Complexity of functional connectivity networks in mild cognitive impairment subjects during a working memory task

Objectives: The objective is to study the changes of brain activity in patients with mild cognitive impairment (MCI). Using magneto-encephalogram (MEG) signals, the authors investigate differences of complexity of functional connectivity network between MCI and normal elderly subjects during a working memory task. Methods: MEGs are obtained from 18 right handed patients with MCI and 19 age-matched elderly participants without cognitive impairment used as the control group. The brain networks’ complexities are measured by Graph Index Complexity (Cr) and Efficiency Complexity (Ce). Results: The results obtained by both measurements show complexity of functional networks involved in the working memory function in MCI subjects is reduced at alpha and theta bands compared with subjects with control subjects, and at the theta band this reduction is more pronounced in the whole brain and intra left hemisphere. Conclusions: Ce would be a better measurement for showing the global differences between normal and MCI brains compared with Cr. Significance: The high accuracy of the classification shows Ce at theta band can be used as an index for assessing deficits associated with working memory, a good biomarker for diagnosis of MC

The effects of aerobic exercise on cognitive performance and sleep quality haemodialysis patients

BackgroundCognitive impairment and sleep disturbance are very common in chronic kidney disease (CKD) and are strongly associated with increased mortality among the patients. Even though, exercise is considered to be a quantifiable activity that improves cognition in animals and humans, but few studies have examined the efficacy of exercise on cognitive function and sleep quality in CKD.AimsThis study was performed to evaluate the effects of aerobic exercise during haemodialysis on the cognitive performance and sleep quality.MethodsIn this clinical trial study, 38 patients with an average age of 47 years under haemodialysis were divided into control (N=11) and experimental (N=27) groups. Patients in experimental group were participated in a 24 weeks training progressive exercise that performed during the first two hours of their haemodialysis on a stationary bicycle, three times a week, for 75 minutes each time. Cognitive performance using Mini-Mental State Examination, Symbol Digit Test and Trail Making Test–B and sleep quality with PSQI questioner were assessed before, 12 weeks and 24 weeks after training program. Statistical analysis was performed using SPSS 18, Mann-Whitney U and repeated measure analysis.ResultsAfter the exercise, there was a significant increase in the Trail Making Test–B and sleep quality during the first 12 weeks and a significant improvement after 24 weeks in Mini-Mental State Examination and Symbol Digit Test in exercise group (P < 0.05).ConclusionIt seems that aerobic exercises has a significant impact on cognitive performance and sleep quality in haemodialysis patients and can be used as part of the treatment for haemodialysis patients but further research is warranted to clarify the involved mechanisms

The Effect of Changing Policies to Increase the Birth Rate on Reproductive Health Rate over a Twelve-Year Period in Islamshahr

Introduction: In recent years, population growth, birth rate promotion and reproductive health policies have been the main approach of population control programs. In this study, the researcher was going to investigate and got a close look to this important issue in the city of Islamshahr. The comparative study of prophylactic methods and their prevalence was conducted among fertile women in 2004 and 2016 to examine how their approach change following the changes in national policy has affected on reproductive health.Materials and Methods: Two thousand reproductive-age women who reside in Islamshahr voluntarily and confidential participated using a questionnaire. All data were analyzed using SPSS software.Results: The findings indicated that despite the decrease in contraceptive use in 2016 compared to 2004 (from 90.8% to 42%), the level of public awareness has been increased about their benefits and reproductive health So that we observed an increased awareness of sexually transmitted diseases and ways to fight them (from 27% to 56%). A decline in illegal abortion rate (from 60% to 22%) and an increase in the knowledge of appropriate lactation methods (from 25.8% to 40%) observed during the study period. Natural methods had the highest prevalence among contraceptive methods at both times of the survey. The knowledge of women about the proper methods for early marriage (from 25.3 to 11%) and emergencies showed a decrease (from 12.2% to 5.6%)

The zona incerta in control of novelty seeking and investigation across species

Many organisms rely on a capacity to rapidly replicate, disperse, and evolve when faced with uncertainty and novelty. But mammals do not evolve and replicate quickly. They rely on a sophisticated nervous system to generate predictions and select responses when confronted with these challenges. An important component of their behavioral repertoire is the adaptive context-dependent seeking or avoiding of perceptually novel objects, even when their values have not yet been learned. Here, we outline recent cross-species breakthroughs that shed light on how the zona incerta (ZI), a relatively evolutionarily conserved brain area, supports novelty-seeking and novelty-related investigations. We then conjecture how the architecture of the ZI\u27s anatomical connectivity - the wide-ranging top-down cortical inputs to the ZI, and its specifically strong outputs to both the brainstem action controllers and to brain areas involved in action value learning - place the ZI in a unique role at the intersection of cognitive control and learning

