2,734 research outputs found

    Automated detection of brain abnormalities in neonatal hypoxia ischemic injury from MR images.

    Get PDF
    We compared the efficacy of three automated brain injury detection methods, namely symmetry-integrated region growing (SIRG), hierarchical region splitting (HRS) and modified watershed segmentation (MWS) in human and animal magnetic resonance imaging (MRI) datasets for the detection of hypoxic ischemic injuries (HIIs). Diffusion weighted imaging (DWI, 1.5T) data from neonatal arterial ischemic stroke (AIS) patients, as well as T2-weighted imaging (T2WI, 11.7T, 4.7T) at seven different time-points (1, 4, 7, 10, 17, 24 and 31 days post HII) in rat-pup model of hypoxic ischemic injury were used to assess the temporal efficacy of our computational approaches. Sensitivity, specificity, and similarity were used as performance metrics based on manual ('gold standard') injury detection to quantify comparisons. When compared to the manual gold standard, automated injury location results from SIRG performed the best in 62% of the data, while 29% for HRS and 9% for MWS. Injury severity detection revealed that SIRG performed the best in 67% cases while 33% for HRS. Prior information is required by HRS and MWS, but not by SIRG. However, SIRG is sensitive to parameter-tuning, while HRS and MWS are not. Among these methods, SIRG performs the best in detecting lesion volumes; HRS is the most robust, while MWS lags behind in both respects

    Striatal Morphological and Functional Alterations Induced by Prenatal Alcohol Exposure

    Get PDF
    Prenatal alcohol exposure (PAE) is an insidious yet preventable cause of developmental disability. The prenatal stage is a critical period for brain development with the concurrence of high vulnerability to the acute and prolonged effects of PAE. There is substantial evidence from both human observations and laboratory experiments that PAE is a common risk factor that predisposes to an array of postnatal mental disorders, including emotional, cognitive, and motor deficits. Although it is well accepted that PAE causes substantial morbidity, available treatments are limited. One reason is the lack of sufficient understanding about the neuroalterations induced by PAE, and how these changes contribute to PAE-induced mental disorders. Among a number of brain structures that have been explored extensively in PAE, the striatum has attracted great attention in the last 20 years in the field of PAE neurobiology. Interestingly, in animal models, the striatum has been considered as a pivotal switch of brain dysfunction induced by PAE, such as addiction, anxiety, depression, and neurodegeneration. In this review, we focus on recent advances in the understanding of morphological and functional changes in brain regions related to alterations after PAE, in particular the striatum. Because this region is central for behavior, emotion and cognition, there is an urgent need for more studies to uncover the PAE-induced alterations at the circuit, neuronal, synaptic and molecular levels, which will not only improve our understanding of the neuroplasticity induced by PAE, but also provide novel biological targets to treat PAE-related mental disorders with translational significance

    Electroencephalographic functional connectivity in extreme prematurity: a pilot study based on graph theory

    Get PDF
    Background: Connectivity studies based on functional magnetic resonance imaging (MRI) provided new insights in neonatal brain development but cannot be performed at bedside in the clinical setting. The electroencephalogram (EEG) connectivity has been less studied, particularly using the new approach based on graph theory. This study aimed to explore the functional EEG connectivity using graph theory analysis at an early post-conception age in extremely premature and late-preterm babies free of medical complications and overt brain damage. Methods: Sixteen neonates (8 extremely low gestational age (ELGA) and 8 late-preterm infants), both groups having performed multichannel EEG recordings at 35 weeks’ post-conception, were recruited in a single tertiary-level neonatal intensive care unit and well-baby nursery, respectively. Global (i.e., small-worldness) and local (i.e., clustering and strength) connectivity measures were calculated on a single-subject connectivity matrix of EEG data. Results: Both ELGA and late-preterm infants showed small-worldness organization at 35 weeks’ post-conception. The ELGA group had the strength parameter of the theta frequency band lower in the right than in the left hemisphere. This asymmetry did not emerge in the late-preterm group. Moreover, the mean strength parameter was significantly greater in the right hemisphere in the late preterms than in the ELGA group. Conclusion: EEG connectivity measures could represent an index of left-to-right maturation and developmental disadvantage in extremely preterm infants

    Regional White Matter Atrophy Correlates with Spike Activity in Encephalopathy Related to Status Epilepticus During Slow Sleep (ESES) After Early Thalamic Lesions

