Delayed Matching-to-sample Research Articles

Association between gray matter regional structural-functional connectivity couplings and visual memory in major depressive disorder.

Alterations in structural-functional (SC-FC) coupling have been linked to major depressive disorder (MDD). A newly developed algorithm for regional-specific SC-FC coupling analysis shows potential in advancing psychiatric research. In this study, we calculated the gray matter regional-specific SC-FC coupling of 114 MDD patients and 131 healthy controls (HCs). The delayed matching to sample (DMS) and Pattern Recognition Memory (PRM) subtests of the computerized Cambridge Neurocognitive Test Automated Battery (CANTAB) were used to evaluate visual memory. We found that the Xgboost model exhibited robust discriminative performance (Area under the ROC curve [95% CI]: 0.75 [0.65 to 0.85], Accuracy [95% CI]: 0.73 [0.63 to 0.84], Sensitivity [95% CI]: 0.65 [0.53 to 0.76], Specificity [95% CI]: 0.82 [0.77 to 0.87]). MDD patients showed lower SC-FC coupling in the left inferior frontal orbital gyrus (IFGorb_L) and the right inferior occipital gyrus (IOG_R) and higher SC-FC coupling in the left superior temporal pole (TPOsup_L) and the right middle temporal pole (TPOmid_R) than HCs. SC-FC coupling of IFGorb_L negatively correlated with current duration of illness (r = -0.26, P = 0.007), IOG_R negatively correlated with HAMD-17 cognitive factor score (r = -0.24, P = 0.011), while TPOsup_L positively correlated with percent correct in PRM delayed task among MDD patients (r = 0.31, P = 0.003). In conclusion, the study suggested that altered regional SC-FC coupling may be involved in MDD pathophysiology and associated with visual memory impairment.

Investigating Working Memory Deficits in School-Age Children with Attention-Deficit/Hyperactivity Disorder: An Event-Related Potentials Study During Delayed-Match-to-Sample Task.

To investigate the neural mechanisms underlying working memory (WM) deficits in children with ADHD. WM was compared between thirty-four children with ADHD and thirty-four matched controls using neuropsychological tests, spatial and verbal versions of modified delayed matching-to-sample (DMTS) tasks, and the event-related potential technique. Children with ADHD demonstrated poor behavioral performance, delayed P3 latencies in high-load spatial modified DMTS tasks during encoding, and delayed P2 and N2 latencies during retrieval in spatial modified DMTS tasks. In high-load verbal modified DMTS tasks during encoding, they showed a smaller P3 amplitude. Pronounced deficits in the central executive system in children with ADHD were exhibited by neuropsychological tests and the modified DMTS task. Children with ADHD exhibited a slowing of processing speed during encoding. Under high-load conditions, they showed a reduced P3 amplitude during retrieval, suggesting reduced neural resource allocation was available when the central executive of the working memory was heavily loaded.

Correlative comparison of visual working memory paradigms and associated models

When studying the working memory (WM), the ‘slot model’ and the ‘resource model’ are two main theories used to describe how information retention occurs. The slot model shows that WM capacity consists of a certain number of predefined slots available for information storage. This theory explains that there is a binary condition during information recall in which information is either wholly maintained within a slot or forgotten. The resource model has a resolution-based approach, suggesting a continuous resource able to be distributed among a number of items in WM capacity. Recently hybrid models have been introduced, suggesting that WM may not strictly conform to only one model. Accordingly, to understand the relationship between two of the most widely used paradigms in WM evaluation, we implemented a correlational assessment in two different psychophysics tasks, an analog recall paradigm with sequential bar presentation and a delayed match-to-sample (DMS) task with checkerboard stimuli. Our study revealed significant correlations between WM performance in the DMS task and recall error, precision, and sources of errors in the sequential paradigm. Overall, the findings emphasize the importance of considering both tasks in understanding WM processes, as they shed light on the debate between the slot and resource models by revealing overlapping elements in both theories and the tasks used to evaluate WM capacity.

