Measure Of Recognition Memory Research Articles

Oxidative stress as a potential mechanism linking gestational phthalates exposure to cognitive development in infancy

BackgroundGestational exposure to phthalates, endocrine disrupting chemicals widely used in consumer products, has been associated with poor recognition memory in infancy. Oxidative stress may represent one pathway linking this association. Hence, we examined whether exposure to phthalates was associated with elevated oxidative stress during pregnancy, and whether oxidative stress mediates the relationship between phthalate exposure and recognition memory. MethodsOur analysis included a subset of mother-child pairs enrolled in the Illinois Kids Development Study (IKIDS, N = 225, recruitment years 2013–2018). Concentrations of 12 phthalate metabolites were quantified in 2nd trimester urine samples. Four oxidative stress biomarkers (8-isoprostane-PGF2α, 2,3-dinor-5,6-dihydro-8-isoPGF2α, 2,3-dinor-8-isoPGF2α, and prostaglandin-F2α) were measured in 2nd and 3rd trimester urine. Recognition memory was evaluated at 7.5 months, with looking times to familiar and novel stimuli recorded via infrared eye-tracking. Novelty preference (proportion of time looking at a novel stimulus when paired with a familiar one) was considered a measure of recognition memory. Linear mixed effect models were used to estimate associations between monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (ΣDEHP), sum of di(isononyl) phthalate metabolites (ΣDINP), and sum of anti-androgenic phthalate metabolites (ΣAA) and oxidative stress biomarkers. Mediation analysis was performed to assess whether oxidative stress biomarkers mediated the effect of gestational phthalate exposure on novelty preference. ResultsThe average maternal age at delivery was 31 years and approximately 50 % of participants had a graduate degree. A natural log unit increase in ΣAA, ΣDINP, and ΣDEHP was associated with a statistically significant increase in 8-isoPGF2α, 2,3-dinor-5,6-dihydro-8-isoPGF2α, and 2,3-dinor-8-isoPGF2α. The association was greatest in magnitude for ΣAA and 2,3-dinor-5,6-dihydro-8-isoPGF2α (β = 0.45, 95 % confidence interval = 0.14, 0.76). The relationship between ΣAA, ΣDINP, ΣDEHP, and novelty preference was partially mediated by 2,3-dinor-8-isoPGF2α. ConclusionsGestational exposure to some phthalates is positively associated with oxidative stress biomarkers, highlighting one mechanistic pathway through which these chemicals may impair early cognitive development.

Pupil old/new effect as an objective measure of recognition memory: a meta-analysis of 17 eye-tracking experiments

ABSTRACT Recognition memory, the ability to recognise previously encountered information, correlates with pupil diameter changes during the recognition period. This physiological response, known as the pupil old/new effect, generally reflects the variation in pupil dilation when encountering previously studied (old) stimuli compared to new stimuli. To develop a more precise understanding of the pupil old/new effect, we conducted a meta-analysis of 17 eye-tracking experiments (across 12 articles spanning from 2008 to 2023) involving 560 healthy adults with a mean age of 22.31 years. Analysis of publication bias showed a rather low risk of bias in the selected articles. The main meta-analysis revealed a significant and large pooled pupil old/new effect (Cohen’s dz = 0.73, 95% CI [0.50, 0.95]). Further analysis of moderators showed that the number of participants included in the experiments and the criteria for selecting trials (only correct trials vs. all trials) had a significant impact on the meta-analytic results. In general, the analyses revealed a robust pupil old/new effect across all selected articles. This finding underscores its potential utility as a marker of recognition memory across different stimuli type, and various experimental designs.

Children's Memory for Events: The Challenge of Free Recall.

