Obesity is a potential risk factor for cognitive deficits in the elder humans. Using a high-fat diet (HFD)–induced obese mouse model, we investigated the impacts of HFD on obesity, metabolic and ...stress hormones, learning performance, and hippocampal synaptic plasticity. Both male and female C57BL/6J mice fed with HFD (3 weeks to 9–12 months) gained significantly more weights than the sex-specific control groups. Compared with the obese female mice, the obese males had similar energy intake but developed more weight gains. The obese male mice developed hyperglycemia, hyperinsulinemia, hypercholesterolemia, and hyperleptinemia, but not hypertriglyceridemia. The obese females had less hyperinsulinemia and hypercholesterolemia than the obese males, and no hyperglycemia and hypertriglyceridemia. In the contextual fear conditioning and step-down passive avoidance tasks, the obese male, but not female, mice showed poorer learning performance than their normal counterparts. These learning deficits were not due to sensorimotor impairment as verified by the open-field and hot-plate tests. Although, basal synaptic transmission characteristics (input–output transfer and paired-pulse facilitation (PPF) ratio) were not significantly different between normal and HFD groups, the magnitudes of synaptic plasticity (long-term potentiation (LTP) and long-term depression (LTD)) were lower at the Schaffer collateral-CA1 synapses of the hippocampal slices isolated from the obese male, but not female, mice, as compared with their sex-specific controls. Our results suggest that male mice are more vulnerable than the females to the impacts of HFD on weight gains, metabolic alterations and deficits of learning, and hippocampal synaptic plasticity.
The present study builds on our previous study within the framework of Wyer and Collin's comprehension–elaboration theory of humor processing. In this study, an attempt is made to segregate the ...neural substrates of incongruity detection and incongruity resolution during the comprehension of verbal jokes. Although a number of fMRI studies have investigated the incongruity-resolution process, the differential neurological substrates of comprehension are still not fully understood. The present study utilized an event-related fMRI design incorporating three conditions (unfunny, nonsensical and funny) to examine distinct brain regions associated with the detection and resolution of incongruities. Stimuli in the unfunny condition contained no incongruities; stimuli in the nonsensical condition contained irresolvable incongruities; and stimuli in the funny condition contained resolvable incongruities. The results showed that the detection of incongruities was associated with greater activation in the right middle temporal gyrus and right medial frontal gyrus, and the resolution of incongruities with greater activation in the left superior frontal gyrus and left inferior parietal lobule. Further analysis based on participants' rating scores provided converging results. Our findings suggest a three-stage neural circuit model of verbal humor processing: incongruity detection and incongruity resolution during humor comprehension and inducement of the feeling of amusement during humor elaboration.
► This study sought to isolate the neural substrates underlying humor comprehension. ► Incongruity detection and resolution were segregated using a ‘nonsensical’ condition. ► Detection activated the right middle temporal gyrus and right medial frontal gyrus. ► Resolution activated the left superior frontal gyrus and left inferior parietal lobe. ► A neural circuit model of humor comprehension and elaboration processing is proposed.
Chronic hyperglycemia-associated inflammation plays critical roles in disease initiation and the progression of diabetic complications, including Alzheimer's disease (AD). However, the association of ...chronic hyperglycemia with acute inflammation of the central nervous system in the progression of AD still needs to be elucidated. In addition, recent evidence suggests that Glucagon-like peptide-1 receptor (GLP-1R) protects against neuronal damage in the brain. Therefore, the neuroprotective effects of the GLP-1R agonist exendin-4 (EX-4) against hyperglycemia/lipopolysaccharides (LPS) damage were also evaluated in this study.
Ten days after streptozotocin (STZ) or vehicle (sodium citrate) treatment in mice, EX-4 treatment (10 µg/kg/day) was applied to the mice before intrahippocampal CA1 injection of LPS or vehicle (saline) and continued for 28 days. This study examined the molecular alterations in these mice after LPS and EX4 application, respectively. The mouse cognitive function was evaluated during the last 6 days of EX-4 treatment. The results showed that the activation of NF-κB-related inflammatory responses induced cognitive dysfunction in both the hyperglycemic mice and the mice that received acute intrahippocampal LPS injection. Furthermore, acute intrahippocampal LPS injection exacerbated the impairment of spatial learning and memory through a strong decrease in monoaminergic neurons and increases in astrocytes activation and apoptosis in the hyperglycemic mice. However, EX-4 treatment protected against the cognitive dysfunction resulting from hyperglycemia or/and intrahippocampal LPS injection.
