensory signals are selectively read out by postsensory decision mechanisms (efficient readout). Even in the context of simple behavioral tasks, it is unclear how well each of these mechanisms can account for the relationship between attention-modulated changes in behavior and neural activity because few studies have systematically mapped changes between stimulus intensity, attentional focus, neural activity, and behavioral performance. Here, we used a combination of psychophysics, event-related potentials (ERPs), and quantitative modeling to explicitly link attention-related changes in perceptual sensitivity with changes in the ERP amplitudes recorded from human observers. Spatial attention led to a multiplicative increase in the amplitude of an early sensory ERP component (the P1, peaking ∼80-130 ms poststimulus) and in the amplitude of the late positive deflection component (peaking ∼230-330 ms poststimulus). A simple model based on signal detection theory demonstrates that these multiplicative gain changes were sufficient to account for attention-related improvements in perceptual sensitivity, without a need to invoke noise modulation. Moreover, combining the observed multiplicative gain with a postsensory readout mechanism resulted in a significantly poorer description of the observed behavioral data. We conclude that, at least in the context of relatively simple visual discrimination tasks, spatial attention modulates perceptual sensitivity primarily by modulating the gain of neural responses during early sensory processing.

Perceptual Learning of Simple Stimuli Modifies Stimulus Representations in Posterior Inferior Temporal Cortex

Practicing simple visual detection and discrimination tasks improves performance, a signature of adult brain plasticity. The neural mechanisms that underlie these changes in performance are still unclear. Previously, we reported that practice in discriminating the orientation of noisy gratings (coarse orientation discrimination) increased the ability of single neurons in the early visual area V4 to discriminate the trained stimuli. Here, we ask whether practice in this task also changes the stimulus tuning properties of later visual cortical areas, despite the use of simple grating stimuli. To identify candidate areas, we used fMRI to map activations to noisy gratings in trained rhesus monkeys, revealing a region in the posterior inferior temporal (PIT) cortex. Subsequent single unit recordings in PIT showed that the degree of orientation selectivity was similar to that of area V4 and that the PIT neurons discriminated the trained orientations better than the untrained orientations. Unlike in previous single unit studies of perceptual learning in early visual cortex, more PIT neurons preferred trained compared with untrained orientations. The effects of training on the responses to the grating stimuli were also present when the animals were performing a difficult orthogonal task in which the grating stimuli were task-irrelevant, suggesting that the training effect does not need attention to be expressed. The PIT neurons could support orientation discrimination at low signal-to-noise levels. These findings suggest that extensive practice in discriminating simple grating stimuli not only affects early visual cortex but also changes the stimulus tuning of a late visual cortical area.

Dynamic functional brain networks involved in simple visual discrimination learning

Visual discrimination tasks have been widely used to evaluate many types of learning and memory processes. However, little is known about the brain regions involved at different stages of visual discrimination learning. We used cytochrome c oxidase histochemistry to evaluate changes in regional brain oxidative metabolism during visual discrimination learning in a water-T maze at different time points during training. As compared with control groups, the results of the present study reveal the gradual activation of cortical (prefrontal and temporal cortices) and subcortical brain regions (including the striatum and the hippocampus) associated to the mastery of a simple visual discrimination task. On the other hand, the brain regions involved and their functional interactions changed progressively over days of training. Regions associated with novelty, emotion, visuo-spatial orientation and motor aspects of the behavioral task seem to be relevant during the earlier phase of training, whereas a brain network comprising the prefrontal cortex was found along the whole learning process. This study highlights the relevance of functional interactions among brain regions to investigate learning and memory processes.

A Strong Interactive Link between Sensory Discriminations and Intelligence

Early psychologists, including Galton, Cattell, and Spearman, proposed that intelligence and simple sensory discriminations are constrained by common neural processes, predicting a close link between them. However, strong supporting evidence for this hypothesis remains elusive. Although people with higher intelligence quotients (IQs) are quicker at processing sensory stimuli, these broadly replicated findings explain a relatively modest proportion of variance in IQ. Processing speed alone is, arguably, a poor match for the information processing demands on the neural system. Our brains operate on overwhelming amounts of information, and thus their efficiency is fundamentally constrained by an ability to suppress irrelevant information. Here, we show that individual variability in a simple visual discrimination task that reflects both processing speed and perceptual suppression strongly correlates with IQ. High-IQ individuals, although quick at perceiving small moving objects, exhibit disproportionately large impairments in perceiving motion as stimulus size increases. These findings link intelligence with low-level sensory suppression of large moving patterns--background-like stimuli that are ecologically less relevant. We conjecture that the ability to suppress irrelevant and rapidly process relevant information fundamentally constrains both sensory discriminations and intelligence, providing an information-processing basis for the observed link.

Spatial probability cuing and right hemisphere damage

In this experiment we studied statistical learning, inter-trial priming, and visual attention. We assessed healthy controls and right brain damaged (RBD) patients with and without neglect, on a simple visual discrimination task designed to measure priming effects and probability learning. All participants showed a preserved priming effect for item color. Contrary to healthy controls and RBD participants without neglect, RBD participants with neglect did not show positional priming and both RBD groups learned the underlying spatial probability distribution of target locations to a lesser degree. To see if the latter deficiency could be improved, we tested a patient with long standing chronic spatial neglect on three separate days and observed improved identification times for left sided, high probability, targets. In summary, we found preservation of priming per se in people with spatial neglect. However, this was only clearly demonstrable for color priming and not for positional priming. Associated with this impairment was a difficulty in learning the overall statistical structure of target locations. In a patient with severe persistent neglect we were able to demonstrate that the deficit in statistical learning was not absolute, as this subject improved his identification times for targets appearing in high probability regions of the test display.

Medial prefrontal lesions in mice impair sustained attention but spare maintenance of information in working memory

Working memory and attention are complex cognitive functions that are disrupted in several neuropsychiatric disorders. Mouse models of such human diseases are commonly subjected to maze-based tests that can neither distinguish between these cognitive functions nor isolate specific aspects of either function. Here, we have adapted a simple visual discrimination task, and by varying only the timing of events within the same task construct, we are able to measure independently the behavioral response to increasing attentional demand and increasing length of time that information must be maintained in working memory. We determined that mPFC lesions in mice impair attention but not working memory maintenance.

The neural substrates of deliberative decision making: contrasting effects of hippocampus lesions on performance and vicarious trial-and-error behavior in a spatial memory task and a visual discrimination task

Vicarious trial-and-errors (VTEs) are back-and-forth movements of the head exhibited by rodents and other animals when faced with a decision. These behaviors have recently been associated with prospective sweeps of hippocampal place cell firing, and thus may reflect a rodent model of deliberative decision-making. The aim of the current study was to test whether the hippocampus is essential for VTEs in a spatial memory task and in a simple visual discrimination (VD) task. We found that lesions of the hippocampus with ibotenic acid produced a significant impairment in the accuracy of choices in a serial spatial reversal (SR) task. In terms of VTEs, whereas sham-lesioned animals engaged in more VTE behavior prior to identifying the location of the reward as opposed to repeated trials after it had been located, the lesioned animals failed to show this difference. In contrast, damage to the hippocampus had no effect on acquisition of a VD or on the VTEs seen in this task. For both lesion and sham-lesion animals, adding an additional choice to the VD increased the number of VTEs and decreased the accuracy of choices. Together, these results suggest that the hippocampus may be specifically involved in VTE behavior during spatial decision making.