Reaction Time Variability Research Articles

Exploring the steps of learning: computational modeling of initiatory-actions among individuals with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is characterized by difficulty in acting in a goal-directed manner. While most environments require a sequence of actions for goal attainment, ADHD was never studied in the context of value-based sequence learning. Here, we made use of current advancements in hierarchical reinforcement-learning algorithms to track the internal value and choice policy of individuals with ADHD performing a three-stage sequence learning task. Specifically, 54 participants (28 ADHD, 26 controls) completed a value-based reinforcement-learning task that allowed us to estimate internal action values for each trial and stage using computational modeling. We found attenuated sensitivity to action values in ADHD compared to controls, both in choice and reaction-time variability estimates. Remarkably, this was found only for first-stage actions (i.e., initiatory actions), while for actions performed just before outcome delivery the two groups were strikingly indistinguishable. These results suggest a difficulty in following value estimation for initiatory actions in ADHD.

Is it possible to objectively determine morning stiffness in rheumatoid arthritis?

This study aimed to objectively and quantitatively exhibit morning stiffness by using electrophysiological methods. The prospective, controlled study was conducted with 52 participants between February 2013 and February 2014. Of the participants, 26 were recruited among RA patients (3 males, 23 females; mean age: 55.9±11.2 years; range, 24 to 74 years) followed at the rheumatology clinic, and 26 were healthy subjects (4 males, 22 females; mean age: 54.9±8.3 years; range, 41 to 70 years) for the control group. Duration and severity of morning stiffness were recorded for all participants. Activity of disease and functional status were evaluated by the Disease Activity Score 28 and Health Assessment Questionnaire (HAQ), respectively. Electrophysiological reaction times, severity of pain (Visual Analog Scale), HAQ, and grip strength were measured for each participant twice in 24 h in the morning (08:00-09:00 am) and afternoon (03:00-05:00 pm). In the RA group, motor reaction and response times and severity of pain values were significantly lower in the afternoon compared to the morning (p=0.030, p=0.031, and p=0.002, respectively), and hand grip strengths were significantly higher in the afternoon (p=0.007). In the control group, no change was observed between morning and afternoon measurements in the strength and reaction time variables. Our hypothesis that stiffness would slow down the movements in the morning in RA was supported by the prolonged motor and response times in the morning compared to the afternoon. However, in the control group (no morning stiffness), there was no difference in reaction time variables between the morning and afternoon, objectively demonstrating the concept of morning stiffness in this study.

General low alertness in people with obstructive sleep apnea.

In patients with obstructive sleep apnea (OSA), a previous study using a Go/No-Go task reported an average attention deficit. However, the temporal dynamics of such a deficit are unknown. Here, we investigated whether attention deficits in different subdomains increased as the test progressed. We also investigated the effect of target frequency and speed of stimulus presentation on performance. Twenty-seven untreated people with OSA and 27 age- and sex-matched controls underwent a 15-minute Go/No-Go task, divided into 6 blocks. Each block was subdivided into 3 different interstimulus intervals (1, 2, and 4 seconds). Three blocks had a low and three had a high target probability (20% and 80%, respectively). Reaction time (alertness), variability of reaction time (sustained attention), commission errors (response inhibition), and omission errors (focused attention) were measured. Alertness was lower in the group with OSA compared with controls, as evidenced by a significantly higher average reaction time. This effect was seen from the start of the task and continued until the end but did not increase in test progression. The temporal pattern of intrinsic alertness deficits in patients with OSA was found to be independent of target frequency or interstimulus interval. The primary attention problem in OSA is on the alertness subdomain irrespective of the number of required responses or speed of stimulus presentation. The present results support the notion that OSA is distinct from other neurological and psychiatric conditions, such as depression or chronic pain. The results also suggest significant concerns regarding daily life activities (eg, driving). de Souza Bezerra ML, van Duinkerken E, Simões E, Schmidt SL. General low alertness in people with obstructive sleep apnea. J Clin Sleep Med. 2024;20(5):689-698.

