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Cells May 2022The process of chromosome congression and alignment is at the core of mitotic fidelity. In this review, we discuss distinct spatial routes that the chromosomes take to... (Review)
Review
The process of chromosome congression and alignment is at the core of mitotic fidelity. In this review, we discuss distinct spatial routes that the chromosomes take to align during prometaphase, which are characterized by distinct biomolecular requirements. Peripheral polar chromosomes are an intriguing case as their alignment depends on the activity of kinetochore motors, polar ejection forces, and a transition from lateral to end-on attachments to microtubules, all of which can result in the delayed alignment of these chromosomes. Due to their undesirable position close to and often behind the spindle pole, these chromosomes may be particularly prone to the formation of erroneous kinetochore-microtubule interactions, such as merotelic attachments. To prevent such errors, the cell employs intricate mechanisms to preposition the spindle poles with respect to chromosomes, ensure the formation of end-on attachments in restricted spindle regions, repair faulty attachments by error correction mechanisms, and delay segregation by the spindle assembly checkpoint. Despite this protective machinery, there are several ways in which polar chromosomes can fail in alignment, mis-segregate, and lead to aneuploidy. In agreement with this, polar chromosomes are present in certain tumors and may even be involved in the process of tumorigenesis.
Topics: Chromosome Segregation; Kinetochores; Microtubules; Mitosis; Spindle Apparatus
PubMed: 35563837
DOI: 10.3390/cells11091531 -
Developmental Psychobiology Sep 2021The purpose of this study was to quantify the relationship between early motor skills, such as sitting, and the development of problem-solving skills in children with...
INTRODUCTION
The purpose of this study was to quantify the relationship between early motor skills, such as sitting, and the development of problem-solving skills in children with motor delays.
METHODS
Motor (Gross Motor Function Measure) and problem-solving (Assessment of Problem-Solving in Play) skills of 134 children 7-16 months adjusted age at baseline with motor delay were assessed up to 5 times over 12 months. Participants were divided into two groups: mild and significant motor delay.
RESULTS
Motor and problem-solving scores had large (r's = 0.53-0.67) and statistically significant (p's > .01) correlations at all visits. Baseline motor skills predicted baseline and change in problem solving over time. The associations between motor and problem-solving skills were moderated by level of motor delay, with children with significant motor delay generally having stronger associations compared to those with mild motor delay.
CONCLUSIONS
These findings suggest that overall baseline motor skills are predictive of current and future development of problem-solving skills and that children with significant motor delay have a stronger and more stable association between motor and problem-solving skills over time. This highlights that children with motor delays are at risk for secondary delays in problem solving, and this risk increases as degree of motor delay increases.
Topics: Child; Child Development; Child, Preschool; Developmental Disabilities; Humans; Infant; Motor Skills; Motor Skills Disorders; Problem Solving
PubMed: 33942902
DOI: 10.1002/dev.22123 -
Journal of Cognitive Neuroscience Apr 2009Sensory responses to stimuli that are triggered by a self-initiated motor act are suppressed when compared with the response to the same stimuli triggered externally, a...
Sensory responses to stimuli that are triggered by a self-initiated motor act are suppressed when compared with the response to the same stimuli triggered externally, a phenomenon referred to as motor-induced suppression (MIS) of sensory cortical feedback. Studies in the somatosensory system suggest that such suppression might be sensitive to delays between the motor act and the stimulus onset, and a recent study in the auditory system suggests that such MIS develops rapidly. In three MEG experiments, we characterize the properties of MIS by examining the M100 response from the auditory cortex to a simple tone triggered by a button press. In Experiment 1, we found that MIS develops for zero delays but does not generalize to nonzero delays. In Experiment 2, we found that MIS developed for 100-msec delays within 300 trials and occurs in excess of auditory habituation. In Experiment 3, we found that unlike MIS for zero delays, MIS for nonzero delays does not exhibit sensitivity to sensory, delay, or motor-command changes. These results are discussed in relation to suppression to self-produced speech and a general model of sensory motor processing and control.
Topics: Acoustic Stimulation; Adult; Analysis of Variance; Auditory Cortex; Brain Mapping; Electroencephalography; Feedback; Female; Functional Laterality; Habituation, Psychophysiologic; Humans; Magnetoencephalography; Male; Neural Inhibition; Psychomotor Performance; Reaction Time; Time Factors; Young Adult
PubMed: 18593265
DOI: 10.1162/jocn.2009.21055 -
Nature Apr 2021Mutations in the X-linked gene MECP2 cause Rett syndrome, a progressive neurological disorder in which children develop normally for the first one or two years of life...