Early childhood is a critical period for episodic memory development, with sharp behavioral improvements between ages 4 to 7 years. Prior work has demonstrated this extensively with prompted memory tasks, but we explored performance on unprompted, free recall of a naturalistic experience in children, and how their performance relates to other cognitive measures. We asked children and adults to view a television episode, a naturalistic task for which there exists a ground truth, and assessed their free recall memory for the episode. Children's free recall performance improved dramatically with age, with many young children producing no verbal free recall whatsoever, although prompted recognition memory measures showed retention of material. However, the detail in free recall was related to both recognition and temporal order forced-choice memory performance in our full sample, showing agreement among memory measures. Free recall was strongly predicted by verbal skills, suggesting that children's sparse recall reflects verbal skill development rather than a pure mnemonic deficit. We propose that free recall has a more protracted developmental trajectory because it requires more substantial verbal skills as well as metacognitive skills that direct memory search, as compared with forced-choice memory tasks.

Novelty preference assessed by eye tracking: A sensitive measure of impaired recognition memory in epilepsy

ObjectiveEpilepsy patients often report memory deficits despite normal objective testing, suggesting that available measures are insensitive or that non-mnemonic factors are involved. The Visual Paired Comparison Task (VPCT) assesses novelty preference, the tendency to fixate on novel images rather than previously viewed items, requiring recognition memory for the “old” images. As novelty preference is a sensitive measure of hippocampal-dependent memory function, we predicted impaired VPCT performance in epilepsy patients compared to healthy controls. MethodsWe assessed 26 healthy adult controls and 31 epilepsy patients (16 focal-onset, 13 generalized-onset, 2 unknown-onset) with the VPCT using delays of 2 or 30 s between encoding and recognition. Fifteen healthy controls and 17 epilepsy patients (10 focal-onset, 5 generalized-onset, 2 unknown-onset) completed the task at 2-, 5-, and 30-minute delays. Subjects also performed standard memory measures, including the Medical College of Georgia (MCG) Paragraph Test, California Verbal Learning Test-Second Edition (CVLT-II), and Brief Visual Memory Test-Revised (BVMT-R). ResultsThe epilepsy group was high functioning, with greater estimated IQ (p = 0.041), greater years of education (p = 0.034), and higher BVMT-R scores (p = 0.024) compared to controls. Both the control group and epilepsy cohort, as well as focal- and generalized-onset subgroups, had intact novelty preference at the 2- and 30-second delays (p-values ≤ 0.001) and declined at 30 min (p-values > 0.05). Only the epilepsy patients had early declines at 2- and 5-minute delays (controls with intact novelty preference at p = 0.003 and p ≤ 0.001, respectively; epilepsy groups’ p-values > 0.05). ConclusionsMemory for the “old” items decayed more rapidly in overall, focal-onset, and generalized-onset epilepsy groups. The VPCT detected deficits while standard memory measures were largely intact, suggesting that the VPCT may be a more sensitive measure of temporal lobe memory function than standard neuropsychological batteries.

A Spatial Memory Deficit in Male But Not Female Rats After Neonatal Diazepam Exposure: A New Model for Developmental Sedative Neurotoxicity.

Developmental anesthetic neurotoxicity is well described in animal models for GABAergic, sedating drugs. Here we investigate the role of the benzodiazepine, diazepam on spatial and recognition memory of young adult rats after neonatal exposure. On postnatal day 7, male (n = 30) and female (n = 30) rats were exposed to diazepam (30 mg/kg intraperitoneally) or vehicle. On postnatal day 42, animals started a series of behavioral tests including Barnes maze (spatial memory), object recognition battery (recognition memory), and open field and elevated plus maze (anxiety). In a separate cohort, blood gases were obtained from diazepam-exposed animals and compared to isoflurane-exposed animals (1 MAC for 4 hours). Male animals exposed to diazepam had impaired performance in the Barnes maze and were unable to differentiate the goal quadrant from chance (1-sample t test; tdiazepam/male (14) = 1.49, P = .158). Female rats exposed to diazepam performed the same as the vehicle controls ( tdiazepam/female (12) = 3.4, P = .005, tvehicle/female (14) = 3.62, P = .003, tvehicle/male (13) = 4.76, P < .001). There were no statistical differences in either males or females in measures of recognition memory, anxiety, or locomotor activity in other behavioral tests. Physiologic measurements of arterial blood gases taken from animals under sedation with diazepam were much less aberrant than those exposed to the volatile anesthetic isoflurane by t test (pH diazepam [M = 7.56, standard deviation {SD} = 0.11] versus pH Isoflurane [M = 7.15, SD = 0.02], t (10) = 8.93, P < .001; Paco 2diazepam [M = 32.8 mm Hg, SD = 10.1] versus Paco 2Isoflurane [M = 91.8 mm Hg, SD = 5.8], t (10) = 8.93, P < .001). The spatial memory results are consistent with volatile anesthetic suggesting a model in which development of the GABA system plays a critical role in determining susceptibility to behavioral deficits.

