Cognitive Function In Healthy Individuals Research Articles

Investigating the neural mechanisms of transcranial direct current stimulation effects on human cognition: current issues and potential solutions.

Transcranial direct current stimulation (tDCS) has been studied extensively for its potential to enhance human cognitive functions in healthy individuals and to treat cognitive impairment in various clinical populations. However, little is known about how tDCS modulates the neural networks supporting cognition and the complex interplay with mediating factors that may explain the frequently observed variability of stimulation effects within and between studies. Moreover, research in this field has been characterized by substantial methodological variability, frequent lack of rigorous experimental control and small sample sizes, thereby limiting the generalizability of findings and translational potential of tDCS. The present manuscript aims to delineate how these important issues can be addressed within a neuroimaging context, to reveal the neural underpinnings, predictors and mediators of tDCS-induced behavioral modulation. We will focus on functional magnetic resonance imaging (fMRI), because it allows the investigation of tDCS effects with excellent spatial precision and sufficient temporal resolution across the entire brain. Moreover, high resolution structural imaging data can be acquired for precise localization of stimulation effects, verification of electrode positions on the scalp and realistic current modeling based on individual head and brain anatomy. However, the general principles outlined in this review will also be applicable to other imaging modalities. Following an introduction to the overall state-of-the-art in this field, we will discuss in more detail the underlying causes of variability in previous tDCS studies. Moreover, we will elaborate on design considerations for tDCS-fMRI studies, optimization of tDCS and imaging protocols and how to assure high-level experimental control. Two additional sections address the pressing need for more systematic investigation of tDCS effects across the healthy human lifespan and implications for tDCS studies in age-associated disease, and potential benefits of establishing large-scale, multidisciplinary consortia for more coordinated tDCS research in the future. We hope that this review will contribute to more coordinated, methodologically sound, transparent and reproducible research in this field. Ultimately, our aim is to facilitate a better understanding of the underlying mechanisms by which tDCS modulates human cognitive functions and more effective and individually tailored translational and clinical applications of this technique in the future.

Photobiomodulation Therapy on Brain: Pioneering an Innovative Approach to Revolutionize Cognitive Dynamics.

Photobiomodulation (PBM) therapy on the brain employs red to near-infrared (NIR) light to treat various neurological and psychological disorders. The mechanism involves the activation of cytochrome c oxidase in the mitochondrial respiratory chain, thereby enhancing ATP synthesis. Additionally, light absorption by ion channels triggers the release of calcium ions, instigating the activation of transcription factors and subsequent gene expression. This cascade of events not only augments neuronal metabolic capacity but also orchestrates anti-oxidant, anti-inflammatory, and anti-apoptotic responses, fostering neurogenesis and synaptogenesis. It shows promise for treating conditions like dementia, stroke, brain trauma, Parkinson's disease, and depression, even enhancing cognitive functions in healthy individuals and eliciting growing interest within the medical community. However, delivering sufficient light to the brain through transcranial approaches poses a significant challenge due to its limited penetration into tissue, prompting an exploration of alternative delivery methods such as intracranial and intranasal approaches. This comprehensive review aims to explore the mechanisms through which PBM exerts its effects on the brain and provide a summary of notable preclinical investigations and clinical trials conducted on various brain disorders, highlighting PBM's potential as a therapeutic modality capable of effectively impeding disease progression within the organism-a task often elusive with conventional pharmacological interventions.

Peripheral inflammation is associated with impaired sadness recognition in euthymic bipolar patients

BackgroundInflammation impairs cognitive function in healthy individuals and people with psychiatric disorders, such as bipolar disorder (BD). This effect may also impact emotion recognition, a fundamental element of social cognition. Our study aimed to investigate the relationships between pro-inflammatory cytokines and emotion recognition in euthymic BD patients and healthy controls (HCs). MethodsWe recruited forty-four euthymic BD patients and forty healthy controls (HCs) and measured their inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and TNF-α. We applied validated cognitive tasks, the Wisconsin Card-Sorting Test (WCST) and Continuous Performance Test (CPT), and a social cognitive task for emotion recognition, Diagnostic Analyses of Nonverbal Accuracy, Taiwanese Version (DANVA-2-TW). We analyzed the relationships between cytokines and cognition and then explored possible predictive factors of sadness recognition accuracy. ResultsRegarding pro-inflammatory cytokines, TNF-α was elevated in euthymic BD patients relative to HCs. In euthymic BD patients only, higher TNF-α levels were associated with lower accuracy of sadness recognition. Regression analysis revealed that TNF-α was an independent predictive factor of sadness recognition in patients with euthymic BD when neurocognition was controlled for.Conclusions: We demonstrated that enhanced inflammation, indicated by increased TNF-α, was an independent predictive factor of impaired sadness recognition in BD patients but not in HCs. Our findings suggested a direct influence of TNF-α on sadness recognition and indicated vulnerability to depression in euthymic BD patients with chronic inflammation.

