Dysfunctional hippocampal-prefrontal network underlies a multidimensional neuropsychiatric phenotype following early-life seizure.

Brain disturbances during development can have a lasting impact on neural function and behavior. Seizures during this critical period are linked to significant long-term consequences such as neurodevelopmental disorders, cognitive impairments, and psychiatric symptoms, resulting in a complex spectrum of multimorbidity. The hippocampus-prefrontal cortex (HPC-PFC) circuit emerges as a potential common link between such disorders. However, the mechanisms underlying these outcomes and how they relate to specific behavioral alterations are unclear. We hypothesized that specific dysfunctions of hippocampal-cortical communication due to early-life seizure would be associated with distinct behavioral alterations observed in adulthood. Here, we performed a multilevel study to investigate behavioral, electrophysiological, histopathological, and neurochemical long-term consequences of early-life Status epilepticus in male rats. We show that adult animals submitted to early-life seizure (ELS) present working memory impairments and sensorimotor disturbances, such as hyperlocomotion, poor sensorimotor gating, and sensitivity to psychostimulants despite not exhibiting neuronal loss. Surprisingly, cognitive deficits were linked to an aberrant increase in the HPC-PFC long-term potentiation (LTP) in a U-shaped manner, while sensorimotor alterations were associated with heightened neuroinflammation, as verified by glial fibrillary acidic protein (GFAP) expression, and altered dopamine neurotransmission. Furthermore, ELS rats displayed impaired HPC-PFC theta-gamma coordination and an abnormal brain state during active behavior resembling rapid eye movement (REM) sleep oscillatory dynamics. Our results point to impaired HPC-PFC functional connectivity as a possible pathophysiological mechanism by which ELS can cause cognitive deficits and psychiatric-like manifestations even without neuronal loss, bearing translational implications for understanding the spectrum of multidimensional developmental disorders linked to early-life seizures.

Alpha desynchronization during the filtering initiation phase reflects active processing of distractors.

The ability to select task-relevant information and filter out task-irrelevant information is critical to our success in daily goal-directed behavior. Researchers call this ability filtering efficiency and divide it into three cognitive processing stages: detection of distractors, initiation of filtering, and unnecessary storage. Although researchers have conducted more studies on ERP components related to filtration efficiency, there are few studies related to neural oscillations. Alpha oscillation activity is related to the active processing of information and the suppression of distractors. In the current EEG study, we used the change detection task with distracted items to examine whether alpha activity during filtering initiation reflects reactive suppression of distractors by manipulating memory load levels and the presence or absence of distractors. Results showed that, the presence of the distractors caused an increase in the degree of desynchronization of the alpha oscillations, and in the subsequent time, the alpha activity level returned to a level consistent with the absence of interference conditions. Phase synchronization between frontal and posterior brain regions in the upper alpha oscillations found no effects associated with distractors. Based on these results, we believed that the alpha activity during the filtering initiation phase reflected the active processing of distractors, but this may also be due to lower perceptual load of the target items. In addition, we observed a dominance effect of the right hemisphere in both time-frequency results and connectivity results. We speculate that this effect is related to the activation of the right ventral frontoparietal network.

Evidence and sources of placebo effects in transcranial direct current stimulation during a single session of visuospatial working memory practice.

Transcranial direct current stimulation (tDCS) can be used to non-invasively augment cognitive training. However, the benefits of tDCS may be due in part to placebo effects, which have not been well-characterized. The purpose of this study was to determine whether tDCS can have a measurable placebo effect on cognitive training and to identify potential sources of this effect. Eighty-three right-handed adults were randomly assigned to one of three groups: control (no exposure to tDCS), sham tDCS, or active tDCS. The sham and active tDCS groups were double-blinded. Each group performed 20 min of an adapted Corsi Block Tapping Task (CBTT), a visuospatial working memory task. Anodal or sham tDCS was applied during CBTT training in a right parietal-left supraorbital montage. After training, active and sham tDCS groups were surveyed on expectations about tDCS efficacy. Linear mixed effects models showed that the tDCS groups (active and sham combined) improved more on the CBTT with training than the control group, suggesting a placebo effect of tDCS. Participants' tDCS expectations were significantly related to the placebo effect, as was the belief of receiving active stimulation. This placebo effect shows that the benefits of tDCS on cognitive training can occur even in absence of active stimulation. Future tDCS studies should consider how treatment expectations may be a source of the placebo effect in tDCS research, and identify ways to potentially leverage them to maximize treatment benefit.

