Biology subjects

Rezayat, E.

Publications and source records attributed to Rezayat, E..

16 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↗

bioRxiv2025

The Gut-Brain Axis Shapes Cognitive-Emotional Processing: Evidence for Attentional Avoidance of Bloating Cues in IBS

BackgroundIrritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by significant gut-brain interactions and various symptoms such as abdominal pain, bloating, and altered bowel habits. Cognitive deficits in IBS have been linked to attentional biases, particularly towards somatic and symptom-related cues. Despite increasing interest in understanding these cognitive processes, the specific patterns of attentional biases and their relationship with anxiety in IBS remain inadequately explored. MethodThis study employed a dot-probe task to compare attentional biases toward somatic (bloating, pain) and social threat cues (angry/disgusted faces) in 15 patients with IBS, 15 individuals with high anxiety (HA), and 15 healthy controls (HC). Participants completed two tasks (Body/Face) with 500 ms stimulus exposure. Attentional bias indices (RT incongruent - RT congruent) were analyzed using mixed-design ANOVAs, controlling for anxiety (STAI) and IBS symptom severity (IBS-SSS). ResultsPatients with IBS exhibited significant avoidance of bloating-related stimuli compared to HC (p =.013), but not pain-related cues. Anxiety modulated attentional processing in IBS (p =.015) and HC (p =.013). HA showed no significant biases. IBS patients demonstrated slower overall reaction times than HC (p=.024), suggesting cognitive load. A positive IBS severity-anxiety correlation was observed in IBS (r = 0.574, p =.020). ConclusionsThe findings demonstrate that IBS is associated with selective avoidance of bloating-related stimuli, driven by a maladaptive interplay between hyper-precise symptom expectations and interoceptive noise--a mechanism distinct from anxiety-related attentional patterns. While anxiety amplifies this avoidance, it does not independently account for the cognitive profile of IBS. These results underscore the gut-brain axis role in shaping cognitive-emotional processing.

neuroscience↗

bioRxiv2025

How Autism Impacts Children's Working Memory for Faces

This study investigates how visual working memory (WM) functions in children with Autism Spectrum Disorder (ASD) compared to typically developing (TD) children aged 7 to 12, focusing on their ability to remember faces. The primary goal was to understand the differences in visual WM performance between these two groups and identify the sources of memory recall errors. Findings indicate that children with ASD demonstrated significantly poorer visual WM compared to their TD counterparts, particularly in the precision of memory recall. Despite this difference, both groups exhibited similar rates of random guessing, suggesting that the challenges faced by children with ASD are more about accuracy than guessing strategy. This research sheds light on the specific deficits in visual WM associated with ASD, enhancing our understanding of the cognitive mechanisms at play and highlighting potential areas for targeted interventions to support these children.

neuroscience↗

bioRxiv2025

Attention in Irritable Bowel Syndrome: A Systematic Review of Affected Domains and Brain-Gut Axis Interactions

BackgroundIrritable Bowel Syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by abdominal pain and altered bowel habits, significantly impacting patients quality of life. Recent research suggests that attention may be affected in individuals with IBS, potentially influencing symptom perception and emotional distress. ObjectiveThis systematic review aims to investigate the relationship between attention and IBS, focusing on the affected domains of attention and the interactions within the brain-gut axis. MethodsA comprehensive literature search was conducted across multiple databases, including MEDLINE/PubMed, PsychINFO, and Scopus, from January 1990 to December 2024. Studies were included if they assessed attention in adult IBS patients and employed valid measurement tools. A total of 24 studies were selected for analysis, encompassing various methodologies, including neuroimaging and behavioral assessments. ResultsThe findings indicate that IBS patients exhibit significant attentional biases, particularly towards gastrointestinal-related stimuli, reflecting heightened sensitivity and hypervigilance. Specific domains of attention, including selective attention, sustained attention, and pre-attentional processing, were identified as being affected. The review highlights the role of psychological factors, such as anxiety and depression, in modulating attention in IBS. Neuroimaging studies revealed altered brain activation patterns in regions associated with attention and emotional processing, suggesting a complex interplay between cognitive function and the brain-gut axis. ConclusionThis systematic review underscores the multifaceted nature of attention in IBS, revealing specific attentional deficits and biases that may contribute to symptom exacerbation and emotional distress. The findings emphasize the need for further research to explore the underlying mechanisms and potential therapeutic interventions aimed at addressing attention in IBS patients.