A Novel Ketone-Supplemented Diet Improves Recognition Memory and Hippocampal Mitochondrial Efficiency in Healthy Adult Mice.

Mitochondrial dysfunction and cognitive impairment are common symptoms in many neurologic and psychiatric disorders, as well as nonpathological aging. Ketones have been suggested as therapeutic for their efficacy in epilepsy and other brain pathologies such as Alzheimer's disease and major depressive disorder. However, their effects on cognitive function in healthy individuals is less established. Here, we explored the mitochondrial and performative outcomes of a novel eight-week ketone-supplemented ketogenic (KETO) diet in healthy adult male and female mice. In a novel object recognition test, KETO mice spent more time with the novel, compared to familiar, object, indicating an improvement in recognition memory. High-resolution respirometry on permeabilized hippocampal tissue returned significant reductions in mitochondrial O2 consumption. No changes in ATP production were observed, yielding a significantly higher ATP:O2 ratio, a measure of mitochondrial efficiency. Together, these findings demonstrate the KETO diet improves hippocampal mitochondrial efficiency. They add to a growing body of evidence that suggests ketones and ketogenic diets are neuroprotective and metabolically and cognitively relevant, even in healthy adults. They also suggest that ketogenic lifestyle changes may be effective strategies for protecting against cognitive decline associated with aging and disease.

General intelligence and executive functioning are overlapping but separable at genetic and molecular pathway levels: An analytical review of existing GWAS findings.

Understanding the genomic architecture and molecular mechanisms of cognitive functioning in healthy individuals is critical for developing tailored interventions to enhance cognitive functioning, as well as for identifying targets for treating impaired cognition. There has been substantial progress in uncovering the genetic composition of the general cognitive ability (g). However, there is an ongoing debate whether executive functioning (EF)–another key predictor of cognitive health and performance, is separable from general g. To provide an analytical review on existing findings on genetic influences on the relationship between g and EF, we re-analysed a subset of genome-wide association studies (GWAS) from the GWAS catalogue that used measures of g and EF as outcomes in non-clinical populations. We identified two sets of single nucleotide polymorphisms (SNPs) associated with g (1,372 SNPs across 12 studies), and EF (300 SNPs across 5 studies) at p<5x10-6. A comparative analysis of GWAS-identified g and EF SNPs in high linkage disequilibrium (LD), followed by pathway enrichment analyses suggest that g and EF are overlapping but separable at genetic variant and molecular pathway levels, however more evidence is required to characterize the genetic overlap/distinction between the two constructs. While not without limitations, these findings may have implications for navigating further research towards translatable genetic findings for cognitive remediation, enhancement, and augmentation.

The relationship between cognitive reserve and cognition in healthy adults: a systematic review

The concept of Cognitive Reserve (CR) refers to the individual differences allowing some people to cope better with brain pathology. The aim of the present review was to explore the relationship between CR and cognition in adulthood. This association has been addressed in several neuro(psycho)logical disorders and in healthy elderly people. However, few studies explored this issue in adulthood (age range 18–65), when individuals might take advantage the most from psychoeducational approaches aimed at increasing CR. For our systematic review, we selected studies assessing CR and adopting neuropsychological and experimental tasks for evaluation of cognitive functioning in healthy individuals. In the selected articles, we examined the relationship of singular proxies, composite indexes or standardized scales of CR with measures of general cognition, attention, inhibitory control, verbal fluency, constructional abilities, and verbal and spatial memory. The results suggested a positive relationship between singular CR proxies, composite indexes or standardized scales, and almost all the explored cognitive domains. No clear conclusion could be made on constructional abilities due to the scarcity of available studies. CR seems associated with better cognitive performance in adulthood, but definite methodological improvements and the use of standardized scales for CR are necessary to reduce inconsistencies among studies.