These findings reveal that both hyperglycemia and intrahippocampal LPS injection induced cognitive dysfunction via activation of NF-κB-related inflammatory responses. However, acute intrahippocampal LPS injection exacerbated the progression of cognitive dysfunction in the hyperglycemic mice via a large increase in astrocytes activation-related responses. Furthermore, EX-4 might be considered as a potential adjuvant entity to protect against neurodegenerative diseases.
The comprehension–elaboration theory of humor claims that the elicitation of humor can be segregated into two stages, comprehension and elaboration. Comprehension includes detection and resolution of ...incongruity, and elaboration involves inducement of the experience of amusement. Previous imaging research has sought to identify the neural substrates of humor processing by comparing funny and unfunny conditions. However, such studies have not been able to segregate the comprehension and elaboration stages. The present study was designed to differentiate the respective brain areas corresponding to comprehension and elaboration with an additional condition, garden path sentences. The results suggest that the bilateral inferior frontal gyri and left superior frontal gyrus may be associated with humor comprehension, whereas the cortical region in left ventromedial prefrontal cortex and the subcortical regions in bilateral amygdalae and bilateral parahippocampal gyri may be responsible for the feeling of amusement during the elaboration process.
Abstract Exercise may contribute to prevention of the cognitive decline and delay the onset of the Alzheimer's disease (AD). We evaluated the effects of continuous non-shock treadmill exercise in ...adult and aged male APP/PS1 double mutant transgenic mice. Adult (7–8 month-old) and aged (24 month-old) male APP/PS1 transgenic and wild-type mice were randomly assigned to either sedentary or exercise groups. The exercise program included a one-week treadmill acclimatization to adapt to the novel environment. After acclimation, mice ran on a treadmill 5 days/week until sacrificed for pathological analyses. During exercise training, no tail shock was used in the exercise paradigm; only gentle tail touching was used to induce the mice to run, to minimize the stress otherwise associated with treadmill exercise. We found that the exercise program selectively improved the spatial learning and memory associated with an increase in both cholinergic neurons in the medial septum (MS)/vertical diagonal band (VDB) and serotonergic neurons in the raphe nucleus of aged APP/PS1 transgenic mice. In adult APP/PS1 transgenic mice, the exercise paradigm increased exploratory activity and reduced anxiety with an associated increase in numbers of serotonergic neurons in the raphe nucleus. In addition, the exercise paradigm also reduced amyloid-β peptide (Aβ) levels and microglia activation, but not enough to reduce the plaque loading in the hippocampus of the APP/PS1 transgenic mice. Therefore, these findings suggest that there may exist an age-related difference in the effect of continuous non-shock treadmill exercise training on AD.
Highlights
Ultra-small and highly dispersed rhodium nanoparticles anchored in 2D ultra-thin boron nanosheets (BNS) were synthesized by a rapid NaBH
4
reduction and facile freeze-dry approach.
Due to ...the strong metal-support interaction effect, the optimized electrocatalyst exhibits excellent hydrogen evolution reaction (HER) catalytic activity and stability in the wide pH range electrolytes.
Based on the stable surface, the oxidized boron surface facilitates the coupling of BNS and metal, giving catalyst outstanding HER performance.
High-efficiency electrochemical hydrogen evolution reaction (HER) offers a promising strategy to address energy and environmental crisis. Platinum is the most effective electrocatalyst for the HER. However, challenging scarcity, valuableness, and poor electrochemical stability still hinder its wide application. Here, we designed an outstanding HER electrocatalyst, highly dispersed rhodium (Rh) nanoparticles with an average diameter of only 3 nm supported on boron (B) nanosheets. The HER catalytic activity is even comparable to that of commercial platinum catalysts, with an overpotential of only 66 mV in 0.5 M H
2
SO
4
and 101 mV in 1 M KOH to reach the current density of 10 mA cm
−2
. Meanwhile, the catalyst exhibited impressive electrochemical durability during long-term electrochemical processes in acidic and alkaline media, even the simulated seawater environment. Theoretical calculations unraveled that the structure–activity relationship between B(104) crystal plane and Rh(111) crystal plane is beneficial to the release of hydrogen, and surface O plays a vital role in the catalysis process. Our work may gain insights into the development of supported metal catalysts with robust catalytic performance through precise engineering of the strong metal-supported interaction effect.