Associations of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) with measures of cognition in 7.5-month-old infants: An exploratory study

BackgroundPrenatal exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to a wide array of adverse maternal and child health outcomes. However, studies examining PFAS in relation to offspring cognition have been inconclusive. ObjectiveWe examined whether prenatal exposure to a mixture of PFAS was related to cognition in 7.5-month-old infants. MethodsOur analytic sample included participants enrolled in the Chemicals in Our Bodies (CIOB) and Illinois Kids Development Study (IKIDS) cohorts (N = 163). Seven PFAS were measured in 2nd trimester maternal serum samples and were detected in >65% of participants. Infant cognition was measured with a visual recognition memory task using an infrared eye tracker when infants were 7.5 months old. This task included familiarization trials where each infant was shown two identical faces and test trials where each infant was shown the familiar face paired with a novel face. In familiarization, we assessed average run duration (time looking at familiarization stimuli before looking away) as a measure of information processing speed, in addition to time to familiarization (time to reach 20 s of looking at stimuli) and shift rate (the number of times infants looked between stimuli), both as measures of attention. In test trials, we assessed novelty preference (proportion of time looking to the novel face) to measure recognition memory. Linear regression was used to estimate associations of individual PFAS with cognitive outcomes, while Bayesian kernel machine regression (BKMR) was used to estimate mixture effects. ResultsIn adjusted single-PFAS linear regression models, an interquartile range increase in PFNA, PFOA, PFOS, PFHxS, PFDeA, and PFUdA was associated with an increase in shift rate, reflecting better visual attention. Using BKMR, increasing quartiles of the PFAS mixture was similarly associated with a modest increase in shift rate. There were no significant associations between PFAS exposure and time to reach familiarization (another measure of attention), average run duration (information processing speed), or novelty preference (visual recognition memory). ConclusionIn our study population, prenatal PFAS exposure was modestly associated with an increase in shift rate and was not strongly associated with any adverse cognitive outcomes in 7.5-month-old infants.

Neurophysiological correlates of memory change in children with fetal alcohol spectrum disorders treated with choline.

BackgroundPrenatal and early postnatal choline supplementation reduces cognitive and behavioral deficits in animal models of Fetal Alcohol Spectrum Disorder (FASD). In a previously published 9-month clinical trial of choline supplementation in children with FASD, we reported that postnatal choline was associated with improved performance on a hippocampal-dependent recognition memory task. The current paper describes the neurophysiological correlates of that memory performance for trial completers.MethodsChildren with FASD (N = 24) who were enrolled in a clinical trial of choline supplementation were followed for 9 months. Delayed recall on a 9-step elicited imitation task (EI) served as the behavioral measure of recognition memory. Neurophysiological correlates of memory were assessed via event-related potentials (ERP).ResultsDelayed recall on EI was correlated with two ERP components commonly associated with recognition memory in young children: middle latency negative component (Nc amplitude; range: r = −0.41 to r = −0.44) and positive slow wave (PSW area under the curve; range: r = −0.45 to r = −0.63). No significant ERP differences were observed between the choline and placebo groups at the conclusion of the trial.ConclusionAlthough the small sample size limits the ability to draw clear conclusions about the treatment effect of choline on ERP, the results suggest a relationship between memory performance and underlying neurophysiological status in FASD. This trial was registered.1

The Benton Visual Form Discrimination Test as a Predictor of Neurocognitive Disorder in Older Veterans.

