Abnormal Spontaneous Brain Activity in Left-Onset Parkinson Disease: A Resting-State Functional MRI Study

Objective: Motor asymmetry is characteristic in Parkinson disease (PD). This phenomenon is originated from uneven degeneration of bilateral substantia nigra. However, this asymmetry may not restrict to substantia nigra or striatum. We aimed to determine the effect of asymmetry on spontaneous brain activity across the whole brain. Methods: We consecutively recruited 71 patients with PD, as well as 35 healthy controls, and collected relevant demographic, clinical, and neuropsychological information. The PD patients were divided into two groups according to the side of motor symptom onset. All the participants underwent resting-state functional magnetic resonance imaging, and spontaneous brain activity was assessed using amplitude of low-frequency fluctuation (ALFF). The associations between areas showing significant group differences and various clinical and neuropsychological measures were analyzed. Results: Finally, the data of 30 PD patients with left-onset (LPD), 27 PD patients with right-onset (RPD), and 32 healthy controls were obtained. The three groups had similar age and gender ratios. Our results demonstrated that LPD patients had increased ALFF in the left inferior temporal gyrus and decreased ALFF in bilateral thalamus and cerebellum anterior lobes than the control group. The value of ALFF of the left inferior temporal gyrus was correlated with motor function, and ALFF value of the thalamus was associated with cognition. Comparisons between LPD and RPD patients and between RPD patients and the controls did not yield significant difference. Conclusions: The present study provides new insights into the distinct characteristics of spontaneous brain activity in LPD, which may be associated with motor and cognitive function.

Persons with Multiple Sclerosis Exhibit Strength Asymmetries in both Upper and Lower Extremities

OBJECTIVE

To characterize strength asymmetries in the upper and lower extremities in persons with multiple sclerosis (PwMS) with severe disability, and examine associations between asymmetries and functional, symptomatic, and participatory outcomes.

DESIGN

Cross-sectional.

SETTING

University research laboratory.

PARTICIPANTS

25 PwMS with Expanded Disability Status Scale scores between 6.0-8.0.

MAIN OUTCOME MEASURES

Bilateral strength and asymmetry scores for muscle groups at the ankle, knee, and shoulder joints in addition to grip strength.

RESULTS

Significant differences were observed between all contralateral strength measures, with asymmetry scores ranging between 20-32%. A high prevalence of asymmetry (i.e., score>10%) was observed for all strength measures, with 92% of participants having four or more affected measures. Significant associations were observed between dorsiflexion asymmetry and physical health-related quality of life (ρ= -0.69; p<0.001), and between shoulder flexion asymmetry and lower extremity function (ρ= -0.62; p=0.001). Plantarflexion (ρ= 0.61; p=0.003) and knee flexion (ρ= 0.63; p=0.002) asymmetry were significantly associated with lower extremity functional asymmetry.

CONCLUSIONS

A high prevalence of asymmetry in the upper and lower extremities was observed, with asymmetry scores exceeding those previously reported in PwMS with mild-to-moderate disability. Rehabilitation strategies should consider a full body approach to address strength asymmetries.

Effect of Botulinum Toxin Injection on Asymmetric Lower Face with Chin Deviation

The purpose of this study was to compare the efficacy of botulinum toxin (BoNT) in masseter muscle reduction depending on the amount of chin deviation. Exploring distinctive effects of BoNT relative to the characteristics of facial asymmetry will aid in planning and predicting treatment outcomes. Sixteen adult volunteers were classified into two groups according to the degree of menton deviation observed in posteroanterior cephalograms. Eight had a menton deviation of 3 mm or more and the other eight had less than 3 mm. A total of 25 Units of BoNT was injected into the unilateral masseter muscle of the prominent side for each participant. Changes in the volume and bulkiest height of the lower face on each side were measured with a 3D laser scan at four time points: before and 4, 8, and 12 weeks after the injection. Two-way mixed ANOVA was employed for analyses. The volume and bulkiest height of the injected side decreased over time in both types of asymmetry, with significant differences at each time point. The reductions in the volume and bulkiest height were significantly greater in subjects without chin deviation. The reductions in the volume and bulkiest height of the lower face using BoNT are more effective for subjects without chin deviation.