Mutations in the X-linked gene MECP2 cause Rett syndrome, a progressive neurological disorder in which children develop normally for the first one or two years of life before experiencing profound motor and cognitive decline. At present there are no effective treatments for Rett syndrome, but we hypothesized that using the period of normal development to strengthen motor and memory skills might confer some benefit. Here we find, using a mouse model of Rett syndrome, that intensive training beginning in the presymptomatic period dramatically improves the performance of specific motor and memory tasks, and significantly delays the onset of symptoms. These benefits are not observed when the training begins after symptom onset. Markers of neuronal activity and chemogenetic manipulation reveal that task-specific neurons that are repeatedly activated during training develop more dendritic arbors and have better neurophysiological responses than those in untrained animals, thereby enhancing their functionality and delaying symptom onset. These results provide a rationale for genetic screening of newborns for Rett syndrome, as presymptomatic intervention might mitigate symptoms or delay their onset. Similar strategies should be studied for other childhood neurological disorders.
Topics: Animals; Biomedical Enhancement; Disease Models, Animal; Electrophysiology; Female; Male; Mice; Morris Water Maze Test; Neurons; Prodromal Symptoms; Psychomotor Performance; Rett Syndrome; Rotarod Performance Test; Spatial Learning; Time Factors
PubMed: 33762729
DOI: 10.1038/s41586-021-03369-7 -
Archives of Disease in Childhood Feb 1988The association of joint hypermobility and motor development was sequentially investigated in 715 infants from the ages of 8 to 14 months. Seven joints were evaluated...
The association of joint hypermobility and motor development was sequentially investigated in 715 infants from the ages of 8 to 14 months. Seven joints were evaluated for mobility, and each infant underwent a physical and neurological examination. Parents were given a Denver Developmental Parents' Questionnaire. All subjects with a general developmental delay, systemic illness or syndrome were excluded. The infants were classified as having normal or delayed motor development with normal or delayed joint mobility. They were re-examined six months later. Multivariate statistical techniques was used for categorical analysis, and three joints were found to be significantly associated with motor delay at the first examination--hip abduction, elbow hyperextension, and foot dorsiflexion. Of the 715 infants, 126 had joint hypermobility and of these 38 (30.2%) had motor delay. Sixty four of 589 (10.9%) with normal joints had delayed motor development. Six months later 23 out of 35 of the group with joint hypermobility and 42 out of 53 of the group with normal joints had normal motor function. Joint hypermobility is associated with an increased incidence of motor delay in infancy. Over the ensuing six months most of the subjects will catch up. These findings, indicating a favourable prognosis, have implications regarding clinical assessment and parental counselling.
Topics: Child Development; Female; Humans; Infant; Joint Instability; Male; Motor Skills; Socioeconomic Factors
PubMed: 3348663
DOI: 10.1136/adc.63.2.159 -
ISA Transactions Sep 2019In this paper, an output feedback H controller is proposed for active suspension of an electric vehicle driven by in-wheel motors with actuator faults and time delay....
In this paper, an output feedback H controller is proposed for active suspension of an electric vehicle driven by in-wheel motors with actuator faults and time delay. The dynamic damping in-wheel motor driven system, in which the in-wheel motor is designed as a dynamic vibration absorber (DVA), is developed to improve ride quality and isolate the force transmitted to motor bearings. Furthermore, parameters of vehicle suspension and DVA are optimized based on the particle swarm optimization (PSO) to achieve better suspension performance. As some of the states such as the DVA velocity and unsprung mass velocity are difficult to measure, a robust H output feedback controller is developed to deal with the problem of active suspension control with actuator faults and time delay. The proposed controller could guarantee the system's asymptotic stability and H performance, simultaneously satisfying the performance constraints such as road holding, suspension stroke, and actuator limitation. Finally, the effectiveness of the proposed output feedback controllers is demonstrated based on the quarter vehicle suspension model under bump and random road excitations.
PubMed: 30837127
DOI: 10.1016/j.isatra.2019.02.016 -
Journal of the Neurological Sciences Oct 2020Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative neuromuscular disease with limited treatment options. The diagnosis of ALS can be challenging for... (Review)
Review
Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative neuromuscular disease with limited treatment options. The diagnosis of ALS can be challenging for numerous reasons, resulting in delays that may compromise optimal management and enrollment into clinical trials. Several studies have examined the process and challenges regarding the clinical diagnosis of ALS. Twenty-one studies that were almost exclusively from the English literature published between 1990 and 2020 were identified via PubMed using relevant search terms and included patient populations from the United States, Canada, Japan, Egypt, and several countries in South America and Europe. Probable or definitive ALS patients were identified using El Escorial or revised El Escorial/Airlie House Criteria. Time to diagnosis or diagnostic delay was defined as mean or median time from patient-reported first symptom onset to formal diagnosis by a physician, as recorded in medical records. The typical time to diagnosis was 10-16 months from symptom onset. Several points of delay in the diagnosis course were identified, including specialist referrals and misdiagnoses, often resulting in unnecessary procedures and surgeries. Bulbar onset was noted to significantly reduce time to ALS diagnosis. Future interventions and potential research opportunities were reviewed.