Transcranial random noise stimulation (tRNS) improves hot and cold executive functions in children with attention deficit-hyperactivity disorder (ADHD).

Children with attention deficit-hyperactivity disorder (ADHD) have impaired hot and cold executive functions, which is thought to be related to impaired ventromedial and dorsolateral prefrontal cortex (vmPFC and dlPFC) functions. The present study aimed to assess the impact concurrent stimulation of dlPFC and vmPFC through transcranial random noise stimulation (tRNS), a non-invasive brain stimulation tool which enhances cortical excitability via application of alternating sinusoidal currents with random frequencies and amplitudes over the respective target regions on hot and cold executive functions. Eighteen children with ADHD received real and sham tRNS over the left dlPFC and the right vmPFC in two sessions with one week interval. The participants performed Circle Tracing, Go/No-Go, Wisconsin Card Sorting, and Balloon Analogue Risk Tasks during stimulation in each session. The results showed improved ongoing inhibition, prepotent inhibition, working memory, and decision making, but not set-shifting performance, during real, as compared to sham stimulation. This indicates that simultaneous stimulation of the dlPFC and the vmPFC improves hot and cold executive functions in children with ADHD.

Greater up-modulation of intra-individual brain signal variability makes a high-load cognitive task more arduous for older adults.

The extent to which brain responses are less distinctive across varying cognitive loads in older adults is referred to as neural dedifferentiation. Moment-to-moment brain signal variability, an emerging indicator, reveals not only the adaptability of an individual's brain as an inter-individual trait, but also the allocation of neural resources within an individual due to ever-changing task demands, thus shedding novel insight into the process of neural dedifferentiation. However, how the modulation of intra-individual brain signal variability reflects behavioral differences related to cognitively demanding tasks remains unclear. In this study, we employed functional near-infrared spectroscopy (fNIRS) imaging to capture the variability of brain signals, which was quantified by the standard deviation, during both the resting state and an n-back task (n = 1, 2, 3) in 57 healthy older adults. Using multivariate Partial Least Squares (PLS) analysis, we found that fNIRS signal variability increased from the resting state to the task and increased with working memory load in older adults. We further confirmed that greater fNIRS signal variability generally supported faster and more stable response time in the 2- and 3-back conditions. However, the intra-individual level analysis showed that the greater the up-modulation in fNIRS signal variability with cognitive loads, the more its accuracy decreases and mean response time increases, suggesting that a greater intra-individual brain signal variability up-modulation may reflect decreased efficiency in neural information processing. Taken together, our findings offer new insights into the nature of brain signal variability, suggesting that inter- and intra-individual brain signal variability may index distinct theoretical constructs.

Functional correlates of cognitive performance and working memory in temporal lobe epilepsy: Insights from task-based and resting-state fMRI.

Temporal lobe epilepsy (TLE) is a common form of medically intractable epilepsy. Although seizures originate in mesial temporal structures, there are widespread abnormalities of gray and white matter beyond the temporal lobes that negatively impact functional networks and cognition. Previous studies have focused either on the global impact on functional networks, or on the functional correlates of specific cognitive abilities. Here, we use a two-pronged approach to evaluate the link between whole-brain functional connectivity (FC) anomalies to overall cognitive performance, and how such abnormal connectivity alters the fronto-parietal brain regions involved in working memory (WMem), a cognitive disability often reported by TLE patients. We evaluated 31 TLE patients and 35 healthy subjects through extensive cognitive testing, resting-state functional magnetic resonance imaging (RS-fMRI), and task-based fMRI using Sternberg's task to evaluate WMem. As a group, TLE patients displayed cognitive abnormalities across different domains, although considerable within-group variability was identified. TLE patients showed disruptions of functional networks between and within the default mode network (DMN) and task-positive networks (TPN) resulting in associations with cognitive performance. Furthermore, during the WMem task, TLE patients showed abnormal activity of fronto-parietal regions that were associated with other forms of memory, and alterations of seed-based connectivity analyses. Our results show that different degrees of abnormal functional brain activity and connectivity are related to the severity of disabilities across cognitive spheres. Differential co-activation patterns between patients and healthy subjects suggest potential compensatory mechanisms to preserve adequate cognitive performance.

