Effects of the Loss of Binocular and Motion Parallax on Static Postural Stability.

Depth information is important for postural stability and is generated by two visual systems: binocular and motion parallax. The effect of each type of parallax on postural stability remains unclear. We investigated the effects of binocular and motion parallax loss on static postural stability using a virtual reality (VR) system with a head-mounted display (HMD). A total of 24 healthy young adults were asked to stand still on a foam surface fixed on a force plate. They wore an HMD and faced a visual background in the VR system under four visual test conditions: normal vision (Control), absence of motion parallax (Non-MP)/binocular parallax (Non-BP), and absence of both motion and binocular parallax (Non-P). The sway area and velocity in the anteroposterior and mediolateral directions of the center-of-pressure displacements were measured. All postural stability measurements were significantly higher under the Non-MP and Non-P conditions than those under the Control and Non-BP conditions, with no significant differences in the postural stability measurements between the Control and Non-BP conditions. In conclusion, motion parallax has a more prominent effect on static postural stability than binocular parallax, which clarifies the underlying mechanisms of postural instability and informs the development of rehabilitation methods for people with visual impairments.

Intergenerational Transmission of Maternal Adverse Childhood Experiences on Next Generation's Development: A Mini-Review.

(Adverse childhood experiences (ACEs) have extremely harmful impacts on an individual's physical, social and mental health throughout their life-span. Recently, it has been reported that maternal ACEs increase the risk of developmental delay in the offspring across generations. This mini review focuses on the direct relationship between maternal ACEs and child developmental delay, and potential mediators/moderators that associate their relationship. Six studies were identified using three search engines. The results indicated that four out of six studies reported at least one significant direct association between maternal ACEs and child development. Additionally, maternal biological, psychological, and social factors were identified as mediators or moderators. In summary, we identified that maternal ACEs increased the risk of developmental delay in children via biological and psychosocial pathways. Future research should examine potential buffering factors and identify when it is crucial to break the intergenerational transmission.

Population genetic structure and diversity of the East Balkan Swine (Sus scrofa) in Bulgaria, revealed by mitochondrial DNA and microsatellite analyses.

The East Balkan Swine (EBS) is the only indigenous pig breed in Bulgaria. We analyzed the mitochondrial DNA (mtDNA) control region and 21 microsatellite loci for 198 individuals from 11 farms in Bulgaria. Obtained 11 mtDNA haplotypes including three novel ones were grouped to two major clades, European clade E1 (146/198 individuals, 73.7%) and Asian clade A (52/198, 26.3%). The mixture of the two clades may have resulted from historical crossbreeding between the European and Asian pig breeds. Clade A was frequent in southeastern Bulgaria (Burgas Province), but less frequent or absent in northeastern Bulgaria (Varna and Shumen Provinces). The distribution of Europe- and Asia-specific haplotypes relative to EBS farm locations could be attributed to regional differences of breeding systems (e.g., crossbreeding with imported commercial pigs). A microsatellite analysis showed high heterozygosities for all the EBS farms, and negative inbreeding coefficients presumably due to crossing with commercial pigs or wild boars and/or efforts to reduce inbreeding by farmers. Bayesian clustering analyses showed that all farm populations are genetically well distinguishable from one another. Although diversity has been maintained by the efforts of farmers and a breeding association, the effective population size remains small, and conservation efforts should be continued.

Effects of simulated peripheral visual field loss on the static postural control in young healthy adults.

BACKGROUND: Integration of visual, vestibular, and proprioceptive sensations contributes to postural control. People with peripheral visual field loss have serious postural instability. However, the directional specificity of postural stability and sensory reweighting caused by gradual peripheral visual field loss remain unclear. RESEARCH QUESTION: What are the effects of peripheral visual field loss on static postural control? METHODS: Fifteen healthy young adults participated in this study. The participants were asked to stand quietly on a foam surface. Three conditions of virtual visual field loss (90°, 45°, and 15°) were provided by a head-mounted display, and ground reaction forces were collected using a force plate to calculate the displacements of the center of pressure (COP). RESULTS: The root mean square (RMS), mean velocity, and 95% ellipse area of COP displacements in the horizontal plane increased, and RMS in the anteroposterior (AP) direction was unchanged under the smallest visual field condition compared to the largest one. The power spectrum density of COP displacements in the low-frequency band was decreased and that in the medium-frequency band was increased in the AP direction. SIGNIFICANCE: During quiet standing of young healthy adults with peripheral visual field loss, increased peripheral visual field loss resulted in lower postural stability. Postural stability in the AP direction was maintained contrary to the functional sensitivity hypothesis. Peripheral visual field loss reduced the weighting of the visual input and increased that of the vestibular input in the AP direction to maintain equilibrium.

Short-term effects of postural control by standing on a tilting board in patients with Parkinson's disease.

Background: People with Parkinson's disease (PD) often have backward displacement of their center of pressure (COP) during quiet standing and reduced stability limits, as compared to healthy controls. These kinetic characteristics may induce postural instability in people with PD.Objective: To investigate the short-term effects on COP displacements during quiet standing and forward leaning brought about by the post-incline leaning after-effects in people with PD.Methods: Twenty participants with PD were randomly divided into two groups (tilting and control groups). The tilting group was required to stand upright quietly on a tilting board angled to raise the front part of the feet. The control group was asked to voluntarily lean their bodies forward as far as possible. The total time of the intervention was 60 seconds for each group. The COP displacements during quiet standing and forward leaning were recorded before and after the intervention.Results: In the tilting group, the COP significantly shifted forward after the intervention compared to that before the intervention during quiet standing as well as forward stability limits; this did not happen in the control group.Conclusions: The post-incline leaning after-effects may induce the short-term effects of forward shifting of COP during quiet standing and expand the forward stability limits in people with PD.