The Effect of Hydrothermal Reaction Time on the Antibacterial Activity of Synthesized Manganese Oxide Nanoparticles

In the context of growing antibiotic resistance and the associated side effects of traditional antibiotics, this research explores the use of nanosized manganese oxide (Mn3O4) as a novel antibacterial agent. This study pioneers the synthesis of Mn3O4 through an eco-friendly hydrothermal method, varying reaction times (2, 4 and 6 hours) at a consistent temperature of 180 °C. Characterization techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy and Scanning electron microscopy, provide insights into their crystallinity, functional groups and morphology. The synthesized Mn3O4 demonstrates remarkable antibacterial efficacy, with larger inhibition zones against both Gram-positive and Gram-negative strains compared to standard antibiotics. This research presents the synthesizing of an eco-friendly, cost-effective antibacterial agent through a straightforward hydrothermal method. Varying reaction times unveil distinctive antibacterial capabilities, making Mn3O4 a promising candidate for future antimicrobial systems and medical applications.

Cognitive and perceptual load have opposing effects on brain network efficiency and behavioral variability in ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder associated with suboptimal outcomes throughout the life-span. Extant work suggests that ADHD-related deficits in task performance may be magnified under high cognitive load and minimized under high perceptual load, but these effects have yet to be systematically examined, and the neural mechanisms that undergird these effects are as yet unknown. Herein, we report results from three experiments investigating how performance in ADHD is modulated by cognitive load and perceptual load during a naturalistic task. Results indicate that cognitive load and perceptual load influence task performance, reaction time variability (RTV), and brain network topology in an ADHD-specific fashion. Increasing cognitive load resulted in reduced performance, greater RTV, and reduced brain network efficiency in individuals with ADHD relative to those without. In contrast, increased perceptual load led to relatively greater performance, reduced RTV, and greater brain network efficiency in ADHD. These results provide converging evidence that brain network efficiency and intraindividual variability in ADHD are modulated by both cognitive and perceptual load during naturalistic task performance.

Association between attention performance and the different dimensions of DSM-5 depression symptoms.

Depressive symptoms can be assessed with self-reported questionnaires, such as the Patient Health Questionary-9 (PHQ-9). Previous studies have suggested that the PHQ-9 items can be grouped into somatic and non-somatic clusters. However, the classification of the PHQ-9 item "concentration difficulties" into somatic or non-somatic is still controversial. This controversy may be explained by difficulties experienced by subjects in accurately evaluating their attention problems. The primary objective of this study was to determine the correlation between objective attentional performance and the two clusters of depressive symptoms in hospital employees working in stressful conditions. The participants filled out the PHQ-9 to identify their depressive symptoms. Based on the PHQ-9, the somatic or non-somatic symptoms were measured without considering the question about subjective concentration difficulties. Then, a brief version of the Continuous Visual Attention Test (CVAT) was applied to assess four attentional subdomains. The CVAT is a Go/No-go task that measures number of correct responses (focused attention), number of incorrect responses (behavior-inhibition), average reaction time of correct responses (RT-alertness), and variability of reaction time (VRT-sustained attention). The entire task lasted 90 s. Correlation analyses assessed the relationships between attentional performance and the two dimensions of depressive symptoms. After applying the inclusion/exclusion criteria, 359 individuals were selected. Their age ranged from 20 to 70 years (mean = 40.5, SD = 10.37), and the majority was female (67.6%). A predominance in somatic depressive symptoms was present in 231 (64%) participants, whereas 59 (16%) showed a predominance of non-somatic symptoms. Sixty-nine participants (20%) did not show any predominance. Higher somatic scores were associated with higher RTs, whereas higher non-somatic scores were related to an increase in the number of incorrect responses. The predominance of the somatic cluster was related to lower alertness, whereas the predominance of non-somatic cluster was associated with impulsivity/hyperactivity. This result may explain the difficulties associated with correctly classifying the item concentration difficulties. A brief attentional task can be used as an auxiliary tool to correctly identify the different dimensions of attention that are associated with different clusters of depressive symptoms.

