1,943 research outputs found

    The Transfer of Essential Polyunsaturated Fatty Acids From the Yolk to the Tissues During Avian Embryonic Development

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    The quality of the nutrients provided to the developing embryo are of primary importance to ensure the proper functional development of the various organs. The brain and retina require large amounts of certain long chain polyunsaturated fatty acids (PUFA) during embryonic and neonatal life. Docosahexaenoic acid (DHA) is a major component of neural tissues. However, the mechanism of delivery of this fatty acid to the brain still has to be established. The chick embryo was used as model system in the present study. The amounts and proportions of the major fatty acids in the lipids of the yolk, whole embryo, blood plasma, adipose tissue, heart and brain were determined throughout chick embryo development. The results revealed a series of unique features associated with various stages of DHA transport from the yolk to the target tissues. Firstly, DHA was preferentially transferred from the lipids of the yolk complex to the embryo. Secondly, since DHA was present in the initial yolk as a component of phospholipid, but was released into the embryonic circulation in the form of plasma triacylglycerol; it was proposed that DHA is translocated from phospholipid to triacylglycerol in the yolk sac membrane. It was also proposed that the high activity of lipoprotein lipase in the developing adipose tissue promotes the hydrolysis of DHA from plasma triacylglyceroi and the incorporation of this DHA into the triacylglycerol of the adipocytes. The pattern of change in the amount of DHA present in adipose triacylglycerol suggested that this fatty acid may be preferentially mobilised from this tissue to be released into the circulation as the free fatty acid. Experiments involving the incubation of adipose tissue pieces in vitro also provided evidence for the preferential mobilisation of DHA from the tissue. It was proposed that DHA in the form of plasma free fatty acid is readily taken up by the brain. The amount of DHA in brain phospholipid increased continuously during embryonic development but this increase occurred in parallel with the accretion of the other major fatty acids; i.e. there was no evidence for any preferential incorporation of DHA. Brain phospholipid classes were separated using an HPLC system and it was shown that phosphatidylethanolamine and phosphatidylserine were the major DHA-containing fractions in this tissue. Similar results were also obtained using duck embryo brain. On the basis of the findings of this study, a mechanism for the transfer of DHA from the yolk to brain is proposed; the key feature of this mechanism is the role of adipose tissue as a mediator of this process. The possible relevance of these findings to mammalian and human development is discussed

    Resurrecting Brinley Plots for a Novel Use: Meta-Analyses of Functional Brain Imaging Data in Older Adults

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    By plotting response times of young and older adults across a variety of tasks, Brinley spurred investigation and debate into the theory of general cognitive slowing. Though controversial, Brinley plots can assess between-task differences, the impact of increasing task demand, and the relationship between responses in two groups of subjects. Since a relationship exists between response times and the blood-oxygen level dependent (BOLD) signal of functional MRI (fMRI), Brinley's plotting method could be applied as a meta-analysis tool in fMRI studies of aging. Here, fledgling “Peiffer plots” are discussed for their potential impact on understanding general cognitive brain activity in aging. Preliminary results suggest that general cognitive slowing may be localized at the sensorimotor transformation in the precentral gyrus. Although this meta-analysis method is naturally used with imaging studies of aging, theoretically it may be applied to other study pairs (e.g., schizophrenic versus normal) or imaging datasets (e.g., PET)

    Prenatal diagnosis of proximal focal femoral deficiency: Literature review of prenatal sonographic findings

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    Proximal focal femoral deficiency (PFFD) is a rare musculoskeletal malformation that occurs in 0.11-0.2 per 10,000 live births. This congenital anomaly involves the pelvis and proximal femur with widely variable manifestations, from mild femoral shortening and hypoplasia to the absence of any functional femur and acetabular aplasia. Prenatal diagnosis of PFFD is still a challenge, but early recognition of this malformation could provide useful information to both parents and physicians concerning management and therapeutic planning. For this review, we analyzed all the cases of prenatally diagnosed PFFD that were reported in the literature from 1990 to 2014 and provide a description of the most common prenatal sonographic findings

    Semen quality of Italian local pig breeds

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    From 1996 to 1999 a conservation programme was carried out within the framework of EC contract "European gene banking project for the pig genetic resources" (Ollivier et al., 2001) in the Italian local pig breeds. The aims of the program included the primary characterization of the breeds, i.e. information on the organization in charge of the breed, breeding population numbers, breed description and qualifications, and field trials on productive and reproductive performances. In this context the "Semen Bank of Italian local pig breeds" was built. A total of 30,835 straws of four Italian local pig breeds (Cinta Senese, Casertana, Mora Romagnola and Nero Siciliano), collected from 42 sires, have been stored. In this work semen quality traits, lipid composition and freezability of the four Italian local pig breeds are reported

    High Dimensional Classification of Structural MRI Alzheimer’s Disease Data Based on Large Scale Regularization

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    In this work we use a large scale regularization approach based on penalized logistic regression to automatically classify structural MRI images (sMRI) according to cognitive status. Its performance is illustrated using sMRI data from the Alzheimer Disease Neuroimaging Initiative (ADNI) clinical database. We downloaded sMRI data from 98 subjects (49 cognitive normal and 49 patients) matched by age and sex from the ADNI website. Images were segmented and normalized using SPM8 and ANTS software packages. Classification was performed using GLMNET library implementation of penalized logistic regression based on coordinate-wise descent optimization techniques. To avoid optimistic estimates classification accuracy, sensitivity, and specificity were determined based on a combination of three-way split of the data with nested 10-fold cross-validations. One of the main features of this approach is that classification is performed based on large scale regularization. The methodology presented here was highly accurate, sensitive, and specific when automatically classifying sMRI images of cognitive normal subjects and Alzheimer disease (AD) patients. Higher levels of accuracy, sensitivity, and specificity were achieved for gray matter (GM) volume maps (85.7, 82.9, and 90%, respectively) compared to white matter volume maps (81.1, 80.6, and 82.5%, respectively). We found that GM and white matter tissues carry useful information for discriminating patients from cognitive normal subjects using sMRI brain data. Although we have demonstrated the efficacy of this voxel-wise classification method in discriminating cognitive normal subjects from AD patients, in principle it could be applied to any clinical population

