Cognitive Enhancing Effects Research Articles

Evaluation of the Therapeutic Potential of Oral Phycocyanin-Rich Spirulina Extracts in Neuropsychiatric Disorders

Aim: Spirulina is a microalga that is widely used as a food supplement and is regarded as having performance-enhancing and health-promoting properties. We conducted a preliminary evaluation of the possible anti-depressant, anti-anxiety, pro-socialization and cognition-enhancing effects of Spirulina in mouse models. Methods: Sixty male BalbC mice aged 3 weeks were administered with phycocyanin-rich Spirulina extract [PRSE, 545 mg/kg], fluoxetine [20 mg/kg] or water orally for 5 weeks. During the last 2 weeks of the experiment, a series of behavioral-cognitive tests were performed to evaluate motor activity, anti-depressant and anti-anxiety effects, socialization and cognitive effects. Effects of PRSE and fluoxetine were compared to those of water. Results: There was a significant effect of PRSE in the activity domain, manifesting as an increase in velocity in the open field [p=0.0007 vs. water]. Fluoxetine significantly enhanced immobility in the tail suspension test and the forced swim test reflecting the known anti-depressant effect of this compound, but not PRSE. There were no significant effects of PRSE found in the tests of anxiety, socialization or cognition. Conclusions: The most striking observation in this study was that PRSE significantly enhanced activity in the open field test. Further studies are indicated to confirm and extend this finding and investigate the possible mechanisms of action. The results of the current study do not support sporadic reports of possible anti-depressant or cognition-enhancing effects of PRSE. Nevertheless, additional studies are indicated using depression models rather than naïve mice, alternative mouse strains, using additional cognitive tests, and administering higher PRSE doses.

Is non-invasive brain stimulation effective for cognitive enhancement in Alzheimer’s disease? An updated meta-analysis

ObjectiveAlzheimer's disease dementia (AD) and its preclinical stage, mild cognitive impairment (MCI), are critical issues confronting the aging society. Non-invasive brain stimulation (NIBS) techniques have the potential to be effective tools for enhancing cognitive functioning. The main objective of our meta-analysis was to quantify and update the status of the efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) and Transcranial Direct Current Stimulation (tDCS) when applied in AD and MCI. MethodsThe systematic literature search was conducted in PubMed and Web of Science according to PRISMA statement. ResultsPooled effect sizes (Hedges’ g) from 32 studies were analyzed using random effect models. We found both, rTMS and tDCS to have significant immediate cognition-enhancing effect in AD with rTMS inducing also beneficial long-term effects. We found no evidence for synergistic effect of cognitive training with NIBS. ConclusionsIn AD a clinical recommendation can be made for NEURO-ADTM system and for high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC) as probably effective protocols (B-level of evidence) and for anodal tDCS over the left DLPFC as a possibly effective. SignificanceAccording to scientific literature, NIBS may be an effective method for improving cognition in AD and possibly in MCI.

3, 14, 19-Triacetyl Andrographolide alleviates the cognitive dysfunction of 3 × Tg-AD mice by inducing initiation and promoting degradation process of autophagy.

The present study aims to investigate the cognition-enhancing effect of 3, 14, 19-Triacetyl andrographolide (ADA) on learning and memory deficits in 3 × Tg-AD mice and to explore its underlying mechanism. Eight-month-old 3 × Tg-AD mice and C57BL/6J mice were randomly divided into three groups, namely wild-type group, 3 × Tg-AD group, and 3 × Tg-AD+ADA group (5mg/kg, for 21 days, i.p.). We found that ADA significantly improved learning and cognition impairment, inhibited the loss of Nissl body, and reduced Aβ load in the brains of 3 × Tg-AD mice. In addition, ADA enhanced the levels of PSD95 and SYP, which were closely associated with synaptic plasticity. Accumulated autophagosomes, LC3II, and P62 in hippocampus and cortex of 3 × Tg-AD mice were decreased by ADA treatment. Furthermore, ADA administration further down-regulated the expressions of p-AKT and p-mTOR, reduced the level of CTSB, and increased the co-localization of LC3 and LAMP1 in the brains of 3 × Tg-AD mice, implying that ADA-induced autophagy initiation and also promoted the degradation process. In Aβ25-35 -induced HT22 cells, ADA displayed similar effects on autophagy flux as observed in 3 × Tg-AD mice. Our finding verified that ADA could improve synaptic plasticity and cognitive function, which is mainly attributed to the key roles of ADA in autophagy induction and degradation.