Design of thin-film photonic metamaterial L\"uneburg lens using analytical approach

We design an all-dielectric L\"uneburg lens as an adiabatic space-variant lattice explicitly accounting for finite film thickness. We describe an all-analytical approach to compensate for the finite height of subwavelength dielectric structures in the pass-band regime. This method calculates the effective refractive index of the infinite-height lattice from effective medium theory, then embeds a medium of the same effective index into a slab waveguide of finite height and uses the waveguide dispersion diagram to calculate a new effective index. The results are compared with the conventional numerical treatment - a direct band diagram calculation, using a modified three-dimensional lattice with the superstrate and substrate included in the cell geometry. We show that the analytical results are in good agreement with the numerical ones, and the performance of the thin-film L\"uneburg lens is quite different than the estimates obtained assuming infinite height.Comment: 11 pages, 8 figures, uses opex3.st

The frequency of human leukocyte antigen-DRB1 alleles, using sequence-based genotyping in 68 parents-child trios study in Iranian subjects

Background: The human leukocyte antigen-DRB1 (HLA-DRB1) locus is one of the most polymorphic human loci and has a crucial role in the immune system. Assessing the allelic frequencies of HLA-DRB1 locus would be a fundamental factor in defining the origin of populations, relationships with other populations, disease association studies and the constitution of unrelated bone marrow donor registries. In the current study HLA-DRB1 alleles and their frequencies are determined in a family-based study by DNA sequencing-based typing high-resolution (2 field) level of typing. Materials and Methods: Genomic DNA from 3 members of 68 unrelated families (a total of 204 individuals) was extracted. Exon 2 of DRB1 gene was amplified and performed useing AssignTM SBT v4.7 sequence analysis software.Results: We had DRB1*11:04 with frequency of 0.0931, DRB1*03:01 with 0.0882, DRB1*11:01 with 0.0735, DRB1*13:01 with 0.071 and also alleles DRB1*08:03, DRB1*13:42, DRB1*14:04 and DRB1*14:07 with frequency of 0.0024.Conclusion: A total of 34 different alleles were found in the study subjects with DRB1*11:04, DRB1*03:01, DRB1*11:01 being the most frequent alleles respectively.  

Horizontal visibility graphs transformed from fractional Brownian motions: Topological properties versus Hurst index

Nonlinear time series analysis aims at understanding the dynamics of stochastic or chaotic processes. In recent years, quite a few methods have been proposed to transform a single time series to a complex network so that the dynamics of the process can be understood by investigating the topological properties of the network. We study the topological properties of horizontal visibility graphs constructed from fractional Brownian motions with different Hurst index $H\in(0,1)$. Special attention has been paid to the impact of Hurst index on the topological properties. It is found that the clustering coefficient $C$ decreases when $H$ increases. We also found that the mean length $L$ of the shortest paths increases exponentially with $H$ for fixed length $N$ of the original time series. In addition, $L$ increases linearly with respect to $N$ when $H$ is close to 1 and in a logarithmic form when $H$ is close to 0. Although the occurrence of different motifs changes with $H$, the motif rank pattern remains unchanged for different $H$. Adopting the node-covering box-counting method, the horizontal visibility graphs are found to be fractals and the fractal dimension $d_B$ decreases with $H$. Furthermore, the Pearson coefficients of the networks are positive and the degree-degree correlations increase with the degree, which indicate that the horizontal visibility graphs are assortative. With the increase of $H$, the Pearson coefficient decreases first and then increases, in which the turning point is around $H=0.6$. The presence of both fractality and assortativity in the horizontal visibility graphs converted from fractional Brownian motions is different from many cases where fractal networks are usually disassortative.Comment: 12 pages, 8 figure

A cell type-specific cortico-subcortical brain circuit for investigatory and novelty-seeking behavior