Adult hippocampal neurogenesis is important for learning and memory, especially after a brain injury such as ischemia. Newborn hippocampal neurons contribute to memory performance by establishing ...functional synapses with target cells. This study demonstrated that the maturation of hippocampal neurons is enhanced by postischemia intermittent hypoxia (IH) intervention. The effects of IH intervention in cultured neurons were mediated by increased synaptogenesis, which was primarily regulated by brain-derived neurotrophic factor (BDNF)/PI3K/AKT. Hippocampal neo-neurons expressed BDNF and exhibited enhanced presynaptic function as indicated by increases in the pSynapsin expression, synaptophysin intensity, and postsynapse density following IH intervention after ischemia. Postischemia IH-induced hippocampal neo-neurons were affected by presynaptic activity, which reflected the dynamic plasticity of the glutamatergic receptors. These alterations were also associated with the alleviation of ischemia-induced long-term memory impairment. Our results suggest that postischemia IH intervention rescued ischemia-induced spatial learning and memory impairment by inducing hippocampal neurogenesis and functional synaptogenesis via BDNF expression.
Although empathic emotion is closely related to prosocial behavior, neuronal substrate that accounts for empathy-associated prosocial action remains poorly understood. We recorded neurons in the ...anterior cingulate cortex (ACC) and insular cortex (InC) in rats when they observed another rat in pain. We discovered neurons with anti-mirror properties in the ACC and InC, in addition to those with mirror properties. ACC neurons show higher coupling between activation of self-in-pain and others-in-pain, whereas the InC has a higher ratio of neurons with anti-mirror properties. During others-in-pain, ACC neurons activated more when actively nose-poking toward others and InC neurons activated more when freezing. To further illustrate prosocial function, we examined neuronal activities in the helping behavior test. Both ACC and InC neurons showed specific activation to rat rescuing which is contributed by mirror, but not anti-mirror neurons. Our work indicates the functional involvement of mirror neuron system in prosocial behaviors.
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•Affective anti-mirror neurons have higher ratio in InC than ACC•Mirror and anti-mirror neurons associated with socially active and passive behaviors•InC and ACC but not MI showed helping-specific behaviors•Mirror neurons activated before helping-specific behaviors
Behavioral neuroscience; Molecular neuroscience; Cellular neuroscience
While it is known that some individuals can effectively perform two tasks simultaneously, other individuals cannot. How the brain deals with performing simultaneous tasks remains unclear. In the ...present study, we aimed to assess which brain areas corresponded to various phenomena in task performance. Nineteen subjects were requested to sequentially perform three blocks of tasks, including two unimodal tasks and one bimodal task. The unimodal tasks measured either visual feature binding or auditory pitch comparison, while the bimodal task required performance of the two tasks simultaneously. The functional magnetic resonance imaging (fMRI) results are compatible with previous studies showing that distinct brain areas, such as the visual cortices, frontal eye field (FEF), lateral parietal lobe (BA7), and medial and inferior frontal lobe, are involved in processing of visual unimodal tasks. In addition, the temporal lobes and Brodmann area 43 (BA43) were involved in processing of auditory unimodal tasks. These results lend support to concepts of modality-specific attention. Compared to the unimodal tasks, bimodal tasks required activation of additional brain areas. Furthermore, while deactivated brain areas were related to good performance in the bimodal task, these areas were not deactivated where the subject performed well in only one of the two simultaneous tasks. These results indicate that efficient information processing does not require some brain areas to be overly active; rather, the specific brain areas need to be relatively deactivated to remain alert and perform well on two tasks simultaneously. Meanwhile, it can also offer a neural basis for biofeedback in training courses, such as courses in how to perform multiple tasks simultaneously.
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