The Beauty of Asymmetric Membranes: Reconstitution of the Outer Membrane of Gram-Negative Bacteria

The architecture of the lipid matrix of the outer membrane of Gram-negative bacteria is extremely asymmetric: Whereas the inner leaflet is composed of a phospholipid mixture, the outer leaflet is built up by glycolipids. For most Gram-negative species, these glycolipids are lipopolysaccharides (LPS), for a few species, however, glycosphingolipids. We demonstrate experimental approaches for the reconstitution of these asymmetric membranes as (i) solid supported membranes prepared by the Langmuir-Blodgett technique, (ii) planar lipid bilayers prepared by the Montal-Mueller technique, and (iii) giant unilamellar vesicles (GUVs) prepared by the phase transfer method. The asymmetric GUVs (aGUVs) composed of LPS on one leaflet are shown for the first time. They are characterized with respect to their phase behavior, flip-flop of lipids and their usability to investigate the interaction with membrane active peptides or proteins. For the antimicrobial peptide LL-32 and for the bacterial porin OmpF the specificity of the interaction with asymmetric membranes is shown. The three reconstitution systems are compared with respect to their usability to investigate domain formation and interactions with peptides and proteins.

Light-dependent development of the tectorotundal projection in pigeons

Left-right differences in the structural and functional organization of the brain are widespread in the animal kingdom and develop in close gene-environment interactions. The visual system of birds like chicks and pigeons exemplifies how sensory experience shapes lateralized visual processing. Owing to an asymmetrical posture of the embryo in the egg, the right eye/ left brain side is more strongly light-stimulated what triggers asymmetrical differentiation processes leading to a left-hemispheric dominance for visuomotor control. In pigeons (Columba livia), a critical neuroanatomical element is the asymmetrically organized tectofugal pathway. Here, more fibres cross from the right tectum to the left rotundus than vice versa. In the current study, we tested whether the emergence of this projection asymmetry depends on embryonic light stimulation by tracing tectorotundal neurons in pigeons with and without lateralized embryonic light experience. The quantitative tracing pattern confirmed higher bilateral innervation of the left rotundus in light-exposed and thus, asymmetrically light-stimulated pigeons. This was the same in light-deprived pigeons. Here, however, also the right rotundus received an equally strong bilateral input. This suggests that embryonic light stimulation does not increase bilateral tectal innervation of the stronger stimulated left but rather decreases such an input pattern to the right brain side. Combined with a morphometric analysis, our data indicate that embryonic photic stimulation specifically affects differentiation of the contralateral cell population. Differential modification of ipsi- and contralateral tectorotundal connections could have important impact on the regulation of intra- and interhemispheric information transfer and ultimately on hemispheric dominance pattern during visual processing.

Outer Membrane Lipid Secretion and the Innate Immune Response to Gram-Negative Bacteria

The outer membrane (OM) of Gram-negative bacteria is an asymmetric lipid bilayer that consists of inner leaflet phospholipids and outer leaflet lipopolysaccharides (LPS). The asymmetric character and unique biochemistry of LPS molecules contribute to the OM's ability to function as a molecular permeability barrier that protects the bacterium against hazards in the environment. Assembly and regulation of the OM have been extensively studied for understanding mechanisms of antibiotic resistance and bacterial defense against host immunity; however, there is little knowledge on how Gram-negative bacteria release their OMs into their environment to manipulate their hosts. Discoveries in bacterial lipid trafficking, OM lipid homeostasis, and host recognition of microbial patterns have shed new light on how microbes secrete OM vesicles (OMVs) to influence inflammation, cell death, and disease pathogenesis. Pathogens release OMVs that contain phospholipids, like cardiolipins, and components of LPS molecules, like lipid A endotoxins. These multiacylated lipid amphiphiles are molecular patterns that are differentially detected by host receptors like the Toll-like receptor 4/myeloid differentiation factor 2 complex (TLR4/MD-2), mouse caspase-11, and human caspases 4 and 5. We discuss how lipid ligands on OMVs engage these pattern recognition receptors on the membranes and in the cytosol of mammalian cells. We then detail how bacteria regulate OM lipid asymmetry, negative membrane curvature, and the phospholipid-to-LPS ratio to control OMV formation. The goal is to highlight intersections between OM lipid regulation and host immunity and to provide working models for how bacterial lipids influence vesicle formation.