[Neuroanatomical mapping of inhibitory attention and working memory with functional magnetic resonance imaging in healthy children]. / Mapeo neuroanatómico de atención inhibitoria y memoria de trabajo con resonancia magnética funcional en niños sanos.

INTRODUCTION: The objective is to produce an average brain activation mapping template in healthy children using functional magnetic resonance imaging (fMRI), with specific paradigms for activating inhibitory attention and working memory functions. SUBJECTS AND METHODS: A nutritional and neuropsychological evaluation was performed on 87 right-handed children. The inclusion criteria were met by 30 children (15 boys and 15 girls) between 9 and 11 years old, who were studied with fMRI in two inhibitory attention tests (Go/No Go), with food cues, a working memory test (Continuous Performance Test Identical Pairs) and measurement of anatomical volumes. These data were subsequently processed with the FSL-v5 program, with a threshold of p < 0.05 (cluster-wise). The brain areas activated were located using a standard Montreal Neurological Institute brain template and the Harvard-Oxford structural cortical atlas. RESULTS: The inhibitory attention tests showed activation frontal areas predominantly on the right, and the cingulate, parietal and occipital areas, with preponderance in occipital areas in the food cues test. In the Continuous Performance Test-Identical Pairs test, activation was obtained predominantly in the occipital, frontal and parietal areas. CONCLUSIONS: Brain activity mapping templates are obtained in healthy children with tests for inhibitory attention, food cues and working memory. The activation areas are mostly those reported in the literature. This provides baseline brain activation patterns for studying pathologies related to inhibitory attention, impulsivity and working memory.

TITLE: Mapeo neuroanatómico de atención inhibitoria y memoria de trabajo con resonancia magnética funcional en niños sanos.Introducción. El objetivo es lograr una plantilla de mapeo de activación cerebral promedio en niños sanos usando la resonancia magnética funcional (RMf), con paradigmas específicos para activar funciones de atención inhibitoria y de memoria de trabajo. Sujetos y métodos. Se realizó una evaluación nutricional y neuropsicológica a 87 niños diestros. Cumplieron los criterios de inclusión 30 (15 niños y 15 niñas) entre 9 y 11 años, a quienes se estudió con RMf con realización de dos pruebas de atención inhibitoria (Go/No Go), con letras e imágenes de alimentos, un test de memoria de trabajo (Test de Atención Continua-Pares Idénticos) y obtención de volúmenes anatómicos. Los datos posteriormente se procesaron con el programa FSL-v5 con un umbral de p < 0,05 (cluster-wise). Las áreas cerebrales activadas se localizaron utilizando una plantilla cerebral estándar del Montreal Neurological Institute y el atlas cortical estructural de Harvard-Oxford. Resultados. En las pruebas de atención inhibitoria hay activación en áreas frontales de predominio derecho, cíngulo, parietales y occipitales, con preponderancia en áreas occipitales en la prueba con alimentos. En la prueba Test de Atención Continua-Pares Idénticos se obtuvo activación de predominio en áreas occipitales, frontales y parietales. Conclusiones. Se obtienen plantillas de mapeo de actividad cerebral en niños sanos con test de atención inhibitoria, de alimentos y de memoria de trabajo. Las áreas de activación corresponden mayoritariamente a las descritas en la bibliografía. Esto nos permite tener patrones basales de activación cerebral para estudiar patologías relacionadas con la atención inhibitoria, la impulsividad y la memoria de trabajo.

Be prepared for interruptions: EEG correlates of anticipation when dealing with task interruptions and the role of aging.

Dealing with task interruptions requires the flexible use of working memory and attentional control mechanisms, which are prone to age-related changes. We investigated effects of age on dealing with task interruptions and potential advantages of anticipating an interruption using EEG and a retrospective cueing (retro-cue) paradigm. Thirty-two young (18-30 years) and 28 older (55-70 years) participants performed a visual working memory task, where they had to report the orientation of a target following a retro-cue. Within blocks of 10 trials, they were always, never, or randomly interrupted with an arithmetic task before the onset of the retro-cue. The interruption-induced decline in primary task performance was more pronounced in older participants, while only these benefited from anticipation. The EEG analysis revealed reduced theta and alpha/beta response to the retro-cue following interruptions, especially for the older participants. In both groups, anticipated interruptions were associated with increased theta and alpha/beta power prior and during the interruption, and stronger beta suppression to the retro-cue. The results indicate that interruptions impede the refocusing of attention on the task-relevant representation of the primary task, especially in older people, while anticipation facilitates preparation for the interruption task and resumption of the primary task.

