Switch Trials Research Articles

Left superior parietal lobe mediates the link between spontaneous mind-wandering tendency and task-switching performance

While increasing studies have documented the link between mind wandering and task switching, less is known about which brain regions mediate this relationship. Using the MPI-Leipzig Mind-Brain-Body dataset (N = 173), we investigated the association between trait-level tendencies of mind wandering, task-switching performance, structural connectivity, and resting-state functional connectivity. At the behavioral level, we found that higher spontaneous mind-wandering trait scores were associated with shorter reaction times on both repeat and switch trials. The whole brain cortical thickness analysis revealed a strong mediating role of the left superior parietal lobe, which is part of the dorsal attention network, in the link between spontaneous mind-wandering tendency and task-switching performance. The resting-state functional connectivity analysis further demonstrated that this association was partly mediated by the negative dorsal attention network-default mode network functional connectivity. No significant mediating effects were found for deliberate mind-wandering tendency. Overall, the findings highlight the pivotal role of the left superior parietal lobe in activating new mental set during mind-wandering and task-switching processes, providing another evidence in favor of a role for switching in mind wandering.

1587. SOLAR 12-Month North American Results: Randomized Switch Trial of CAB+RPV LA vs. Oral BIC/FTC/TAF

Abstract Background Cabotegravir + rilpivirine (CAB+RPV) administered monthly or every 2 months (Q2M) is the only complete long-acting (LA) regimen for maintaining HIV-1 suppression and may address challenges associated with daily oral therapy. In the Phase 3b SOLAR study, switching to CAB+RPV LA Q2M was noninferior to continuing daily oral bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). We present results for North American (NA; United States and Canada) participants. Methods SOLAR (NCT04542070) is the first randomized (2:1), open-label, multicenter, noninferiority study assessing switching virologically suppressed adults to CAB+RPV LA Q2M (with oral lead-in or starting with injections) vs. continuing BIC/FTC/TAF. The primary analysis was based on the prespecified modified intention-to-treat exposed (mITT-E) population (n=11 from 1 study site excluded from the ITT-E population for protocol deviation) at Month (M) 12. The primary endpoint was the proportion with plasma HIV-1 RNA ≥50 c/mL. Other endpoints were the proportion with plasma HIV-1 RNA < 50 c/mL, incidence of confirmed virologic failure (CVF; 2 consecutive HIV-1 RNA ≥200 c/mL), safety and tolerability (ITT-E), and treatment satisfaction (HIV Treatment Satisfaction Questionnaire status version [HIVTSQs]). Results Of 670 participants (mITT-E), 325 were from North America; 66% (n=216/325) switched to LA and 34% (n=109/325) continued BIC/FTC/TAF. Baseline (BL) characteristics were similar between arms (Table 1). At M12, 1 participant in each arm had HIV-1 RNA ≥50 c/mL (Table 2). No NA participant had CVF in the mITT-E population; 1 (0.3%) NA participant excluded from the mITT-E population due to protocol violation had CVF (LA arm). Adverse events (AEs), excluding injection site reactions (ISRs), were similar between the LA (74% [n=164/223]) and BIC/FTC/TAF arms (73% [n=83/113]). More participants in the LA vs. BIC/FTC/TAF arm withdrew due to AEs (8% [n=17/223] vs. < 1% [n=1/113]). Mean adjusted HIVTSQs scores improved significantly (p< 0.001) from BL to M12 for LA (+3.40) vs. BIC/FTC/TAF (–1.07) participants. Conclusion Consistent with the overall SOLAR study population, switching to CAB+RPV LA from BIC/FTC/TAF was efficacious and well tolerated, with improved treatment satisfaction, in NA participants. Disclosures Mehri McKellar, MD, Gilead Sciences, Inc: Grant/Research Support Paula Teichner, PharmD, GlaxoSmithKline: Stocks/Bonds|ViiV Healthcare: Employment Jonathan Angel, MD, Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Gilead: Honoraria|Merck: Grant/Research Support|ViiV Canada: Advisor/Consultant|ViiV Canada: Grant/Research Support|ViiV Canada: Honoraria Lori A. Gordon, PharmD, ViiV Healthcare: Stocks/Bonds Kenneth Sutton, MA, ViiV Healthcare: Employment|ViiV Healthcare: Stocks/Bonds Denise Sutherland-Phillips, MD, ViiV Healthcare: Employment|ViiV Healthcare: Stocks/Bonds Christine L. Talarico, M.S., ViiV Healthcare: Stocks/Bonds Rimgaile Urbaityte, MSc, GSK: Employment|GSK: Stocks/Bonds Rodica Van Solingen-Ristea, MD, Janssen R&D: Employee Bryan Baugh, MD, Johnson & Johnson: Stocks/Bonds Ronald D'Amico, DO, MSc, ViiV Healthcare Ltd: Stocks/Bonds Jean A. van Wyk, MBChB, MFPM, ViiV Healthcare Ltd: Stocks/Bonds

