Highlights • Liraglutide and lixisenatide protect mice from MPTP toxicity, a model of Parkinson’s disease. • Both drugs are currently on the market to treat type 2 diabetes. • Neuroprotective effects ...in PD are shown for the first time here. • Clinical trials are in preparation in Parkinson’s patients, testing these drugs.
The cultural and geographical properties of the environment have been shown to deeply influence cognition and mental health
. Living near green spaces has been found to be strongly beneficial
, ...and urban residence has been associated with a higher risk of some psychiatric disorders
-although some studies suggest that dense socioeconomic networks found in larger cities provide a buffer against depression
. However, how the environment in which one grew up affects later cognitive abilities remains poorly understood. Here we used a cognitive task embedded in a video game
to measure non-verbal spatial navigation ability in 397,162 people from 38 countries across the world. Overall, we found that people who grew up outside cities were better at navigation. More specifically, people were better at navigating in environments that were topologically similar to where they grew up. Growing up in cities with a low street network entropy (for example, Chicago) led to better results at video game levels with a regular layout, whereas growing up outside cities or in cities with a higher street network entropy (for example, Prague) led to better results at more entropic video game levels. This provides evidence of the effect of the environment on human cognition on a global scale, and highlights the importance of urban design in human cognition and brain function.
Cognitive abilities can vary widely. Some people excel in certain skills, others struggle. However, not all those who describe themselves as gifted are. One possible influence on self-estimates is ...the surrounding culture. Some cultures may amplify self-assurance and others cultivate humility. Past research has shown that people in different countries can be grouped into a set of consistent cultural clusters with similar values and tendencies, such as attitudes to masculinity or individualism. Here we explored whether such cultural dimensions might relate to the extent to which populations in 46 countries overestimate or underestimate their cognitive abilities in the domain of spatial navigation. Using the Sea Hero Quest navigation test and a large sample (N = 383,187) we found cultural clusters of countries tend to be similar in how they self-rate ability relative to their actual performance. Across the world population sampled, higher self-ratings were associated with better performance. However, at the national level, higher self-ratings as a nation were not associated with better performance as a nation. Germanic and Near East countries were found to be most overconfident in their abilities and Nordic countries to be most under-confident in their abilities. Gender stereotypes may play a role in mediating this pattern, with larger national positive attitudes to male stereotyped roles (Hofstede's masculinity dimension) associated with a greater overconfidence in performance at the national level. We also replicate, with higher precision than prior studies, evidence that older men tend to overestimate their navigation skill more than other groups. These findings give insight into how culture and demographics may impact self-estimates of our abilities.
Tuberculosis control relies on the identification and preventive treatment of individuals who are latently infected with Mycobacterium tuberculosis. However, direct identification of latent ...tuberculosis infection is not possible. The diagnostic tests used to identify individuals latently infected with M. tuberculosis, the in vivo tuberculin skin test and the ex vivo interferon-gamma release assays (IGRAs), are designed to identify an adaptive immune response against, but not necessarily a latent infection with, M. tuberculosis. The proportion of individuals who truly remain infected with M. tuberculosis after tuberculin skin test or IGRA conversion is unknown. It is also uncertain how long adaptive immune responses towards mycobacterial antigens persist in the absence of live mycobacteria. Clinical management and public healthcare policies for preventive chemotherapy against tuberculosis could be improved, if we were to gain a better understanding on M. tuberculosis latency and reactivation. This statement by the TBNET summarises knowledge and limitations of the currently available tests used in adults and children for the diagnosis of latent tuberculosis infection. In summary, the main issue regarding testing is to restrict it to those who are known to be at higher risk of developing tuberculosis and who are willing to accept preventive chemotherapy.
High-calorie diet has been shown to impair learning ability and hippocampal synaptic plasticity in rodents. This study examined effects of daily treatment with the glucagon-like peptide-1 mimetic, ...exendin-4, on cognitive function and hippocampal synaptic plasticity in a model of diet-induced obesity, which exhibits compromised cognitive performance. Mice fed a high-fat diet were treated with exendin-4 (25 nmol kg−1 bodyweight; twice daily) or saline vehicle (0.9% (w/v) NaCl) over 21 days. In addition to improving metabolic control, exendin-4-treated mice exhibited a marked increase in recognition index highlighting improved learning and memory. High-fat diet resulted in the elimination of in vivo electrophysiological long-term potentiation, which was rescued following exendin-4 treatment. This study shows that exendin-4 therapy improves cognitive function and ameliorates impaired hippocampal synaptic plasticity in dietary-induced obesity.
Consumption of high-fat diet exerts adverse effects on learning and memory formation, which is linked to impaired hippocampal function. Activation of glucagon-like peptide-1 (GLP-1) signalling ...ameliorates detrimental effects of obesity-diabetes on cognitive function; however, mechanisms underlying these beneficial actions remain unclear. This study examined effects of daily subcutaneous treatment with GLP-1 mimetic, Liraglutide, on synaptic plasticity, hippocampal gene expression and metabolic control in adult obese diabetic (ob/ob) mice.