Repetitive Transcranial Alternating Current Stimulation to Improve Working Memory: An EEG-fNIRS Study.

Transcranial electrical stimulation has demonstrated the potential to enhance cognitive functions such as working memory, learning capacity, and attentional allocation. Recently, it was shown that periodic stimulation within a specific duration could augment the human brain's neuroplasticity. This study investigates the effects of repetitive transcranial alternating current stimulation (tACS; 1 mA, 5 Hz, 2 min duration) on cognitive function, functional connectivity, and topographic changes using both electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Fifteen healthy subjects were recruited to measure brain activity in the pre-, during-, and post-stimulation sessions under tACS and sham stimulation conditions. Fourteen trials of working memory tasks and eight repetitions of tACS/sham stimulation with a 1-minute intersession interval were applied to the frontal cortex of the participants. The working memory score, EEG band-wise powers, EEG topography, concentration changes of oxygenated hemoglobin, and functional connectivity (FC) were individually analyzed to quantify the behavioral and neurophysiological effects of tACS. Our results indicate that tACS increases: i) behavioral scores (i.e., 15.08, ) and EEG band-wise powers (i.e., theta and beta bands) compared to the sham stimulation condition, ii) FC of both EEG-fNIRS signals, especially in the large-scale brain network communication and interhemispheric connections, and iii) the hemodynamic response in comparison to the pre-stimulation session and the sham condition. Conclusively, the repetitive theta-band tACS stimulation improves the working memory capacity regarding behavioral and neuroplasticity perspectives. Additionally, the proposed fNIRS biomarkers (mean, slope), EEG band-wise powers, and FC can be used as neuro-feedback indices for closed-loop brain stimulation.

Transcranial Ultrasound Stimulation Improves Memory Performance of Parkinsonian Mice.

Cognitive impairment is one of the most common non-motor symptoms of Parkinson's disease (PD). Previous studies have demonstrated that low-intensity transcranial ultrasound stimulation can significantly suppress the motor symptoms of PD. However, whether ultrasound stimulation can improve cognitive ability in PD and the related neural oscillation mechanism remain unclear to date. To evaluate the effect of ultrasound stimulation on memory ability in PD and explore its neural oscillation mechanism. Ultrasonography was used for 7-day stimulation of the CA1 in transgenic mice with PD. The working memory ability of the PD mice was then tested using novel object discrimination, and the local field potential and spikes in the mice CA1 were recorded at the same time as in the behavioral test. We found that ultrasound stimulation of the PD mice CA1 for 4 days: 1) significantly increased their learning and memory ability, although the learning and memory ability on the 7th day after the stimulation stopped was not significantly different from that before stimulation (P>0.05); 2) significantly increased the relative power of theta, low gamma, and high gamma frequency bands of the local field potential, and the phase amplitude coupling strength between theta and low gamma and between theta and high gamma; and 3) modulated the phase-locking angle between the spike of interneuron and theta wave to a 180°-360° rise cycle. Transcranial ultrasound stimulation can improve the learning and memory abilities of PD mice, and evoking neural oscillations in the CA1 is the potential mechanism.

Online and offline effects of parietal 10 Hz repetitive transcranial magnetic stimulation on working memory in healthy controls.

Parietal alpha activity shows a specific pattern of phasic changes during working memory. It decreases during the encoding and recall phases but increases during the maintenance phase. This study tested whether online rTMS delivered to the parietal cortex during the maintenance phase of a working memory task would increase alpha activity and hence improve working memory. Then, 46 healthy volunteers were randomly assigned to two groups to receive 3-day parietal 10 Hz online rTMS (either real or sham, 3600 pulses in total) that were time-locked to the maintenance phase of a spatial span task (180 trials in total). Behavioral performance on another spatial span task and EEG signals during a change detection task were recorded on the day before the first rTMS (pretest) and the day after the last rTMS (posttest). We found that rTMS improved performance on both online and offline spatial span tasks. For the offline change detection task, rTMS enhanced alpha activity within the maintenance phase and improved interference control of working memory at both behavioral (K score) and neural (contralateral delay activity) levels. These results suggested that rTMS with alpha frequency time-locked to the maintenance phase is a promising way to boost working memory.

Neural flip-flops I: Short-term memory.