Cognition-enhancing effect of YL-IPA08, a potent ligand for the translocator protein (18 kDa) in the 5 × FAD transgenic mouse model of Alzheimer's pathology.

Intracerebral translocator protein 18 kDa (TSPO) mediates the transport of cholesterol from cytoplasm to mitochondria and activation of microglia. The change of TSPO and the dysfunction of microglia are closely related to the pathogenesis of Alzheimer's disease (AD). This study aimed to investigate the effects of microglial TSPO and its selective ligand YL-IPA08 on the cognitive function of transgenic mice in 5 × familial Alzheimer's disease (FAD) mouse model of AD. The TSPO knockout 5 × FAD transgenic mice were bred, and tested by Morris water maze. The effects of YL-IPA08 on cognitive abilities and expression of Aβ in 5 × FAD mice were also explored into. The latency of escape by TSPO knockout 5 × FAD mice was significantly prolonged compared with the 5 × FAD group, indicating that the cognitive impairment of mice aggravated. With the attenuated phagocytic ability of microglia, the deposition of Aβ in prefrontal cortex of TSPO knockout 5 × FAD mice increased, and the expression of proinflammatory factors (IL-1β, TNF-α, IL-6) were upregulated. In addition, YL-IPA08 significantly reduced the latency of escape by 5 × FAD mice, increased the number of times of crossing over the platform by mice, and inhibited the deposition of Aβ in the prefrontal cortex of 5 × FAD mice without affecting the cleavage of APP. Our findings suggested that TSPO knockout in 5 × FAD mice inhibited microglial phagocytosis, promoted Aβ deposition and neuroinflammation, and aggravated cognitive dysfunction in AD mice. YL-IPA08 had a significant cognition-enhancing effect in 5 × FAD transgenic mice, which might provide a new basis for potential drug candidates in AD treatment.

Memory-Enhancing Effect of 8-Week Consumption of the Quercetin-Enriched Culinary Herbs-Derived Functional Ingredients: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

Due to great demand for memory enhancers, the memory-enhancing effects and the possible underlying mechanisms of the functional ingredients derived from the combined extract of Polygonum odoratum and Morus alba were investigated. A total of 45 participants randomly received either a placebo or the developed herbal supplement at a dose of 50 or 1500 mg/day. The consumption was done once daily for 8 weeks. Working memory was assessed via both an event-related potential and computerized battery tests at baseline and at the end of the 8-week study period. Acetylcholinesterase (AChE) and monoamine oxidase type A and type B (MAO-A, MAO-B) levels were also measured at the end of the study. The subjects who consumed the supplement containing a developed functional ingredient at a dose of 1500 mg/day showed reduced latencies but increased amplitudes of N100 and P300. An improvement in working memory and the suppression of AChE, MAO-A, and MAO-B activities were also observed. Therefore, this study clearly demonstrates the cognitive enhancing effect of the developed herbal congee, which may be associated with the suppressions of AChE and both types of MAO.

Striatal dopamine dissociates methylphenidate effects on value-based versus surprise-based reversal learning

Psychostimulants such as methylphenidate are widely used for their cognitive enhancing effects, but there is large variability in the direction and extent of these effects. We tested the hypothesis that methylphenidate enhances or impairs reward/punishment-based reversal learning depending on baseline striatal dopamine levels and corticostriatal gating of reward/punishment-related representations in stimulus-specific sensory cortex. Young healthy adults (N = 100) were scanned with functional magnetic resonance imaging during a reward/punishment reversal learning task, after intake of methylphenidate or the selective D2/3-receptor antagonist sulpiride. Striatal dopamine synthesis capacity was indexed with [18F]DOPA positron emission tomography. Methylphenidate improved and sulpiride decreased overall accuracy and response speed. Both drugs boosted reward versus punishment learning signals to a greater degree in participants with higher dopamine synthesis capacity. By contrast, striatal and stimulus-specific sensory surprise signals were boosted in participants with lower dopamine synthesis. These results unravel the mechanisms by which methylphenidate gates both attention and reward learning.