Comparative microwave- and conventional oven-assisted hydrothermal syntheses of BaTiO3 nanoparticles for improved electroceramics

Barium titanate (BT) nanoparticles were prepared using both microwave- and conventional oven-assisted hydrothermal syntheses with varying reaction times (1 h, 3 h, and 6 h). In the case of the conventional oven-assisted hydrothermal syntheses, 16 h, 24 h, 48 h and 72 h reaction times were also studied. Structural and morphological evolution of BT particles were investigated. Microwave-assisted hydrothermal synthesis allowed for the rapid formation of nearly pure barium titanate (BT) phase in just 1 h at 200 °C. On the other hand, using a conventional oven as the heat source required at least 6 h of synthesis to achieve a similar material. When the different BT powders were pelletized and sintered at 1300 °C, ceramics with over 95 % density were obtained. The room-temperature (RT) dielectric permittivity exceeded 1750 for BT particles prepared over 6 h using both heating methods. However, a significant distinction emerged when comparing the piezoelectric coefficient (d33) values. The BT pellet obtained through the sintering of BT synthesized in the conventional oven for 6 h exhibited a notably higher d33 value, approximately 171 pC/N, as opposed to the 146 pC/N value observed in BT ceramics resulting from the microwave synthesized powders. Among the ceramic BT variations, the one derived from the best-crystallized tetragonal BT particles (CON_72h) displayed the lowest d33 value at 79 pC/N. These findings underscore the immense potential of microwave- and conventional oven-assisted hydrothermal syntheses in the sustainable production of BT nanomaterials, which can then be sintered to enable the preparation of ceramics with enhanced ferroelectric and piezoelectric properties.

Relationship between reaction time variability on go/no go tasks and neuropsychological functioning in younger and older adults

ABSTRACT Introduction Early detection of cognitive impairment in older adults is important for the prevention of dementia. Intra-individual variability in reaction time (IIV-RT) during go/no-go tasks can be used for the early detection of cognitive impairment in older adults living in the community. This study aimed to determine the relationship between IIV-RT and cognitive function during go/no-go tasks and the cutoff values for determining the risk of cognitive impairment in community-dwelling older adults. Methods This study included 31 older adults without cognitive impairment, 15 community-dwelling older adults with cognitive impairment, and 34 healthy young adults. All participants performed a go/no-go task to assess the IIV-RT. Additionally, older adults underwent neuropsychological testing. Based on the results of the Japanese version of the Montreal Test of Cognitive Abilities (MoCA-J), older adults were divided into those with normal cognition and those with cognitive impairment. Results There were significant differences in the IIV-RT among groups, including a higher IIV in the cognitively impaired group than in young adults and cognitively normal older adults. Moreover, the IIV-RT was correlated with the MoCA-J (r = −0.531, p < 0.001), Trail Making Test Part A (r = 0.571, p < 0.001), and Verbal Fluency Test scores (r = −0.442, p = 0.002). Receiver operating curve analysis showed that the area under the curve for IIV-RT was 0.935, and the cutoff value at which the IIV-RT identified cognitive impairment was 25.37%. Conclusions These findings indicate that the IIV-RT during go/no-go tasks is a useful early indicator of cognitive impairment in community-dwelling older adults.

Enhancement of dieckol extraction yield from Ecklonia cava through optimization of major variables in generally recognized as safe solvent-based process

Ecklonia cava (EC), an edible brown macroalga abundant in intertidal areas of East Asia (Korea, Japan, and China), contains high-value bioactive compounds such as dieckol, which has antifungal, anti-inflammatory, antitumor, and antihyperlipidemic activities. However, no studies have been reported on the utilization of EC as a biorefinery feedstock, and the design of a more economical and high-yield process is required for the utilization of dieckol for the human healthcare industry. In this study, we designed a bioprocess for the high-yield recovery of dieckol from EC in a generally recognized as safe (GRAS) solvent to facilitate its application in the food and healthcare industries. Preliminary studies identified ethanol as an efficient solvent with the highest dieckol extraction yield (2.9 mg/g biomass). In order to maximize the recovery of dieckol from EC, the major extraction variables (solvent concentration, reaction temperature, and reaction time) were optimized based on statistical methods. Based on the predictive model, the numerical optimization determined that the solution with the highest dieckol content per weight of extract (62.6 vol% ethanol concentration, 54.2°C temperature, 13.2 min) was the optimal extraction condition. Under the determined conditions, the dieckol yield from EC achieved 6.4 mg dieckol/g EC (95.5% agreement with the predicted value). The designed process offers several advantages, including improving the utilization feasibility of EC, utilizing GRAS solvents with potential human applications, short extraction time (13.2 min), maximized process yield, and the highest dieckol recovery compared to previous reports.