Enhancing Multiple Object Analysis Skills Across Early and Late Adulthood Through Diverse Tasks

Tasks on multiple targets involve, to some extent, at least two capacity-limited classes of mechanisms: attentional individuation and visuo-spatial working memory (vWM). It is also known that these mechanisms tend to decline with aging. In this study, we hypothesized that if both mechanisms underlie the analysis of multiple objects, then training one task involving multiple objects should benefit other tasks requiring multiple object processing, regardless of task contents or instructions. In addition, we predicted that older adults would benefit more from the training protocol. To test these hypotheses, we trained two groups of young and older participants, one with a delayed match-to-sample (DMTS) task and one with rapid enumeration. Training effects (compared to test/re-test effects of a passive control group) were assessed on both DMTS and rapid enumeration. Results indicated a training-related benefit within and across tasks, regardless of age. Older adults’ gain from training was larger compared to the young counterpart. In addition, and irrespective of age, individual differences in baseline performance correlate with training outcomes, with compensatory activity likely occurring for low-performing individuals.

Cognitive function and skeletal size and mineral density at age 6–7 years: Findings from the Southampton Women's Survey

IntroductionPoor cognitive function and osteoporosis commonly co-exist in later life. In women, this is often attributed to post-menopausal estrogen loss. However, a common early life origin for these conditions and the associations between cognitive function and bone mineral density (BMD) in childhood have not previously been explored. We examined these relationships at age 6–7 years in the Southampton Women's Survey (SWS) mother-offspring cohort. MethodsChild occipitofrontal circumference (OFC), a proxy for brain volume, intelligence quotient (IQ) [Wechsler Abbreviated Scale of Intelligence] and visual recognition and working memory [CANTAB® Delayed Matching to Sample (DMS) and Spatial Span Length (SSP), respectively] were assessed. Whole-body-less-head (WBLH) and lumbar spine dual-energy X-ray absorptiometry [Hologic Discovery] (DXA) were performed to measure bone area (BA), bone mineral content (BMC), BMD and bone mineral apparent density (BMAD). Linear regression was used to examine associations between age and sex standardized variables (β represent standard deviation (SD) difference per SD of cognitive function). ResultsDXA was performed in 1331 children (mean (SD) age 6.8 (0.33) years, 51.5 % male), with OFC, IQ, DMS and SSP assessed in 1250, 551, 490 and 460, respectively. OFC (β = 0.25 SD/SD, 95%CI 0.20,0.30), IQ (β = 0.11 SD/SD, 95%CI 0.02,0.19), and DMS (β = 0.11, SD/SD, 95%CI 0.01,0.20) were positively associated with WBLH BA, with similar associations for lumbar spine BA. OFC and DMS were also positively associated with WBLH BMC, but only OFC was associated with BMD (WBLH: β = 0.38 SD/SD, 95%CI 0.33,0.43; LS: β = 0.19 SD/SD, 95%CI 0.13,0.24). ConclusionChildhood brain volume was positively associated with measures of skeletal size and BMD, whereas IQ and memory were associated only with skeletal size. These findings suggest that common early life determinants for skeletal growth and BMD and cognitive function should be explored to identify potential early-life approaches to preventing osteoporosis and cognitive decline.

Dynamic fading memory and expectancy effects in the monkey primary visual cortex

In order to investigate the involvement of the primary visual cortex (V1) in working memory (WM), parallel, multisite recordings of multi-unit activity were obtained from monkey V1 while the animals performed a delayed match-to-sample (DMS) task. During the delay period, V1 population firing rate vectors maintained a lingering trace of the sample stimulus that could be reactivated by intervening impulse stimuli that enhanced neuronal firing. This fading trace of the sample did not require active engagement of the monkeys in the DMS task and likely reflects the intrinsic dynamics of recurrent cortical networks in lower visual areas. This renders an active, attention-dependent involvement of V1 in the maintenance of WM contents unlikely. By contrast, population responses to the test stimulus depended on the probabilistic contingencies between sample and test stimuli. Responses to tests that matched expectations were reduced which agrees with concepts of predictive coding.

Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall of stimulus features and categories.