    Get PDF
    Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is an age-related, epileptic syndrome, which associates cognitive/behavioral disturbances with a peculiar pattern of spike activity. One promising line of research is the study of ESES in cases of early thalamic lesions. We studied 7 ESES patients with unilateral thalamic lesions using magnetic resonance imaging to assess regional white matter (WM) and thalamic nuclei volume differences, and long-term electroencephalogram recordings to localize the epileptogenic cortex. N170 event-related potentials were used to demonstrate the dysfunctional character of the WM abnormalities. Diffusion-weighted images in a subset of 4 patients were used to parcellate the thalamus and evaluate volume asymmetries, based on cortical connectivity. Large WM regional atrophy in the hemisphere with the thalamic lesion was associated with both cortical dysfunction and epileptic activity. A correlation was demonstrated between lesions in the pulvinar and the mediodorsal thalamic nuclei and WM atrophy of the corresponding cortical projection areas. We propose that these abnormalities are due to the widespread structural disconnection produced by the thalamic lesions associated to a yet unknown age-dependent factor. Further exploration of WM regional atrophy association with the spike activity in other etiologies could lend support to the cortical disconnection role in ESES genesis.info:eu-repo/semantics/publishedVersio

    Development Trends of White Matter Connectivity in the First Years of Life

    Get PDF
    The human brain is organized into a collection of interacting networks with specialized functions to support various cognitive functions. Recent research has reached a consensus that the brain manifests small-world topology, which implicates both global and local efficiency at minimal wiring costs, and also modular organization, which indicates functional segregation and specialization. However, the important questions of how and when the small-world topology and modular organization come into existence remain largely unanswered. Taking a graph theoretic approach, we attempt to shed light on this matter by an in vivo study, using diffusion tensor imaging based fiber tractography, on 39 healthy pediatric subjects with longitudinal data collected at average ages of 2 weeks, 1 year, and 2 years. Our results indicate that the small-world architecture exists at birth with efficiency that increases in later stages of development. In addition, we found that the networks are broad scale in nature, signifying the existence of pivotal connection hubs and resilience of the brain network to random and targeted attacks. We also observed, with development, that the brain network seems to evolve progressively from a local, predominantly proximity based, connectivity pattern to a more distributed, predominantly functional based, connectivity pattern. These observations suggest that the brain in the early years of life has relatively efficient systems that may solve similar information processing problems, but in divergent ways

    Brain structural connectivity and neurodevelopment in post-Fontan adolescents

    Full text link
    Congenital heart disease (CHD) is the most common congenital anomaly, with single ventricle (SV) defects accounting for nearly 10% of all CHD. SV defects tend to be the most severe forms of CHD: all patients born with SV require multiple open heart surgeries, often beginning in the neonatal period, ultimately leading to the Fontan procedure. Due to improvements in surgical procedures and medical care, more patients are surviving into adolescence and adulthood. Brain imaging and pathology studies have shown that patients with SV have differences in brain structure and metabolism even before the first surgery, and as early as in utero. Furthermore, a significant number of patients have new or more severe lesions after the initial surgery, and many still have brain abnormalities into early childhood. However, there are no detailed brain structural data of SV patients in adolescence. Our group recruited a large cohort of post-Fontan SV patients aged 10-19 years. Separate analyses of neuropsychological and behavioral outcomes in these patients show deficits in multiple areas of cognition, increased rates of attention deficit-hyperactivity disorder (ADHD), and increased use of remedial and/or special education services compared to a control group. Post-Fontan adolescents have more gross brain abnormalities, including evidence of chronic ischemic stroke. Furthermore, there are widespread reductions in cortical and subcortical gray matter volume and cortical thickness, some of which are associated with medical and surgical variables. Diffusion tensor imaging (DTI) analyses show widespread areas of altered white matter microstructure in deep subcortical and cerebellar white matter. In this dissertation, I use graph theory methods to characterize structural connectivity based on gray matter (cortical thickness covariance) and white matter (DTI tractography), and examine associations between brain structure and neurodevelopment. I found that brain network connectivity differs in post-Fontan patients compared with controls, both at the global and regional level. Additionally, deficits in overall network structure were associated with impaired neurodevelopment in several domains, including general intelligence, executive function, and visuospatial skills. These data suggest that early neuroprotection should be a major focus in the care of SV patients, with the goal of improving long-term neurodevelopmental outcomes

    A Review on the Cognitive Neuroscience of Autism

    Get PDF
    With increased recognition in the media, heightened prevalence, and advances in research technologies, investigation into the causes of autism has broadened in recent years. Studies at the molecular, structural, and behavioral levels have resulted in significant findings, linking autism to qualitative differences in neurological function and an alteration of early development. Familial aggregation of autism demonstrate a strong genetic factor, although genetics can not completely account for its pathogenesis. Studies show autism having one of the most complex pathologies among neurodevelopmental disorders. Future studies applying sophisticated methodologies in new areas may shed light on current mysteries surrounding the disorder