Enhancing memory capacity by experimentally slowing theta frequency oscillations using combined EEG-tACS

The coupling of gamma oscillation (~ 40+ Hz) amplitude to the phase of ongoing theta (~ 6 Hz) oscillations has been proposed to be directly relevant for memory performance. Current theories suggest that memory capacity scales with number of gamma cycles that can be fitted into the preferred phase of a theta cycle. Following this logic, transcranial alternating current stimulation (tACS) may be used to adjust theta cycles (increasing/decreasing theta frequency) to decrease or increase memory performance during stimulation. Here, we used individualized EEG-informed theta tACS to (1) experimentally “slow down” individual theta frequency (ITF), (2) evaluate cognitive after effects on a battery of memory and learning tasks, and (3) link the cognitive performance changes to tACS-induced effects on theta-band oscillations as measured by post EEG. We found frequency- and task-specific tACS after effects demonstrating a specific enhancement in memory capacity. This tACS-induced cognitive enhancement was specific to the visual memory task performed immediately after tACS offset, and specific to the ITF-1 Hz (slowing) stimulation condition and thus following a protocol specifically designed to slow down theta frequency to enhance memory capacity. Follow-up correlation analyses in this group linked the enhanced memory performance to increased left frontal-parietal theta-band connectivity. Interestingly, resting-state theta power immediately after tACS offset revealed a theta power increase not for the ITF-1 Hz group, but only for the ITF group where the tACS frequency was ‘optimal’ for entrainment. These results suggest that while individually calibrated tACS at peak frequency maximally modulates resting-state oscillatory power, tACS stimulation slightly below this optimal peak theta frequency is better suited to enhance memory capacity performance. Importantly, our results further suggest that such cognitive enhancement effects can last beyond the period of stimulation and are linked to increased network connectivity, opening the door towards more clinical and applied relevance of using tACS in cognitive rehabilitation and/or neurocognitive enhancement.

Pharmacological attributes of Bacopa monnieri extract: Current updates and clinical manifestation.

Bacopa monnieri has been used for centuries in Ayurvedic medicine, alone or in combination with other herbs, as a memory and learning enhancer, sedative, and anti-epileptic. This review aimed to highlight the health benefits of B. monnieri extracts (BME), focusing on anti-cancer and neurodegenerative diseases. We examined the clinical studies on phytochemistry and pharmacological application of BME. We further highlighted the mechanism of action of these extracts in varying types of cancer and their therapeutic implications. In addition, we investigated the underlying molecular mechanism in therapeutic interventions, toxicities, safety concerns and synergistic potential in cognition and neuroprotection. Overall, this review provides deeper insights into the therapeutic implications of Brahmi as a lead formulation for treating neurological disorders and exerting cognitive-enhancing effects.

Investigating neuroprotective roles of Bacopa monnieri extracts: Mechanistic insights and therapeutic implications

Bacopa monnieri (Brahmi) is a well-known perennial, creeping herb of the Indian Ayurveda system; it contains numerous bioactive phytoconstituents implicated in the therapeutic management of several life-threatening diseases. This herb was used by Ancient Vedic scholars due to its pharmacological effect, especially as a nerve tonic and nootropic booster. However, to better understand the roles of Bacopa monnieri extract (BME) in neurological disorders and memory-related diseases, it is necessary to understand its active phytochemical constituents and their molecular mechanisms. Several clinical studies suggested that BME have neuroprotective effects, making it worth revising a notable herb. Here we investigated the contours of BME's phytochemistry and pharmacological features, focusing on neuronal disorders. We further analyzed the underlying molecular mechanisms in therapeutic intervention. Various clinical concerns and synergistic potential of BME were explored for their effective use in cognition and neuroprotection. The generation of reactive oxygen species increases neuroinflammation and neurotoxicity and is associated with Tau and amyloid-beta (Aβ) aggregation, leading to a neurological disorder. Our findings provide deeper mechanistic insights into the neuroprotective roles of BME, which can be further implicated in the therapeutic management of neurological disorders and exerting cognitive-enhancing effects.