neuroscience↗

bioRxiv2025

Short-Term Arcade-Action Video Gaming Enhances Working Memory Precision

Working-memory (WM) precision depends on top-down control by dorsolateral prefrontal cortex (dlPFC). Whether a brief session of action video-game play can sharpen this control, and which neural processes mediate any benefit, remains unknown. Thirty-four adults were randomly assigned to 30 min of fast-paced gaming (Snail Mail; Experiment) or time-matched cartoon viewing (Control). Delayed continuous-report precision and 128-channel resting EEG were collected before and after the intervention. Absolute recall error fell in the Experiment group (p < .001) but rose in Controls (p = .005); the groups did not differ at baseline (p = .164) yet the Experiment group outperformed Control at post-test (p < .001). In the EEG subset (N = 30), gaming selectively increased high-alpha (10-13 Hz) power over left dlPFC (AFF7h; p = .041), an effect absents in Controls and significant between groups (p = .010). Across participants, the magnitude of this prefrontal alpha gain predicted the improvement in WM precision (r = .53, p = .0025), whereas concurrent flattening of the global 1/f slope was unrelated (|r| < .24, p > .21). A single, ecologically realistic gaming session therefore yields measurable enhancement of mnemonic precision together with local up-regulation of dlPFC-centered alpha oscillations, identifying a plausible cortical mechanism for rapid, low-cost cognitive plasticity.

neuroscience↗

bioRxiv2024

Emotional content effects the precision of visual working memory

ObjectivesOur working memory (WM) is susceptible to errors influenced by various sources. Recent research has illuminated the intricate relationship between emotional valence and working memory performance. This study aims to comprehensively investigate memory recall biases across different emotional categories. MethodTo explore this relationship, we designed and implemented a delayed-reproduction facial emotion n-back task. Participants were tasked with recalling the emotional valence of target faces across various n-back conditions, selecting their responses from a continuum of 19 morphed faces ranging from sad to happy. ResultsOur findings indicate that participants generally exhibit a negativity bias, struggling more with happy faces. Interestingly, they also perceive happy faces as less happy and sad faces as less sad, suggesting both positive and negative reappraisal in their emotional valence perception. This underscores the complex interplay between emotional valence and cognitive performance. Notably, recall of neutral images remained stable and was unaffected by preceding emotional contexts. ConclusionThese findings demonstrate that emotional content in working memory significantly impacts errors during WM tasks, with more emotionally charged faces leading to a greater drift toward the lower valence axis. This highlights the need for further exploration of how emotional factors influence cognitive processes in working memory.

neuroscience↗

bioRxiv2024

Investigating the Effects of Synbiotic Intervention on Working Memory performance in Healthy Young Women

The gut-brain axis plays a key role in the bidirectional communication between the gastrointestinal system and the brain, with gut microbiota significantly influencing cognitive function. While synbiotic and probiotic interventions have shown potential cognitive benefits, results across studies remain mixed. This randomized, controlled, repeated-measures study investigated the effects of a 15-day synbiotic intervention on cognitive performance in 28 healthy women (aged 18-32), assigned to either a synbiotic or no-treatment control group. Cognitive performance was assessed before and after the intervention using the Parametric Auditory Working Memory Task and the Integrated Visual and Auditory Continuous Performance Test (IVA-CPT). Compared to the control group, participants in the synbiotic group demonstrated selective improvements in attention, particularly in overall visual attention and visual sustained attention, as indicated by significant group-by-time interactions (ps < .05). No significant changes were observed in auditory working memory or inhibitory control. These results suggest that short-term synbiotic supplementation may selectively enhance visual attention without broadly affecting executive functions.

neuroscience↗

bioRxiv2024

Conscious and Unconscious Emotional Processing: Insights from Behavioral and Pupillary Responses

Emotions are crucial in social interactions, influencing communication and relationships. Distinguishing the perceived emotion in conscious and unconscious emotional processing is a key research area with cognitive and physiological implications. This study investigates conscious and unconscious emotional processing through behavioral and pupillary responses. Participants completed emotion recognition tasks under varying states, revealing higher accuracy in conscious emotion identification. Emotions like anger, happiness, fear, surprise, and neutral elicited distinct response patterns. Pupillometry data showed pupil size suppression in the conscious state and enhancement in the unconscious state, with differences in peak pupil size across emotions. Task-related components, amplitude, and latency parameters differed between conscious and unconscious states, highlighting the role of awareness in emotional regulation. These findings emphasize the complex interplay of cognitive and physiological processes in emotional responses, providing insights into emotional recognition mechanisms. This study contributes to understanding emotional processing dynamics and has implications for psychology and neuroscience research.

neuroscience↗

bioRxiv2024

A low-cost protocol for reconditioning of deep-brain neural microelectrodes with material failure for electrophysiology recording

Up to now, a large variety of neural microelectrodes are developed. Although there are a lot of published works in this area, the majority of them are about the fabrication methods and rarely discuss the reconditioning procedure or how to re-use the electrodes that their performance is decreased because of material failure. In this paper, firstly, it is answered that why the performance of neural microelectrodes decreases. Secondly, a general low-cost protocol for reconditioning and re-using electrodes are proposed that can be utilized for the most types of electrodes with material failure. Lastly, the proposed reconditioning protocol is applied experimentally to single-site tungsten microelectrodes to demonstrate the effectiveness of the protocol. Neural signal recording Results clearly indicate that a large number of electrodes can be reconditioned well.

bioengineering↗

bioRxiv2023

The Spatial Frequency Representation Predicts Category Coding in the Inferior Temporal Cortex