Lower-Limb Flexibility Profile Analysis in Youth Competitive Inline Hockey Players

During puberty, the growth of the bones is faster than that of the muscles, which may result in muscular tightness. Muscular tightness and asymmetry have been associated with an increase in injury incidence. The assessment of a joint range of motion (ROM) could help to identify athletes classified as high injury risk. The objectives of the present study were to describe the lower-extremity flexibility profile (LEFP) of youth competitive inline hockey players using the ROM-SPORT battery (I) and to identify muscular tightness and asymmetry (II). Seventy-four young players were examined for maximum passive ankle, knee, and hip ROMs. Muscle asymmetry or tightness was classified according to cutoff scores previously described. The LEFP of the 74 players was 10.8° for hip extension, 26° for hip adduction, 33.6° for ankle dorsiflexion, 38.6° for ankle dorsiflexion with knee flexed, 36.7° for hip abduction, 46° for hip internal rotation, 60.6° for hip external rotation, 65.1° for hip abduction with the hip flexed, 66.3° for hip flexion with the knee extended, 119.7° for knee flexion, and 133.7° for hip flexion. The individual analysis of the flexibility values identified tightness in all players for one or more movement, except for hip abduction. A low prevalence of asymmetries was observed (range: 5.4% to 17.6% of players) depending on the ROM.

Occupational noise exposure and asymmetric hearing loss: Results from the HUNT population study in Norway

BACKGROUND

A large population study with adequate data on confounders is required to determine whether asymmetric hearing loss (AHL) is associated with occupational noise exposure.

METHODS

We performed a cross-sectional population study in Norway (the Health Investigation in Nord-Trøndelag: HUNT) with 24 183 participants, using pure-tone audiometry and questionnaires. AHL was defined as a difference in hearing threshold between the right and left ears of greater than or equal to 15 dB for the pure-tone average of 0.5 to 2 or 3 to 6 kHz.

RESULTS

The mean age of the participants was 53 years (range, 19-99); 53% were women. The prevalence of AHL in this general Norwegian population was 6% for the 0.5 to 2 kHz range and 15% for 3 to 6 kHz. In unadjusted regression models, subjects reporting prolonged occupational noise exposure to high-level noise sources (N = 1652) had a higher risk of AHL at 3 to 6 kHz than those reporting no prior exposure (odds ratio [OR], 1.98; 95% confidence interval [CI], 1.75-2.25). After adjustment for age and sex, OR was 1.08; (95% CI, 0.95-1.24). After additional adjustment for head trauma, ear infections, blasting or shooting (all associated with AHL), smoking, and diabetes, OR was 1.00 (95% CI, 0.87-1.16). No association between occupational noise and right-ear hearing threshold advantage (left-right ear difference) was observed after adjustment for confounders.

CONCLUSION

Our study suggests that AHL is relatively common in the general population, especially at the high-frequency range in men and elderly subjects. Our study showed no relation between occupational noise exposure and AHL after confounder adjustment.

Stress-Related Neuronal Clusters in Sublenticular Extended Amygdala of Basal Forebrain Show Individual Differences of Positions

To understand functional neuronal circuits for emotion in the basal forebrain, patterns of neuronal activation were examined in mice by immunohistochemistry of immediate-early gene products (Zif268/Egr1 and c-Fos). In all mice examined, clusters of 30–50 neurons expressing Zif268 were found on both sides in the area between the extended amygdala (EA) and globus pallidus (GP), generally designated as sublenticular extended amygdala (SLEA). The clusters consisted of 79.9 ± 3.0% of GABAergic neurons in GAD65-mCherry mice. The expression of the cholinergic marker choline acetyltransferase and the GP markers parvalbumin, proenkephalin, and FoxP2 indicated that these neurons were different from known types of neurons in the EA and GP; therefore, we named them the sublenticular extended amygdalar Zif268/Egr1-expressing neuronal cluster (SLEA-zNC). Sublenticular extended amygdalar Zif268/Egr1-expressing neuronal clusters participated in stress processing because increasing numbers of cells were observed in SLEA-zNCs after exposure to restraint stress (RS), the induction of which was suppressed by diazepam treatment. Mapping SLEA-zNCs showed that their positions and arrangement varied individually; SLEA-zNCs were distributed asymmetrically and tended to be situated mainly in the middle region between the anterior commissure (AC) and posterior end of the GP. However, the total cell number in SLEA-zNCs was compatible between the right and left hemispheres after activation by RS. Therefore, SLEA-zNCs were distributed asymmetrically but were not lateralized. Because time courses of activation differed between the Zif268 and c-Fos, the sequential dual treatment of RSs enabled us to differentiate SLEA-zNCs activated by the first and second RS. The results supported that the same SLEA-zNCs responded to both the first and second RS, and this also applied for all SLEA-zNCs. Thus, we concluded that the cluster positions were invariable under RS in each mouse but were distributed differently between individual mice. We name these newly identified neuronal clusters as stress-related neuronal clusters, SLEA-zNCs, which are considered to be novel functional units of “islands of activation.” Moreover, SLEA-zNCs were situated at different positions in all mice examined, showing individual differences in their positions.