41 Adaptive Implementation of Cognitive Control in School-Aged Children with ADHD: A Diffusion-Model Analysis

Objective:Because cognitive resources are limited, models of cognitive control predict that additional control is engaged only if it improves task performance. Increased response caution, which occurs when individuals increase the threshold of information needed before making a decision, is one example of cognitive control adaptation. While previous studies have measured increased response caution via increased reaction time, the diffusion model can be used to derive a boundary separation parameter that directly indexes response caution and eliminates capturing alternative influences on reaction time. This study aims to determine if school-aged children, either with or without ADHD, show adaptive changes in response caution during a set-shifting task. These groups have demonstrated mixed results when analyzing reaction time, so this study utilizes diffusion modeling to measure response caution more directly. The set-shifting task presents switches in a random order such that they cannot be predicted; therefore, increasing response caution is only adaptive following errors, called post-error slowing (PES), but not following switch trials. It is predicted that children will show increased response caution only when adaptive. If child with ADHD adapt their response caution fundamentally differently, then there will be individual differences in change in boundary separation.Participants and Methods:Children ages 8-12 with (n=193) and without (n=70) ADHD completed the Navon set-shifting task. Participants saw one of four global shapes made up of local shapes and were asked to identify one or the other based upon the background color. Of the 144 trials, 70 presented a switch between global and local. Trials were presented in the same randomized order for all participants, self-paced, and followed by feedback on correctness. The diffusion model parameters boundary separation (a), drift rate (v), and nondecision time (Ter) were estimated by condition, including a) post-error versus after correct and b) post-switch versus post-same. For PES analyses, only participants with a sufficient number of errors for modeling were included (ADHD n=113, control n=19).Results:Participants were slower on trials immediately following errors (F(1, 130)=119.76, p<.001, n2=.48) and switches (F(1, 261)=154.93, p<.001, n2=.37). In PES, slowing was attributable to increased boundary separation, F(1, 130)=16.11, p<.001, n2=.11, as well as slower drift rate and longer nondecision time (both p<.01, n2 >.05). However, as predicted, post-switch slowing was only attributable slower drift rate and longer nondecision time (both p<.001, n2 >.10), not increased boundary separation, F(1, 261)=0.77, p=.38, n2<.01. Overall, children with ADHD had slower drift rates (F(1, 261)=4.63, p<.001, n2=.10) and narrower boundary separation (F(1, 261)=10.56, p=.001, n2=.04). However, there were no ADHD x trial-type interactions for PES or post-switch (both p>.33, n2<.01).Conclusions:School-aged children demonstrated increased response caution following errors, but not following switches. This demonstrates an adaptive use of cognitive control. The diffusion model was crucial in determining this, as reaction time slowed following switches for reasons unrelated to cognitive control. Additionally, although children with ADHD demonstrated slower drift rates and narrower boundary separation overall, they showed no differences when adapting response caution.