The Benton Visual Form Discrimination Test (VFDT) is a commonly used measure of visual discrimination and visual recognition memory and has shown promise in distinguishing between different levels of cognitive impairment. We assess the predictive diagnostic utility of the VFDT in a sample of older Veterans with cognitive concerns. Subjects included a total of 172 mostly male Veterans over the age of 64 (mean = 76.0; SD = 7.6) recruited from a VA clinic specializing in neuropsychological assessment of older Veterans. The clinical sample included 56 subjects diagnosed with Major Neurocognitive Disorder, 74 diagnosed with Mild Neurocognitive Disorder, and 42 with No Neurocognitive Impairment. Impairment categories were modeled in separate multinomial logistic regressions with two versions of the VFDT as predictors: the Visual Form Discrimination Test-Recognition Subtest (VFDT-Rec) test (visual recognition memory) and the Visual Form Discrimination Test-Matching Subtest VFDT-Mat test (visual form discrimination). Years of education were included as a covariate. After adjusting for education, higher VFDT-Rec total scores were associated with lower odds of being categorized with a greater degree of cognitive/functional impairment (OR 0.66-0.83, p < .001). VFDT-Mat scores showed a similar pattern, but only reached statistical significance for the Major versus No Neurocognitive Impairment (OR = 0.77, p = .0010) and Major versus Mild comparisons (OR = 0.89, p = .0233). The VFDT may enhance the confidence of differential diagnosis of dementia in older adult Veterans. Formal education-adjusted norms need to be established for clinical use.

Adaptive design optimization for a Mnemonic Similarity Task

The Mnemonic Similarity Task (MST: Stark et al., 2019) is a modified recognition memory task designed to place strong demand on pattern separation. The sensitivity and reliability of the MST make it an extremely valuable tool in clinical settings, where it has been used to identify hippocampal dysfunction associated with healthy aging, dementia, schizophrenia, depression, and other disorders. As with any test used in a clinical setting, it is especially important for the MST to be administered as efficiently as possible. We apply adaptive design optimization methods (Lesmes et al.,2015; Myung et al., 2013) to optimize the presentation of test stimuli in accordance with previous responses. This optimization is based on a signal detection model of an individual’s memory capabilities and decision-making processes. We demonstrate that the adaptive design optimization approach generally reduces the number of test stimuli needed to measure recognition memory.

Short Juvenile Stress Has No Long-Lasting Effects on Anxiety-Like Behavior, Object Recognition Memory, or Gross Brain Morphology but Affects Dendritic Spines in the Hippocampus in Male Rats

Purpose: During the juvenile stage, such areas as the hippocampus and corpus callosum (CC) are still immature and sensitive to stress exposure. The present study investigated whether two different types of stressors in the juvenile stage of life have a long-lasting impact on behavior and biological outcomes in adult rats. Methods: Male juvenile rats were exposed to restraint or predator stress on postnatal day 25 (P25) for 3 days. Thirty-two days later (P60-74), behavioral and biological analyses were conducted. The behavioral analysis included measures of anxiety-like behavior and recognition memory. The biological analysis investigated gross cerebral morphology, based on volume analysis of the CC and hippocampus, perirhinal cortex thickness, and dendritic spine density. Results: Neither restraint stress nor predator stress affected anxiety-like behavior or object recognition memory in adulthood. Body weight and adrenal gland weight were unaffected by both types of stress. Overall, volumetric measures of the CC and hippocampus were not significant, with no changes in perirhinal cortex thickness. Spine density in the medial prefrontal cortex also was unaffected, but a decrease in dendritic spine density was found in the hippocampus in response to restraint stress and an increase to predator stress. Conclusion: Short-term and daily restraint and predator stress during the juvenile stage had no long-lasting effects on anxiety-like behavior, object memory, volume of the CC or hippocampus, or perirhinal cortex thickness, but a decrease in dendritic spine density was found in the hippocampus. These findings suggest that different types of stressors have different impacts on microstructures in the brain without affecting behavior or the gross morphology of stress-sensitive brain areas.