Beware (Surprisingly Common) Left-Right Flips in Your MRI Data: An Efficient and Robust Method to Check MRI Dataset Consistency Using AFNI

Knowing the difference between left and right is generally assumed throughout the brain MRI research community. However, we note widespread occurrences of left-right orientation errors in MRI open database repositories where volumes have contained systematic left-right flips between subject EPIs and anatomicals, due to having incorrect or missing file header information. Here we present a simple method in AFNI for determining the consistency of left and right within a pair of acquired volumes for a particular subject; the presence of EPI-anatomical inconsistency, for example, is a sign that dataset header information likely requires correction. The method contains both a quantitative evaluation as well as a visualizable verification. We test the functionality using publicly available datasets. Left-right flipping is not immediately obvious in most cases, so we also present visualization methods for looking at this problem (and other potential problems), using examples from both FMRI and DTI datasets.

Mechanical Plantar Foot Stimulation in Parkinson's Disease: A Scoping Review

Background: Parkinson′s disease (PD) is the second most prevalent neurodegenerative disease in older individuals. Neurorehabilitation-based interventions such as those improving gait are crucial for a holistic approach and to limit falls. Several studies have recently shown that mechanical plantar foot stimulation is a beneficial intervention for improving gait impairment in PD patients. The objective of this scoping review is to evaluate the beneficial effects of this stimulation on gait parameters, and to analyse protocols of foot stimulation and other effects in non-motor symptoms. Relevant articles were searched in the Medline database using Pubmed and Scopus, using the primary search terms ‘foot stimulation’ OR ‘plantar stimulation’ AND ‘Parkinson’s disease*’. Several protocols have been used for mechanical plantar foot stimulation (ranging from medical devices to textured insoles). The gait parameters that have been shown to be improved are stride length and walking speed. The beneficial effects are achieved after both acute and repeated plantar foot stimulation. Beneficial effects are observed in other organs and systems, such as muscle activation, brain connectivity, cardiovascular control in the central nervous system, and the release of brain-derived neurotrophic factor and cortisol in blood added evidence about this intervention’s impact on brain function. Mechanical plantar foot stimulation is a safe and effective add-on treatment able for improving gait impairments in PD patients during the L-dopa off state. Randomized and controlled clinical trials to study its eventual potentiating effect with different pharmacotherapy regimens are warranted.

Resting State EEG in Exercise Intervention Studies: A Systematic Review of Effects and Methods

Background: Exercise has been shown to alter brain plasticity and is explored as a therapeutic intervention in a wide variety of neurological diseases. Electroencephalography (EEG) offers an inexpensive method of studying brain electrocortical activity shortly after exercise and thus offers a way of exploring the influence of exercise on the brain. We conducted a systematic review to summarize the current body of evidence regarding methods of EEG analysis and the reported effects of exercise interventions on EEG.

Methods: PubMed, Web of Science and EMBASE were searched for studies investigating resting state EEG in exercise intervention studies carried out in participants >17 years of age and with no history of epilepsy. Further, studies solely investigating event-related potentials as an outcome measure were excluded. Relevant data were extracted, and a risk-of-bias assessment was carried out using the Cochrane risk-of-bias tool. A qualitative synthesis of results was carried out. A protocol for the systematic review was uploaded to https://www.crd.york.ac.uk/PROSPERO/ (ID: CRD42019134570) and the Preferred Reporting Items for Systematic Reviews (PRISMA) statement was followed.