Effects of auditory white noise stimulation on sustained attention and response time variability.

"The moderate brain arousal model" claims that white noise improves attention by optimizing brain arousal. We analyze Conners' Continuous Performance Test-3 (CCPT-3) performance, expecting to find reduced reaction time variability with noise mediated by decrease under long event-rates and in later parts of the test, indicating that noise reverse fall in phasic and tonic arousal. Sixty-five children with high or lower ADHD-symptoms from a child psychiatric unit, succeeded to complete the CCPT-3 with and without white noise. Noise reduced overall variability, improved performance in later parts of the test, and reduced response variability under the longest event rate particularly in the high symptoms group. No overall change in omissions and commissions, but the high symptoms group made fewer omissions during noise compared the low symptom group. The study indicates an arousal effect of noise but should be replicated with other noise variants and amplitudes to improve effect and compliance.

Attention deficit in primary-school-age children with attention deficit hyperactivity disorder measured with the attention network test: a systematic review and meta-analysis.

To review and meta-analyze patterns of attention deficit in primary-school-age children with ADHD measured with the neuropsychological attention network test (ANT). Six electronic databases were searched to 5.05.2022. Selection criteria included prospective cohort and intervention studies; ANT used; primary-school-age; diagnosis of ADHD/at high risk. Seven studies met inclusion criteria (N = 3,826). Compared with controls, children with ADHD had higher scores for Reaction Time (Hedges' g = 0.433; 95% CI: 0.135-0.731), Reaction Time Variability (Hedges' g = 0.334; 95% CI: 0.012-0.657), and Alerting Network (Hedges' g = 0.235; 95% CI: 0.021-0.449) while children at high risk had higher Alerting Network scores (Hedges' g = 0.176; 95% CI: 0.003-0.349) and Correctness scores (Hedges' g = 1.956; 95% CI: 0.020-3.892). Children with ADHD and at risk of ADHD had different ANT results from children without ADHD only for the alerting network. There were no significant differences for executive and orienting outcomes. Children at risk of ADHD also made more errors (commission and omission) measured with the ANT compared with children without ADHD. Reaction time was longer and reaction time variability higher in children with ADHD than in children without ADHD, and in children at risk of ADHD compared with children without ADHD. A protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO) database (registration number: CRD42021249768).

Modulatory effects of transcutaneous auricular vagus nerve stimulation (taVNS) on attentional processes

BackgroundThe modulatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) on attention has varied in previous studies. This inconsistency might be attributed to the combined influence of the modulation effect...

Naturalistic Assessment of Reaction Time Variability in Older Adults at Risk for Alzheimer’s Disease

AbstractBackgroundBreakdowns in attentional control may underscore cognitive changes seen in the earliest stages of Alzheimer’s disease (AD). One way to measure these changes is to assess variability in cognitive performance. Variability in cognition may be most evident when repeatedly sampled over hours or days and in different environmental contexts or at different times of day. We analyzed data from an ongoing smartphone‐based study of cognition in AD which utilizes extremely brief cognitive tests taken remotely over several days in natural environments.MethodOlder adults (N = 319, aged 75 +/‐ 5 years) completed repeated cognitive testing on the Ambulatory Research in Cognition (ARC) platform and had CSF or PET amyloid biomarkers and APOE genotype available. RTSD was assessed in a brief processing speed task by taking the SD of correct RTs. All models adjusted for baseline age, education, and gender.ResultAveraging across sessions, symptomatic participants (indicated by Clinical Dementia Rating® (CDR®) &gt; 0) showed more variability than asymptomatic (CDR 0) participants (p = 0.009). APOE ε4 carriers showed more variability than non‐carriers, although this was not significant (p = 0.067). More fine‐grained models considered RTSD within each session (e.g. from trial‐to‐trial) using mixed effects models. Symptomatic participants exhibited greater trial‐to‐trial RTSD compared to asymptomatic participants (p = 0.001). APOE ε4 carriers also exhibited greater trial‐to‐trial RTSD compared to non‐carriers (p = 0.004). When limiting the sample to asymptomatic participants to determine if there were changes in the preclinical stage of AD, there remained a strong APOE ε4 effect, with carriers exhibiting greater trial‐to‐trial RTSD than non‐carriers (p = 0.005). Interestingly, amyloid was not significant in any models.ConclusionOlder adults at risk for AD show increased RTSD even in brief assessments. These subtle fluctuations in attention were most evident in APOE e4 carriers at very short time intervals, and less so when averaged across trials and sessions. Overall, these findings suggest that fluctuations in attention in preclinical AD are most evident from moment to moment, highlighting the need for fine‐grained and repeated assessment of attentional control.