Cognitive enhancement: Effects of methylphenidate, modafinil, and caffeine on latent memory and resting state functional connectivity in healthy adults.

Stimulants like methylphenidate, modafinil, and caffeine have repeatedly shown to enhance cognitive processes such as attention and memory. However, brain‐functional mechanisms underlying such cognitive enhancing effects of stimulants are still poorly characterized. Here, we utilized behavioral and resting‐state fMRI data from a double‐blind randomized placebocontrolled study of methylphenidate, modafinil, and caffeine in 48 healthy male adults. The results show that performance in different memory tasks is enhanced, and functional connectivity (FC) specifically between the frontoparietal network (FPN) and default mode network (DMN) is modulated by the stimulants in comparison to placebo. Decreased negative connectivity between right prefrontal and medial parietal but also between medial temporal lobe and visual brain regions predicted stimulant‐induced latent memory enhancement. We discuss dopamine's role in attention and memory as well as its ability to modulate FC between large‐scale neural networks (e.g., FPN and DMN) as a potential cognitive enhancement mechanism.

Activation of mental imagery neural network revealed during listening to Fatihah Chapter; a neuroimaging study

Background: Listening to Quranic recitation has been claimed to enhance educational performance and cognitive functionality. Unfortunately, scientific evidence for this remains scarce. Aim: Hence, we aimed to investigate the neural mechanism underlined the psychoacoustic and cognitive enhancement effects from listening to Quranic recitation. Occipital lobe beta rhythms (14-30 Hz) were excerpted from electroencephalography (EEG) data during psychoacoustic stimulation from sham (Rest), Arabic news and the Fatihah Chapter recitation. The stimulation comes in random sequence in the same length of duration of 5,8,6,6,10, 8 and 20 seconds for verses 1 to 7, respectively. The brain’s oscillatory waveforms were pre-processed using EGI System and then were analysed by Fast Fourier Transform (FFT) to derive the power spectrum in the Beta frequency band (14-30 Hz). Data were analysed by repeated-measures ANOVA and Discriminant Analysis from XLSTAT statistical package. Result: A profound and significant reduction of the power spectrum was found in the left occipital lobe while listening to theFatihah Chapter. In contrast, no significant changes were observed in the occipital lobe during listening to Arabic news. It may be postulated that listening to the Fatihah Chapter activates an oscillatory neural network associated with visual mental imagery. Bangladesh Journal of Medical Science Vol. 21 No. 03 July’22 Page: 710-716

Caffeine Consumption among Various University Students in the UAE, Exploring the Frequencies, Different Sources and Reporting Adverse Effects and Withdrawal Symptoms.

Background Caffeine is widely consumed among students due to its cognitive and physical enhancing effects. However, little is known about the consumption pattern of different caffeinated products among university students in the United Arab Emirates (UAE). Aim To investigate the frequency of caffeine consumption among the young population of students, assess types of caffeinated products consumed, and document adverse effects and withdrawal symptoms experienced by university students. Methods A cross-sectional study was conducted in the UAE from December 2019 to March 2020. A random sample of 500 university students from different universities in the UAE were approached and asked to complete a self-administered online-based questionnaire. Data were analyzed using the Statistical Package for Social Science (SPSS) version 26. Results Of (n = 500) surveyed students, (n = 467) completed the survey 93.4%. The average level of caffeine consumption was significantly higher in females compared to male students (p < 0.005). Coffee was the highest favored source of caffeine (67.7%) followed by tea (47.3%). The average daily intake of caffeine was found to be 264 mg/day. Surprisingly, almost a third of students reported a high level of daily consumption (>400 mg/day) and more than half of them consumed less than 199 mg/day. Large proportions of students 91.1% have their caffeinated beverage after or while eating meals and 42.8% considered that this habit helped in avoiding acid reflux. Interestingly, around one third of participants have poor knowledge of caffeine-containing medical products, which seemed to affect the level of consumption in the student population (p < 0.05). The highest reported reason for caffeine intake was for studying purposes (59.4%). Conclusion Caffeine consumption is highly prevalent among university students in the UAE. Yet, there is insufficiency in the current knowledge of safe caffeine consumption patterns reflecting the importance of health awareness programs and nutritional lectures to decrease the long-term health issues and unintentional overdose of caffeine.