Results: Out of 1,993 records screened, 54 studies were included in a final qualitative synthesis with a total of 1,445 participants. Our synthesis showed that studies were mainly carried out using frequency analysis as an analytical method. Generally, findings across studies were inconsistent and few were adjusted for multiple comparisons. Studies were mainly of low quality and usually carried out in small populations, lowering the significance of results reported.

Conclusions: Changes in the EEG as a result of an exercise intervention are elusive and difficult to replicate. Future studies should provide biologically sound hypotheses underlying assumptions, include larger populations and use standardized EEG methods to increase replicability. EEG remains an interesting methodology to examine the effects of exercise on the brain.

Asymmetric interactions of seed-predation network contribute to rare-species advantage

Although the asymmetry of species linkage within ecological networks is now well recognized, its effect on communities has scarcely been empirically investigated. Based on theory, we predicted that an asymmetric architecture of antagonistic plant-herbivore networks would emerge at the community level and that this asymmetry would negatively affect community-common plants more than rare ones. We tested this prediction by analyzing the architectural properties of an alpine plant and pre-dispersal seed-predator network and its effect on seed loss rate of plants in the Tibetan Plateau. This network showed an asymmetric architecture, where the common plant species (with a larger aboveground biomass per area) were infested by a higher number of predator species. Moreover, they asymmetrically interacted with specialized herbivores, presumably because of greater seed resource abundance. In turn, the asymmetric interactions led to a higher proportion of seed loss in the common plants at the species level. Our results suggest that asymmetric antagonistic networks may improve species coexistence by contributing to a mechanism of rare-species advantage.

Differences in dental arch characteristics between genders in patients with suspected condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress in conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to analysis the difference of dental arch characteristics  based on genders in orthodontic patients with suspected CH in a North Sumatra subpopulation.

Methods: This is a retrospective study of suspected CH patient’s clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior crossbite and midline deviation), the positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, the distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length.

Results: There was a significant difference (p<0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form were mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these suspected CH patients.

Conclusion: Indeed skeletal asymmetry, the evaluation of the dental arch characteristic symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with suspected  CH in the North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Ability of Macular Inner Retinal Layer Thickness Asymmetry Evaluated by Optical Coherence Tomography to Detect Preperimetric Glaucoma

Purpose

We assessed the ability to detect preperimetric glaucoma (PPG) based on asymmetry in the thickness of the macular inner retinal layers measured by spectral-domain optical coherence tomography.

Methods

We studied 45 normal eyes and 50 PPG eyes retrospectively. Three-dimensional optical coherence tomography macular area scans were used to obtain the thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer/inner plexiform layer (GCL/IPL), and ganglion cell complex (GCC). We calculated the thickness differences between the upper and lower macular hemispheres for the corresponding superpixels, then evaluated the mean absolute value of the thickness differences and the number of superpixels in which the thickness difference was greater than X µm, where X is an integer number from 1 to 10. Areas under the receiver operating characteristic curves (AUCs) for their PPG diagnostic performances were compared to the average thickness measurements of the total and hemiretinal sectors. X was determined at the maximum AUC value.

Results

The AUC for the mean absolute value of the difference in GCL/IPL thickness (0.923) was higher than the difference in RNFL and GCC thickness (0.710 and 0.905, respectively). The AUC for the number of superpixels in which the GCL/IPL thickness difference was greater than 8 µm (X = 8) was 0.914. The ability to diagnose PPG using these GCL/IPL parameters was statistically higher than for total or superior and inferior hemiretinal GCL/IPL thicknesses.

Conclusions

Asymmetry in the thickness of the GCL/IPL shows good PPG diagnostic performance.

Translational Relevance

This approach would be useful in the early detection of glaucoma.