Combined Effect of Repetitive Transcranial Magnetic Stimulation and Cognitive Rehabilitation on Working Memory of Patients with Chronic Stroke

Background: Working memory is one of the cognitive aspects that may be damaged in patients suffering from a stroke. According to evidence, repetitive Transcranial Magnetic Stimulation (rTMS) and cognitive interventions could affect cognitive function in healthy individuals or patients with neurological diseases. Objectives: This study aimed to evaluate the combined effect of high-frequency rTMS in the left Dorsolateral Prefrontal Cortex (DLPFC) region of the brain and cognitive rehabilitation on the working memory of stroke patients. Methods: In this double-blind, randomized clinical trial with a pretest-posttest design, 18 post-stroke chronic patients aged 55 to 75 years were randomly divided into two experimental and control groups. The working memory score was measured using the N-back test in the two groups before the interventions. Then, both groups participated in rTMS intervention sessions, except that in the control group, changing the coil angle prevented the waves from reaching the brain. The rTMS interventions were performed for each patient in 15 sessions of six minutes, three days a week. In addition, both groups received computer-based cognitive rehabilitation therapy immediately after each rTMS session for 30 to 40 minutes. These practices included working memory rehabilitation in Captain's Log software used at the adult level. Each level had 15 steps, and the difficulty of the exercises increased with increasing steps. Finally, the working memory was remeasured after the intervention sessions. Results: The use of rTMS on the left DLPFC region significantly improved the working memory of stroke people in the experimental group compared to the control group (P = 0.027). In addition, the difference before and after the interventions in both groups was significant for this variable (P &lt; 0.001), which indicates the positive effect of cognitive rehabilitation on reducing cognitive problems. Conclusions: Although cognitive rehabilitation using software is effective on working memory, using rTMS along with cognitive rehabilitation in the left DLPFC area has a more significant effect on improving working memory in people with chronic stroke.

Combined Effect of Repetitive Transcableranial Magnetic Stimulation and Cognitive Rehabilitation on Working Memory of Patients with Chronic Stroke

Background: Working memory is one of the cognitive aspects that may be damaged in patients suffering from a stroke. According to evidence, repetitive Transcranial Magnetic Stimulation (rTMS) and cognitive interventions could affect cognitive function in healthy individuals or patients with neurological diseases. Objectives: This study aimed to evaluate the combined effect of high-frequency rTMS in the left Dorsolateral Prefrontal Cortex (DLPFC) region of the brain and cognitive rehabilitation on the working memory of stroke patients. Methods: In this double-blind, randomized clinical trial with a pretest-posttest design, 18 post-stroke chronic patients aged 55 to 75 years were randomly divided into two experimental and control groups. The working memory score was measured using the N-back test in the two groups before the interventions. Then, both groups participated in rTMS intervention sessions, except that in the control group, changing the coil angle prevented the waves from reaching the brain. The rTMS interventions were performed for each patient in 15 sessions of six minutes, three days a week. In addition, both groups received computer-based cognitive rehabilitation therapy immediately after each rTMS session for 30 to 40 minutes. These practices included working memory rehabilitation in Captain's Log software used at the adult level. Each level had 15 steps, and the difficulty of the exercises increased with increasing steps. Finally, the working memory was remeasured after the intervention sessions. Results: The use of rTMS on the left DLPFC region significantly improved the working memory of stroke people in the experimental group compared to the control group (P = 0.027). In addition, the difference before and after the interventions in both groups was significant for this variable (P &lt; 0.001), which indicates the positive effect of cognitive rehabilitation on reducing cognitive problems. Conclusions: Although cognitive rehabilitation using software is effective on working memory, using rTMS along with cognitive rehabilitation in the left DLPFC area has a more significant effect on improving working memory in people with chronic stroke.