The networks proposed here show how neurons can be connected to form flip-flops, the basic building blocks in sequential logic systems. The novel neural flip-flops (NFFs) are explicit, dynamic, and can generate known phenomena of short-term memory. For each network design, all neurons, connections, and types of synapses are shown explicitly. The neurons' operation depends only on explicitly stated, minimal properties of excitement and inhibition. This operation is dynamic in the sense that the level of neuron activity is the only cellular change, making the NFFs' operation consistent with the speed of most brain functions. Memory tests have shown that certain neurons fire continuously at a high frequency while information is held in short-term memory. These neurons exhibit seven characteristics associated with memory formation, retention, retrieval, termination, and errors. One of the neurons in each of the NFFs produces all of the characteristics. This neuron and a second neighboring neuron together predict eight unknown phenomena. These predictions can be tested by the same methods that led to the discovery of the first seven phenomena. NFFs, together with a decoder from a previous paper, suggest a resolution to the longstanding controversy of whether short-term memory depends on neurons firing persistently or in brief, coordinated bursts. Two novel NFFs are composed of two and four neurons. Their designs follow directly from a standard electronic flip-flop design by moving each negation symbol from one end of the connection to the other. This does not affect the logic of the network, but it changes the logic of each component to a logic function that can be implemented by a single neuron. This transformation is reversible and is apparently new to engineering as well as neuroscience.

Onscreen presence of instructors in video lectures affects learners' neural synchrony and visual attention during multimedia learning.

COVID-19 forced students to rely on online learning using multimedia tools, and multimedia learning continues to impact education beyond the pandemic. In this study, we combined behavioral, eye-tracking, and neuroimaging paradigms to identify multimedia learning processes and outcomes. College students viewed four video lectures including slides with either an onscreen human instructor, an animated instructor, or no onscreen instructor. Brain activity was recorded via fMRI, visual attention was recorded via eye-tracking, and learning outcome was assessed via post-tests. Onscreen presence of instructor, compared with no instructor presence, resulted in superior post-test performance, less visual attention on the slide, more synchronized eye movements during learning, and higher neural synchronization in cortical networks associated with socio-emotional processing and working memory. Individual variation in cognitive and socio-emotional abilities and intersubject neural synchronization revealed different levels of cognitive and socio-emotional processing in different learning conditions. The instructor-present condition evoked increased synchronization, likely reflecting extra processing demands in attentional control, working memory engagement, and socio-emotional processing. Although human instructors and animated instructors led to comparable learning outcomes, the effects were due to the dynamic interplay of information processing vs. attentional distraction. These findings reflect a benefit-cost trade-off where multimedia learning outcome is enhanced only when the cognitive benefits motivated by the social presence of onscreen instructor outweigh the cognitive costs brought about by concurrent attentional distraction unrelated to learning.

Hearing fearful prosody impairs visual working memory maintenance.

Interference by distractors has been associated multiple times with diminished visual and auditory working memory (WM) performance. Negative emotional distractors in particular lead to detrimental effects on WM. However, these associations have only been seen when distractors and items to maintain in WM are from the same sensory modality. In this study, we investigate cross-modal interference on WM. We invited 20 participants to complete a visual change-detection task, assessing visual WM (VWM), while hearing emotional (fearful) and neutral auditory distractors. Electrophysiological activity was recorded to measure contralateral delay activity (CDA) and auditory P2 event-related potentials (ERP), indexing WM maintenance and distractor salience respectively. At the behavioral level, fearful prosody didn't decrease significantly working memory accuracy, compared to neutral prosody. Regarding ERPs, fearful distractors evoked a greater P2 amplitude than neutral distractors. Correlations between the two ERP potentials indicated that P2 amplitude difference between the two types of prosody was associated with the difference in CDA amplitude for fearful and neutral trials. This association suggests that cognitive resources required to process fearful prosody detrimentally impact VWM maintenance. That result provides a piece of additional evidence that negative emotional stimuli produce greater interference than neutral stimuli and that the cognitive resources used to process stimuli from different modalities come from a common pool.

Using transcranial alternating current stimulation to enhance working memory skills in youths with 22q11.2 deletion syndrome: A randomized double-blind sham-controlled study.