Hemispheric specialization in spatial versus ordinal processing in the day-old domestic chick (Gallus gallus)

Different species show an intriguing similarity in representing numerosity in space, starting from left to right. This bias has been attributed to a right hemisphere dominance in processing spatial information. Here, to disentangle the role of each hemisphere in dealing with spatial versus ordinal-numerical information, we tested domestic chicks during monocular versus binocular vision. In the avian brain, the contralateral hemisphere mainly processes the visual input from each eye. Four-day-old chicks learned to peck at the fourth element in a sagittal series of 10 identical elements. At testing, chicks faced a left-to-right-oriented series where the interelement distance was manipulated so that the third element was where the fourth had been at training; this compelled chicks to use either spatial or ordinal cues. Chicks tested binocularly selected both the fourth left and (to a lesser extent) right elements. Chicks tested monocularly chose the third and fourth elements on the seeing side equally. Interhemispheric cooperation resulted in the use of ordinal-numerical information, while each single hemisphere could rely on spatial or ordinal-numerical cue. Both hemispheres can process spatial and ordinal-numerical information, but their interaction results in the supremacy of processing the ordinal-numerical cue.

Interhemispheric asymmetry of c-Fos expression in glomeruli and the olfactory tubercle following repeated odor stimulation

Odor adaptation allows the olfactory system to regulate sensitivity to different stimulus intensities, which is essential for preventing saturation of the cell‐transducing machinery and maintaining high sensitivity to persistent and repetitive odor stimuli. Although many studies have investigated the structure and mechanisms of the mammalian olfactory system that responds to chemical sensation, few studies have considered differences in neuronal activation that depend on the manner in which the olfactory system is exposed to odorants, or examined activity patterns of olfactory‐related regions in the brain under different odor exposure conditions. To address these questions, we designed three different odor exposure conditions that mimicked diverse odor environments and analyzed c‐Fos‐expressing cells (c‐Fos+ cells) in the odor columns of the olfactory bulb (OB). We then measured differences in the proportions of c‐Fos‐expressing cell types depending on the odor exposure condition. Surprisingly, under the specific odor condition in which the olfactory system was repeatedly exposed to the odorant for 1 min at 5‐min intervals, one of the lateral odor columns and the ipsilateral hemisphere of the olfactory tubercle had more c‐Fos+ cells than the other three odor columns and the contralateral hemisphere of the olfactory tubercle. However, this interhemispheric asymmetry of c‐Fos expression was not observed in the anterior piriform cortex. To confirm whether the anterior olfactory nucleus pars externa (AONpE), which connects the left and right OB, contributes to this asymmetry, AONpE‐lesioned mice were analyzed under the specific odor exposure condition. Asymmetric c‐Fos expression was not observed in the OB or the olfactory tubercle. These data indicate that the c‐Fos expression patterns of the olfactory‐related regions in the brain are influenced by the odor exposure condition and that asymmetric c‐Fos expression in these regions was observed under a specific odor exposure condition due to synaptic linkage via the AONpE.

Embryonic development of skull bones in the Sahara horned viper (Cerastes cerastes), with new insights into structures related to the basicranium and braincase roof

Ontogenetic studies are crucial for understanding functional morphology, origin and adaptation of skulls in vertebrates. However, very few studies have so far released complete embryonic series focusing on skull embryonic development in species showing diverse and extreme cranial morphologies such as snakes. The wide distribution and unique reproductive and ecological behaviors of venomous vipers, including the heterogeneity in breeding and egg incubation periods in oviparous species, make this group an excellent new model for studying the diversity of skull developmental processes in snakes. Here we present the first complete description of osteocranium development in a viperine snake, Cerastes cerastes, using detailed analysis of the ossification pattern of individual bones across different embryonic stages based on high-resolution micro-computed tomography data. Particularly, we describe in detail the development of the laterosphenoid from its dorsal and ventral components, dividing the trigeminal foramen into maxillary and mandibular foramina. Furthermore, our data help clarify some controversy concerning the presence and/or origin of structures related to the snake basicranium and braincase roof. For example, our detailed description of supraoccipital development suggests that this bone derived, at least in part, from the tectum posterius, although the involvement of the tectum synoticum cannot be totally excluded. Similarly, the epiotic centers of supraoccipital ossification are confirmed during braincase development, and the ancestral lacrimal bone primordium is observed as a ventral element at the early stages of prefrontal development. Finally, our embryonic C. cerastes data highlight a plausible asymmetry in snake skull development, mostly occurring in the basicranium region, but further investigations of embryonic samples and viper species would be required to confirm such phenomenon.