    Newborn brain structural characteristics and their relationships with maternal prenatal distress : Findings from the FinnBrain Birth Cohort MRI Study

    Get PDF
    Plasticity renders the brain sensitive to its intrauterine environment and susceptible to alterations during early brain development. The amygdala and hippocampus, structures key in socioemotional functions, are susceptible to these alterations. Understanding the normal variation in the newborn brain facilitates the recognition of such aberrant developmental trajectories, which may occur after exposure to maternal prenatal psychological distress (PPD) and result in a predisposition to psychopathology. This study aimed to 1) describe the normal variation of newborn brain volumetric measures in relation to newborn characteristics; 2) assess the prevalence and risk factors of incidental findings in newborn brain magnetic resonance imaging (MRI); 3) investigate how different types and timings of maternal PPD associate with newborn amygdalar and hippocampal volumes, and whether this association is modified by newborn sex. Information on maternal depressive and anxiety symptoms was gathered at gestational weeks (GW) 14, 24 and 34, and pregnancy¬specific anxiety (PSA) symptoms at GW24. Newborns were imaged with MRI at two to five weeks of postnatal age (n=175). The sub studies constituted variant samples sizes from the total population. Newborn brain lobar volumes were similarly asymmetric in both sexes. Modest sex differences were observed in regional brain volumes. Newborn age predicted larger volumes of gray and white matter. The prevalence of incidental findings in brain MRI was 7.4 % and that of hemorrhages 6.9 %. Risk factors for hemorrhages were vaginal and vacuum-assisted deliveries. All the different types of PPD associated with the left newborn amygdalar volume at GW24 in a sex-specific manner. In males, PPD predicted smaller amygdalar volumes, while in females larger amygdalar volumes. Further analyses suggested a negative association between PSA and the right hippocampal volume in females. Newborn sex appears to be a significant factor moderating the relationship between PPD and newborn brain structures, suggesting sex-specific susceptibility to psychopathologies.Vastasyntyneen aivojen rakenteelliset ominaisuudet ja niiden yhteydet äidin raskaudenaikaiseen stressiin – tuloksia FinnBrain syntymäkohortin MRI-tutkimuksesta Aivojen muovautuvuus herkistää aivot kohdunsisäiselle ympäristölle ja lisää alttiutta muutoksille niiden kehityksessä. Muutoksille herkkiä rakenteita ovat mantelitumake ja aivoturso, jotka ovat tärkeitä sosioemotionaalisissa toiminnoissa. Aivorakenteiden normaalivaihtelun ymmärtäminen helpottaa poikkeavien kehityssuuntien havait¬semista, jollaisia voi kehittyä äidin raskaudenaikaiselle psykologiselle stressille (RPS) altistumisen jälkeen ja jotka voivat altistaa psykiatrisille häiriöille. Tutkimuksen tavoitteena oli 1) kuvata vastasyntyneiden aivorakenteiden tilavuuksien normaalivaihtelua suhteessa vastasyntyneen ominaisuuksiin; 2) kartoittaa vastasyntyneiden aivojen magneettikuvantamisen sattumalöydösten esiin¬tyvyys ja riskitekijät; 3) tutkia äidin RPS:n eri tyyppien ja ajoituksen yhteyttä vastasyntyneen mantelitumakkeen ja aivoturson tilavuuksiin, sekä vaikuttaako vastasyntyneen sukupuoli yhteyteen. Raskaana olevien äitien masennus-ja ahdistuneisuusoireita mitattiin raskausviikoilla (RV) 14, 24, 34 ja raskausspesifistä ahdistuneisuutta (RSA) RV:lla 24. Vastasyntyneet (n=175) kuvattiin magneetti¬kameralla kahden-viiden viikon ikäisinä syntymän jälkeen. Osatutkimuksien otoskoot koostuivat vaihtelevista osista koko tutkimuspopulaatiota. Vastasyntyneen aivolohkojen asymmetriassa ei ollut eroa sukupuolten välillä. Maltillisia sukupuolieroja havaittiin aivotilavuuksissa rajatuilla alueilla. Vasta¬syntyneen ikä ennusti suurempia harmaan ja valkean aineen tilavuuksia. Sattuma¬löydösten esiintyvyys aivokuvissa oli 7.4 % ja verenvuotojen 6.9 %. Verenvuotojen riskitekijät olivat alatie-ja imukuppisynnytykset. RPS:n eri tyypit olivat vahvimmin yhteydessä vastasyntyneiden vasemman mantelitumaketilavuuden