However, to our knowledge, detailed data concerning growth trajectories of various brain structures are lacking in healthy and VPT populations. An alternative possibility is that corpus callosum development in VPT individuals follows a different trajectory than in term individuals and that increased growth is a phenomenon particular to the VPT group.
The late growth of the corpus callosum could represent a plastic response to environmental demands or stimuli. As previously discussed, the VPT brain is likely to have reduced white matter connectivity and delayed or reduced myelinization. Whether such a process would be successful in allowing individuals to successfully transition to adulthood could be answered by follow-up of VPT individuals into their 20s and 30s.
Our results suggest that the late growth of the corpus callosum is associated with better adult neuropsychological performance, but adults born VPT continue to underperform on neuropsychological tests compared with their term-born peers, suggesting that late neuroplasticity may not completely compensate for early white matter damage.
We did not find a relationship between birth weight or degree of prematurity and corpus callosum growth. This is consistent with the findings by Nosarti et al, 6 who also found no relationship between corpus callosum size and birth weight or gestational age in a similar cohort at the age of 14 years.
We also found no association between the severity of perinatal white matter damage assessed by ultrasonography and adolescent growth of the corpus callosum. This may reflect the limited spatial resolution of ultrasonography, which makes it much less sensitive to diffuse white matter abnormalities than MRI and may, thus, underestimate the prevalence and severity of perinatal brain lesions.
White matter networks, including the corpus callosum, are necessary for distributed cognitive functions. Particularly, there are no such relationships in adolescence in the VPT group, whereas strong associations are found between performance IQ and corpus callosum size in adulthood. The pattern in the term group is more complex, with weak negative and positive correlations, predominantly with verbal IQ, at both ages. The different patterns of relationships between neuropsychological performance and corpus callosum growth in the VPT and term groups would be consistent with the plastic reorganization of brain structure and connectivity in VPT brains.
In addition, in the term group, we find that growth of the anterior segment is correlated with improvement in verbal fluency performance phonological and semantic. A similar pattern was not seen in the VPT group, again indicative of different patterns of associations between callosal growth and neuropsychological performance in the 2 groups. We demonstrate a correlation between adult performance IQ and corpus callosum growth in the VPT group.
Performance IQ on the Wechsler Abbreviated Scale of Intelligence is estimated from 2 scaled subtests: block design and matrix reasoning. The block design subtest is a timed test in which subjects are asked to reproduce patterns using bicolored cubes. It thus requires bimanual manipulation of objects near the visual midline and integration of sensory and motor information between hemispheres.
The anatomical localization that we demonstrate in the VPT group is also plausible in this regard. In their healthy sample, Barnea-Goraly et al 27 found white matter density to increase with age in the body of the corpus callosum, an area containing fibers linking hemispheric motor, sensory, and auditory processing areas.
Growth of anterior callosal connections should allow rapid communication between frontal and premotor cortices, 36 - 38 which would be essential to successful completion of the block design subtest. There were no correlations between midanterior corpus callosum growth and performance IQ in the VPT group.
This region of the corpus callosum is likely to carry the relatively sparse connections between left and right motor and sensory cortices. It seems possible that such connections mature earlier than connections between association areas, where late maturation may underlie maturation of cognition. This was a relatively large follow-up study, but it only included 2 time points.
Thus, we are unable to draw firm conclusions about growth trajectories in either the term or VPT group in adolescence. There was considerable dropout, particularly of the term group, between the ages of 15 and 19 years, and this may have introduced biases. The 2 subject groups were different in age, with the VPT group being slightly older at both assessment ages. The effect of this difference, however, would be to reduce the likelihood of finding a difference between the groups; in addition, we have attempted to correct for this in the statistical analyses.
The correlations between corpus callosum growth and neuropsychological variables have not been corrected for the effect of multiple testing, so it remains possible that some of them are chance findings. The pattern of the correlations suggests a genuine effect, but these results should perhaps be regarded as preliminary.
In summary, we have demonstrated a striking pattern of enhanced growth of the corpus callosum in VPT adolescents. This late maturation of brain structure may be of clinical significance eg, in deciding the timing of social and psychological interventions in VPT individuals. Author Contributions: Dr Allin had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Analysis and interpretation of data : Allin, Nosarti, Rifkin, and Murray. Drafting of the manuscript : Allin, Nosarti, Walshe, and Kalpakidou.
Critical revision of the manuscript for important intellectual content : Narberhaus, Frearson, Wyatt, Rifkin, and Murray. Statistical analysis : Narberhaus. Obtained funding : Murray. Administrative, technical, and material support : Nosarti, Walshe, and Wyatt. Study supervision : Allin, Rifkin, and Murray. Role of the Sponsor: The funding bodies had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Additional Contributions: We thank the preterm and term-born individuals who took part in this study. Arch Pediatr Adolesc Med. Coronavirus Resource Center. Description There are a group of disorders of the corpus callosum. These are birth defects in which there are problems with the connection between the left and the right side of the brain termed the corpus callosum.
This can occur by itself or in combination with other brain formation problems or syndromes. For many children, we cannot identify a single cause.
In these cases, there are likely multiple. These factors may include genetics, metabolic disorders, and structural interruptions. Diagnosis is made by viewing the brain. Children with disorders of the corpus callosum have a range of learning abilities and disabilities. Research about callosal disorders is ongoing.
But there are some common features of agenesis of the corpus callosum, although they vary from person to person. They can be broken down into four categories :. If the corpus callosum has not grown properly during fetal development, then it never will. There is no direct treatment for agenesis of the corpus callosum.
Symptoms will be identified and potentially treated, as they occur. Treatment is available for many of the medical conditions associated with agenesis of the corpus callosum, such as seizures. Therapy and counseling can also help to improve language and social skills. A doctor will be able to outline all of the treatment options available in individual cases. Neuroscientists recently studied that 'Aha! It is linked to reward centers and our evolutionary….
A new study shows that the brain's immune cells retain a memory of previous inflammation, which causes them to react differently to toxic brain….
Scientists have found a 'switch' that controls the fight-or-flight response in the brains of mice. The findings are relevant to humans living with…. New research examines what goes on in the brain when people perform a task in front of an audience versus when they are not being watched.
For many years, scientists have thought that brain cells in the hippocampus stop generating as we get older. The latest study concludes the reverse. Known causes include:. If there are no other brain development abnormalities, infants may have few, if any, significant difficulties in later life. Newborns with agenesis of the corpus callosum may not show symptoms right away, especially if they have no other associated conditions.
Common symptoms that may become more apparent during infancy and childhood include:. Your physician may suspect agenesis of the corpus callosum based on routine prenatal ultrasound exams performed during pregnancy. Tests may include:. Currently, there are no treatments to restore the corpus callosum to normal. The main course of treatment for agenesis of the corpus callosum is to manage any complications that may arise.
0コメント