Effects of environmental enrichment on recognition memory in zebrafish larvae

Zebrafish (Danio rerio) constitute a useful model for studying memory function and impairment in vertebrates and are now widely used in translational research. On the one hand, the adoption of simple, fast and reliable tests such as novel object recognition (NOR) has increased our knowledge considerable about memory mechanisms in animals. On the other hand, in many model organisms, exposure to environmental enrichment, especially during the early stages of development, affects various cognitive functions. Evidence for the effects of environmental enrichment on zebrafish has been accumulating rapidly, but most of this evidence has been collected in adult subjects. We compared larvae raised in either an enriched or barren environments and measured their memory performance at 14-days post-fertilization. Initially, subjects were allowed to familiarize with two identical novel objects (i.e., pattern of 2D-geometrical figures). After a time interval, larvae faced a two-choice task presenting the same objects paired with a new one. As a measure of recognition memory, we exploit the tendency of individuals to explore a novel object over a familiar one. Our results indicate that larvae from the barren environment spent more time exploring familiar stimuli than novel ones, showing the innate presence of recognition memory capacity in zebrafish larvae. Conversely, subjects bred in a visually enriched environment explore both familiar and novel stimuli almost equally. The increase of exploratory behavior and, consequently, the reduction of avoidance to the novel object may explain the performance shown by larvae exposed to an enrichment environment compared to the larvae bred in a barren environment. Taken together, these results confirm that early-stage zebrafish possess complex visual discrimination capacities and that rearing subjects in a structurally complex environment might hinder memory performance by reducing their neophobic response.

Effect of Alzheimer’s pathology on the functional architecture of memory networks during rest and task states in aging

AbstractBackgroundIntrinsic brain networks are relatively consistently organized between rest and task states in young individuals. We performed this study in order to determine whether the same is true in aging, and whether measures of AD pathology affect this relationship.MethodWe used task‐based (mnemonic discrimination task with object and scene stimuli) and rest fMRI to measure functional connectivity (FC) in an anterior temporal (AT) and posteromedial (PM) network in older (OA; N=49, 74±5 years, 31F) and younger adults (YA; N=24, 27±4 years, 9F). We calculated the correlation between rest and task FC states by conducting a Pearson’s correlation between the rest and task FC matrices for each participant. We used PiB‐PET to measure global Aβ (using threshold of 1.065 to classify OA as PiB+/‐) and FTP‐PET to measure tau within an AT and PM composite ROI in OA. We also measured recognition memory performance during the mnemonic discrimination task requiring discrimination of repeated stimuli from lures.ResultResting state and task FC in the ATPM network were less correlated in older compared to younger adults. In addition, less correlated rest vs. task FC was associated with higher levels of FTP in ATPM networks in PiB+ older adults. Finally, less correlated rest vs. task FC was associated with worse recognition performance (among all participants and OA alone) during the object trials.ConclusionThese findings link AD pathology to disruption of the functional architecture of intrinsic brain networks during rest and memory task states in OA. They also suggest that memory decline in some older adults may be influenced by the extent of change in functional architecture between rest and task demands. Overall, dynamic FC changes from rest to task may provide a novel mechanism in which aging impacts cognition.

Effectiveness of source‐monitoring training in reducing halo error and negativity bias in a performance appraisal setting

AbstractThe goal of the present study was to examine the effectiveness of a source‐monitoring procedure in reducing halo error and negativity bias in a performance appraisal setting. Participants watched videotaped performance segments of an instructor presumably taking place over a school year (N = 126). Then, participants in the source‐monitoring training condition received instructions teaching them how to differentiate memories that evoke detailed representations (remember judgments) from memories that evoke mere feelings of familiarity (know judgments). With this distinction in mind, participants in the training condition made significantly more accurate judgments than participants in the control condition. The training was successful in increasing the accuracy of performance ratings and reducing halo error and the negativity bias. Recognition memory measures showed that improvements were due to increased reliance on specific memory traces in the training condition. There was evidence of heuristic reliance on general impressions in the control condition.