Reversed asymmetrical switch costs in voluntary language switching: Evidence from typed responses

Aims and objectives/purpose/research questions: Prior research has put forward that asymmetrical switch costs in language switching do not occur when bilinguals are in a voluntary language-switching context. While several studies have provided evidence along these lines, two very recent studies have put this into question. This study further investigates the possibility that voluntary language switching abolishes asymmetrical switch costs. Design/methodology/approach: We presented German-English bilinguals ( n = 79) with pictures that had to be named in either German or English, whichever they chose, by typing. Data and analysis: Reaction times (both the latency of the first keystroke and interkeystroke intervals) were analyzed using linear mixed-effects regression modeling with the factors Trial type (switch vs. repetition trial) and Language (German vs. English), whereas the error rates were analyzed using logistic mixed-effects regression modeling. Findings/conclusions: The onset latencies and inter-keystroke intervals both showed larger second-language (English) than first-language (German) switch costs (i.e., reversed asymmetrical switch costs). As switch costs were modulated by language dominance in a voluntary language-switching context, this study provides evidence that voluntary language switching is not a boundary condition for asymmetrical switch costs. Originality: In contrast to most previous language-switching studies, we used typed rather than vocal responses in a voluntary language-switching paradigm. In addition, our findings further support and generalize very recent findings of (reversed) asymmetrical switch costs in voluntary language switching. Significance/implications: Since asymmetrical switch costs, an important measure of bilingual inhibitory control, are not consistently observed throughout the language-switching literature, it is essential to understand its boundary conditions.

THU173 Subanalysis By Tanner Stage In Phase 3 Trials In Children And Adolescents With Growth Hormone Deficiency Treated With Lonapegsomatropin

Abstract Disclosure: P. Hofman: Speaker; Self; Novo Nordisk, Eli Lilly & Company. P.S. Thornton: Research Investigator; Self; Ascendis, Pfizer, Inc., Opko, Zealand, Rezolute, Spruce. Other; Self; Johnson &Johnson, Rezolute. U.M. Nadgir: None. P. Saenger: None. E. Chertok: None. E.M. Aghajanova: Speaker; Self; Berlin Hemi Menarini. M. Mao: Employee; Self; Ascendis Pharma. C. Zhao: Employee; Self; Ascendis Pharma. M.R. Ochoa-Maya: Employee; Self; Ascendis Pharma. A. Komirenko: Employee; Self; Ascendis Pharma. A.D. Shu: Employee; Self; Ascendis Pharma. A.K. Maniatis: Advisory Board Member; Self; Novo Nordisk, Ascendis Pharma, Pfizer, Inc. Consulting Fee; Self; Novo Nordisk, Ascendis Pharma. Research Investigator; Self; Novo Nordisk, Pfizer, Inc., OPKO, Ascendis Pharma. Speaker; Self; Novo Nordisk, Ascendis Pharma. Background: Historically, the treatment paradigm in pediatric growth hormone deficiency (GHD) has been to consider increased doses (up to 0.7 mg hGH/kg/week) later in pubertal development to maximize growth outcomes, although this is not a routine recommendation (Mauras et al. JCEM. 2000;85(10):3653-3660, Grimberg et al. Horm Res Paeds. 2016;86(6):361-397). The enliGHten open-label extension trial of once-weekly lonapegsomatropin provided the opportunity to evaluate dosing, efficacy, and safety outcomes in a group of children that includes more advanced Tanner Stages. Lonapegsomatropin (TransCon hGH), a once-weekly prodrug of somatropin approved for the treatment of pediatric GHD by the FDA and EMA, uses TransCon technology to transiently link a parent drug to an inert carrier. In the pivotal phase 3 heiGHt trial, lonapegsomatropin demonstrated noninferior and superior annualized height velocity and a comparable safety profile to daily somatropin in children with GHD. The current analysis explores IGF-1 levels, dose adjustments, and height outcomes by Tanner Stage. Methods: Three phase 3 trials assessed safety and efficacy of lonapegsomatropin: heiGHt (treatment-naïve trial), fliGHt (switch trial), and enliGHten (open-label extension trial). Participants treated in the 3 phase 3 trials were included in this analysis (data snapshot date, September 1, 2021). Data were analyzed by the most recent Tanner Stage at time of assessment in 3 groups: Stage 1 and 2; Stage 3; and Stage 4 and 5. Association between Tanner Stage and IGF-1 SDS measurements, lonapegsomatropin dose, and height SDS were examined using mixed repeated models with Tanner stage as time-varying covariate. Relationship between dose reduction and change in IGF-1 SDS was summarized by Tanner stage. Results: With a mean follow-up of 157 weeks (N=306) on lonapegsomatropin treatment, the analysis showed that later Tanner Stages (3, 4-5) were correlated with higher average IGF-1 SDS (versus Stages 1-2). There was a small difference in lonapegsomatropin dose across Tanner Stage groups, with participants in Stages 4-5 receiving the lowest mean dose (0.19 mg hGH/kg/wk) compared with Stages 1-2 (0.23 mg hGH/kg/wk) or Stage 3 (0.22 mg hGH/kg/wk). Among patients with dose reduction, a decrease of lonapegsomatropin of 0.02 mg hGH/kg corresponded to a consistent drop in average IGF-1 SDS across all Tanner Stages (overall, 0.16 SDS; Stages 1-2, 0.21 SDS; Stage 3, 0.16 SDS; Stages 4-5, 0.21 SDS). Participants across all subgroups experienced continued growth as expected over time. Conclusions: This analysis showed that it was possible to maintain consistent height SDS improvements in children and adolescents in Tanner Stages 3-5 without an increase in the mean lonapegsomatropin dose. Lonapegsomatropin dose reductions resulted in predictable linear IGF-1 decreases across Tanner Stages. Presentation: Thursday, June 15, 2023