Thermal Rectification in Asymmetric Graphene/Hexagonal Boron Nitride van der Waals Heterostructures

Graphene/hexagonal boron nitride (h-BN) heterostructures assembled by van der Waals (vdW) interactions show numerous unique physical properties such as quantum Hall effects and exotic correlated states, which have promising potential applications in the design of novel electronic devices. Understanding thermal transport in such junctions is critical to control the performance and stability of prospective nanodevices. In this work, using nonequilibrium molecular dynamics simulations, we systematically investigate the thermal transport in asymmetric graphene/h-BN vdW heterostructures. It is found that the heat prefers to flow from the monolayer to the multilayer regions, resulting in a significant thermal rectification (TR) effect. To determine the optimum conditions for TR, the influences of sample length, defect density, asymmetric degree, ambient temperature, and vdW interaction strength are studied. Particularly, we found that the TR ratio could be improved by about 1 order of magnitude via increasing the coupling strength from 1 to 10, which clearly distinguishes from the commonly held notion that the TR ratio is practically insensitive or even decreasing with the interaction strength. Detailed spectral analysis reveals that this unexpected increase of the TR ratio can be attributed to heavily modified phonon properties of encased graphene due to enhanced interlayer coupling. Our results elucidate the importance of vdW interactions to heat conduction in nanostructures.

Impact of maternal childhood trauma on child behavioral problems: The role of child frontal alpha asymmetry

Childhood trauma is associated with many long-term negative outcomes, and is not limited to the individual experiencing the trauma, but extends to subsequent generations. However, mechanisms underlying the association between maternal childhood trauma and child psychopathology are not well understood. Here, we targeted frontal alpha asymmetry (FAA) as a potential underlying factor of the relationship between maternal childhood trauma and child behavioral problems. Electroencephalography (EEG) was recorded from (N = 45) children (Mean age = 57.9 months, SD = 3.13) during an eyes-closed paradigm in order to evaluate FAA. Mothers reported on their childhood trauma experiences using the Childhood Trauma Questionnaire (CTQ), and on their child's behavior using the child behavior checklist (CBCL). We found that maternal childhood trauma significantly predicted child total, internalizing, and externalizing behavior at age 5 years. We also observed a role for FAA such that it acted as a moderator, but not mediator, for behavioral problems. We found that children with relative more right/less left frontal activity were more at risk to develop behavioral problems when their mother had been exposed to trauma in her childhood. These results indicate that child frontal asymmetry may serve as a susceptibility marker for child behavioral problems.

Unusual Characteristics and Variable Expressivity in a Brazilian Family with Cherubism

Cherubism is a rare genetic condition characterized by a bone nonneoplastic disease. We aimed to report a 6-year-old girl with cherubism presenting similar cases in the maternal family. However, her mother and grandmother seemed to be asymptomatic. The patient had an enlarged and asymmetric jaw with multiple enlarged cervical lymph nodes that increased in size with time. Sanger sequencing revealed a heterozygous mutation in exon 9 of SH3BP2 not only in the patient but also in her mother. Thus, we observed a variable expression and a probably reduced penetrance within the family, as well as unusual characteristics of the patient (in this case, the asymmetrical involvement of the jaw).

Left-Right and Upper-Lower Light Sensitivity Asymmetry in Visual Field Defects Caused by Pituitary Adenoma: A Retrospective Observational Study

Purpose

The purpose of this study was to quantitatively investigate light sensitivity asymmetry both between left and right eyes and between upper and lower quadrant in the 30-degree visual field of patients with visual field defects caused by pituitary adenoma.

Patients and Methods

Preoperative Humphrey 30–2 perimetry results were reviewed retrospectively using the charts of 28 pituitary adenoma patients who underwent surgery. Inter-eye light sensitivity comparisons of the temporal and nasal hemifields between the left and right eyes were conducted in each patient to study left-right asymmetry. Upper-lower asymmetry was investigated by comparing the frequency of severe scotoma (light sensitivity 5 dB or less) in the upper and lower visual field quadrants in the temporal and nasal hemifields.