A passive and objective measure of recognition memory in Alzheimer's disease using Fastball memory assessment.

Earlier diagnosis of Alzheimer's disease requires biomarkers sensitive to associated structural and functional changes. While considerable progress has been made in the development of structural biomarkers, functional biomarkers of early cognitive change, unconfounded by effort, practice and level of education, are still needed. We present Fastball, a new EEG method for the passive and objective measurement of recognition memory, that requires no behavioural memory response or comprehension of the task . Younger adults, older adults and Alzheimer's disease patients (n = 20 per group) completed the Fastball task, lasting just under 3 min. Participants passively viewed rapidly presented images and EEG assessed their automatic ability to differentiate between images based on previous exposure, i.e. old/new. Participants were not instructed to attend to previously seen images and provided no behavioural response. Following the Fastball task, participants completed a two-alternative forced choice (2AFC) task to measure their explicit behavioural recognition of previously seen stimuli. Fastball EEG detected significantly impaired recognition memory in Alzheimer's disease compared to healthy older adults (P < 0.001, Cohen's d = 1.52), whereas behavioural recognition was not significantly different between Alzheimer's disease and healthy older adults. Alzheimer's disease patients could be discriminated with high accuracy from healthy older adult controls using the Fastball measure of recognition memory (AUC = 0.86, P < 0.001), whereas discrimination performance was poor using behavioural 2AFC accuracy (AUC = 0.63, P = 0.148). There were no significant effects of healthy ageing, with older and younger adult controls performing equivalently in both the Fastball task and behavioural 2AFC task. Early diagnosis of Alzheimer's disease offers potential for early treatment when quality of life and independence can be retained through disease modification and cognitive enhancement. Fastball provides an alternative way of testing recognition responses that holds promise as a functional marker of disease pathology in stages where behavioural performance deficits are not yet evident. It is passive, non-invasive, quick to administer and uses cheap, scalable EEG technology. Fastball provides a new powerful method for the assessment of cognition in dementia and opens a new door in the development of early diagnosis tools.

Active video games in fully immersive virtual reality elicit moderate-to-vigorous physical activity and improve cognitive performance in sedentary college students

BackgroundActive video games are a new method for increasing physical activity (PA). Fully immersive virtual reality (VR) is a hardware device on which an active video game can run. Active (video games in) VR (AVR), might increase immersion, game engagement, and moderate-to-vigorous PA (MVPA), thereby yielding greater exercise-related benefits, e.g., cognitive performance. MethodsWe examined the induction of MVPA via an AVR and a sedentary VR (SVR) as well as the effects of VR play on cognitive performance, which was monitored using 2 different methods. Each of 29 sedentary college students attended three 20-min laboratory sessions (AVR, SVR, or control) in a randomized order; during the control session, they sat quietly doing nothing. A fully immersive headset was used for the 2 video game sessions. We monitored and computed participants’ PA using hip-worn accelerometers (wGT3x-bt; ActiGraph, Pensacola, FL, USA) and a heart rate band (Polar H7; Polar, Kempele, Finland). After each session, the participants completed a mnemonic similarity test (MST) to measure recognition memory. They also filled out a motion sickness questionnaire and an abbreviated game experience questionnaire. ResultsThe AVR session induced a significantly greater heart rate and more time spent in MVPA than did either of the other 2 sessions regardless of the PA monitoring method. AVR elicited greater game experience questionnaire-assessed sensory and imaginative immersion, challenge, and positive affect than did SVR. The mnemonic similarity test recognition score was marginally higher post-AVR session than it was post-SVR session. ConclusionAVR elicited MVPA without a significant increase in motion sickness and induced a better game experience and better borderline cognitive performance than did SVR.

Referential Form and Memory for the Discourse History.