Long-term potentiation (LTP) induced by area CA1 was completely abolished in ob/ob mice compared with lean controls. Deleterious effects on LTP were rescued (P<0.001) with Liraglutide. Indeed, Liraglutide-treated mice exhibited superior LTP profile compared with lean controls (P<0.01). Expression of hippocampal brain-derived neurotropic factor and neurotrophic tyrosine kinase receptor-type 2 were not significantly different, but synaptophysin and Mash1 were decreased in ob/ob mice. Treatment with Liraglutide over 21 days increased expression of Mash1 in ob/ob mice (2.0-fold; P<0.01). These changes were associated with significantly reduced plasma glucose (21% reduction; P<0.05) and markedly improved plasma insulin concentrations (2.1- to 3.3-fold; P<0.05 to P<0.01). Liraglutide also significantly reduced the glycaemic excursion following an intraperitonal glucose load (area under curve (AUC) values: 22%; P<0.05) and markedly enhanced the insulin response to glucose (AUC values: 1.6-fold; P<0.05). O2 consumption, CO2 production, respiratory exchange ratio and energy expenditure were not altered by Liraglutide therapy. On day 21, accumulated food intake (32% reduction; P<0.05) and number of feeding bouts (32% reduction; P<0.05) were significantly reduced but simple energy restriction was not responsible for the beneficial actions of Liraglutide.
Liraglutide elicits beneficial effects on metabolic control and synaptic plasticity in mice with severe obesity and insulin resistance mediated in part through increased expression of Mash1 believed to improve hippocampal neurogenesis and cell survival.
Virtual reality (VR) systems are useful tools that enable users to alter environmental settings and the location of landmarks in an accurate and fast way. Primates have been shown to be able to ...navigate in virtual environments. For rodents, however, all previous attempts to develop VR systems in which rats behave in the same way as in corresponding 3-D environments have failed. The question arises as to whether, in principle, rodents can be trained to navigate in a properly designed virtual environment (VE), or whether this peculiarity is limited to primates and humans. We built a virtual reality set-up that takes the wide-angle visual system of rats into account. We show for the first time that rats learn spatial tasks in this VE quite readily. This set-up opens up new opportunities for investigations of information processing in navigation (e.g. the importance of optic flow or vestibular input).
Highlights • Lixisenatide, a novel drug treatment for diabetes, shows neuroprotective effects. • Lixisenatide prevented the Aβ25–35 induced impairment in spatial learning. • The drug prevented the ...Aβ25–35 induced block of LTP in the hippocampus. • The drug inhibited the Aβ25–35 induced activation of glycogen synthase kinase 3β.
The discovery of the intercellular messenger nitric oxide (NO) stimulated new concepts of how synaptic plasticity could be induced in the nervous system. While initial reports found evidence that NO ...is of importance for the formation of long-term potentiation of synaptic transmission (LTP) and spatial learning in rats, later reports failed to confirm these results. Novel approaches such as deletion of the gene that encodes NO synthase in mice showed that the neuronal and the endothelial isoforms are expressed in neurones. Deletion of both isoforms reduced the inducibility of LTP. Furthermore, novel selective inhibitors of NO synthase impaired spatial learning. These results support the hypothesis that NO plays an important role in synaptic transmission and explain some but not all previously contradictory results.
Patient expectations of the scar after Mohs micrographic surgery (MMS) are often not realistic, leading to subsequent psychosocial sequelae such as anxiety, depression, and avoidance of social ...situations. When patient expectations are not met, this may also contribute to a decrease in patient satisfaction after surgery. Therefore, altering expectation levels may change patient satisfaction and psychosocial distress levels after surgery. To assess whether patient satisfaction improves in patients after MMS when patients view the surgical defect prior to reconstruction. Patients undergoing facial MMS between December 2017 and September 2019 were included. Patients received or did not receive a mirror after MMS to view the surgical defect before closing the defect. Patients were asked to complete the Dutch FACE-Q Skin Cancer before, one-week, three-months, and one-year after MMS. A total of 113 patients where included. One-hundred-eight (95.6%), 113 (100%), and 93 (82.3%) questionnaires were completed, one-week, three-months, and one-year follow-up, respectively. Satisfaction with facial appearance and appraisal of scars significantly improved over time for all patients, no such improvement was seen for appearance-related distress. Female patients who looked in the mirror had higher satisfaction with facial appearance than female patients who did not look in the mirror. Also, lower appearance-related distress scores were seen in patients who looked in the mirror prior to a flap reconstruction. Showing the defect in the mirror prior to the reconstruction may result in higher patient satisfaction in female patients and patients before undergoing a flap reconstruction.
PDF