A combined experimental-correlational approach to the construct validity of performance-based and self-report-based measures of sustained attention.

The ability to sustain attention is often measured with either objective performance indicators, like within-person RT variability, or subjective self-reports, like mind wandering propensity. A more construct valid approach, however, may be to assess the covariation in these performance and self-report measures, given that each of these is influenced by different sources of measurement error. If the correlation between performance-variability and self-report measures reflects the sustained attention construct, then task manipulations aimed at reducing the sustained attention demands of tasks should reduce the correlation between them (in addition to reducing mean levels of variability and mind wandering). The current study investigated this claim with a combined experimental-correlation approach. In two experiments (Ns ~ 1,500 each), participants completed tasks that either maximized or minimized the demand for sustained attention. Our demand manipulations successfully reduced the mean levels of sustained attention failures in both the objective and subjective measures, in both experiments. In neither experiment, however, did the covariation between these measures change as a function of the sustained attention demands of the tasks. We can therefore claim only minimal support for the construct validity of our measurement approach to sustained attention.

Mesoporous configuration effects on the physicochemical features of hierarchical ZSM-5 supported cobalt oxide as catalysts in methane partial oxidation

Hierarchical porous system has become a prevalent method to overcome the diffusion limitation of conventional zeolites. Two types of mesopores characterized as intra-crystalline (mesopores in the zeolite pore wall) and inter-crystalline mesopores (meso-sized voids between nano-zeolite aggregates) could be formed in the synthesis of hierarchical zeolites. In an attempt to investigate the influence of mesopores structure on the physicochemical properties of hierarchical ZSM-5, specifically cobalt oxide impregnated ZSM-5 zeolite samples with intra- and inter-crystalline mesopores were synthesized through two different synthesis strategies. Analysis of the physicochemical properties of the as-modified hierarchical ZSM-5 catalysts were carried out using SEM, TEM, XPS, and H2-TPR which showed distinct features given by the two mesopores configurations. Co-oxide impregnated on ZSM-5 with inter-crystalline mesopores was dominated by Co(II) species, while Co-oxide/ZSM-5 showed a fair amount of Co(III) and Co(II). Furthermore, analysis of the catalytic activity was conducted using methane partial oxidation as a model reaction. With a variation in reaction time, various types of oxygenated products, i.e. methanol, formaldehyde, formic acid, and a small trace of carbon dioxide were observed. Catalytic results suggested that the Co-oxide/ZSM-5 material with inter-crystalline mesopores configuration is more active for the methane partial oxidation reaction compared to the Co-oxide/ZSM-5 with intracrystalline mesopores. This was confirmed by the formation of formaldehyde rather than methanol as the major product in the brief reaction time of 30 min.

Modulating the magnetic anisotropy in SmCo/Co nanocomposites through alteration in spin–orbit coupling

In the present work, one-dimensional (1-D) as-synthesized SmCo/Co magnetic nanocomposites were prepared through magnetically-assisted chemical reduction method. The samples were prepared with the varying reaction times between 1 and 10 h labelled as SC1, SC2, SC5, SC7 and SC10. The Rietveld refinement of XRD patterns revealed the presence of Sm(OH)3 (P63/m), hcp-Co (P63/mmc), cubic-Co (Fm-3 m) and Sm2Co17 (P63/mmc) phases with varying phase fractions. The nanocomposites were found to possess the highest aspect ratio (∼7) with lowest crystallite size (∼50 nm) along with the highest developed lattice strain in SC5. The decisive influence of the reaction time was observed on the magnetic response of the samples indicating highest saturation magnetization of ∼ 150 emu/g and effective magnetic anisotropy of ∼ 1.5 x 106 erg/cm3 in SC5. The generalized form of Bloch law was employed to study the origin of magnetic anisotropy determined as spin–orbit coupling which was found to be highest in SC5. It was suggested that the enhanced magnetic properties of the nanocomposites are attributable to the high fraction of magnetic phases with the soft magnetic character and coupling between multiple phases.

