Biology subjects

Makhsous, M.

Publications and source records attributed to Makhsous, M..

4 recordsLinked to original sources

bioRxiv2026

Emotional Modulation of Face Working Memory Precision in Specific Learning Disorders: Valence Flattening and Mnemonic Distortions

This study examined whether emotional valence modulates face working memory precision in adolescents with specific learning disorders (SLD) and whether mnemonic distortions differ across subtypes. Fifty-four adolescents with SLD (dyslexia: n = 19; dysgraphia: n = 18; dyscalculia: n = 17) and 42 typically developing peers completed a morphed delayed reproduction task using sad, neutral, and happy faces. Using a von Mises + uniform mixture model, we decomposed recall errors into precision, systematic bias, and guessing. The SLD group made significantly larger errors (r = 8722;0.61) and responded more slowly (r = -0.33). Mixture modeling showed that deficits arose from reduced precision ({kappa}: TD M = 8.72 vs. SLD M = 4.15; r = 0.54) and stronger systematic bias toward neutrality (: TD M = -0.66 vs. SLD M = -4.15; r = 0.34), with no differences in random guessing. Valence flattening was consistently larger in SLD. Among subtypes, dyscalculia showed the greatest working memory impairment, yet all three exhibited the same valence flattening pattern. Thus, emotional faces disrupt face working memory in SLD through reduced precision and systematic affective distortion. The bias parameter from mixture modeling may offer a clinically useful metric for subtype-sensitive assessment.

neuroscience↗

bioRxiv2026

Chess expertise improves rule-guided flexibility and visual working memory precision

Studying chess experts helps researchers understand how intensive practice shapes thinking skills. Cognitive flexibility is the ability to adjust thoughts when rules or tasks change. Working memory is the ability to hold and use information over short periods. This study compared cognitive flexibility and working memory precision between adolescent chess players and non-players. Twenty-four professional chess players and twenty-five controls completed two novel behavioral tasks. Chess players showed better accuracy in both tasks than controls. They adapted more efficiently when rules changed during a continuous learning task. They also remembered facial expressions more precisely in a working memory task. Learning rates in the flexibility task did not differ between groups. These results indicate that chess expertise may improve rule-guided flexibility and visual working memory precision in adolescents.

neuroscience↗

bioRxiv2026

Mapping Lifespan Trajectories of Cognitive Flexibility with a Continuous Probabilistic Reversal Learning Measure

Cognitive flexibility is the ability to change the way of responding when the demands of the environment change. This study tested how cognitive flexibility develops across the lifespan. We used a new computerized task that gives a continuous score instead of just right or wrong answers. 221 healthy adults aged 18 to 71 completed the Continuous-score Probabilistic Reversal Learning Test (CPRLT). We calculated mean absolute error and adjusted error for rule-based learning, and fitted a Rescorla-Wagner model to estimate each persons learning rate (alpha) for reward-based learning. All three scores have one breakpoint, performance improved rapidly from childhood to young adulthood, then declined slowly. Rule-based learning peaked around age 20. Reward-based learning peaked earlier, around age 18. This suggests that reward-based learning matures before rule-based learning. The pattern fits with brain development: reward circuits mature earlier, while prefrontal regions for rule-based learning develop later. Our continuous measure captured this difference, which binary tasks would miss.

neuroscience↗

bioRxiv2025

Auditory Working Memory in Adolescents with Specific Learning Disorders

Specific Learning Disorders (SLD), including dyslexia, dyscalculia, and dysgraphia, are associated with deficits in executive functions such as auditory working memory (AWM). This study investigated AWM performance and metacognitive monitoring in adolescents diagnosed with SLD using an auditory delayed-match-to-sample task. Thirty-six participants (18 with SLD and 18 neurotypical controls) were assessed on accuracy, reaction time, and confidence ratings. Adolescents with SLD exhibited reduced sensitivity to auditory intensity differences, slower reaction times, and more conservative decision-making strategies. Drift diffusion modeling revealed lower evidence accumulation rates and wider decision boundaries in the SLD group. Moreover, confidence ratings were less influenced by stimulus differences, particularly among participants with dyslexia. These findings highlight impairments in auditory processing, decision-making, and metacognitive self-monitoring in adolescents with SLD. The results underscore the importance of interventions that address not only linguistic skills but also auditory decision-making and metacognitive strategies to support learning outcomes.

neuroscience↗