Here, we demonstrate the first successful use of static neural stimulation patterns for specific information content. These static patterns were derived by a model that was applied to a subject's own hippocampal spatiotemporal neural codes for memory. We constructed a new model of processes by which the hippocampus encodes specific memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of targeted content into short-term memory. A memory decoding model (MDM) of hippocampal CA3 and CA1 neural firing was computed which derives a stimulation pattern for CA1 and CA3 neurons to be applied during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. MDM electrical stimulation delivered to the CA1 and CA3 locations in the hippocampus during the sample phase of DMS trials facilitated memory of images from the DMS task during a delayed recognition (DR) task that also included control images that were not from the DMS task. Across all subjects, the stimulated trials exhibited significant changes in performance in 22.4% of patient and category combinations. Changes in performance were a combination of both increased memory performance and decreased memory performance, with increases in performance occurring at almost 2 to 1 relative to decreases in performance. Across patients with impaired memory that received bilateral stimulation, significant changes in over 37.9% of patient and category combinations was seen with the changes in memory performance show a ratio of increased to decreased performance of over 4 to 1. Modification of memory performance was dependent on whether memory function was intact or impaired, and if stimulation was applied bilaterally or unilaterally, with nearly all increase in performance seen in subjects with impaired memory receiving bilateral stimulation. These results demonstrate that memory encoding in patients with impaired memory function can be facilitated for specific memory content, which offers a stimulation method for a future implantable neural prosthetic to improve human memory.

Wearable functional near-infrared spectroscopy for measuring dissociable activation dynamics of prefrontal cortex subregions during working memory.

The prefrontal cortex (PFC) has been extensively studied in relation to various cognitive abilities, including executive function, attention, and memory. Nevertheless, there is a gap in our scientific knowledge regarding the functionally dissociable neural dynamics across the PFC during a cognitive task and their individual differences in performance. Here, we explored this possibility using a delayed match-to-sample (DMTS) working memory (WM) task using NIRSIT, a high-density, wireless, wearable functional near-infrared spectroscopy (fNIRS) system. First, upon presentation of the sample stimulus, we observed an immediate signal increase in the ventral (orbitofrontal) region of the anterior PFC, followed by activity in the dorsolateral PFC. After the DMTS test stimulus appeared, the orbitofrontal cortex activated once again, while the rest of the PFC showed overall disengagement. Individuals with higher accuracy showed earlier and sustained activation of the PFC across the trial. Furthermore, higher network efficiency and functional connectivity in the PFC were correlated with individual WM performance. Our study sheds new light on the dynamics of PFC subregional activity during a cognitive task and its potential applicability in explaining individual differences in experimental, educational, or clinical populations. PRACTITIONER POINTS: Wearable functional near-infrared spectroscopy (fNIRS) captured dissociable temporal dynamics across prefrontal subregions during a delayed match-to-sample task. Anterior regions of the orbitofrontal cortex (OFC) activated first during the delay period, followed by the dorsolateral prefrontal cortex (PFC). PFC disengaged overall after the delay, but the OFC reactivated to the test stimulus. Earlier and sustained activation of PFC was associated with better accuracy. Functional connectivity and network efficiency also varied with task performance.

Automating licking bias correction in a two-choice delayed match-to-sample task to accelerate learning

Animals often display choice bias, or a preference for one option over the others, which can significantly impede learning new tasks. Delayed match-to-sample (DMS) tasks with two-alternative choices of lickports on the left and right have been widely used to study sensory processing, working memory, and associative memory in head-fixed animals. However, extensive training time, primarily due to the animals' biased licking responses, limits their practical utility. Here, we present the implementation of an automated side bias correction system in an olfactory DMS task, where the lickport positions and the ratio of left- and right-rewarded trials are dynamically adjusted to counterbalance mouse’s biased licking responses during training. The correction algorithm moves the preferred lickport farther away from the mouse’s mouth and the non-preferred lickport closer, while also increasing the proportion of non-preferred side trials when biased licking occurs. We found that adjusting lickport distances and the proportions of left- versus right-rewarded trials effectively reduces the mouse’s side bias. Further analyses reveal that these adjustments also correlate with subsequent improvements in behavioral performance. Our findings suggest that the automated side bias correction system is a valuable tool for enhancing the applicability of behavioral tasks involving two-alternative lickport choices.

