Brain development - from Fetus to Adolescence
Cerebral Palsy (CP)
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication, and restricted and repetitive behavior.
MR imaging studies have reported significant changes in gray-matter and white matter in subjects with autism compared to age-matched controls. Differences were detected in several brain regions both in the cerebrum and cerebellum. One of the most consistent findings in autism research is increased brain volume during the first 2-3 years of life. Recent studies support the hypothesis of autism as a disorder of neuronal connectivity.
Our group has performed several imaging studies on young subjects with autism, using advanced MR methods to study structural and functional connectivity. Our work was the first to show abnormal maturation and increased restriction in several brain regions of young children with autism. Based on our findings we suggested that early and "accelerated" abnormal maturation occurring in young subjects with autism is in line with brain overgrowth at these ages.
In addition, we showed that children with autism have abnormal white matter developmental trajectories in various brain regions as compared to controls.
Top row: T1-weighted images (T1-WI-A), fractional anisotropy (B), probability (C) and displacement (D) in a healthy 22-year-old participant.
Bottom row: White matter pixel count (WMPC) of Fractional anisotropy (FA, A), Probability (Prob, B) and Displacement (Disp, C). Individual values of typically developing (TD) controls and children with autism are plotted against the predicted developmental curve.
Accelerated maturation of white matter in young children with autism: a high b value DWI study
Abnormal white matter integrity in young children with autism
Abnormal Developmental Trajectories of White Matter in Autism
Abnormal white matter in language related brain tracts in non-verbal children with autism
Isolated mild white matter signal changes in preterm infants:a regional approach for comparison of cranial ultrasound and MRI findings.
Diffuse excessive high signal intensity in low-risk preterm infants at term-equivalent age does not predict outcome at 1 year: a prospective study.
Neonatal neuropsychology: Emerging relations of neonatal sensory-motor responses to white matter integrity.
The motor and visual networks in preterm infants: An fMRI and DTI study Brain Research
Cerebral Palsy (CP)
Cerebral palsy (CP) results from early brain injury, either pre or perinatal, and affects 2-3 in 1000 children. Approximately 30% of children with CP have hemiparesis, which manifests as motor impairments and weakness on one side of the body, causing substantial functional impairment in day-to-day tasks. Beyond unilateral impairments, children with hemiparesis also have impairments in bimanual coordination.
Our studies focused on exploring neuroplasticity, using MRI following 60 hours of hand-arm bimanual intensive therapy (HABIT) in children with hemiparesis. Serial behavioral evaluations and MR imaging, including high resolution structural imaging, DTI, fMRI and resting state fMRI, were performed before, immediately after, and 6 weeks following treatment.
Children took part in a Magic HABIT day camp intervention (60 hours over 2 weeks) in Israel and in London1.
The children showed improvement after intervention on at least one measure, with most showing improvement on two or more tests. Cortical reorganization was detected in the hemisphere contra-lateral to the lesion, to compensate for the injury early in life, mainly among gray matter in motor and language areas.
Following intervention, changes in the pattern of brain activation was observed (more lateralized). Evaluating the predictive value of baseline imaging markers for interventional response revealed that children with greater structural, functional and connective brain damage showed enhanced responses to a bimanual intervention.
A multi-site study of functional outcomes following a themed approach to hand–arm bimanual intensive therapy for children with hemiplegia
Cortical reorganization following injury early in life
Brain Plasticity Following Intensive Bimanual Therapy in Children with Hemiplegia: Preliminary Evidence
Imaging Predictors of Improvement from a Motor Learning Based Intervention for Children with Hemiplegia
The development of the human brain involves extensive structural, functional and neuro-chemical changes throughout life; with different tissue types, brain structures, and neural circuits exhibiting distinct developmental trajectories. MRI provides information that enables the study of brain development and characterizes age-related changes in brain structure, function and metabolism.
Using advanced methods for image acquisition and analysis, we can improve our understanding of typical development and better characterize and diagnose abnormal development.
Prematurity is a risk factor for mild to severe neuro-developmental impairments, which occur in more than 50% of preterm infants. Several studies using multiple MR methods have been performed by our group to improve assessment of preterm infants and provide early prediction for neurodevelopmental outcomes.
Preterm infants were scanned at term equivalent age, and neurobehavioural assessments were performed at term (44 weeks), at one and at two years of age (age corrected for prematurity).
In our studies, we showed that the transientechogenicity (detected in ultra-sound) in preterm infants did not have predictive value for neurobehavioral outcomes and was not associated with the diffuse excessive high signal intensity (DEHSI), detected in MRI in all brain regions1. In addition, DEHSI was not a predictive measure for short-term adverse neurobehavioral outcomes2. Using DTI, reduced tissue integrity of several major white matter fibers was found to be associated with sensory-motor function3. Using resting state fMRI, functional connectivity was found to correlate with tissue integrity in several networks4.
Our studies highlight the importance of understanding the spatial-temporal changes occurring during this sensitive period of development and the potential effect of extra uterine exposure on brain development.
Dr. Artzi's research is focused on quantitative tissue characterization and classification based on advanced methods for MR acquisition and analysis. Studies are conducted on healthy subjects and patients with pathologies of the central nervous system. The aim of her research is to improve patient assessment, therapy response monitoring and prediction of clinical outcomes.