The Effects of Physical Exercise on Mental Health: From Cognitive Improvements to Risk of Addiction

(1) Background: we aimed to investigate the effects of physical activity on cognitive functions and deficits of healthy population and other needy groups. Secondly, we investigated the relation between healthy habits and psychopathological risks. Finally, we investigated the impact of COVID-19 pandemic on exercise addiction and possible associated disorders. (2) Methods: From April 2021 to October 2021, we conducted a review aimed at identifying the effects of physical exercise on mental health, from cognitive improvements to risk of addiction; we searched for relevant studies on PubMed, Web of Science, EMBASE, PsycINFO and CINHAL. (3) Results: For the first purpose, results indicated multiple effects such as better precision and response speed in information processing tasks on healthy populations; improvement of executive functions, cognitive flexibility and school performance in children; improvement of attention and executive functions and less hyperactivity and impulsiveness on children with attention deficit hyperactivity disorder (ADHD); improvement of executive and global functions on adults; improvement of overall cognitive functioning on patients with schizophrenic spectrum disorder or bipolar disorder. Data also demonstrated that exercise addiction seems to be related to low levels of education, low self-esteem, eating disorders and body dysmorphisms. Eventually, it was found that people with lower traits and intolerance of uncertainty show a strong association between COVID-19 anxiety and compulsive exercise and eating disorder. (4) Conclusions: these findings underline on one side the beneficial effects of physical activity on cognitive function in healthy individuals in a preventive and curative key, while on the other side the importance of an adequate evaluation of psychological distress and personality characteristics associated with exercise addiction.

Sex-specific effects of polygenic risk for schizophrenia on lifespan cognitive functioning in healthy individuals

Polygenic risk for schizophrenia has been associated with lower cognitive ability and age-related cognitive change in healthy individuals. Despite well-established neuropsychological sex differences in schizophrenia patients, genetic studies on sex differences in schizophrenia in relation to cognitive phenotypes are scarce. Here, we investigated whether the effect of a polygenic risk score (PRS) for schizophrenia on childhood, midlife, and late-life cognitive function in healthy individuals is modified by sex, and if PRS is linked to accelerated cognitive decline. Using a longitudinal data set from healthy individuals aged 25–100 years (N = 1459) spanning a 25-year period, we found that PRS was associated with lower cognitive ability (episodic memory, semantic memory, visuospatial ability), but not with accelerated cognitive decline. A significant interaction effect between sex and PRS was seen on cognitive task performance, and sex-stratified analyses showed that the effect of PRS was male-specific. In a sub-sample, we observed a male-specific effect of the PRS on school performance at age 12 (N = 496). Our findings of sex-specific effects of schizophrenia genetics on cognitive functioning across the lifespan indicate that the effects of underlying disease genetics on cognitive functioning is dependent on biological processes that differ between the sexes.

Effects of a moderate intensity aerobic exercise on serum levels of BDNF, DCX, and DBHB in triathlon male adolescents

Background: Various serum factors in response to aerobic exercise improve cognitive function in healthy individuals; nonetheless, the effect of moderate intensity aerobic exercise on their levels has not been studied. Therefore, the present study aimed to assess the effect of a moderate intensity aerobic exercise on serum levels of Brain-derived neurotrophic factor (BDNF), Doublecortin (DCX), and D-β-hydroxybutyrate (DBHB) in triathlon male adolescents in Tuyserkan. Materials and Methods: A total of 22 triathlon male adolescents (age: 17.60±0.52 years, weight: 60.74±4.96 kg, height: 175.60±5.52 cm) voluntarily participated in this quasi-experimental study. Subjects in one session performed 60 minutes of running with an intensity of 12-13 on the Borg scale. Blood samples were taken from the subjects 5 min before and after training. Serum levels of BDNF, DCX and DBHB were measured by ELISA. To analyze the data, paired samples t-test was used, and a p-value less than 0.05 was considered statistically significant. In addition, the percentage of changes was compared to pre-test. Results: Based on the results, the serum levels of DCX (P=0.0005), BDNF (P=0.0005), and DBHB (P=0.001) increased significantly, compared to those in the pretest. Furthermore, serum levels of BDNF (21.30%), DBHB (12.95%) and DCX (12.01%) had the highest increase, as compared to the pretest, respectively. Conclusion: All three serum factors BDNF, DCX, and DBHB have a significant positive response to moderate-intensity aerobic exercise in triathlon male adolescents. Nevertheless, neurotrophin/growth factor BDNF demonstrates more changes and appears to play a greater role in neuroprotection, improving memory, learning, and cognitive function.