Task sets define boundaries of learned cognitive flexibility in list-wide proportion switch manipulations.

Different contexts in daily life often require varying levels of cognitive flexibility. Previous research has shown that people adapt their level of flexibility to match changing contextual demands for task switching in cued-switching paradigms that vary the proportion of switch trials within lists of trials. Specifically, the behavioral costs of switching as opposed to repeating tasks scale inversely with the proportion of switches-a finding referred to as the list-wide proportion switch (LWPS) effect. Previous research found that flexibility adaptations transferred across stimuli, but were specifically tied to task sets, rather than block-wide changes in flexibility state. In the current study, we conducted additional tests of the hypothesis that flexibility learning is task specific in the LWPS paradigm. In Experiments 1 and 2, we used trial-unique stimuli and unbiased task cues to control for associative learning tied to stimulus or cue features. Experiment 3 further tested whether task-specific learning occurred even for tasks performed on integrated features of the same stimuli. Across these three experiments, we found robust task-specific flexibility learning, which transferred across novel stimuli and unbiased cues and occurred regardless of stimulus-feature overlap between tasks. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Proactive and reactive language control in bilingual language production revealed by decoding sustained potentials and electroencephalography oscillations.

Adopting highly sensitive multivariate electroencephalography (EEG) and alpha-band decoding analyses, the present study investigated proactive and reactive language control during bilingual language production. In a language-switching task, Chinese-English bilinguals were asked to name pictures based on visually presented cues. EEG and alpha-band decoding accuracy associated with switch and non-switch trials were used as indicators for inhibition over the non-target language. Multivariate EEG decoding analyses showed that the decoding accuracy in L1 but not in L2, was above chance level shortly after cue onset. In addition, alpha-band decoding results showed that the decoding accuracy in L1 rose above chance level in an early time window and a late time window locked to the stimulus. Together, these asymmetric patterns of decoding accuracy indicate that both proactive and reactive attentional control over the dominant L1 are exerted during bilingual word production, with a possibility of overlap between two control mechanisms. We addressed theoretical implications based on these findings for bilingual language control models.

