Turner syndrome: Neuroimaging findings: Structural and functional

Department of Psychiatry, Research and Education Centre, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland.
Developmental Disabilities Research Reviews (Impact Factor: 2.75). 01/2009; 15(4):279-83. DOI: 10.1002/ddrr.87
Source: PubMed


Neuroimaging studies of Turner syndrome can advance our understanding of the X chromosome in brain development, and the modulatory influence of endocrine factors. There is increasing evidence from neuroimaging studies that TX individuals have significant differences in the anatomy, function, and metabolism of a number of brain regions; including the parietal lobe; cerebellum, amygdala, hippocampus; and basal ganglia; and perhaps differences in "connectivity" between frontal and parieto-occipital regions. Finally, there is preliminary evidence that genomic imprinting, sex hormones and growth hormone have significant modulatory effects on brain maturation in TS.

1 Follower
25 Reads
  • Source
    • "TS patients naturally lose one of their 2 normal X chromosomes; therefore, these individuals serve as a valuable human " knockout model " for studying how the X chromosome affects the human brain and cognition. A number of MRI studies have been conducted on TS patients, but they have primarily focused on structural brain anomalies or functional changes during specific cognitive tasks (Mullaney and Murphy 2009 "
    [Show abstract] [Hide abstract]
    ABSTRACT: Turner syndrome (TS), a disorder caused by the congenital absence of one of the 2 X chromosomes in female humans, provides a valuable human “knockout model” for studying the functions of the X chromosome. At present, it remains unknown whether and how the loss of the X chromosome influences intrinsic functional connectivity (FC), a fundamental phenotype of the human brain. To address this, we performed resting-state functional magnetic resonance imaging and specific cognitive assessments on 22 TS patients and 17 age-matched control girls. A novel data-driven approach was applied to identify the disrupted patterns of intrinsic FC in TS. The TS girls exhibited significantly reduced whole-brain FC strength within the bilateral postcentral gyrus/intraparietal sulcus, angular gyrus, and cuneus and the right cerebellum. Furthermore, a specific functional subnetwork was identified in which the intrinsic FC between nodes was mostly reduced in TS patients. Particularly, this subnetwork is composed of 3 functional modules, and the disruption of intrinsic FC within one of these modules was associated with the deficits of TS patients in math-related cognition. Taken together, these findings provide novel insight into how the X chromosome affects the human brain and cognition, and emphasize an important role of X-linked genes in intrinsic neural coupling.
    Full-text · Article · Oct 2015 · Cerebral Cortex
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new kind of light beam called the elliptical Hermite–Gaussian beam (EHGB) is introduced in this paper by using tensor method. The EHGB can be used to describe the generalized higher-order laser beams, such as hollow laser beams and the twisted Hermite–Gaussian beams conveniently. It includes the conventional Hermite–Gaussian beams as special cases. Using the generalized Collins integral, we derive the propagation formula of the EHGB passing through axially non-symmetrical paraxial optical systems. The EHGB allows us to treat the propagation and transformation of some complicated laser beams analytically. As an application example, we treat the elliptical flattened Gaussian beams by expressing it as superposition of a series of EHGBs by using polynomial expansion.
    Full-text · Article · Jun 2002 · Optics Communications
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: There is little debate that mammalian sexual differentiation starts from the perspective of two primary sexes that correspond to differential sex chromosomes (X versus Y) that lead to individuals with sex typical characteristics. Sex steroid hormones account for most aspects of brain sexual differentiation, however, a growing literature has raised important questions about the role of sex chromosomal genes separate from sex steroid actions. Several important model animals are being used to address these issues and, in particular, they are taking advantage of molecular genetic approaches using different mouse strains. The current review examines the cooperation of genetic and endocrine influences from the perspective of behavioral and morphological hypothalamic sexual differentiation, first in adults and then in development. In the final analysis, there is an ongoing need to account for the influence of hormones in the context of underlying genetic circumstances and null hormone conditions.
    Full-text · Article · Feb 2011 · Frontiers in Neuroendocrinology
Show more