Summary Motor behaviors recruit task-specific neuronal ensembles in motor cortices, which are consolidated over subsequent learning. However, little is known about the molecules that can identify the participating neurons and predict the outcomes of the consolidation process. Using a mouse rotarod-learning task, we showed that lesion or inactivation of the secondary motor (M2) cortex disrupts learning of skilled movements. We tracked the endogenous promoter activity of the neuronal activity-regulated gene Arc in individual M2 neurons during rotarod learning by in vivo two-photon imaging of a knock-in reporter. We found that task training initially recruits Arc-promoter-activated neurons and then consolidates them into a specific ensemble exhibiting persistent reactivation of Arc-promoter. The intensity of a neuron’s initial Arc-promoter activation predicts its reactivation probability and neurons with weak initial Arc-promoter activation are dismissed from the ensemble during subsequent training. Our findings demonstrate a task-specific Arc-dependent cellular consolidation process in M2 cortex during motor learning.

BackgroundAntioxidant vitamin (vitamin E, beta-carotene, and vitamin C) are widely used for preventing major cardiovascular outcomes. However, the effect of antioxidant vitamin on cardiovascular events remains unclear.Methodology and Principal FindingsWe searched PubMed, EmBase, the Cochrane Central Register of Controlled Trials, and the proceedings of major conferences for relevant literature. Eligible studies were randomized controlled trials that reported on the effects of antioxidant vitamin on cardiovascular outcomes as compared to placebo. Outcomes analyzed were major cardiovascular events, myocardial infarction, stroke, cardiac death, total death, and any possible adverse events. We used the I2 statistic to measure heterogeneity between trials and calculated risk estimates for cardiovascular outcomes with random-effect meta-analysis. Independent extraction was performed by two reviewers and consensus was reached. Of 293 identified studies, we included 15 trials reporting data on 188209 participants. These studies reported 12749 major cardiovascular events, 6699 myocardial infarction, 3749 strokes, 14122 total death, and 5980 cardiac deaths. Overall, antioxidant vitamin supplementation as compared to placebo had no effect on major cardiovascular events (RR, 1.00; 95%CI, 0.96–1.03), myocardial infarction (RR, 0.98; 95%CI, 0.92–1.04), stroke (RR, 0.99; 95%CI, 0.93–1.05), total death (RR, 1.03; 95%CI, 0.98–1.07), cardiac death (RR, 1.02; 95%CI, 0.97–1.07), revascularization (RR, 1.00; 95%CI, 0.95–1.05), total CHD (RR, 0.96; 95%CI, 0.87–1.05), angina (RR, 0.98; 95%CI, 0.90–1.07), and congestive heart failure (RR, 1.07; 95%CI, 0.96 to 1.19).Conclusion/SignificanceAntioxidant vitamin supplementation has no effect on the incidence of major cardiovascular events, myocardial infarction, stroke, total death, and cardiac death.

The mesofrontal dopaminergic circuit, which connects the midbrain motivation center to the cortical executive center, is engaged in control of motivated behaviors. In addition, deficiencies in this circuit are associated with adolescent-onset psychiatric disorders in humans. Developmental studies suggest that the mesofrontal circuit exhibits a protracted maturation through adolescence. However, whether the structure and function of this circuit are modifiable by activity in dopaminergic neurons during adolescence remains unknown. Using optogenetic stimulation and in vivo two-photon imaging in adolescent mice, we found that phasic, but not tonic, dopamine neuron activity induces the formation of mesofrontal axonal boutons. In contrast, in adult mice, the effect of phasic activity diminishes. Furthermore, our results showed that dopaminergic and glutamatergic transmission regulate this axonal plasticity in adolescence and inhibition of dopamine D2-type receptors restores this plasticity in adulthood. Finally, we found that phasic activation of dopamine neurons also induces greater changes in mesofrontal circuit activity and psychomotor response in adolescent mice than in adult mice. Together, our findings demonstrate that the structure and function of the mesofrontal circuit are modifiable by phasic activity in dopaminergic neurons during adolescence and suggest that the greater plasticity in adolescence may facilitate activity-dependent strengthening of dopaminergic input and improvement in behavioral control.

BackgroundNext generation sequencing (NGS) is being increasingly applied for assisting cancer molecular diagnosis. However, it is still needed to validate NGS accuracy on detection of DNA alternations based on a large number of clinical samples, especially for DNA rearrangements and copy number variations (CNVs). This study is to set up basic parameters of targeted NGS for clinical diagnosis and to understand advantage of targeted NGS in comparison with the conventional methods of molecular diagnosis.MethodsGenomic DNA from 1000 Genomes Project and DNA from cancer cell lines have been used to establish the basic parameters for targeted NGS. The following confirmation was conducted by clinical samples. The multiple variants tested by amplification-refractory mutation system (ARMS), fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) were evaluated by targeted NGS to determine the sensitivity. Furthermore, the multiple variants detected by targeted NGS were confirmed by current conventional methods to elucidate the specificity.ResultsAt sequencing depth of 500×, the maximal sensitivities on detecting single nucletic variances (SNVs) and small insertions/deletions (Indels) can reach 99% and 98.7% respectively, and in 20% of cancer cells, CNV detection can reach to the maximal level. The following confirmation of the sensitivity and specificity was conducted by a large cohort of clinical samples. For SNV and indel detection in clinical samples, targeted NGS can identify all hotspot mutations with 100% sensitivity and specificity. On ALK fusion detection, about 86% IHC-identified cases could be identified by targeted NGS and all ALK fusion detected by targeted NGS were confirmed by IHC. For HER2-amplification, 14 HER2-amplification cases identified by target NGS were all confirmed by FISH and about 93.3% of Her-2 IHC (3+) cases were identified by targeted NGS. Finally, the targeted NGS platform developed here has accurately detected EGFR hotspot mutations in 215 NSCLC patients.ConclusionsDNA from cancer cell lines is better than standard DNA as a reference to establish basic parameters for targeted NGS. Comparison of the conventional methods using a large cohort of patient samples confirmed the high preformance of targeted NGS on detecting DNA alterations.Electronic supplementary materialThe online version of this article (10.1186/s13046-017-0591-4) contains supplementary material, which is available to authorized users.