Swimming exercise improves short- and long-term memories: Time-course changes.

The beneficial effects of exercise training on memory formation are well documented. However, the memory enhancement profile following the time‐course of exercise training remains unknown. In this investigation, changes in the spatial hippocampal memory following a time‐course of swimming exercise training were examined. Young adult Wistar rats were tested for both short‐term and long‐term memories using the radial arm water maize (RAWM) paradigm following 0, 1, 7, 14, and 28 days of swimming exercise training (60 min per day, 5 days/week)s. The mean total errors on RAWM during the learning phase and memory testing remained the same (p > 0.5) after 1 day of swimming exercise. On the other hand, swimming exercise‐induced significant enhancement to the learning phase and memory formation after 7 days of training (p < 0.01). Errors decreased (p < 0.0001) after 7 days of training and remained lower (p < 0.0001) than baseline without differences between 7, 14, and 28 days (p > 0.5). Similarly, short‐ and long‐term memories improved after 7 days (p < 0.05) of training as compared to the baseline without differences between 7, 14, and 28 days (p > 0.05). The time course of improvement of learning and both short‐ and long‐term memories after swimming exercise were evident after 7 days and plateaued thereafter. Results of the current study could form the base for future utilization of exercises to enhance cognitive function in healthy individuals.

The Role of Sleep Quality, Trait Anxiety and Hypothalamic-Pituitary-Adrenal Axis Measures in Cognitive Abilities of Healthy Individuals.

Sleep plays a crucial role in cognitive processes. Sleep and wake memory consolidation seem to be regulated by glucocorticoids, pointing out the potential role of the hypothalamic-pituitary-adrenal (HPA) axis in the relationship between sleep quality and cognitive abilities. Trait anxiety is another factor that is likely to moderate the relationship between sleep and cognition, because poorer sleep quality and subtle HPA axis abnormalities have been reported in people with high trait anxiety. The current study aimed to explore whether HPA axis activity or trait anxiety moderate the relationship between sleep quality and cognitive abilities in healthy individuals. We studied 203 healthy individuals. We measured verbal and visual memory, working memory, processing speed, attention and executive function. Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Trait anxiety was assessed with the State-Trait Anxiety Inventory. HPA axis measures included the cortisol awakening response (CAR), diurnal cortisol slope and cortisol levels during the day. Multiple linear regression analyses explored the relationship between sleep quality and cognition and tested potential moderating effects by HPA axis measures and trait anxiety. Poor sleep quality was associated with poorer performance in memory, processing speed and executive function tasks. In people with poorer sleep quality, a blunted CAR was associated with poorer verbal and visual memory and executive functions, and higher cortisol levels during the day were associated with poorer processing speed. Trait anxiety was a moderator of visual memory and executive functioning. These results suggest that subtle abnormalities in the HPA axis and higher trait anxiety contribute to the relationship between lower sleep quality and poorer cognitive functioning in healthy individuals.

White Matter Measures and Cognition in Schizophrenia.

White matter (WM) abnormalities are commonly reported in schizophrenia but whether these arise from the axon or myelin compartments or both is not known. In addition, the relationship between WM abnormalities and cognitive function is not fully explored in this condition. We recruited 39 individuals with schizophrenia spectrum disorders and 37 healthy comparison subjects. All participants underwent MRI scanning at 4 Tesla to collect data in the prefrontal white matter on magnetization transfer ratio (MTR) and diffusion tensor spectroscopy (DTS) which provide information on myelin and axon compartments, respectively. We also collected Matrics Composite Cognitive Battery (MCCB) and Stroop cognitive data. We found an elevated N-acetylaspartate (NAA) apparent diffusion coefficient in schizophrenia in this cohort as in our previous work; we also observed poorer performance on both the MCCB composite and the Stroop in schizophrenia patients compared to controls. The MTR measure was correlated with the MCCB composite (r = 0.363, p = 0.032) and Stroop scores (r = 0.387, p = 0.029) in healthy individuals but not in schizophrenia. Since this is the first exploration of the relationship between these WM and cognitive measures, we consider our analyses exploratory and did not adjust for multiple comparisons; the findings are not statistically significant if adjusted for multiple comparisons. These findings indicate that WM integrity is associated with cognitive function in healthy individuals but this relationship breaks down in patients with schizophrenia.