Abnormal cognitive development, particularly working memory (WM) deficits, is among the first apparent manifestations of psychosis. Yet, cognitive impairment only shows limited response to current pharmacological treatment. Alternative interventions to target cognition are highly needed in individuals at high risk for psychosis, like carriers of 22q11.2 deletion syndrome (22q11.2DS). Here we applied theta-tuned transcranial alternating current stimulation (tACS) between frontal and temporal regions during a visual WM task in 34 deletion carriers. We conducted a double-blind sham-controlled study over three consecutive days. The stimulation parameters were derived from individual structural MRI scan and HD-EEG data acquired at baseline (Day 1) to model current intensity and individual preferential theta peak. Participants were randomized to either sham or tACS (Days 2 and 3) and then completed a visual WM task and a control task. Our findings reveal that tACS was safe and well-tolerated among participants. We found a significantly increased accuracy in the visual WM but not the control task following tACS. Moreover, this enhancement in WM accuracy was greater after tACS than during tACS, indicating stronger offline effects than online effects. Our study therefore supports the application of repeated sessions of brain stimulation in 22q11.2DS.

Causal functional maps of brain rhythms in working memory.

Human working memory is a key cognitive process that engages multiple functional anatomical nodes across the brain. Despite a plethora of correlative neuroimaging evidence regarding the working memory architecture, our understanding of critical hubs causally controlling overall performance is incomplete. Causal interpretation requires cognitive testing following safe, temporal, and controllable neuromodulation of specific functional anatomical nodes. Such experiments became available in healthy humans with the advance of transcranial alternating current stimulation (tACS). Here, we synthesize findings of 28 placebo-controlled studies (in total, 1,057 participants) that applied frequency-specific noninvasive stimulation of neural oscillations and examined working memory performance in neurotypical adults. We use a computational meta-modeling method to simulate each intervention in realistic virtual brains and test reported behavioral outcomes against the stimulation-induced electric fields in different brain nodes. Our results show that stimulating anterior frontal and medial temporal theta oscillations and occipitoparietal gamma rhythms leads to significant dose-dependent improvement in working memory task performance. Conversely, prefrontal gamma modulation is detrimental to performance. Moreover, we found distinct spatial expression of theta subbands, where working memory changes followed orbitofrontal high-theta modulation and medial temporal low-theta modulation. Finally, all these results are driven by changes in working memory accuracy rather than processing time measures. These findings provide a fresh view of the working memory mechanisms, complementary to neuroimaging research, and propose hypothesis-driven targets for the clinical treatment of working memory deficits.

Alcohol use disorder and time perception: The mediating role of attention and working memory.

Alcohol use disorder (AUD) has been associated with attentional deficits and impairments of working memory. Meanwhile, attention and working memory are critical for time perception. However, it remains unclear how time perception alters in AUD patients and how attention and working memory affect their time perception. The current study aims to clarify the time perception characteristics of AUD patients and the cognitive mechanisms underlying their time perception dysfunction. Thirty-one patients (three of them were excluded) with AUD and thirty-one matched controls completed the Time Bisection Task, Attention Network Test and Digital Span Backward Test to assess their abilities in time perception, attention network and working memory, respectively. The results showed that, after controlling for anxiety, depression, and impulsivity, AUD patients had a lower proportion of 'long' responses at intervals of 600, 750, 900, 1050 and 1200 ms. Furthermore, they displayed higher subjective equivalence points and higher Weber ratios compared to controls. Moreover, AUD patients showed impaired alerting and executive control networks as well as reduced working memory resources. Only working memory resources mediated the impact of AUD on time perception. In conclusion, our findings suggested that the duration underestimation in AUD patients is predominantly caused by working memory deficits.

The reading-attention relationship: Variations in working memory network activity during single word decoding in children with and without dyslexia.

This study utilized a neuroimaging task to assess working memory (WM) network recruitment during single word reading. Associations between WM and reading comprehension skills are well documented. Several converging models suggest WM may also contribute to foundational reading skills, but few studies have assessed this contribution directly. Two groups of children (77 developmental dyslexia (DD), 22 controls) completed a functional magnetic resonance imaging (fMRI) task to identify activation of a priori defined regions of the WM network. fMRI trials consisted of familiar word, pseudoword, and false font stimuli within a 1-back oddball task to assess how activation in the WM network differs in response to stimuli that can respectively be processed using word recognition, phonological decoding, or non-word strategies. Results showed children with DD recruited WM regions bilaterally in response to all stimulus types, whereas control children recruited left-lateralized WM regions during the pseudoword condition only. Group-level comparisons revealed activation differences in the defined WM network regions for false font and familiar word, but not pseudoword conditions. This effect was driven by increased activity in participants with DD in right hemisphere frontal, parietal, and motor regions despite poorer task performance. Findings suggest the WM network may contribute to inefficient decoding and word recognition strategies in children with DD.