PDE4D inhibitor: a novel weapon against mild cognitive impairment and Alzheimer’s disease?

A classical hallmark of Alzheimer’s disease (AD) is the accumulation of amyloid‐β (Aβ), which correlates significantly with progressive cognitive and learning and memory impairment. BPN14770, an allosteric inhibitor of PDE4D, has been proposed to improve memory deficits induced by Aβ oligomers (AβOs) and provide overall AD pathology improvement. However, the causal relationship between PDE4D‐related cAMP signaling and the prevalence of AβOs‐induced cognitive deficits has not been investigated. The present study examined whether the memory and cognitive enhancing effects of BPN14770 in humanized PDE4D‐APP/PS1 (hPDE4D/Tg‐AD) mice, which are engineered to express a primate‐specific N‐terminal region of PDE4D and crossed with transgenic APP/PS1 mice, were directly involved in reduced cAMP signaling dependent amyloid pathway. The results suggested that the PDE4D inhibitor BPN14770 significantly improved cognitive index in novel object recognition task, and memory acquisition and retrieval in Morris water maze test in h hPDE4D/Tg‐AD mice. Pretreatment with protein kinase A (PKA) inhibitor H89 completely blocked this BPN14770‐induced memory and cognitive enhancement, suggesting the key role of PDE4D dependent cAMP signaling in cognitive processes. Furthermore, the hPDE4D/Tg‐AD mice showed increases in Aβ plaque and soluble/insoluble Aβ concentration both in the cortex and hippocampus. While treatment of BPN14770 for two weeks (via gavage) prevented these pathological changes, which can be blocked by H89. The subsequent studies suggested that BPN14770 affected the synthesis and degradation of Aβ as evidenced by decreases in amyloidgenic and non‐amyloidgenic pathways such as BACE‐1, sAPPβ, ADAM10 and sAPPα protein expression, and increases in Aβ degrading enzymes including IDE and NEP levels, and downstream neuroprotective proteins such as pCREB/CREB and BDNF expression in hAPP/PS1‐PDE4D mice. Further chromatin co‐immunoprecipitation assays showed cAMP‐dependent CREB directly increased ADAM10 and IDE expression, and inhibited BACE‐1 expression through NF‐κB, resulting in reduction of Aβ production and increase in Aβ degradation. These findings reveal a causal relationship between PDE4D signaling and the progress of AD and demonstrate the clinical potential of BPN14770 in the treatment of AD.

Impact of Nicotine on Cognition in Patients With Schizophrenia: A Narrative Review.

Nicotine is the psychoactive component given tobacco has several main components and acts as an agonist for nicotinic acetylcholine receptors (nAChRs) in the nervous system. Although the ligand-gated cation channels known as nAChRs are found throughout the nervous system and body, this review focuses on neuronal nAChRs. Individuals with psychiatric diseases such as schizophrenia, comorbid substance use disorders, attention-deficit hyperactivity disorder, major depression, and bipolar disorder have increased rates of smoking. These psychiatric disorders are associated with various cognitive deficits, including working memory, deficits in attention, and response inhibition functions. The cognitive-enhancing effects of nicotine may be particularly relevant predictors of smoking initiation and continuation in this comorbid population. Individuals with schizophrenia make up a significant proportion of smokers. Literature suggests that patients smoke to alleviate cognitive deficiencies due to the stimulating effects of nicotine. This narrative review examines the role of nicotine on cognition in schizophrenia.