INTRODUCTION: Motivational drives are internal states that can be different even in similar interactions with external stimuli. Curiosity as the motivational drive for novelty-seeking and investigating the surrounding environment is for survival as essential and intrinsic as hunger. Curiosity, hunger, and appetitive aggression drive three different goal-directed behaviors—novelty seeking, food eating, and hunting—but these behaviors are composed of similar actions in animals. This similarity of actions has made it challenging to study novelty seeking and distinguish it from eating and hunting in nonarticulating animals. The brain mechanisms underlying this basic survival drive, curiosity, and novelty-seeking behavior have remained unclear. RATIONALE: In spite of having well-developed techniques to study mouse brain circuits, there are many controversial and different results in the field of motivational behavior. This has left the functions of motivational brain regions such as the zona incerta (ZI) still uncertain. Not having a transparent, nonreinforced, and easily replicable paradigm is one of the main causes of this uncertainty. Therefore, we chose a simple solution to conduct our research: giving the mouse freedom to choose what it wants—double free-access choice. By examining mice in an experimental battery of object free-access double-choice (FADC) and social interaction tests—using optogenetics, chemogenetics, calcium fiber photometry, multichannel recording electrophysiology, and multicolor mRNA in situ hybridization—we uncovered a cell type–specific cortico-subcortical brain circuit of the curiosity and novelty-seeking behavior. RESULTS: We analyzed the transitions within action sequences in object FADC and social interaction tests. Frequency and hidden Markov model analyses showed that mice choose different action sequences in interaction with novel objects and in early periods of interaction with novel conspecifics compared with interaction with familiar objects or later periods of interaction with conspecifics, which we categorized as deep and shallow investigation, respectively. This finding helped us to define a measure of depth of investigation that indicates how much a mouse prefers deep over shallow investigation and reflects the mouse’s motivational level to investigate, regardless of total duration of investigation. Optogenetic activation of inhibitory neurons in medial ZI (ZIm), ZImGAD2 neurons, showed a dramatic increase in positive arousal level, depth of investigation, and duration of interaction with conspecifics and novel objects compared with familiar objects, crickets, and food. Optogenetic or chemogenetic deactivation of these neurons decreased depth and duration of investigation. Moreover, we found that ZImGAD2 neurons are more active during deep investigation as compared with during shallow investigation. We found that activation of prelimbic cortex (PL) axons into ZIm increases arousal level, and chemogenetic deactivation of these axons decreases the duration and depth of investigation. Calcium fiber photometry of these axons showed no difference in activity between shallow and deep investigation, suggesting a nonspecific motivation. Optogenetic activation of ZImGAD2 axons into lateral periaqueductal gray (lPAG) increases the arousal level, whereas chemogenetic deactivation of these axons decreases duration and depth of investigation. Calcium fiber photometry of these axons showed high activity during deep investigation and no significant activity during shallow investigation, suggesting a thresholding mechanism. Last, we found a new subpopulation of inhibitory neurons in ZIm expressing tachykinin 1 (TAC1) that monosynaptically receive PL inputs and project to lPAG. Optogenetic activation and deactivation of these neurons, respectively, increased and decreased depth and duration of investigation. CONCLUSION: Our experiments revealed different action sequences based on the motivational level of novelty seeking. Moreover, we uncovered a new brain circuit underlying curiosity and novelty-seeking behavior, connecting excitatory neurons of PL to lPAG through TAC1+ inhibitory neurons of ZIm

Visualization of Multichannel EEG Coherence Networks Based on Community Structure

An electroencephalography (EEG) coherence network is a representation of functional brain connectivity. However, typical visualizations of coherence networks do not allow an easy embedding of spatial information or suffer from visual clutter, especially for multichannel EEG coherence networks. In this paper, a new method for data-driven visualization of multichannel EEG coherence networks is proposed to avoid the drawbacks of conventional methods. This method partitions electrodes into dense groups of spatially connected regions. It not only preserves spatial relationships between regions, but also allows an analysis of the functional connectivity within and between brain regions, which could be used to explore the relationship between functional connectivity and underlying brain structures. In addition, we employ an example to illustrate the difference between the proposed method and two other data-driven methods when applied to coherence networks in older and younger adults who perform a cognitive task. The proposed method can serve as an preprocessing step before a more detailed analysis of EEG coherence networks

Wildland Fire Susceptibility Mapping Using Support Vector Regression and Adaptive Neuro-Fuzzy Inference System-Based Whale Optimization Algorithm and Simulated Annealing

Fires are one of the most destructive forces in natural ecosystems. This study aims to develop and compare four hybrid models using two well-known machine learning models, support vector regression (SVR) and the adaptive neuro-fuzzy inference system (ANFIS), as well as two meta-heuristic models, the whale optimization algorithm (WOA) and simulated annealing (SA) to map wildland fires in Jerash Province, Jordan. For modeling, 109 fire locations were used along with 14 relevant factors, including elevation, slope, aspect, land use, normalized difference vegetation index (NDVI), rainfall, temperature, wind speed, solar radiation, soil texture, topographic wetness index (TWI), distance to drainage, and population density, as the variables affecting the fire occurrence. The area under the receiver operating characteristic (AUROC) was used to evaluate the accuracy of the models. The findings indicated that SVR-based hybrid models yielded a higher AUROC value (0.965 and 0.949) than the ANFIS-based hybrid models (0.904 and 0.894, respectively). Wildland fire susceptibility maps can play a major role in shaping firefighting tactics