An fMRI study of inflectional encoding in spoken word production: Role of domain-general inhibition

A major issue concerning inflectional encoding in spoken word production is whether or not regular forms (e.g., past tense walked) are encoded by rule application and irregular forms (e.g., swam) by retrieval from associative memory and inhibition of the regular rule. We used functional magnetic resonance imaging (fMRI) to examine the involvement of domain-general inhibition, thought to be underpinned by right inferior frontal gyrus (IFG), right pre-supplementary motor area (SMA), and right basal ganglia. Participants were presented with infinitive verbs that take either regular or irregular past tense. They switched between producing the past tense of these regular and irregular verbs in one block, and between inflecting or reading these infinitive verbs aloud in another block. As concerns corticobasal areas, compared to reading, inflecting activated left IFG and left preSMA/SMA. Regulars yielded higher activation than irregulars in these frontal areas, both on switch and repeat trials, which did not differ in activation. Switching between inflecting and reading activated left preSMA/SMA. These results indicate that inflectional encoding, and switching between inflecting and reading, engage frontal areas in the left hemisphere, including left preSMA/SMA for both and left IFG for inflecting, without recruiting the domain-general inhibition circuitry in the right hemisphere. We advance an account of inflectional encoding in spoken word production that assumes a distinction between regulars and irregulars, but without engaging domain-general inhibition.

Planning ahead: Predictable switching recruits task-active and resting-state networks.

Switching is a difficult cognitive process characterised by costs in task performance; specifically, slowed responses and reduced accuracy. It is associated with the recruitment of a large coalition of task-positive regions including those referred to as the multiple demand cortex (MDC). The neural correlates of switching not only include the MDC, but occasionally the default mode network (DMN), a characteristically task-negative network. To unpick the role of the DMN during switching we collected fMRI data from 24 participants playing a switching paradigm that perturbed predictability (i.e., cognitive load) across three switch dimensions-sequential, perceptual, and spatial predictability. We computed the activity maps unique to switch vs. stay trials and all switch dimensions, then evaluated functional connectivity under these switch conditions by computing the pairwise mutual information functional connectivity (miFC) between regional timeseries. Switch trials exhibited an expected cost in reaction time while sequential predictability produced a significant benefit to task accuracy. Our results showed that switch trials recruited a broader activity map than stay trials, including regions of the DMN, the MDC, and task-positive networks such as visual, somatomotor, dorsal, salience/ventral attention networks. More sequentially predictable trials recruited increased activity in the somatomotor and salience/ventral attention networks. Notably, changes in sequential and perceptual predictability, but not spatial predictability, had significant effects on miFC. Increases in perceptual predictability related to decreased miFC between control, visual, somatomotor, and DMN regions, whereas increases in sequential predictability increased miFC between regions in the same networks, as well as regions within ventral attention/ salience, dorsal attention, limbic, and temporal parietal networks. These results provide novel clues as to how DMN may contribute to executive task performance. Specifically, the improved task performance, unique activity, and increased miFC associated with increased sequential predictability suggest that the DMN may coordinate more strongly with the MDC to generate a temporal schema of upcoming task events, which may attenuate switching costs.

An object's categorizability impacts whether infants encode surface features into their object representations.

Infants encode the surface features of simple, unfamiliar objects (e.g., red triangle) and the categorical identities of familiar, categorizable objects (e.g., car) into their representations of these objects. We asked whether 16-18-month-olds ignore non-diagnostic surface features (e.g., color) in favor of encoding an object's categorical identity (e.g., car) when objects are from familiar categories. In Experiment 1 (n=18), we hid a categorizable object inside an opaque box. In No Switch trials, infants retrieved the object that was hidden. In Switch trials, infants retrieved a different object: an object from a different category (Between-Category-Switch trials) or a different object from the same category (Within-Category-Switch trials). We measured infants' subsequent searching in the box. Infants' pattern of searching suggested that only infants who completed a Within-Category-Switch trial as their first Switch trial encoded objects' surface features, and an exploratory analysis suggested that infants who completed a Between-Category-Switch trial as their first Switch trial only encoded objects' categories. In Experiment 2 (n=18), we confirmed that these results were due to objects' categorizability. These results suggest infants may tailor the way they encode categorizable objects depending on which object dimensions are perceived to be task relevant.

The Effect of Phonetic Similarity on Domain-General Executive Control in Color-Shape Task: Evidence from Cantonese-Mandarin and Beijing-Dialect-Mandarin Bidialectals.