Evaluating Nicotine as a Cognitive Enhancer

Nicotine is a bicyclic chemical compound that is derived from tobacco plants. Due to its effect on the brain, nicotine is addictive and has long been used as a popular recreational drug. In numerous studies, nicotine has been shown to improve memory and reaction time performances. Some nicotine skin patch studies have exhibited characteristics of a possible treatment for cognitive impairments (Rezvani and Levin, 2001). Although many studies have shown that nicotine has cognitive-enhancing effects, there is not sufficient research conducted to examine the specific impacts of nicotine on reaction time. The aim of this study is to assess how reaction time differs before and after nicotine use for people who regularly use the drug and to test how the reaction times of non-users compares to those of regular users. This study was conducted on individuals aged 18 to 22. A Brain Gauge device and its associated software was used to collect reaction time data. Each user completed the Hardware Reaction Time test, which required the participant to press a button with their right index finger as soon as they felt the stimulus that was delivered to their right ring finger. It was found that people who did not use nicotine had faster reaction times than those who use nicotine regularly. However, regular nicotine users had slower reaction times before nicotine use as compared to after nicotine use. Although these results improve our understanding of the effects of nicotine use, there were limitations to the study. The experiment was not well-controlled as the environment of each participant was different, and the population tested consisted of mostly people in their early 20s. Further studies should be conducted with more controlled testing conditions and with a more diverse population.

Potential Role of Ginger (Zingiber officinale Roscoe) in the Prevention of Neurodegenerative Diseases.

Ginger is composed of multiple bioactive compounds, including 6-gingerol, 6-shogaol, 10-gingerol, gingerdiones, gingerdiols, paradols, 6-dehydrogingerols, 5-acetoxy-6-gingerol, 3,5-diacetoxy-6-gingerdiol, and 12-gingerol, that contribute to its recognized biological activities. Among them, the major active compounds are 6-shogaol and 6-gingerol. Scientific evidence supports the beneficial properties of ginger, including antioxidant and anti-inflammatory capacities and in contrast, a specific and less studied bioactivity is the possible neuroprotective effect. The increase in life expectancy has raised the incidence of neurodegenerative diseases (NDs), which present common neuropathological features as increased oxidative stress, neuroinflammation and protein misfolding. The structure-activity relationships of ginger phytochemicals show that ginger can be a candidate to treat NDs by targeting different ligand sites. Its bioactive compounds may improve neurological symptoms and pathological conditions by modulating cell death or cell survival signaling molecules. The cognitive enhancing effects of ginger might be partly explained via alteration of both the monoamine and the cholinergic systems in various brain areas. Moreover, ginger decreases the production of inflammatory related factors. The aim of the present review is to summarize the effects of ginger in the prevention of major neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and multiple sclerosis.

Clathrin-nanoparticles deliver BDNF to hippocampus and enhance neurogenesis, synaptogenesis and cognition in HIV/neuroAIDS mouse model

Brain derived neurotrophic factor (BDNF) promotes the growth, differentiation, maintenance and survival of neurons. These attributes make BDNF a potentially powerful therapeutic agent. However, its charge, instability in blood, and poor blood brain barrier (BBB) penetrability have impeded its development. Here, we show that engineered clathrin triskelia (CT) conjugated to BDNF (BDNF-CT) and delivered intranasally increased hippocampal BDNF concentrations 400-fold above that achieved previously with intranasal BDNF alone. We also show that BDNF-CT targeted Tropomyosin receptor kinase B (TrkB) and increased TrkB expression and downstream signaling in iTat mouse brains. Mice were induced to conditionally express neurotoxic HIV Transactivator-of-Transcription (Tat) protein that decreases BDNF. Down-regulation of BDNF is correlated with increased severity of HIV/neuroAIDS. BDNF-CT enhanced neurorestorative effects in the hippocampus including newborn cell proliferation and survival, granule cell neurogenesis, synaptogenesis and increased dendritic integrity. BDNF-CT exerted cognitive-enhancing effects by reducing Tat-induced learning and memory deficits. These results show that CT bionanoparticles efficiently deliver BDNF to the brain, making them potentially powerful tools in regenerative medicine.