Biophysical approach to modeling reflection: basis, methods, results

The approach used by physics is based on the identification and study of ideal objects, which is also the basis of biophysics, in combination with von Neumann heuristic modeling and functional fractionation according to R.Rosen is discussed as a tool for studying the properties of consciousness. The object of the study is a kind of line of analog systems: the human brain, the vertebrate brain, the invertebrate brain and artificial neural networks capable of reflection, which is a key property characteristic of consciousness. Reflection in the broad sense of the word, understood as an internal representation of the external world, is characteristic of a wide range of animals, and some of them (bumblebees, fish) even demonstrate reflection in the narrow sense of the word, understood as an inner self-representation. This complex behavior is realized by miniature brains of ~1 million neurons. The use of simple recurrent neural networks (RNNs) to obtain answers to general questions is illustrated. For example, it has been shown a small RNS is able to pass delayed matching to sample (DMTS) test, forming an individual dynamic representation of the received stimulus, allowing decoding by a special external neural detector. . It has been demonstrated in the reflexive game “even-odd”, the RNS has a huge advantage over a multi-layered neural network, with the same and a larger number of neurons – reflection defeats regression. It was found that the asymmetry of outcomes in the odd-even game, which was explained by various causes, including psychological ones – “it’s easier to catch up than to run away”, is reproduced in the game of two RNNs. Obviously, there are no psychological causes here and the advantage of the player playing for “even” is explained by the more complex strategy of the “odd” player – he needs to predict the opponent’s move and choose the opposite one.

Evidence of precurrent responses expanding equivalence classes in a delayed matching-to-sample task.

Delayed matching to sample (DMTS) increases the probability of equivalence class formation. Precurrent responses can mediate the retention interval in DMTS trials and control the selection of comparisons. In human participants, precurrent responses usually consist of naming the experimental stimuli based on their similarities to meaningful stimuli with preexperimental history. We tested whether precurrents expand classes by serving as nodes between experimental and meaningful stimuli. A DMTS (2 s) was used throughout the entire experiment. Eleven undergraduates learned A1B1 and A2B2 relations and then were submitted to ArC trials that required them to answer math problems presented during the DMTS interval: when the sample was A1, the problems resulted in 12 and C1 was correct; when the sample was A2, they resulted in 9 and C2 was correct. Response-as-node tests assessed whether participants would relate B1 and C1 to the printed number 12 and B2 and C2 to the printed number 9. Ten participants responded accordingly to this pattern, showing that the responses to the problems expanded the classes. Parity tests using the words "even" and "odd" further confirmed this hypothesis. These results contribute to understanding why DMTS enhances equivalence performances. Implications of using this procedure in stimulus-equivalence studies are discussed.

Effect of short-term androgen supplementation on cognitive performance in older male rhesus macaques

Old male rhesus macaques often show cognitive impairment, and also have attenuated circulating levels of testosterone and dehydroepiandrosterone sulfate (DHEAS). However, it is unclear if these age-associated decreases in circulating androgen levels are casually related to mechanisms that support cognition. To test this possibility, old male rhesus macaques were given daily supplements of testosterone and DHEA for ∼7 months, using a paradigm designed to mimic the 24-hour circulating hormone patterns of young adults. Animals completed the Delayed Match-to-Sample (DMS) task to assess recognition, and the Delayed Response (DR) task to assess working memory. The animals all showed significant delay-dependent performance, with longer delays resulting in lower accuracy; and timepoint-dependent performance, showing improvement with the repeated opportunities for practice. However, there were no differences between the androgen supplemented animals and age-matched controls. These data indicate that the specific short-term supplementation paradigm employed here offers no obvious benefits for DMS or DR task performance.

TgF344-AD Rat Model of Alzheimer's Disease: Spatial Disorientation and Asymmetry in Hemispheric Neurodegeneration.