Interactome overlap between schizophrenia and cognition

Cognitive impairments constitute a core feature of schizophrenia, and a genetic overlap between schizophrenia and cognitive functioning in healthy individuals has been identified. However, due to the high polygenicity and complex genetic architecture of both traits, overlapping biological pathways have not yet been identified between schizophrenia and normal cognitive ability. Network medicine offers a framework to study underlying biological pathways through protein-protein interactions among risk genes. Here, established network-based methods were used to characterize the biological relatedness of schizophrenia and cognition by examining the genetic link between schizophrenia risk genes and genes associated with cognitive performance in healthy individuals, through the protein interactome. First, network separation showed a profound interactome overlap between schizophrenia risk genes and genes associated with cognitive performance (SAB = −0.22, z-score = −6.80, p = 5.38e−12). To characterize this overlap, network propagation was thereafter used to identify schizophrenia risk genes that are close to cognition-associated genes in the interactome network space (n = 140, of which 54 were part of the direct genetic overlap). Schizophrenia risk genes close to cognition were enriched for pathways including long-term potentiation and Alzheimer's disease, and included genes with a role in neurotransmitter systems important for cognitive functioning, such as glutamate and dopamine. These results pinpoint a subset of schizophrenia risk genes that are of particular interest for further examination in schizophrenia patient groups, of which some are druggable genes with potential as candidate targets for cognitive enhancing drugs.

O11.4. INTERACTOME OVERLAP BETWEEN SCHIZOPHRENIA AND COGNITION

BackgroundCognitive impairments constitute a core feature of schizophrenia, and a genetic overlap between schizophrenia and cognitive functioning in healthy individuals has been identified. However, due to the high polygenicity and complex genetic architecture of both traits, overlapping biological pathways have not yet been identified between schizophrenia and normal cognitive ability. Network medicine offers a framework to study biologically meaningful gene networks through protein-protein interactions among risk genes. Here, established network-based methods were used to further reveal the biological relatedness of schizophrenia and cognition.MethodsThe protein interactome was used to examine the genetic link between schizophrenia risk genes and genes associated with cognitive performance in healthy individuals. First, we used a method called network separation to examine if there is an overlap between schizophrenia and cognition in the interactome network space. Then, we used network propagation analyses to identify schizophrenia risk genes that are close to cognition-associated genes in the interactome network space. Gene ontology and pathway enrichment analysis was performed to describe the function of this gene set.ResultsNetwork separation analyses showed a profound interactome overlap between schizophrenia risk genes and genes associated with cognitive performance (SAB = -0.22, z-score = -6.80, p = 5.38e-12). We identified 140 schizophrenia risk genes that are close to cognition-associated genes in the interactome. Risk genes close to cognition were enriched for pathways including long-term potentiation and Alzheimer’s disease, and included genes with a role in neurotransmitter systems implemented in cognition, such as glutamate and dopamine, that were not part of the direct genetic overlap. Moreover, schizophrenia risk genes close to cognition included 45 druggable genes not yet used as drug targets.DiscussionThese results pinpoint schizophrenia risk genes of particular interest for further examination in schizophrenia patient groups to reveal the genetic architecture of cognitive impairments in schizophrenia, of which some are druggable genes with potential as candidate targets for cognitive enhancing drugs.

Effects of Chewing Training on Orofacial and Cognitive Function in Healthy Individuals: A Systematic Review

Background: There is some evidence showing significant correlations between acute chewing gum and orofacial function, and between acute chewing gum and cognitive function; however, as far as we are aware, little is known about the chronic effects of chewing gum training on cognitive and orofacial functions in healthy adults. Objectives: To evaluate the chronic effects of chewing gum training on orofacial and cognitive functions in healthy adults. Method: Searches of the electronic databases PubMed, Scopus, BVS, CENTRAL, Scopus, and Google Scholar were conducted from inception to 14 January 2020. The inclusion criteria used were: clinical trial or randomized controlled trial lasting a minimum of four weeks, chewing gum intervention in at least one arm of the study, presence of a non-exercise control group, study population consisting of healthy adults, study outcomes consisting of orofacial function and/or cognitive function. Results: Starting from 5973 sources, a total of six articles met the inclusion criteria, and they were subjected to a systematic review. The main findings were that chewing gum training improved some variables related to orofacial function. No clear effect of chewing gum training on cognitive function was found. Conclusions: Chronic chewing gum training has an unclear positive effect on specific variables related to orofacial and cognitive function in healthy adults.