The Effect of Caffeine and Sleep Quality on Military Pilot Students’ Flight Performance-Related Cognitive Function

ABSTRACT Objective To assess the effect of caffeine and sleep quality on the flight performance-related cognitive function. Background High levels of cognitive performance in pilots is required for flight safety. Methods Students at a military flight school in Thailand were invited to participate in this study. Exclusion criteria was positive screening for caffeine use disorder. We examined three cognitive functions required for flight performance: (1) vigilance (Mackworth Clock Test), (2) situational awareness, including memory (Corsi block-tapping test) and spatial reasoning (mental rotation test), and (3) reaction time (Deary-Liewald task). Neuropsychological tasks were performed before and 30 minutes after drinking a bottle of 220 ml coffee containing 143 mg of caffeine. Sleep quality was measured by the Thai-Pittsburgh Sleep Quality Index. Results Twenty-nine healthy males without caffeine use disorder with a mean age of 25.1 years were enrolled. After low-dose caffeine intake (<3 mg/kg body weight), cognitive performance improved significantly in vigilance, situation awareness, and reaction time. Baseline cognitive performance was not different between high (HSQ) and low sleep quality (LSQ) groups. After drinking coffee, however, participants with HSQ demonstrated improvements in vigilance and reaction time, while the LSQ group had improved vigilance only. Conclusion Low dose caffeine improved vigilance, situational awareness, and reaction time which were cognitive functions required for flight performance. The cognitive-enhancing effect of caffeine was more obvious in student pilots with high-quality sleep.

A multi-parameter evaluation of the neuroprotective and cognitive-enhancing effects of Origanum onites L. (Turkish Oregano) essential oil on scopolamine-induced amnestic rats.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive deterioration of cognitive functions (dementia) and represents a growing public health concern since the population in the age groups at risk is increasing. The latter raises an urgent need to translate research findings in the basic brain and behavioral sciences into anti-AD drugs and disease-modifying therapies. Origanum onites (L.), also called Turkish oregano, is a perennial and herbaceous plant species grown for centuries for medicinal, cosmetic and culinary purposes. This is the first study to investigate the putative neuroprotective and pro-cognitive activities of O. onites essential oil (OOEO) against scopolamine-induced amnesia of AD-type in Wistar albino rats. The results of behavioral tests revealed that OOEO administration was able to significantly alleviate learning and memory impairments induced by scopolamine in vivo. The observed effects could be attributed to inhibition of acetylcholinesterase activity, attenuation of oxidative stress and prevention of neuronal apoptosis in the hippocampus and frontal cortex of AD rats. Modulation of pro-inflammatory enzymes, including cyclooxygenase-2, inducible nitric oxide synthase and myeloperoxidase, might further contribute to the neuroprotective properties of OEOO, as predicted by our in silico models. These findings offer novel insights into the therapeutic potential of OEOO in patients with AD.

Impact of delivery rate on the acute response to intravenous nicotine: A human laboratory study with implications for regulatory science.

Faster delivery rate enhances the abuse potential of drugs of abuse, yet systematic studies on the impact of delivery rate on the acute effects of nicotine in humans are lacking. Using an intravenous (IV) nicotine infusion procedure that allows precise control of rate of delivery, we examined the impact of nicotine delivery rate on the positive subjective drug effects, smoking urges, withdrawal, heart rate, blood pressure and attention function in smokers. Twenty-four male and female (ages 21-35) dependent smokers attended five experimental sessions, following overnight abstinence from smoking. Using a crossover design, participants attended five sessions, where they were assigned to a random sequence of saline infusion or 1mg nicotine delivered over 1, 2.5, 5 or 10min at rates of 1, 0.4, 0.2 or 0.1mg/min, respectively. The positive subjective effects of nicotine were most robust under the two faster delivery rate conditions, 1- and 0.4-mg nicotine/min. In contrast, all nicotine delivery rates were equally more effective than saline in alleviating urges to smoke. Likewise, nicotine-induced heart rate increases did not vary with the rate of nicotine delivery. Lastly, the cognitive enhancing effects of nicotine were observed only under the two slowest delivery rate conditions-0.1- and 0.2-mg nicotine/min. Collectively, these findings support the critical role of delivery rate in optimizing nicotine's abuse potential versus potential therapeutic effects and have timely implications for developing novel therapeutics for nicotine dependence, as well as for tobacco regulatory science.