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders

ABSTRACTBackground: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (β = –0.208, t = –2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

Synthesis of AgFeO2 delafossite catalyst and its application for photo-degradation of dye present in solution

The present work highlights the physicochemical properties of a series of novel silver ferric oxide (AgFeO2) delafossite nanoparticles while employing them as photocatalysts under visible light irradiation. The first sample was synthesized by a facile co-precipitation route (AFO-0) while the second and third samples were prepared at a constant hydrothermal temperature (180 °C) with varying reaction time of 2 h (AFO-2) and 8 h (AFO-8) and all three samples were subjected to visible light irradiation to photo-degrade Malachite Green (MG) dye. The crystalline structure, morphology, functional groups, elemental analysis, and optical property was conducted by their respective characterization techniques. The size of nanocrystals increased with the hydrothermal time and the average particle size of AFO-0, AFO-2 and AFO-8 were 87.7 nm, 154 nm, and 209.3 nm respectively, with AFO-8 exhibiting prominent hexagonal flake-like morphology. The direct band gap of AFO-0, AFO-2 and AFO-8 were 2.74 eV, 2.53 eV and 2.11 eV respectively and the Urbach energy was 0.20 eV, 0.217 eV and 0.254 eV respectively. The photo generated charge isolation efficiency of the samples was conducted where charge recombination sequence was of the order: AFO-8<AFO-2<AFO-0. The sample AFO-8 exhibited the optimum performance which resulted in excellent degradation of MG under visible light irradiation based on all the batch study experiments using solution pH, comparative analysis, catalyst dose, initial pollutant concentration as parameters. Finally, the optimum conditions at which AFO-8 degraded 97 % of MG were: 80 mg catalyst dose, pH 8, 20 mg L−1 (100 mL) MG, 90 min reaction time, 30 °C temperature and 130 rpm agitation speed. As per the quenching tests, the OH° and O2°− radicals were the governing reactive species that were responsible for degrading MG.

17 Norming for the reverse-translated 5-choice continuous performance test (5C-CPT) of attention and cognitive control

Objective:Translatability of preclinical results remains a major obstacle in neuropsychiatric research. Even when cognitive tests in preclinical models show translational validity for human testing, with sensitivity to clinical deficits, there remains the issue of heterogeneity among human participants. Norming of performance on cognitive tasks enable corrections for any differences in performance that may arise from the influence of socioeconomic factors, and thus a more direct comparison with preclinical testing results. The 5-choice continuous performance task (5C-CPT) is a test sensitive to changes in sustained attention and cognitive control in rodent manipulations and clinical populations, including schizophrenia and bipolar disorder. Herein, we present normed results of 5C-CPT data from a cohort of human participants, enabling greater comparison to future clinical and rodent testing.Participants and Methods:5C-CPT data were generated from a range of participants from the Translational Methamphetamine AIDS Research Center (n=82) and a study of bipolar disorder (n=45). Participant demographics were as follows: Age M=38.5, SD=16.7, Education: M=14.5, SD=1.9, 45% female, 10% Asian, 17% African American, 27% Hispanic, and 46% non-Hispanic White. We used the test2norm R-package to create norms for each of the major outcomes from the 5C-CPT. Non-normally distributed raw scores were transformed to generate more normally distributed data needed for the norming process. Raw scores were first converted into uniform scaled scores that range from 0-20 where a higher score indicated better performance. We then generated T-score formulas, which are standardized residuals and scaled to have a mean of 50 and standard deviation of 10. The residuals are obtained from regressions, modeled using multiple fractional polynomial method (MFP), which regresses scaled scores on demographic variables, which a user wishes to control for (gender, age, education, ethnicity, etc.). MFP models allow to fit non-linear effects for numeric demographic factors (e.g., age), if such effects exist.Results:New, demographically corrected T-score formulas were calculated for each major outcome of the 5C-CPT: reaction time (MCL), reaction time variability (VarRT), dprime, hit rate (HR) and false-alarm rate (FAR). MFP models showed that age had a significant effect on MCL, VarRT, dprime, and HR (all p&lt;0.01), while gender only showed a significant effect for MCL and VarRT (all p&lt;0.05). Interestingly, education and ethnicity did not show a significant effect for any MFP model and none of the demographic factors (age, education, gender, ethnicity) were significant in the model for FAR. As defined in the test2norm package, all scaled scores had a mean of 10 and SD of 3 and all T-scores had a mean of 50 and SD of 10.Conclusions:The 5C-CPT is a test of attention and cognitive control available for human testing, reverse-translated from rodent studies. The normative data generated here will enable future comparisons of data without the need for additional control studies. Furthermore, comparing these normative data to manipulations will enable further comparisons to rodent testing, with manipulations relative to baseline becoming more meaningful. Thus, the 5C-CPT is a viable tool for conducting cross-species translational research toward developing novel therapeutics that treat dysfunctional attentional and cognitive control.