The TgF344-AD ratline represents a transgenic animal model of Alzheimer's disease. We previously reported spatial memory impairment in TgF344-AD rats, yet the underlying mechanism remained unknown. We, therefore, set out to determine if spatial memory impairment in TgF344-AD rats is attributed to spatial disorientation. Also, we aimed to investigate whether TgF344-AD rats exhibit signs of asymmetry in hemispheric neurodegeneration, similar to what is reported in spatially disoriented AD patients. Finally, we sought to examine how spatial disorientation correlates with working memory performance. TgF344-AD rats were divided into two groups balanced by sex and genotype. The first group underwent the delayed match-to-sample (DMS) task for the assessment of spatial orientation and working memory, while the second group underwent positron emission tomography (PET) for the assessment of glucose metabolism and microglial activity as in-vivo markers of neurodegeneration. Rats were 13 months old during DMS training and 14-16 months old during DMS testing and PET. In the DMS task, TgF344-AD rats were more likely than their wild-type littermates to display strong preference for one of the two levers, preventing working memory testing. Rats without lever-preference showed similar working memory, regardless of their genotype. PET revealed hemispherically asymmetric clusters of increased microglial activity and altered glucose metabolism in TgF344-AD rats. TgF344-AD rats display spatial disorientation and hemispherically asymmetrical neurodegeneration, suggesting a potential causal relationship consistent with past clinical research. In rats with preserved spatial orientation, working memory remains intact.

A 108-h total sleep deprivation did not impair fur seal performance in delayed matching to sample task.

While the majority of studies have concluded that sleep deprivation causes detrimental effects on various cognitive processes, some studies reported conflicting results. We examined the effects of a 108-h total sleep deprivation (TSD) on working memory in the northern fur seal, an animal with unusual sleep phenomenology and long-range annual migrations. The performance of fur seals was evaluated in a two-choice visual delayed matching to sample (DMTS) task, which is commonly used to evaluate working memory. In baseline conditions, the performance of fur seals in a DMTS task based on the percentage of errors was somewhat comparable with that in nonhuman primates at similar delays. We have determined that a 108-h TSD did not affect fur seals' performance in a visual DMTS task as measured by overall percentage of errors and response latencies. On the contrary, all fur seals improved task performance over the study, including the baseline, TSD and recovery conditions. In addition, TSD did not change the direction and strength of the pattern of behavioral lateralization in fur seals. We conclude that a 108-h TSD did not interfere with working memory in a DMTS test in northern fur seals.

Quantification of Non-Motor Symptoms in Parkinsonian Cynomolgus Monkeys.

Parkinson's disease (PD) is a neurodegenerative disorder that features motor and non-motor deficits. The use of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine neuron degeneration has been widely practiced to produce reliable animal models of PD. However, most previous preclinical studies focused on motor dysfunction, and few non-motor symptoms were evaluated. Thus far, there is a lack of comprehensive investigations of the non-motor symptoms in animal models. In this study, we aim to use a battery of behavioral methods to evaluate non-motor symptoms in MPTP-induced non-human primate PD models. Cognitive function, sleep, and psychiatric behaviors were evaluated in MPTP-treated cynomolgus monkeys. The tests consisted of a delayed matching-to-sample (DMTS) task, the use of a physical activity monitor (PAM), an apathy feeding task (AFT), the human intruder test (HIT), novel fruit test (NFT), and predator confrontation test (PCT). In addition, we tested whether the dopamine receptor agonist pramipexole (PPX) can improve these non-motor symptoms. The present results show that the MPTP-treated monkeys exhibited cognitive deficits, abnormal sleep, and anxiety-like behaviors when compared to the control monkeys. These symptoms were relieved partially by PPX. These results suggest that MPTP-induced PD monkeys displayed non-motor symptoms that were similar to those found in PD patients. PPX treatment showed moderate therapeutic effects on these non-motor symptoms. This battery of behavioral tests may provide a valuable model for future preclinical research.

Nationwide phase II randomized controlled trial of low-dose ibuprofen vs placebo for cancer-related cognitive impairment (CRCI).