The effects of working memory training on attention deficit, adaptive and non-adaptive cognitive emotion regulation of Chinese children with Attention Deficit/Hyperactivity Disorder (ADHD).

BACKGROUND: Attention Deficit/Hyperactivity Disorder (ADHD) poses cognitive and emotional challenges for Chinese children. This study addresses the potential benefits of Working Memory Training for ADHD-affected children. Understanding its impact on Attention, cognitive regulation, and emotional responses is crucial for tailored interventions in the Chinese context. The Trial Registration Number (TRN) for this study is [TRN-2023-123,456], and it was officially registered on July 15, 2023, by Changchun Normal University. OBJECTIVES: This study investigated how Working Memory training influences Attention, adaptive cognitive regulation, and non-adaptive cognitive emotion regulation in Chinese children with ADHD. It also assessed changes in attentional focus, improvements in adaptive cognitive regulation, and alterations in non-adaptive cognitive emotion regulation strategies. METHODOLOGY: This quasi-experimental study aimed to assess the impact of working memory training on Chinese children with ADHD. Using pretest-posttest measures, 120 female students underwent Cogmed software training, targeting attention deficits and cognitive emotion regulation. Three reliable instruments measured outcomes. The procedure involved informed consent, questionnaires, 25 training sessions, and a two-month follow-up. Statistical analyses, including repeated measures ANOVA, assessed training effects. RESULTS: ANOVA revealed a significant impact of Working memory training on attention deficit. Repeated measures ANOVA for cognitive emotion regulation indicated positive changes in adaptive and non-adaptive strategies over time, with sustained improvements in self-blame, rumination, catastrophizing, and blaming others. Bonferroni follow-up tests showed significant differences between pre-test, post-test, and follow-up, favoring the post-test and follow-up tests. CONCLUSIONS: In summary, this research sheds light on the positive impact of memory training on Attention and cognitive emotion regulation in children with ADHD. The study underscores the potential of working memory interventions, particularly software-focused approaches, in enhancing attention levels and improving cognitive emotion regulation. The findings align with existing literature emphasizing the role of working memory deficits in ADHD. IMPLICATIONS: Practically, incorporating memory training interventions into educational settings emerges as a viable strategy to support children with ADHD. This includes integrating memory training programs into both classroom activities and home-based interventions. Additionally, sustained implementation and long-term follow-up assessments are crucial for maximizing the effectiveness of memory training interventions. Tailoring interventions to specific ADHD subtypes and seamlessly integrating memory training activities into daily routines offer practical and personalized solutions for managing ADHD symptoms in diverse settings.

A preliminary study of dynamic neurochemical changes in the dorsolateral prefrontal cortex during working memory.

Working memory (WM) is one of the fundamental cognitive functions associated with the dorsolateral prefrontal cortex (DLPFC). However, the neurochemical mechanisms of WM, including the dynamic changes in neurometabolites such as glutamate and GABA in the DLPFC, remain unclear. Here, we investigated WM-related glutamate and GABA changes, alongside hemodynamic responses in the DLPFC, using a combination of functional magnetic resonance spectroscopy (fMRS) and functional magnetic resonance imaging (fMRI). During a WM task, we measured Glx (glutamate + glutamine) and GABA levels using GABA editing MEscher-GArwood Point REsolved Spectroscopy (MEGA-PRESS) sequence and blood-oxygen-level-dependent (BOLD) signal changes. In the DLPFC, we observed elevated Glx levels and increased BOLD signal changes during a 2-back task. Specifically, the Glx levels in the DLPFC were significantly higher during the 2-back task compared with fixation, although this difference was not significant when compared with a 0-back task. However, Glx levels during the 0-back task were higher than during fixation. Furthermore, there was a positive correlation between Glx levels in the DLPFC during the 2-back task and the corresponding BOLD signal changes. Notably, higher Glx increases were associated with increased DLPFC activation and lower WM task performance in individuals. No notable changes in DLPFC GABA levels were observed during WM processing. These findings suggest that the modulation of glutamatergic activity in the DLPFC may play a crucial role in both working memory processing and its associated performance outcomes.