The present study was carried out to investigate whether bidialectals have a similar advantage in domain-general executive function as bilinguals and if so whether the phonetic similarity between two different dialects can modulate the executive function performance in the conflicting-switching task. The results showed that the latencies for switching trials in mixed block (SMs) were longest, non-switching trials in mixed block (NMs) were medium, and non-switching trials in pure block (NPs) were the shortest in the conflict-switching task in all three groups of participants. Importantly, the difference between NPs and NMs varied as a function of phonetic similarity between two dialects with Cantonese-Mandarin bidialectal speakers being the minimum, Beijing-dialect-Mandarin bidialectals medium, and Mandarin native speakers maximum. These results provide strong evidence that there is an advantage in balanced bidialectals's executive function which is modulated by the phonetic similarity between two dialects suggesting that phonetic similarity plays an important role in domain-general executive function.

Consequences of scarcity: the impact of perceived scarcity on executive functioning and its neural basis.

Previous studies have found a causal relationship between scarcity and the adverse impact it has on executive functioning. However, few studies have directly examined perceived scarcity, and cognitive flexibility (the third component of executive functions) has rarely been included. Using a 2 (group: scarcity group vs. control group) × 2 (trial type: repeat trial vs. switch trial) mixed design, this study directly explored perceived scarcity's impact on cognitive flexibility and revealed its neural basis in the switching tasks. Seventy college students participated in this study through open recruitment in China. A priming task was used to induce perceived scarcity, thus exploring the impact of perceived scarcity on participants' performance in switching tasks and enabling the analysis of the neural activity of the brain, combined with electroencephalograph (EEG) technology. In terms of behavioral outcomes, perceived scarcity led to poorer performance and a greater switching cost of reaction time in the switching tasks. Regarding neural activity, perceived scarcity led to an increase in the amplitude of P3 differential wave (repeat trials minus switch trials) in the parietal cortex during the target-locked epochs in the switching tasks. Perceived scarcity can lead to changes in the neural activity of the brain regions related to executive functioning, resulting in a temporary decrease in cognitive flexibility. It may lead to individuals unable to adapt well to the changing environment, unable to quickly devote themselves to new tasks, and reduce work and learning efficiency in daily life.

Behavioral and oscillatory signatures of switch costs in highly proficient bilinguals

Bilinguals with a high proficiency in their first (L1) and second language (L2) often show comparable reaction times when switching from their L1 to L2 and vice-versa (“symmetrical switch costs”). However, the neurophysiological signatures supporting this effect are not well understood. Here, we ran two separate experiments and assessed behavioral and MEG responses in highly proficient Spanish-Basque bilinguals while they overtly name pictures in a mixed-language context. In the behavioral experiment, bilinguals were slower when naming items in switch relative to non-switch trials, and this switch cost was comparable for both languages (symmetrical). The MEG experiment mimicked the behavioral one, with switch trials showing more desynchronization than non-switch trials across languages (symmetric neural cost) in the alpha band (8–13 Hz). Source-localization revealed the engagement of right parietal and premotor areas, which have been linked to language selection and inhibitory control; and of the left anterior temporal lobe (ATL), a cross-linguistic region housing conceptual knowledge that generalizes across languages. Our results suggest that highly proficient bilinguals implement a language-independent mechanism, supported by alpha oscillations, which is involved in cue-based language selection and facilitates conceptually-driven lexical access in the ATL, possibly by inhibiting non-target lexical items or disinhibiting target ones.

Commonalities between mind wandering and task-set switching: An event-related potential study

Previous research has established that mind wandering does not necessarily disrupt one's task-switching performance. Here we investigated the effects of mind wandering on electrophysiological signatures, measured using event-related potentials (ERPs), during a switching task. In the current study, a final sample of 22 young adults performed a task-switching paradigm while electroencephalography was continuously recorded; mind wandering was assessed via thought probes at the end of each block. Consistent with previous research, we found no significant disruptive effects of mind wandering on task-switching performance. The ERP results showed that at the posterior electrode sites (P3, Pz, and P4), P3 amplitude was higher for mind-wandering switch trials than on-task switch trials, thus opposing the typical pattern of P3 attenuation during periods of mind wandering relative to on-task episodes. Considering that increased P3 amplitude during higher-order switch trials (e.g., response rule switching) may reflect the implementation of new higher-order task sets/rules, the current findings seem to indicate similar executive control processes underlie mind wandering and task-set switching, providing further evidence in favor of a role for switching in mind wandering.