    Development of the paternal brain in expectant fathers during early pregnancy

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    妊娠初期から発達する父親の「親性」脳の活動を確認 --育児に対する父親の脳と心の発達には個人差がある--. 京都大学プレスリリース. 2020-12-02.The human parenting brain network mediates caregiving behaviors. When exposed to the stimuli of their infants, compared with non-parents, both fathers and mothers exhibit distinct patterns of neural activation. As human males, relative to females, do not undergo robust physiological changes during pregnancy, when and how the paternal brain networks begin to form remains unclear. Thus, using functional MRI, we examined brain activation in response to infant-interaction videos in two groups, childless males and first-time expectant fathers during their partners’ early pregnancy before remarkable changes in their partners’ appearances commenced. Multivoxel pattern analysis revealed that expectant fathers’ left anterior insula and inferior frontal gyrus showed incipient changes in response to parenthood during early pregnancy. Furthermore, these changes were associated with several paternal traits, such as a negative image toward parenting. Such external factors might influence the paternal brain's development during early pregnancy

    Head Impact Exposure in Youth Football: Elementary School Ages 9–12 Years and the Effect of Practice Structure

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    Head impact exposure in youth football has not been well-documented, despite children under the age of 14 accounting for 70% of all football players in the United States. The objective of this study was to quantify the head impact exposure of youth football players, age 9–12, for all practices and games over the course of single season. A total of 50 players (age = 11.0 ± 1.1 years) on three teams were equipped with helmet mounted accelerometer arrays, which monitored each impact players sustained during practices and games. During the season, 11,978 impacts were recorded for this age group. Players averaged 240 ± 147 impacts for the season with linear and rotational 95th percentile magnitudes of 43 ± 7 g and 2034 ± 361 rad/s(2). Overall, practice and game sessions involved similar impact frequencies and magnitudes. One of the three teams however, had substantially fewer impacts per practice and lower 95th percentile magnitudes in practices due to a concerted effort to limit contact in practices. The same team also participated in fewer practices, further reducing the number of impacts each player experienced in practice. Head impact exposures in games showed no statistical difference. While the acceleration magnitudes among 9–12 year old players tended to be lower than those reported for older players, some recorded high magnitude impacts were similar to those seen at the high school and college level. Head impact exposure in youth football may be appreciably reduced by limiting contact in practices. Further research is required to assess whether such a reduction in head impact exposure will result in a reduction in concussion incidence

    A dual role for prediction error in associative learning

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    Confronted with a rich sensory environment, the brain must learn statistical regularities across sensory domains to construct causal models of the world. Here, we used functional magnetic resonance imaging and dynamic causal modeling (DCM) to furnish neurophysiological evidence that statistical associations are learnt, even when task-irrelevant. Subjects performed an audio-visual target-detection task while being exposed to distractor stimuli. Unknown to them, auditory distractors predicted the presence or absence of subsequent visual distractors. We modeled incidental learning of these associations using a Rescorla--Wagner (RW) model. Activity in primary visual cortex and putamen reflected learning-dependent surprise: these areas responded progressively more to unpredicted, and progressively less to predicted visual stimuli. Critically, this prediction-error response was observed even when the absence of a visual stimulus was surprising. We investigated the underlying mechanism by embedding the RW model into a DCM to show that auditory to visual connectivity changed significantly over time as a function of prediction error. Thus, consistent with predictive coding models of perception, associative learning is mediated by prediction-error dependent changes in connectivity. These results posit a dual role for prediction-error in encoding surprise and driving associative plasticity

    Exploring the Neural Basis of Avatar Identification in Pathological Internet Gamers and of Self-Reflection in Pathological Social Network Users

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    Background and aims Internet gaming addiction appears to be related to self-concept deficits and increased angular gyrus (AG)-related identification with one’s avatar. For increased social network use, a few existing studies suggest striatal-related positive social feedback as an underlying factor. However, whether an impaired self-concept and its reward-based compensation through the online presentation of an idealized version of the self are related to pathological social network use has not been investigated yet. We aimed to compare different stages of pathological Internet game and social network use to explore the neural basis of avatar and self-identification in addictive use. Methods About 19 pathological Internet gamers, 19 pathological social network users, and 19 healthy controls underwent functional magnetic resonance imaging while completing a self-retrieval paradigm, asking participants to rate the degree to which various self-concept-related characteristics described their self, ideal, and avatar. Self-concept-related characteristics were also psychometrically assessed. Results Psychometric testing indicated that pathological Internet gamers exhibited higher self-concept deficits generally, whereas pathological social network users exhibit deficits in emotion regulation only. We observed left AG hyperactivations in Internet gamers during avatar reflection and a correlation with symptom severity. Striatal hypoactivations during self-reflection (vs. ideal reflection) were observed in social network users and were correlated with symptom severity. Discussion and conclusion Internet gaming addiction appears to be linked to increased identification with one’s avatar, evidenced by high left AG activations in pathological Internet gamers. Addiction to social networks seems to be characterized by emotion regulation deficits, reflected by reduced striatal activation during self-reflection compared to during ideal reflection
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