12116 Background: CRCI is an important clinical problem encompassing difficulties in attention, memory, and executive function. Interventions for CRCI during chemotherapy have not been established. Inflammation is associated with CRCI and thus targeting inflammation may alleviate CRCI. In a nationwide study, we investigated a low-dose of ibuprofen for alleviating CRCI in patients self-reporting cognitive problems during chemotherapy or after recent completion of chemotherapy. Methods: Participants with cancer currently on or recently completed chemotherapy and who self-reported cognitive problems were recruited via the NCI Community Oncology Research Program (URCC NCORP) and 11 affiliates. Participants completed pre-intervention assessments and were stratified by disease type (breast cancer; gastrointestinal cancer; other) and randomized to one of 2 groups for 6 weeks: ibuprofen (200 mg BID) or blinded placebo equivalent. At pre-intervention and post-intervention, participants completed a perceived cognitive function measure (FACT-Cog Perceived Cognitive Impairment (PCI)) and cognitive assessments including Rapid Visual Processing (RVP) latency, Delayed Match to Sample (DMS) visual memory, and Verbal Recognition Memory (VRM) word recall. ANCOVA was used to assess between group differences pre- to post-intervention adjusting for baseline cognitive test score. Results: In total, 87 participants were randomized; 45 were randomized to ibuprofen and 42 randomized to placebo (mean age = 55; 85% female; 47% breast cancer, 29% colon/colorectal cancer; 24% other diagnoses). Most participants were fully compliant and completed post-intervention assessments (86% in Ibuprofen arm, 87% in placebo arm). There were no gastrointestinal bleeding events of any grade in the ibuprofen arm and serious adverse events were rare in both arms occurring in only 4% and 7% of patients in the ibuprofen and placebo arms, respectively. For PCI, both groups significantly reported less impairment from pre- to post-intervention; there were no difference between groups. Patients randomized to ibuprofen had a significant improvement on RVP latency time compared to placebo (110.63 milliseconds; p < 0.005). On the DMS, patients receiving ibuprofen had a trend toward improved function compared to placebo (7.39%; p = 0.08). However, patients in placebo performed better in word recall compared to ibuprofen from pre- to post-intervention (1.64 words; p < 0.05). Conclusions: Low-dose, short duration ibuprofen was safe with minimal adverse events in patients with cancer receiving chemotherapy or recently completed chemotherapy. Ibuprofen showed improvements in processing speed time and visual memory in patients with cancer as hypothesized, but not verbal memory. These novel Phase II findings need to be replicated in a Phase III RCT. Funding: R21CA187500, UG1CA189961. Clinical trial information: NCT03186638 .

Posterior Parietal Cortex Plays a Causal Role in Abstract Memory-Based Visual Categorical Decisions.

Neural activity in the lateral intraparietal cortex (LIP) correlates with both sensory evaluation and motor planning underlying visuomotor decisions. We previously showed that LIP plays a causal role in visually-based perceptual and categorical decisions, and preferentially contributes to evaluating sensory stimuli over motor planning. In that study, however, monkeys reported their decisions with a saccade to a colored target associated with the correct motion category or direction. Since LIP is known to play a role in saccade planning, it remains unclear whether LIP's causal role in such decisions extend to decision-making tasks which do not involve saccades. Here, we employed reversible pharmacological inactivation of LIP neural activity while two male monkeys performed delayed match to category (DMC) and delayed match to sample (DMS) tasks. In both tasks, monkeys needed to maintain gaze fixation throughout the trial and report whether a test stimulus was a categorical match or nonmatch to the previous sample stimulus by releasing a touch bar. LIP inactivation impaired monkeys' behavioral performance in both tasks, with deficits in both accuracy and reaction time (RT). Furthermore, we recorded LIP neural activity in the DMC task targeting the same cortical locations as in the inactivation experiments. We found significant neural encoding of the sample category, which was correlated with monkeys' categorical decisions in the DMC task. Taken together, our results demonstrate that LIP plays a generalized role in visual categorical decisions independent of the task-structure and motor response modality.SIGNIFICANCE STATEMENT Neural activity in the lateral intraparietal cortex (LIP) correlates with perceptual and categorical decisions, in addition to its role in mediating saccadic eye movements. Past work found that LIP is causally involved in visual decisions that are rapidly reported by saccades in a reaction time based decision making task. Here we use reversible inactivation of LIP to test whether LIP is also causally involved in visual decisions when reported by hand movements during delayed matching tasks. Here we show that LIP inactivation impaired monkeys' task performance during both memory-based discrimination and categorization tasks. These results demonstrate that LIP plays a generalized role in visual categorical decisions independent of the task-structure and motor response modality.