Older adults compensate for switch, but not mixing costs, relative to younger adults on an intrinsically cued task switching experiment.

Aging negatively impacts the ability to rapidly and successfully switch between two or more tasks that have different rules or objectives. However, previous work has shown that the context impacts the extent of this age-related impairment: while there is relative age-related invariance when participants must rapidly switch back and forth between two simple tasks (often called "switch costs"), age-related differences emerge when the contexts changes from one in which only one task must be performed to one in which multiple tasks must be performed, but a trial-level switch is not required (e.g., task repeat trials within dual task blocks, often called "mixing costs"). Here, we explored these two kinds of costs behaviorally, and also investigated the neural correlates of these effects. Seventy-one younger adults and 175 older adults completed a task-switching experiment while they underwent fMRI brain imaging. We investigated the impact of age on behavioral performance and neural activity considering two types of potential costs: switch costs (dual-task switch trials minus dual-task non-switch trials), and mixing costs (dual-task non-switch minus single-task trials). We replicated previous behavioral findings, with greater age associated with mixing, but not switch costs. Neurally, we found age-related compensatory activations for switch costs in the dorsal lateral prefrontal cortex, pars opercularis, superior temporal gyrus, and the posterior and anterior cingulate, but age-related under recruitment for mixing costs in fronto-parietal areas including the supramarginal gyrus and pre and supplemental motor areas. These results suggest an age-based dissociation between executive components that contribute to task switching.

English-Learning 12-Month-Olds Do Not Map Function-Like Words to Objects

ABSTRACT By 12 months, English-learning infants have an awareness of the sound patterns of word forms that constitute acceptable labels for objects in their native language. In the following experiments, we replicated and extended previous findings that Canadian English-learning infants will not link function-like words with novel objects. Across three experiments using the Switch task, 101 infants living in Calgary, Canada, were habituated to two CV and VC word-object pairings. At test, infants did not look longer on the Switch trial and the Same trial, suggesting they did not form word-object associations between prototypical function words and a novel object in any of the experiments (ps>0.5). This set of null results extends prior research showing that Canadian English-learning infants will not link function-like words with novel objects and suggests that infants’ prior experience with their native language may constrain their learning of novel labels.

Novelty and learning in cognitive control: evidence from the Simon task

While information that is associated with inappropriate responses can interfere with an ongoing task and be detrimental to performance, cognitive control mechanisms and specific contextual conditions can alleviate interference from unwanted information. In the spatial correspondence (Simon) task, interference has been consistently shown to be reduced by spatial non-correspondence in the previous trial (i.e., correspondence sequence effect, CSE); however the mechanisms supporting this sequential effect are not well understood. Here we investigated the role of novelty and trial-to-trial changes in stimulus and response features in a Simon task, observing similar modulation of CSE for novel and non-novel stimulus changes. However, changing the response modality from trial to trial dampened CSE, and this dampening was more pronounced when the probability of switch trials was higher, suggesting a role for long-term learning. The results are consistent with recent accounts, which indicate that spatial interference can be prevented by cognitive control mechanisms triggered by learned bindings.

Influences of cognitive control on number processing: New evidence from switching between two numerical tasks.