Effect of Epimerized Catechins-Rich Green Tea Extract on Global Cognitive Function in Healthy Individuals: A Pilot Study

Green tea consumption has been shown to have many beneficial effects on brain health. A high-temperature-processed green tea extract (HTP_GTE) were developed with high levels of epimerized catechins and its effects were investigated on brain functions. HTP_GTE was found to protects neuronal cells and reduces neurite length against oxidative stress-induced cell damage (p ≤ 0.001). Furthermore, a double-blind, placebo-controlled, randomized clinical study using the Cambridge Neuropsychological Test Automated Battery (CANTAB) showed that daily administration of 500 mg HTP_GTE for 8 weeks significantly improved global cognitive functions in middle-aged healthy subjects (n=23; 40.9 ± 4.4 yrs) (p = 0.049 vs. placebo). These preliminary results suggest that HTP_GTE may have potential as a nutraceutical for cognitive improvement.

Comparative benefits of simvastatin and exercise in a mouse model of vascular cognitive impairment and dementia.

Aerobic physical exercise (EX) and controlling cardiovascular risk factors in midlife can improve and protect cognitive function in healthy individuals and are considered to be effective at reducing late-onset dementia incidence. By investigating commonalities between these preventative approaches, we sought to identify possible targets for effective interventions. We compared the efficacy of EX and simvastatin (SV) pharmacotherapy to counteract cognitive deficits induced by a high-cholesterol diet (2%, HCD) in mice overexpressing TGF-β1 (TGF mice), a model of vascular cognitive impairment and dementia. Cognitive deficits were found in hypercholesterolemic mice for object recognition memory, and both SV and EX prevented this decline. EX improved stimulus-evoked cerebral blood flow responses and was as effective as SV in normalizing endothelium-dependent vasodilatory responses in cerebral arteries. The up-regulation of galectin-3–positive microglial cells in white matter (WM) of HCD-fed TGF mice with cognitive deficits was significantly reduced by both SV and EX concurrently with cognitive recovery. Altered hippocampal neurogenesis, gray matter astrogliosis, or microgliosis did not correlate with cognitive deficits or benefits. Overall, results indicate that SV and EX prevented cognitive decline in hypercholesterolemic mice and that they share common sites of action in preventing endothelial cell dysfunction and reducing WM inflammation.—Trigiani, L. J., Royea, J., Tong, X.-K., Hamel, E. Comparative benefits of simvastatin and exercise in a mouse model of vascular cognitive impairment and dementia.

A Study to Assess and Correlate Serum Lipid Profile with Reaction Time in Healthy Individuals.

Dyslipidaemia, metabolic syndrome, diabetes mellitus and arterial hypertension contribute to the risk of cognitive disorder and dementia. However very few and conflicting results are available with respect to the impact of lipoprotein ratios on cognitive functions in healthy individuals. Therefore, this study was aimed to investigate the association of lipid profile and its ratios with reaction time in young healthy individuals. 89 individuals (54 male and 35 female) with mean age of 31.20 ± 3.19years were selected for this observational study conducted at AIIMS Rishikesh and written consent was obtained. TC, TG, HDL were measured by semi auto analyzer following the manufacturers' instruction and LDL was calculated by Friedewald formula. Reaction time (simple and choice reaction time) was assessed using a software package, Deary-Liewald reaction time task. Association of various parameters was calculated by pearson's correlation coefficient using SPSS version 23.0. Reaction time showed significant negative association with BMI (r = - 0.323, p = 0.002) in total study participants as well as with TG (r = - 0.440, p = 0.008) and TG/HDL (r = - 0.402, p = 0.025) in female individuals. From this study, it could be concluded that TG/HDL ratio, the superlative predictor of concomitant presence of cardiovascular disease, insulin resistance and metabolic syndrome may be considered as a biomarker for assessment of cognitive function in young healthy female individuals.