The way we refer to things in the world is shaped by the immediate physical context as well as the discourse history. But what part of the discourse history is relevant to language use in the present? In four experiments, we combine the study of task-based conversation with measures of recognition memory to examine the role of physical contextual cues that shape what speakers perceive to be a part of the relevant discourse history. Our studies leverage the differentiation effect, a phenomenon in which speakers are more likely to use a modified expression to refer to an object (e.g., dotted sock) if they had previously described a similar object (e.g., striped sock) than when they had not described a similar object. Two physical cues-the background that framed the to-be-described pictures and the position of the pictures in the display-were manipulated to alter perceptions about the relevant discourse context. We measured the rate with which speakers modify referring expressions to differentiate current from past referents. Recognition memory measures following the conversation probed what was and was not remembered about past discourse referents and contexts. Analysis of modification rates indicated that these contextual grouping cues shaped perceptions about the relevant discourse context. The contextual cues did not affect memory for the referents, but the memory for past referents was better for speakers than for listeners. Our findings show that perceptions about the relevant discourse history are a key determinant of how language is used in the moment but also that conversational partners form asymmetric representations of the discourse history.

Associations of prenatal exposure to phthalates with measures of cognition in 7.5-month-old infants

BackgroundPhthalates are endocrine disrupting chemicals that have been associated with adverse neurobehavior, but little is known about their influence on infant cognition. MethodsA visual recognition memory task was used to assess cognition in 244 7–8-month-old infants (121 females; 123 males) from a prospective cohort study. Phthalate metabolites were quantified in maternal urines pooled from across pregnancy. The task included familiarization trials (infant shown 2 identical faces) and test trials (infant shown the now familiar face paired with a novel one). Half of the infants saw one set of faces as familiar (set 1) and half saw the other set as familiar (set 2). During familiarization trials, average run duration (time looking at stimuli before looking away, measure of processing speed), and time to familiarization (time to reach 20 s looking at the stimuli, measure of attention) were assessed. During test trials, novelty preference (proportion of time looking at the novel face, measure of recognition memory) was assessed. Multivariable generalized linear models were used to assess associations of monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (ΣDEHP), sum of di(isononyl) phthalate metabolites (ΣDINP), and sum of anti-androgenic phthalate metabolites (ΣAA) with each outcome. ResultsMothers were mostly white and college educated, and urine phthalate concentrations were similar to those in reproductive age women in the U.S. population. All phthalate exposure biomarkers, except MEP, were associated with increases in average run duration. However, depending on the phthalate, associations were only in males or infants who saw the set 2 stimuli as familiar. Unexpectedly, ΣAA was associated with a shorter time to reach familiarization. Phthalate biomarkers also were associated with modest decrements in novelty preference, but these associations were nonsignificant. ConclusionPrenatal exposure to phthalates may be related to slower information processing and poorer recognition memory in infants.

A new functional biomarker of cognitive impairment in Alzheimer's disease

AbstractBackgroundFast Periodic Visual Stimulation (FPVS) provides a new objective electroencephalographic method for assessing an individual’s ability to discriminate between different categories of stimuli. Participants do not need to understand the task, or provide any response, making it ideal for the assessment of cognition in patient populations. We have adapted FPVS to examine a range of cognitive processes that deteriorate in Alzheimer’s disease, see Figure 1, with the ultimate aim of developing a functional biomarker to aid early diagnosis.MethodHealthy younger (n=42, ACE‐III=92 +‐ 6) and older adult controls (n=39, ACE‐III=95 +‐5), and Alzheimer’s disease patients (n=20, ACE‐III=62+‐15) completed a battery of FPVS and behavioural tasks designed to measure their recognition memory, semantic categorisation and visual object processing, see Figure 2.ResultFPVS provided an objective measure of recognition memory, semantic categorisation and visual object processing in just 1min of EEG recording time with no behavioural response or comprehension of the task required. There were no significant differences between younger and older adults in any FPVS measures of cognitive function. Alzheimer’s disease patients showed significant FPVS decreases in all three cognitive domains compared to healthy controls, with the greatest deficits in recognition memory (Old vs Alzheimer’s, t(58)=3.68, p=0.001, Hedge’s g = 1.38). FPVS measures of recognition memory separated AD from healthy ageing in binary classification approaches, outperforming behavioural measures, see Figure 3.ConclusionWe have demonstrated that FPVS can be adapted to measure a range of cognitive functions pertinent to dementia. It provides a fast, objective and implicit measure of cognitive function that remains stable in healthy ageing. Alzheimer’s disease has a significant impact on FPVS measures of cognition, and the approach holds promise for the development of new early diagnosis tools.

