A single bout of moderate intensity exercise improves cognitive flexibility: evidence from task-switching.

Executive function entails the core components of response  inhibition, working memory and cognitive flexibility. An accumulating literature has shown that a single bout of exercise improves the response inhibition  and working memory components of executive function; however, limited work has examined a putative exercise-related improvement to cognitive flexibility. To address this limitation, Experiment 1 entailed a 20-min session of moderate intensity aerobic exercise (via cycle ergometer), and pre- and post-exercise cognitive flexibility was examined via a task-switching paradigm involving alternating pro- and antisaccades (AABB: A = prosaccade, B = antisaccade). In Experiment 2, participants sat on the cycle ergometer without exercising (i.e., rest break) and the same AABB paradigm was examined pre- and post-break. We used an AABB pro- and antisaccade paradigm because previous work has shown that a prosaccade preceded by an antisaccade exhibits a reliable-and large magnitude-increase in reaction time, whereas the converse switch does not (i.e., the unidirectional prosaccade switch-cost). Experiment 1 showed a unidirectional prosaccade switch-cost pre-exercise (p = .012)-but not post-exercise (p = .30), and a two one-sided t test indicated that the latter comparison was within an equivalence boundary (p < .01). In contrast, Experiment 2 revealed a unidirectional prosaccade switch-cost at pre- and post-break assessments (ps < .01). Accordingly, our results indicate that a single bout of exercise improves cognitive flexibility and provides convergent evidence that exercise improves global components of executive function.

A Comparison Between Potassium Hydroxide (KOH) Microscopy and Culture for the Detection of Post-COVID-19 Rhino-Orbital-Cerebral Mucormycosis.

Background and objective Mucormycosis is an emerging and serious angioinvasive infection caused by filamentous fungi related to the order of Mucorales and the class of Mucormycetes. There was a marked increase in the number of cases of mucormycosis in India following the second wave of the coronavirus disease 2019 (COVID-19) pandemic in the year 2021. In this study, we aimed to compare potassium hydroxide (KOH) microscopy with culture for the detection of post-COVID-19 rhino-orbital-cerebral mucormycosis (ROCM). Materials and methods The KOH microscopy was performed with a 10% or 20% KOH-mounted slide with specimens collected from suspected cases of post-COVID-19 ROCM. Simultaneously, the culture was done on Sabouraud dextrose agar (SDA). These were incubated at 37 ℃ and 25 â„ƒ for 28 days. Diagnostic parameters were calculated by comparing KOH with gold standard culture. Results KOH mount was positive for broad aseptate fungal hyphae in 322 (54.1%) cases, while it was negative in 244 (41.0%) cases. KOH mount was positive for other fungi in 29 (4.8%) samples. The diagnostic accuracy of the KOH mount for Mucorales was 70.3%. KOH mount had a sensitivity of 84.9%, specificity of 61.5%, positive predictive value (PPV) of 56.9%, and negative predictive value (NPV) of 87.2%. Conclusions Based on our findings, the KOH microscopy positivity rate was higher in tissue samples compared to nasal swabs, with a sensitivity of 84.9%, specificity of 61.5%, PPV of 56.9%, and NPV of 87.2%. The overall diagnostic accuracy of the KOH mount for Mucorales was 70.3%.

A Single Bout of Exercise Provides a Persistent Benefit to Cognitive Flexibility.

Purpose: A single bout of exercise enhances activity within the cortical networks that support executive function. It is, however, unclear whether exercise improves each core component of executive function and for how long a putative benefit might persist. Method: In Experiment 1, participants completed 20-min of aerobic exercise (via cycle ergometer) and cognitive flexibility-a core component of executive function-was examined pre-exercise, and at immediate, 30- and 60-min post-exercise assessments. Experiment 2 entailed a non-exercise control (i.e., participants sat on the ergometer without exercising) involving the same timeline of cognitive flexibility assessment. Cognitive flexibility was measured via stimulus-driven (SD) and minimally delayed (MD) saccades arranged in an AABB paradigm. SD and MD saccades require a response at target onset and after target offset, respectively, with the latter requiring executive control. Work has shown that reaction times for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Results: Experiment 1 showed a unidirectional switch-cost at each assessment; however, the switch-cost magnitude was decreased at immediate and 30-min assessments compared to the pre- and 60-min assessments. In contrast, Experiment 2 did not elicit a change in switch-cost magnitude across the different assessments. Discussion/Conclusion: Thus, a single-bout of exercise benefitted the cognitive flexibility component of executive function in the immediate and 30-min post-exercise assessments.

A Single Bout of Aerobic Exercise Provides an Immediate "Boost" to Cognitive Flexibility.

Executive function includes the core components of working memory, inhibitory control, and cognitive flexibility. A wealth of studies demonstrate that working memory and inhibitory control improve following a single bout of exercise; however, a paucity - and equivocal - body of work has demonstrated a similar benefit for cognitive flexibility. Cognitive flexibility underlies switching between different attentional- and motor-related goals, and a potential limitation of previous work examining this component in an exercise context is that they included tasks involving non-executive processes (i.e., numerosity, parity, and letter judgments). To address this issue, Experiment 1 employed a 20-min bout of aerobic exercise and examined pre- and immediate post-exercise cognitive flexibility via stimulus-driven (SD) and minimally delayed (MD) saccades ordered in an AABB task-switching paradigm. Stimulus-driven saccades are a standard task requiring a response at target onset, whereas MD saccades are a non-standard and top-down task requiring a response only after the target is extinguished. Work has shown that RTs for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Experiment 1 yielded a 28 ms and 8 ms unidirectional switch-cost pre- and post-exercise, respectively (ps < 0.001); however, the magnitude of the switch-cost was reduced post-exercise (p = 0.005). Experiment 2 involved a non-exercise control condition and yielded a reliable and equivalent magnitude unidirectional switch-cost at a pre- (28 ms) and post-break (26 ms) assessment (ps < 0.001). Accordingly, a single-bout of exercise improved task-switching efficiency and thereby provides convergent evidence that exercise provides a global benefit to the core components of executive function.