Topics: Amyotrophic Lateral Sclerosis; Canada; Delayed Diagnosis; Egypt; Europe; Humans; Japan
PubMed: 32763509
DOI: 10.1016/j.jns.2020.117054 -
Pediatric Obesity Oct 2016A consequence of childhood obesity may be poor developmental outcomes.
BACKGROUND
A consequence of childhood obesity may be poor developmental outcomes.
OBJECTIVES
This study aimed to examine the relationship between weight and developmental delays in young children.
METHODS
We conducted a secondary analysis of the Early Childhood Longitudinal Study Birth Cohort data. Logistic regression models quantified the association between different weight statuses (normal weight <85th, overweight ≥90th, obese ≥95th percentile for weight) and delays in motor and mental development.
RESULTS
Children classified as overweight in both waves had higher percentages of delays in wave 2 (motor [7.5 vs. 6.2-6.4%], mental [8.6 vs. 5.9-6.7%]), as well as wave 1 and/or wave 2 (motor [14.8 vs. 10.9-13.0%], mental [11.9 vs. 9.0-10.1%]), compared with other children. This association was also found in children who were obese at both time points in wave 2 (motor delay [8.9 vs. 4.9-7.3%], mental delay [10.3 vs. 6.0-7.2%]), as well as wave 1 and/or wave 2 (motor delay [14.5 vs. 10.9-12.9%], mental delay [14.1 vs. 9.4-10.1%]). In the adjusted models, children classified as always obese were more likely to have a mental delay in wave 2 (adjusted odds ratio [aOR] 1.89, 95% confidence interval [CI]: 1.21-2.95) as well as wave 1 and/or wave 2 (aOR 1.56, 95% CI: 1.08-2.26). These children were also more likely to have motor delay (aOR 1.47, 95% CI: 1.02-2.13) in wave 1 and/or wave 2.
CONCLUSION
Overweight children are more likely than their normal-weight peers to have motor and mental developmental delays. Preventing obesity during infancy may facilitate reducing developmental delays in young children.
Topics: Adolescent; Body Weight; Child; Child Development; Child, Preschool; Developmental Disabilities; Female; Humans; Infant; Logistic Models; Longitudinal Studies; Male; Overweight; Pediatric Obesity
PubMed: 26487592
DOI: 10.1111/ijpo.12077 -
Journal of Autism and Developmental... Feb 2007This study assessed motor delay in young children 21-41 months of age with autism spectrum disorder (ASD), and compared motor scores in children with ASD to those of...
This study assessed motor delay in young children 21-41 months of age with autism spectrum disorder (ASD), and compared motor scores in children with ASD to those of children without ASD. Fifty-six children (42 boys, 14 girls) were in three groups: children with ASD, children with developmental delay (DD), and children with developmental concerns without motor delay. Descriptive analysis showed all children with ASD had delays in gross motor skills, fine motor skills, or both. Children with ASD and children with DD showed significant impairments in motor development compared to children who had developmental concerns without motor delay. Motor scores of young children with ASD did not differ significantly on motor skill measures when compared to young children with DD.
Topics: Autistic Disorder; Child, Preschool; Developmental Disabilities; Female; Humans; Male; Motor Skills Disorders; Severity of Illness Index; Surveys and Questionnaires
PubMed: 16868847
DOI: 10.1007/s10803-006-0170-6 -
Frontiers in Psychology 2018Bodily self-consciousness consists of agency (i.e., the feeling of controlling one's actions and causing external events) and body ownership (i.e., the feeling that...
Bodily self-consciousness consists of agency (i.e., the feeling of controlling one's actions and causing external events) and body ownership (i.e., the feeling that one's body belongs to one's self). If a visual presentation of a virtual (fake) hand matches the active movement of a real hand, both the agency and body ownership of the virtual hand are induced [i.e., the active virtual hand illusion (VHI)]. However, previous active VHI studies have rarely considered the effects of goal-related movement errors (i.e., motor performance) on the senses of agency and ownership. Hence, the current study aimed to clarify the relationship between the active VHI and motor performance. To induce the VHI, 18 healthy subjects (three men and 15 women; 20.7 ± 7.3 years) were required to continuously move a virtual hand around a circle at a predetermined speed (i.e., spatial and temporal goals) using their active hand movements. While moving the virtual hand actively, five visual feedback delays were introduced: 90, 210, 330, 450, and 570 ms. It was found that the subjective ratings of both the agency and body ownership of the virtual hand decreased as a function of the delay intervals, whereas most of the spatial and temporal movement errors linearly increased. Using multiple regression analyses, we examined whether the agency and ownership ratings could be explained effectively by both the delay and movement errors. The results demonstrated that the agency was determined not only by the delay but also by the movement variability, whereas the body ownership was mostly determined by the delay. These findings suggest a possibility that the goal-related motor performance of the active VHI influences the agency judgment more strongly, while its effect on the ownership judgment is weaker.
PubMed: 30515118
DOI: 10.3389/fpsyg.2018.02242