Biomedical subjects

Suzanne E Welcome

Publications and source records attributed to Suzanne E Welcome.

5 recordsLinked to original sources

PubMed2004

Longitudinal mapping of cortical thickness and brain growth in normal children.

Recent advances in magnetic resonance imaging (MRI) technology now allow the tracing of developmental changes in the brains of children. We applied computer-matching algorithms and new techniques for measuring cortical thickness (in millimeters) to the structural MRI images of 45 children scanned twice (2 yr apart) between the ages 5 and 11. Changes in brain size were also assessed, showing local brain growth progressing at a rate of approximately 0.4-1.5 mm per year, most prominently in frontal and occipital regions. Estimated cortical thickness ranged from 1.5 mm in occipital regions to 5.5 mm in dorsomedial frontal cortex. Gray matter thinning coupled with cortical expansion was highly significant in right frontal and bilateral parieto-occipital regions. Significant thickening was restricted to left inferior frontal (Broca's area) and bilateral posterior perisylvian (Wernicke's area on the left) regions. In the left hemisphere, gray matter thickness was correlated with changing cognitive abilities. For the first time, developmental changes in gray matter thickness, brain size, and structure-function relationships have been traced within the same individuals studied longitudinally during a time of rapid cognitive development.

Adult↗

PubMed2004

Mapping brain size and cortical gray matter changes in elderly depression.

BACKGROUND: In elderly depression, volumetric brain imaging findings suggest abnormalities of the frontal lobe, particularly the orbitofrontal cortex, and the hippocampus. No studies to date have mapped cortical abnormalities over the entire brain surface in major depression. Here, we conducted detailed spatial analyses of brain size and gray matter within the cortical mantle in elderly patients with major depression. METHODS: High-resolution, three-dimensional, structural magnetic resonance imaging data and cortical pattern matching methods were used in 24 depressed elderly patients and 19 group-matched controls to measure local brain size and proportions of gray matter at thousands of homologous cortical surface locations. RESULTS: Prominent brain size reductions were observed in the depressed subjects in the orbitofrontal cortex bilaterally. Cortical gray matter measurements revealed significant gray matter increases in the orbitofrontal cortex, adjacent to focal trend level significant decreases of gray matter in the same region. Depressed patients also exhibited significant gray matter increases in parietal cortices, as well as the left temporal cortex. CONCLUSIONS: Complex cortical changes may contribute to the brain size reduction of the orbitofrontal cortex and to the gray matter abnormalities detected in orbitofrontal cortex and temporoparietal cortices, thereby providing a potentially new window into the pathophysiology of elderly depression.

Aged↗

PubMed2003

Cortical abnormalities in children and adolescents with attention-deficit hyperactivity disorder.

BACKGROUND: Results of structural brain imaging studies of patients with attention-deficit hyperactivity disorder have shown subtle reductions in total brain volume and in volumes of the right frontal lobe and caudate nucleus. Although various conventional volumetric and voxel-based methods of image analysis have been used in these studies, regional brain size and grey-matter abnormalities have not yet been mapped over the entire cortical surface in patients with this disorder. We aimed to map these features in patients with attention-deficit hyperactivity disorder. METHODS: We used high-resolution MRI and surface-based, computational image analytic techniques to map regional brain size and grey-matter abnormalities at the cortical surface in a group of 27 children and adolescents with attention-deficit hyperactivity disorder and 46 controls, who were group-matched by age and sex. FINDINGS: Abnormal morphology was noted in the frontal cortices of patients with attention-deficit hyperactivity disorder, with reduced regional brain size localised mainly to inferior portions of dorsal prefrontal cortices bilaterally. Brain size was also reduced in anterior temporal cortices bilaterally. Prominent increases in grey matter were recorded in large portions of the posterior temporal and inferior parietal cortices bilaterally. INTERPRETATION: The frontal, temporal, and parietal regions are heteromodal association cortices that constitute a distributed neural system, which subserves attention and behavioural inhibition. We have identified region-specific anatomical abnormalities in cortical components of attentional systems, which may help better account for the symptoms of attention-deficit hyperactivity disorder.

Adolescent↗

PubMed2003

Mapping cortical change across the human life span.

We used magnetic resonance imaging and cortical matching algorithms to map gray matter density (GMD) in 176 normal individuals ranging in age from 7 to 87 years. We found a significant, nonlinear decline in GMD with age, which was most rapid between 7 and about 60 years, over dorsal frontal and parietal association cortices on both the lateral and interhemispheric surfaces. Age effects were inverted in the left posterior temporal region, where GMD gain continued up to age 30 and then rapidly declined. The trajectory of maturational and aging effects varied considerably over the cortex. Visual, auditory and limbic cortices, which are known to myelinate early, showed a more linear pattern of aging than the frontal and parietal neocortices, which continue myelination into adulthood. Our findings also indicate that the posterior temporal cortices, primarily in the left hemisphere, which typically support language functions, have a more protracted course of maturation than any other cortical region.

Adolescent↗

PubMed2002

Mapping cortical gray matter asymmetry patterns in adolescents with heavy prenatal alcohol exposure.

Here we report on detailed three-dimensional quantitative maps of brain surface and gray matter density asymmetry patterns during normal adolescent development and show how these anatomical features of the brain are disrupted as a result of prenatal exposure to large quantities of alcohol. We studied two independent samples of normally developing children, adolescents, and young adults, totaling 83 subjects from two different research groups, and compared them to 21 individuals with heavy prenatal alcohol exposure. Surface-based image analysis techniques allowed us to match cortical anatomy across subjects and between hemispheres based on manually delineated sulcal landmarks. Quantitative maps of brain surface asymmetry reveal prominent peri-Sylvian hemispheric differences in which the superior temporal and inferior parietal cortices are shifted backward in the left relative to the right hemisphere in both normal and alcohol-exposed subjects. Cortical surface gray matter asymmetry, mapped here in adolescent populations, is most prominent in the posterior inferior temporal lobes (right greater than left), and this effect does not differ between groups of normally developing children, adolescents, or young adults. Alcohol-exposed individuals show a significant reduction in this asymmetry, whether studied with surface-based or more traditional volumetric region of interest analyses. This region of cortex, near the junction of Brodmann's areas 21, 22, and 37, primarily subserves language functions that are known to be impaired on average in the alcohol-exposed subjects. Our findings elucidate regional patterns of brain surface and gray matter asymmetry during normal development and may contribute to a more comprehensive understanding of the neural substrates of cognitive dysfunction after heavy prenatal alcohol exposure.

Adolescent↗