Associations of prenatal exposure to phthalates with measures of cognition in 7.5-month-old infants

Background: Phthalates are endocrine disrupting chemicals found in consumer products. Prenatal exposure has been associated with adverse neurobehavior, but little is known about the influence on infant cognition. Methods: A visual recognition memory task was used to assess cognition in 239 7.5-month-old infants (122 females; 117 males) from a prospective cohort study. Phthalate metabolites were quantified in maternal urine from 16-18 gestational weeks and a pool of five urines collected across pregnancy. The cognitive task included familiarization trials (infant shown 2 identical images/stimuli) and test trials (infant shown a familiar image/stimulus paired with a novel one). During familiarization trials, average time looking at stimuli before looking away (measure of processing speed), and time to reach looking time criterion (measure of attention) were assessed. During test trials, proportion of time looking at the novel stimulus (measure of recognition memory) was assessed. Associations of monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP), and sum of di(isononyl) phthalate metabolites (∑DINP) with each outcome were assessed using generalized linear models adjusted for multiple potential confounders. Infant sex was considered a potential effect modifier. Results: Mothers were mostly white and college educated. Phthalate biomarker concentrations were consistent with the U.S. general population. Each interquartile range (IQR) increase of ∑DEHP at 16-18 weeks was associated with a 5.2-second (95%CI=1.8,8.6) increase in time to reach looking time criterion in males but not females. An IQR increase in ∑DINP in the pooled sample was associated with a 1.0% (95%CI=-1.8,-0.3) decrease in novelty preference across both sexes and similarly associated with 16-18 week ∑DINP. MEP was not associated with cognition. None of the phthalate biomarkers were associated with information processing speed. Conclusion: Prenatal exposure to DEHP may be associated with poorer visual attention in males and DINP with poorer recognition memory in both sexes. ES007326;ES022848;ES028607;RD83543401;OD023272.

Social media use while listening to new material negatively affects short-term memory in college students

Increased access to electronic devices and the ubiquity of social media has resulted in a rapid rise in the prevalence of students “multitasking” while in a classroom setting. While some data indicate the use of electronic devices in class can improve the classroom environment, other studies demonstrate the opposite finding. Moreover, it remains unclear if using social networking sites such as Instagram impacts performance on cognitive tasks when students are presented new material and, if so, what features of Instagram modulate this response. Therefore, in the current study we examined if social media use during or after being presented new information affected short-term memory in college students. Additionally, we assessed if the type or quantity of topics displayed had a modulatory impact on memory. Forty-five college-aged (18–24 years of age) students completed the Logical Memory Immediate Recall (LM I) component of the Wechsler Memory Scale IV, a measure of auditory recognition memory. Subjects were randomly divided into a group that completed the LM I without distraction (controls), a group that completed the LM I while scrolling through their Instagram feed, or a group that completed the LM I after scrolling through their Instagram feed. Subjects that used Instagram while being presented new information demonstrated worse short-term memory recall ability compared to subjects that did not use Instagram during the presentation (71.56% correct answers vs. 80.89%; p = 0.01). Recall ability in the group that used Instagram after hearing the story was not statistically different from the controls. Differences were not observed in the number of topics appearing in subjects’ Instagram feeds and no correlation was found between the number of topics on a subject's Instagram feed and memory recall ability. Collectively, these results suggest that individuals who use their phones to browse Instagram during class or in social settings might have a reduced ability to retain the information given to them when compared to those that are not using their phones scrolling on social media.