Understanding the neural representation of spatial frequency (SF) in the primate cortex is vital for unraveling visual processing mechanisms in object recognition. While numerous studies concentrate on the representation of SF in the primary visual cortex, the characteristics of SF representation and its interaction with category representation remain inadequately understood. To explore SF representation in the inferior temporal (IT) cortex of macaque monkeys, we conducted extracellular recordings with complex stimuli systematically filtered by SF. Our findings disclose an explicit SF coding at single-neuron and population levels in the IT cortex. Moreover, the coding of SF content exhibits a coarse-to-fine pattern, declining as the SF increases. Temporal dynamics analysis of SF representation reveals that low SF (LSF) is decoded faster than high SF (HSF), and the SF preference dynamically shifts from LSF to HSF over time. Additionally, the SF representation for each neuron forms a profile that predicts category selectivity at the population level. IT neurons can be clustered into four groups based on SF preference, each exhibiting different category coding behaviors. Particularly, HSF-preferred neurons demonstrate the highest category decoding performance for face stimuli. Despite the existing connection between SF and category coding, we have identified uncorrelated representations of SF and category. In contrast to the category coding, SF is more sparse and places greater reliance on the representations of individual neurons. Comparing SF representation in the IT cortex to deep neural networks, we observed no relationship between SF representation and category coding. However, SF coding, as a category-orthogonal property, is evident across various ventral stream models. These results dissociate the separate representations of SF and object category, underscoring the pivotal role of SF in object recognition.

neuroscience↗

bioRxiv2023

Aging Decreases the Precision of Visual Working Memory

ObjectivesWorking memory (WM) is a cognitive ability that enables us to hold information temporarily. As age increases during life, cognitive abilities such as WM performance decrease. Errors in WM tasks arise from different sources, such as decreasing precision and random response. In the current study, we investigated the effect of age on WM and elucidated sources of errors. MethodA total of 102 healthy individuals aged 18 to 71, participated in the study. A face-based visual WM task was designed and performed. Responses were collected using a graded scale in a delayed match-to-sample reproduction task. ResultsThe error of participants increased significantly as they aged. According to our analysis of the source of error, the standard deviation of error distribution increased considerably with age. However, there was no significant change in uniform probability with age. These observations were similar between male and female participants. ConclusionWe found that WM performance declines through the lifespan. Investigating the sources of error, we found that the precision of WM decreased with age. This decline was monotonous without any particular age at which a significant drop-off occurred. The results also indicated that the probability of guessing the response as a measure of random response is not affected by age.

neuroscience↗

bioRxiv2021

The Effect of Spatial Frequency on the Visual Category Representation in the Macaque Inferior Temporal Cortex

To expand our knowledge about the object recognition, it is critical to understand the role of spatial frequency (SF) in an object representation that occurs in the inferior temporal (IT) cortex at the final stage of processing the visual information across the ventral visual pathway. Object categories are being recognized hierarchically in at least three levels of abstraction: superordinate (e.g., animal), mid-level (e.g., human face), and subordinate (e.g., face identity). Psychophysical studies have shown rapid access to mid-level category information and low SF (LSF) contents. Although the hierarchical representation of categories has been shown to exist inside the IT cortex, the impact of SF on the multi-level category processing is poorly understood. To gain a deeper understanding of the neural basis of the interaction between SF and category representations at multiple levels, we examined the neural responses within the IT cortex of macaque monkeys viewing several SF-filtered objects. Each stimulus could be either intact or bandpass filtered into either the LSF (coarse shape information) or high SF (HSF) (fine shape information) bands. We found that in both High- and Low-SF contents, the advantage of mid-level representation has not been violated. This evidence suggests that mid-level category boundary maps are strongly represented in the IT cortex and remain unaffected with respect to any changes in the frequency content of stimuli. Our observations indicate the necessity of the HSF content for the superordinate category representation inside the IT cortex. In addition, our findings reveal that the representation of global category information is more dependent on the HSF than the LSF content. Furthermore, the lack of subordinate representation in both LSF and HSF filtered stimuli compared to the intact stimuli provide strong evidence that all SF contents are necessary for fine category visual processing.

neuroscience↗

bioRxiv2020

Frontotemporal Coordination Predicts Working Memory Performance and its Local Neural Signatures

Neurons in some sensory areas reflect the content of working memory (WM) in their spiking activity. However, this spiking activity is seldom related to behavioral performance. We studied the responses of inferotemporal (IT) neurons, which exhibit object-selective activity, along with Frontal Eye Field (FEF) neurons, which exhibit spatially-selective activity, during the delay period of an object WM task. Unlike the spiking activity and local field potentials (LFPs) within these areas, which were poor predictors of behavioral performance, the phase-locking of IT spikes and LFPs with the beta band of FEF LFPs robustly predicted successful WM maintenance. In addition, IT neurons exhibited greater object-selective persistent activity when their spikes were locked to the phase of FEF LFPs. These results demonstrate a key role of coordination between prefrontal and temporal cortex in the successful maintenance of visual information during WM.

neuroscience↗