Results

Left-right asymmetry was demonstrated in 61% of cases in the temporal hemifield and in 57% of cases in the nasal hemifield. Severe scotoma test points were investigated in the worse eye of each patient and were more frequent in the superotemporal quadrant of the visual field compared with the inferotemporal quadrant (P = 0.00029) and in the inferonasal quadrant compared to the superonasal quadrant (P = 0.00268).

Conclusion

Asymmetric visual field defects between left and right eyes are common in patients with pituitary adenoma. Severe scotoma is more frequent in the upper quadrant of the temporal hemifield and in the lower quadrant of the nasal hemifield.

Asymmetric Effect of Business Cycles on Population Health: Evidence From the ASEAN Countries

This study investigates the asymmetric effects of business cycles (measured by real GDP per capita) on population health (measured by life expectancy at birth) from the ASEAN countries, namely, Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam. The panel vector error correction model, together with various panel unit root tests and cointegration tests, suggested a hidden cointegrated relationship between life expectancy at birth and the positive and negative components of real GDP per capita, and the asymmetric effects of business cycles on population health were identified in both in the short run and in the long run. Policymakers should focus on the harmful effects of business cycles on population health, and government interventions should be more forceful in times of economic expansion than during periods of economic recession.

Using Mobile EEG to Investigate Alpha and Beta Asymmetries During Hand and Foot Use

The Edinburgh Handedness Inventory (EHI) and the Waterloo Footedness Questionnaire (WFQ) are two of the most widely used questionnaires to assess lateralized everyday behavior in human participants. However, it is unclear to what extent the specific behavior assessed in these questionnaires elicit lateralized neural activity when performed in real-life situations. To illuminate this unresolved issue, we assessed EEG alpha and beta asymmetries during real-life performance of the behaviors assessed in the EHI and WFQ using a mobile EEG system. This methodology provides high ecological validity for studying neural correlates of motor behavior under more naturalistic conditions. Our results indicate that behavioral performance of items of both the EHI and WFQ differentiate between left- and right-handers and left- and right-footers on the neural level, especially in the alpha frequency band. These results were unaffected by movement parameters. Furthermore, we could demonstrate that neural activity elicited specifically during left-sided task performance provides predictive power for the EHI or WFQ score of the participants. Overall, our results show that these prominent questionnaires not only distinguish between different motor preferences on the behavioral level, but also on the neurophysiological level. Furthermore, we could show that mobile EEG systems are a powerful tool to investigate motor asymmetries in ecologically valid situations outside of the laboratory setting. Future research should focus on other lateralized behavioral phenotypes in real-life settings to provide more insights into lateralized motor functions.

Lower sensitivity to peripheral hypermetropic defocus due to higher order ocular aberrations

PURPOSE

Many myopia control interventions are designed to induce myopic relative peripheral refraction. However, myopes tend to show asymmetries in their sensitivity to defocus, seeing better with hypermetropic rather than myopic defocus. This study aims to determine the influence of chromatic aberrations (CA) and higher-order monochromatic aberrations (HOA) in the peripheral asymmetry to defocus.

METHODS

Peripheral (20° nasal visual field) low-contrast (10%) resolution acuity of nine subjects (four myopes, four emmetropes, one hypermetrope) was evaluated under induced myopic and hypermetropic defocus between ±5 D, under four conditions: (a) Peripheral Best Sphere and Cylinder (BSC) correction in white light; (b) Peripheral BSC correction + CA elimination (green light); (c) Peripheral BSC correction + HOA correction in white light; and (d) Peripheral BSC correction + CA elimination + HOA correction. No cycloplegia was used, and all measurements were repeated three times.

RESULTS

The slopes of the peripheral acuity as a function of positive and negative defocus differed, especially when the natural HOA and CA were present. This asymmetry was quantified as the average of the absolute sum of positive and negative defocus slopes for all subjects (AVS). The AVS was 0.081 and 0.063 logMAR/D for white and green light respectively, when the ocular HOA were present. With adaptive optics correction for HOA, the asymmetry reduced to 0.021 logMAR/D for white and 0.031 logMAR/D for green light, mainly because the sensitivity to hypermetropic defocus increased when HOA were corrected.

CONCLUSION

The asymmetry was only slightly affected by the elimination of the CA of the eye, whereas adaptive optics correction for HOA reduced the asymmetry. The HOA mainly affected the sensitivity to hypermetropic defocus.