kanssa RV:lla 24 sukupuoliriippuvaisella tavalla, mikä ilmeni pienempinä tilavuuksina poikavauvoilla ja suurempina tilavuuksina tyttövauvoilla. Lisäanalyysit viittasivat negatiiviseen yhteyteen RPS:n ja tyttöjen oikean aivotursotilavuuden välillä. Sukupuoli vaikuttaisi säätelevän RPS:n vaikutuksia vastasyntyneen aivoihin mahdollisesti lisäten alttiutta tietyllä sukupuolella toista useammin esiintyville psykiatrisille häiriöille.Vastasyntyneen aivojen rakenteelliset ominaisuudet ja niiden yhteydet äidin raskaudenaikaiseen stressiin – tuloksia FinnBrain syntymäkohortin MRI-tutkimuksesta Aivojen muovautuvuus herkistää aivot kohdunsisäiselle ympäristölle ja lisää alttiutta muutoksille niiden kehityksessä. Muutoksille herkkiä rakenteita ovat mantelitumake ja aivoturso, jotka ovat tärkeitä sosioemotionaalisissa toiminnoissa. Aivorakenteiden normaalivaihtelun ymmärtäminen helpottaa poikkeavien kehityssuuntien havait¬semista, jollaisia voi kehittyä äidin raskaudenaikaiselle psykologiselle stressille (RPS) altistumisen jälkeen ja jotka voivat altistaa psykiatrisille häiriöille. Tutkimuksen tavoitteena oli 1) kuvata vastasyntyneiden aivorakenteiden tilavuuksien normaalivaihtelua suhteessa vastasyntyneen ominaisuuksiin; 2) kartoittaa vastasyntyneiden aivojen magneettikuvantamisen sattumalöydösten esiin¬tyvyys ja riskitekijät; 3) tutkia äidin RPS:n eri tyyppien ja ajoituksen yhteyttä vastasyntyneen mantelitumakkeen ja aivoturson tilavuuksiin, sekä vaikuttaako vastasyntyneen sukupuoli yhteyteen. Raskaana olevien äitien masennus-ja ahdistuneisuusoireita mitattiin raskausviikoilla (RV) 14, 24, 34 ja raskausspesifistä ahdistuneisuutta (RSA) RV:lla 24. Vastasyntyneet (n=175) kuvattiin magneetti¬kameralla kahden-viiden viikon ikäisinä syntymän jälkeen. Osatutkimuksien otoskoot koostuivat vaihtelevista osista koko tutkimuspopulaatiota. Vastasyntyneen aivolohkojen asymmetriassa ei ollut eroa sukupuolten välillä. Maltillisia sukupuolieroja havaittiin aivotilavuuksissa rajatuilla alueilla. Vasta¬syntyneen ikä ennusti suurempia harmaan ja valkean aineen tilavuuksia. Sattuma¬löydösten esiintyvyys aivokuvissa oli 7.4 % ja verenvuotojen 6.9 %. Verenvuotojen riskitekijät olivat alatie-ja imukuppisynnytykset. RPS:n eri tyypit olivat vahvimmin yhteydessä vastasyntyneiden vasemman mantelitumaketilavuuden kanssa RV:lla 24 sukupuoliriippuvaisella tavalla, mikä ilmeni pienempinä tilavuuksina poikavauvoilla ja suurempina tilavuuksina tyttövauvoilla. Lisäanalyysit viittasivat negatiiviseen yhteyteen RPS:n ja tyttöjen oikean aivotursotilavuuden välillä. Sukupuoli vaikuttaisi säätelevän RPS:n vaikutuksia vastasyntyneen aivoihin mahdollisesti lisäten alttiutta tietyllä sukupuolella toista useammin esiintyville psykiatrisille häiriöille

    The Emergence of Human Consciousness: From Fetal to Neonatal Life

    Get PDF
    A simple definition of consciousness is sensory awareness of the body, the self, and the world. The fetus may be aware of the body, for example by perceiving pain. It reacts to touch, smell, and sound, and shows facial expressions responding to exter- nal stimuli. However, these reactions are probably preprogrammed and have a subcortical nonconscious origin. Furthermore, the fetus is almost continuously asleep and unconscious partially due to endog- enous sedation. Conversely, the newborn infant can be awake, exhibit sensory awareness, and process memorized mental representations. It is also able to differentiate between self and nonself touch, express emotions, and show signs of shared feelings. Yet, it is unreflective, present oriented, and makes little reference to concept of him/herself. Newborn infants display features characteristic of what may be referred to as basic consciousness and they still have to undergo considerable maturation to reach the level of adult consciousness. The preterm infant, ex utero, may open its eyes and establish minimal eye contact with its mother. It also shows avoidance reactions to harmful stimuli. However, the thalamocortical connections are not yet fully established, which is why it can only reach a minimal level of consciousness
    • …
    corecore