A growing body of research suggests that basic numerical abilities such as number magnitude and number parity processing are influenced by cognitive control. So far, however, evidence for number processing being influenced by cognitive control came primarily from observed adaptations to stimulus set characteristics (e.g., ratio or order of specific stimulus types) and switches between a numerical and non-numerical task. Complementing this previous research, the present study employed a task switching paradigm exclusively involving numerical tasks (i.e., magnitude comparisons and parity judgements) to examine how cognitive control processes influence number processing. Participants were presented with a single-digit number and had to either judge its parity or compare its magnitude with a standard of 5, depending on a preceding cue. Based on previous results, we expected the numerical distance effect and the spatial-numerical association of response codes (SNARC) effect to be modulated in switch trials requiring the exertion of cognitive control. Partly in line with our expectations, the numerical distance effect was reduced in switch trials. However, no modulation of the SNARC effect was observed. The results pattern suggests that number processing is influenced by cognitive control, depending on task requirements and the type of numerical information (i.e., numerical magnitude vs spatial association of numbers) that is processed. To reconcile the present and previous results, we propose an information prioritisation account, suggesting that cognitive control primarily influences the processing of the information type that requires the most explicit processing.

Bictegravir/emtricitabine/tenofovir alafenamide plus doravirine in highly treatment-experienced men with multidrug-resistant HIV.

To evaluate the safety and efficacy of switching highly treatment-experienced people with HIV (HTE PWH) from rilpivirine/emtricitabine/tenofovir alafenamide (RPV/FTC/TAF) plus dolutegravir (DTG) to bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) plus doravirine (DOR). A pharmacokinetic (PK) analysis was conducted to assess the potential interaction between BIC and DOR. This open-label switch trial enrolled HTE PWH from a primary care private practice in the United States. Eligible participants were male, aged ≥45 years, with documented viral resistance to protease inhibitors, nucleoside reverse transcriptase inhibitors, and/or nonnucleoside reverse transcriptase inhibitors but no resistance to RPV or DOR, and no K65R or T69 insertion mutations. Virologic suppression (≤50 copies/ml) while on RPV/FTC/TAF plus DTG for ≥6 months was required prior to enrollment. The primary endpoint of the study was virologic suppression (<50 and <200 copies/ml) at 48 weeks. Secondary endpoints included safety, tolerability, changes in body mass index (BMI), and identification of PK parameters of BIC and DOR. Twenty males [median age: 65 years (range, 46-74), median time since HIV diagnosis: 37 years (range, 12-42)] completed the study. BIC/FTC/TAF plus DOR was well tolerated with no serious or treatment-related adverse events reported and no appreciable changes in BMI from baseline to Week 48. At Week 48, 100% of participants had <50 viral copies/ml. PK parameters for BIC and DOR ( n = 10) were consistent with published data. Switching from RPV/FTC/TAF plus DTG to BIC/FTC/TAF plus DOR was well tolerated and efficacious in HTE men aged ≥45 years with HIV.

Temporal dynamics of cognitive flexibility in adolescents with anorexia nervosa: A high-density EEG study.

Impairment in cognitive flexibility is a core symptom of anorexia nervosa (AN) and is associated with treatment resistance. Nevertheless, studies on the neural basis of cognitive flexibility in adolescent AN are rare. This study aimed to investigate brain networks underlying cognitive flexibility in adolescents with AN. To address this aim, participants performed a Dimensional Change Card Sorting task during high-density electroencephalography (EEG) recording. Anxiety was measured with the State-Trait Anxiety Inventory. Data were collected on 22 girls with AN and 23 controls. Evoked responses were investigated using global-spatial analysis. Adolescents with AN showed greater overall accuracy, fewer switch trial errors and reduced inverse efficiency switch cost relative to controls, although these effects disappeared after adjusting for trait and state anxiety. EEG results indicated augmented early visual orienting processing (P100) and subsequent impaired attentional mechanisms to task switching (P300b) in subjects with AN. During task switching, diminished activations in subjects with AN were identified in the posterior cingulate, calcarine sulcus and cerebellum, and task repetitions induced diminished activations in a network involving the medial prefrontal cortex, and several posterior regions, compared with controls. No significant associations were found between measures of cognitive flexibility and anxiety in the AN group. Findings of this study suggest atypical neural mechanisms underlying cognitive flexibility in adolescents with AN. More importantly, our findings suggest that different behavioural profiles in AN could relate to differences in anxiety levels. Future research should investigate the efficacy of cognitive training to rebalance brain networks of cognitive flexibility in AN.