24 Mindfulness-based cognitive therapy enhances executive control in recurrent depression in a randomized wait-list controlled trial

Objective:Adults with recurrent depression have been shown to have cognitive deficits also while in remission. Thus, it has been suggested that with a chronic course of depression, poorer executive control can be a vulnerability factor for depressive relapse. This has led to research on how cognitive remediation training can protect against recurrent depressive episodes. Findings indicate that such training has short term effects on cognitive functioning, and small effect on depression symptoms. Less focus has been on how “standard” psychotherapy can have positive effects on executive and attentional control. Mindfulness-based cognitive therapy (MBCT) has been shown to be as effective as antidepressant medication in preventing relapses of depressive episodes. Mindfulness training in healthy samples seems to improve executive and attentional control. However, the few studies of MBCT in recurrent depression show mixed effects on executive and attentional control. As far as we know, no prior study has investigated the effect of MBCT in recurrent depression with the revised version of the attention network test (ANT-R). In a randomized controlled trial, we expected that the MBCT group would show enhanced executive control and lower levels of attentional fluctuations than the wait-list controls (WLC) from pre (T0) to post (T1) treatment. We further investigated if positive effects of MBCT on executive and attentional control were associated with reduction in depression symptoms.Participants and Methods:Adults with recurrent depression in partial or full remission (N = 64) were randomized to MBCT or WLC. In the MBCT and WLC groups, 25 and 29, respectively, performed the ANT-R at T0 and T1. The attention network reaction time scores of executive control, alerting, and orienting were calculated in addition to attention fluctuations scores of intra-individual reaction time variability (IIVRT) and exgaussian-mean of longer reaction times (TAU). Self-reported depression symptoms were measured with BDI-II. The two groups were compared at baseline on full-scale IQ (WASI), executive control (D-KEFS Stroop), and processing speed (D-KEFS TMT).Results:The MBCT and WCL groups did not differ significantly in age or gender distribution, education, full-scale IQ or in baseline executive and attentional control as measured with the ANT-R, Stroop and TMT. The MBCT group showed a higher efficiency in conflict detection as measured with the executive control score from T0 to T1 compared to the WLC. This positive effect of MBCT on executive control was independent from the greater reductions in depression symptoms in the MBCT group compared to in the WLCs. However, reduction in depression symptoms at T1 was associated with enhanced efficiency in responding to alerting cues in conflict detection. No effects of MBCT compared to WLC were found at T1 on the attention fluctuation measures (IIVRT and TAU).Conclusions:The findings from the current study indicates that MBCT enhances executive control in adults with recurrent depression. As such, MBCT may target an important cognitive vulnerability factor in the chronic course of recurrent depression that may contribute to its efficacy in preventing depressive relapses. It was also observed that reductions in depression symptoms led to higher alertness in conflict detection.