Subtle Pathophysiological Changes in Working Memory-Related Potentials and Intrinsic Theta Power in Community-Dwelling Older Adults With Subjective Cognitive Decline.

Individuals with subjective cognitive decline (SCD) who perform normally on objective cognitive tests may have an increased risk of pathological cognitive decline and progression to Alzheimer's disease (AD) and related dementia (ADRD). Working memory is widely regarded as an early sign of pathological cognitive decline. We tested the hypothesis that older adults with SCD already exhibit aberrant neurocognitive processing underlying working memory. Electroencephalography (EEG) was recorded during a delayed match-to-sample (DMS) task and an eyes-closed resting condition in cognitively healthy community-dwelling older adults who were assigned to the SCD or Control group. The SCD and Control groups showed comparable performance on the neuropsychological tests and DMS task. The SCD group showed an enhanced right frontal target-related P300 effect during working memory retrieval and higher frontal theta power during rest. Higher theta power was associated with worse working memory performance and greater left frontal nontarget-related positivity across all older adults. Our findings suggest that older people with SCD have subtle pathophysiological changes in working memory-related potentials and intrinsic theta power, which has important implications for predicting risks and early interventions in older adults in the preclinical stage of ADRD.

Time-frequency neural dynamics of ADHD children and adolescents during a Working Memory task

The present report analyzed the time-frequency changes in Event-Related Spectral perturbations (ERSP) in a sample of ADHD children and adolescents compared to a normodevelopment (ND) sample. A delayed match-to-sample (DMTS) test of working memory (WM) was presented to a group of ADHD subjects (N = 29) and compared with ND group (N = 34) with ages between 6 and 17 years old. Time-frequency decomposition was computed through wavelets. ADHD subjects presented higher Reaction Time (RT), Standard Deviation of RT (Std of RT), and a reduced percentage of correct responses. The results showed a complex pattern of oscillatory bursts during the encoding, maintenance, and recognition phases with similar dynamics in both groups. ADHD children presented a reduced Event-Related Synchronization (ERS) in the Theta range during the encoding phase, and also a reduced Alpha ERS during the late period of the maintenance phase. S1 Early theta ERS was positively correlated with Std of RT. Behavioral data, early Theta, and late Alpha ERS classified correctly above 70 % of ADHD and ND subjects when a linear discriminant analysis was applied. The reduced encoding and maintenance impaired brain dynamics of ADHD subjects would justify the poorer performance of this group of subjects.

Association of indoor dust microbiota with cognitive function and behavior in preschool-aged children

BackgroundChildhood cognitive development depends on neuroimmune interactions. Immunomodulation by early-life microbial exposure may influence neuropsychological function. In this study, we investigate the association between residential indoor microbiota and cognition and behavior among preschoolers.ResultsIndoor-settled dust bacterial and fungal characteristics were assessed using 16S and ITS amplicon sequencing (microbial diversity) and qPCR measurements (microbial loads). Child behavior was assessed using four scales: peer relationship, emotional, conduct, and hyperactivity was assessed by the Strengths and Difficulties Questionnaire (SDQ). Cognitive function was assessed using four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB) software. The first two tasks were designed to assess attention and psychomotor speed (Motor Screening (MOT) and Big/Little Circle (BLC)) and the last two to evaluate the child’s visual recognition/working memory (Spatial Span (SSP) and Delayed Matching to Sample (DMS)). Among the 172 included children (age 4–6 years), we observed a 51% (95%CI;75%;9%) lower odds of children scoring not normal for hyperactivity and a decrease of 3.20% (95%CI, −6.01%; −0.30%) in BLC response time, for every IQR increase in fungal Shannon diversity. Contrarily, microbial loads were directly associated with SDQ scales and response time. For example, a 2-fold increase in Gram-positive bacterial load was associated with 70% (95%CI 18%; 156%) higher odds of scoring not normal for hyperactivity and an increase of 5.17% (95%CI 0.87%; 9.65%) in DMS response time.ConclusionsOur findings show that early-life exposure to diverse indoor fungal communities is associated with better behavioral and cognitive outcomes, whereas higher indoor microbial load was associated with worse outcomes.-hh8RCLyRPCU1iX3VFx5YbVideo