Seven patients with similar phenotypes of developmental delay and microcephaly were found by whole-exome sequencing to have de novo loss-of-function mutations in POGZ. POGZ is a pogo transposable element-derived protein with a zinc finger cluster. The protein is involved in normal kinetochore assembly and mitotic sister chromatid cohesion and mitotic chromosome segregation. POGZ deficiency may affect mitosis, disrupting brain development and function.

Mushroom bodies (MBs), one of the central brain structures in Drosophila melanogaster, are involved in several cognitive behaviors, such as olfactory learning and memory, visual context generalization, choice behavior facing conflicting cues. Attention is a cognitive behavior, and it facilitates a focus on the attended event while filtering out irrelevant events, thereby allowing more rapid and accurate reactions at a lower threshold in primates. Using the visual orientation paradigm in a flight simulator, we observed that MBs modulate salience-based selective fixation behavior, which resembles attention in primates to a certain degree. We found that the fixation ability of MB-deficient flies was significantly reduced when the contrast levels were lowered as well as when a certain amount of background noise was applied. Moreover, MB-deficient flies exhibited poor object fixation ability in the presence of an olfactory 'distracter'. Furthermore, during visual selection among multiple objects of different contrast, flies with MBs were able to 'pop-out' of the most salient object in a three-object selection paradigm. Finally, we determined that flies exhibited cross-modal synergistic integration between olfactory and visual signals during object-fixation behavior, which was independent of MBs. Taken together, our findings suggest that MBs do not contribute to cross-modal synergetic integration between olfactory and visual signals; instead, they confer sensory gain control and inhibitory gating in flies, this property allows entry of the salient signal as well as filters out background noise and irrelevant signals.

The brain encodes information about past experience in specific populations of neurons that communicate with one another by firing action potentials. Studies of experience-dependent neural plasticity have largely focused on individual synaptic changes in response to neuronal input. Indicative of the neuronal output transmitted to downstream neurons, persistent firing patterns are affected by prior experience in selective neuronal populations. However, little is known about the molecular and cellular mechanisms by which experience-related persistent firing patterns are regulated in specific neuronal populations. Using frontal cortical slices prepared from transgenic mice carrying a fluorescent reporter of Arc gene expression, this study investigates how behavioral experience and the activity-regulated Arc gene affect patterns of neuronal firing. We found that motor training increases Arc expression in subsets of excitatory neurons. Those neurons exhibit persistent firing in contrast to Arc-negative neurons from the same mice or neurons from the untrained mice. Furthermore, in mice carrying genetic deletion of Arc, the frontal cortical circuitry is still in place to initiate experiencedependent gene expression, but the level of persistent firing thereafter is diminished. Finally, our results showed that the emergence of persistent activity is associated with Arc-dependent changes in the function of NMDA-type glutamate receptors, rather than changes in AMPA-type receptors or membrane excitability. Our findings therefore reveal an Arc-dependent molecular pathway by which geneexperience interaction regulates the emergence of persistent firing patterns in specific neuronal populations.

Dopamine is a major neuromodulator in both vertebrates and invertebrates and has profound effects on many physiological processes, including the regulation of attention. Most studies of the functions of dopamine use models with long-term blockade of dopamine release and few effects of transient blockade have yet been reported. The goal of the present study was to determine the role of dopamine in attention-like behavior in Drosophila by taking advantage of the fly's orientation behavior during flight. The examination of several different transgenic flies in a single-target visual attention paradigm showed that flies lost their orientation ability if dopamine release was blocked from the beginning of the development of dopaminergic neurons. This is similar to the attention loss in mammals. However, if the blockade of dopamine release was induced during the experimental procedure, flies performed normally. Statistical analysis of the behavioral assessment showed a significant difference between long-term and transient blockade. Using the RNA interference approach, we generated flies with down-regulated J-domain protein, which is a potential cochaperone in synaptic vesicle release, to make an alternative form of long-term dopamine-blockade mutant. Behavioral assays revealed that flies with permanent J-domain protein down-regulation specifically in dopaminergic neurons have an attention defect similar to that induced by long-term blockade of dopamine release. Furthermore, dopamine depletion beginning at eclosion also caused an attention deficit. Our results indicate that prolonged but not transient blockade of dopamine release impairs visual attention-like behavior in Drosophila.