Lower Cognitive Set Shifting Ability Is Associated With Stiffer Balance Recovery Behavior and Larger Perturbation-Evoked Cortical Responses in Older Adults

The mechanisms underlying associations between cognitive set shifting impairments and balance dysfunction are unclear. Cognitive set shifting refers to the ability to flexibly adjust behavior to changes in task rules or contexts, which could be involved in flexibly adjusting balance recovery behavior to different contexts, such as the direction the body is falling. Prior studies found associations between cognitive set shifting impairments and severe balance dysfunction in populations experiencing frequent falls. The objective of this study was to test whether cognitive set shifting ability is expressed in successful balance recovery behavior in older adults with high clinical balance ability (N = 19, 71 ± 7 years, 6 female). We measured cognitive set shifting ability using the Trail Making Test and clinical balance ability using the miniBESTest. For most participants, cognitive set shifting performance (Trail Making Test B-A = 37 ± 20 s) was faster than normative averages (46 s for comparable age and education levels), and balance ability scores (miniBESTest = 25 ± 2/28) were above the threshold for fall risk (23 for people between 70 and 80 years). Reactive balance recovery in response to support-surface translations in anterior and posterior directions was assessed in terms of body motion, muscle activity, and brain activity. Across participants, lower cognitive set shifting ability was associated with smaller peak center of mass displacement during balance recovery, lower directional specificity of late phase balance-correcting muscle activity (i.e., greater antagonist muscle activity 200–300 ms after perturbation onset), and larger cortical N1 responses (100–200 ms). None of these measures were associated with clinical balance ability. Our results suggest that cognitive set shifting ability is expressed in balance recovery behavior even in the absence of profound clinical balance disability. Specifically, our results suggest that lower flexibility in cognitive task performance is associated with lower ability to incorporate the directional context into the cortically mediated later phase of the motor response. The resulting antagonist activity and stiffer balance behavior may help explain associations between cognitive set shifting impairments and frequent falls.

Contributions of Demographics, Language Learning Experience, and Cognitive Control to Chinese Reading Comprehension

The study investigates whether learners’ demographics (e.g., age, education, and intelligence-IQ), language learning experience, and cognitive control predict Chinese (L2) reading comprehension in young adults. Thirty-four international students who studied mandarin Chinese in mainland China (10 females, 24 males) from Bangladesh, Burundi, Congo, Madagascar, Nigeria, Rwanda, South Africa, and Zimbabwe were tested on a series of measures including demographic questionnaires, IQ test, two cognitive control tasks [Flanker Task measuring inhibition and Wisconsin Card Sorting Test (WCST) measuring mental set shifting], and a Chinese reading comprehension test (HSK level 4). The results of correlation analyses showed that education, L2 learning history, L2 proficiency, and previous category errors of the WCST were significantly correlated with Chinese reading comprehension. Further multiple regression analyses indicated that Chinese learning history, IQ, and previous category errors of the WCST significantly predicted Chinese reading comprehension. These findings reveal that aside from IQ and the time spent on L2 learning, the component mental set shifting of cognitive control also predicts reading outcomes, which suggests that cognitive control has a place in reading comprehension models over and above traditional predictors of language learning experience.

Sociolinguistic Diversity Can Boost Cognitive Functions

This study investigates the link between sociolinguistic diversity and executive functions. 127 healthy adults from Malaysia were recruited to complete three cognitive tasks and the Contextual Linguistic Profile Questionnaire (CLiP-Q). A sociolinguistic diversity score was derived for each participant, with a higher score reflecting a greater exposure and use of diverse languages both at the individual and the societal level. The results demonstrated a sociolinguistic diversity advantage in cognitive functions. Higher sociolinguistic diversity scores were associated with lesser interference in the Flanker task and better accuracy in the 2-back task. Additionally, a significant interaction between sociolinguistic diversity and socioeconomic status was found for the set-shifting task, showing that sociolinguistic diversity could reduce mixing costs and improve set-shifting task accuracy for low socioeconomic status participants who are usually disadvantaged in cognitive control. Thus, it is important for research in the multilingualism field to take sociolinguistic diversity context into account.

A Hierarchical Reinforcement Learning Model Explains Individual Differences in Attentional Set Shifting

Attentional set shifting refers to the ease with which the focus of attention is directed and switched. Cognitive tasks such as CANTAB IED reveal great variation in set shifting ability in the general population, with notable impairments in those with psychiatric diagnoses. The attentional and learning processes underlying this cognitive ability, and how they lead to the observed variation remain unknown. To directly test this, we used a modelling approach on two independent large-scale online general-population samples performing CANTAB IED and psychiatric symptom assessment. We found a hierarchical model that learnt both feature values and dimension attention best explained the data, and that compulsive symptoms were associated with slower learning and higher attentional bias to the first relevant stimulus dimension. This data showcase a new methodology to analyse data from the CANTAB IED task, and suggest a possible mechanistic explanation for the variation in set shifting performance, and its relationship to compulsive symptoms.

Infralimbic BDNF signaling is necessary for the beneficial effects of extinction on set shifting in stressed rats

Current pharmacotherapies for posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are ineffective for many patients, and often do not restore cognitive dysfunction associated with these disorders. Behavioral therapies, such as exposure therapy, can be effective for treatment-resistant patients. The mechanisms underlying exposure therapy are not well-understood. Fear extinction as an intervention after chronic stress can model the beneficial effects of exposure therapy in rats. Extinction requires neuronal activity and protein synthesis in the infralimbic (IL) cortex for its beneficial effects. We hypothesized that extinction requires Brain-Derived Neurotrophic Factor (BDNF) activity in the IL cortex to reverse stress-induced cognitive flexibility impairments. Extinction learning reversed set-shifting deficits induced by Chronic Unpredictable Stress (CUS), tested 24 h after extinction. Blocking BDNF signaling in the IL cortex during extinction by local administration of a neutralizing antibody prevented the beneficial effects of extinction on set shifting after stress. Extinction induced activation of the BDNF TrkB receptor, and signaling pathways associated with BDNF (Akt and Erk). Administration of exogenous BDNF into IL cortex in the absence of extinction was sufficient to reverse the effects of stress on set shifting. The effects of extinction were prevented by blocking either Erk or Akt signaling in the IL cortex, whereas the effects of exogenous BDNF were dependent on Erk, but not Akt, signaling. Our observations suggest that BDNF-Erk signaling induced by extinction underlies plastic changes that can reverse or counteract the effects of chronic stress in the IL cortex.

A-3 Cingulo-Opercular and Frontoparietal Control Network Connectivity and Executive Functioning in Older Adults

Objective Executive functioning is a cognitive domain that typically declines with normal aging. Age-related disrupted connectivity in cingulo-opercular (CON) and frontoparietal control (FPCN) resting-state networks is associated with worse performance across various executive functioning tasks. This study examines the relationships between CON and FPCN connectivity and executive functioning performance in older adults across three subdomains: working memory, inhibition, and set-shifting. Methods 274 healthy older adults (age M = 71.7, SD = 5.1; 87% Caucasian) from a clinical trial at the University of Florida and University of Arizona completed tasks of working memory (Digit Span Backwards [DSB]; Letter Number Sequencing [LNS]), inhibition (Stroop), and set-shifting (Trail Making Test Part B [TMT-B]). Participants underwent resting-state functional magnetic resonance imaging. CONN Toolbox (18b) was used for extracting average within-network connectivity of CON and FPCN. Multiple linear regressions were conducted with average network connectivity predicting performance, controlling for age, sex, education, and scanner. Results Greater average CON connectivity was associated with better performance on DSB (β = 0.26, p < 0.001), LNS (β = 0.23, p < 0.001), Stroop (β = 0.24, p < 0.001), and TMT-B (β = −0.26, p < 0.001). Greater average FPCN connectivity was associated with better performance on DSB (β = 0.22, p < 0.001) and LNS (β = 0.18, p = 0.002). Conclusions CON connectivity was significantly associated with working memory, inhibition, and set-shifting. FPCN connectivity was significantly associated with working memory. Future research should conduct regional connectivity analyses within these networks to identify intervention targets to improve executive functioning in older adults.