Abnormalities in gray matter microstructure in young adults with 22q11.2 deletion syndrome

Abstract

Background22q11.2 Deletion Syndrome (22q11DS) is a genetic, neurodevelopmental disorder characterized by a chromosomal deletion and a distinct cognitive profile. Although abnormalities in the macrostructure of the cortex have been identified in individuals with 22q11DS, it is not known if there are additional microstructural changes in gray matter regions in this syndrome, and/or if such microstructural changes are associated with cognitive functioning.MethodsThis study employed a novel diffusion MRI measure, the Heterogeneity of Fractional Anisotropy (HFA), to examine variability in the microstructural organization of the cortex in healthy young adults (N = 30) and those with 22q11DS (N = 56). Diffusion MRI, structural MRI, clinical and cognitive data were acquired.ResultsCompared to controls, individuals with 22q11DS evinced increased HFA in cortical association (p = .003, d = 0.86) and paralimbic (p < .0001, d = 1.2) brain areas, whereas no significant differences were found between the two groups in primary cortical brain areas. Additionally, increased HFA of the right paralimbic area was associated with poorer performance on tests of response inhibition, i.e., the Stroop Test (rho = −0.37 p = .005) and the Gordon Diagnostic System Vigilance Commission (rho = −0.41 p = .002) in the 22q11DS group. No significant correlations were found between HFA and cognitive abilities in the healthy control group.ConclusionsThese findings suggest that cortical microstructural disorganization may be a neural correlate of response inhibition in individuals with 22q11DS. Given that the migration pattern of neural crest cells is disrupted at the time of early brain development in 22q11DS, we hypothesize that these neural alterations may be neurodevelopmental in origin, and reflect cortical dysfunction associated with cognitive deficits.

Mammillothalamic Disconnection Alters Hippocampocortical Oscillatory Activity and Microstructure: Implications for Diencephalic Amnesia

“…Inspection of the generated FA and MD maps revealed asymmetric noise related to the acquisition procedure. To remedy this, mean hemispheric maps were produced (e.g., Kikinis et al, 2019). This approach was deemed appropriate due to the following: (1) the bilateral lesioning of the MTT (Vann and Albasser, 2009); and (2) the assumption that lesion-induced and training-induced changes would not show laterality (e.g., Sagi et al, 2012).…”

Mammillothalamic disconnection alters hippocampo-cortical oscillatory activity and microstructure: Implications for diencephalic amnesia

“…To remedy this, mean hemispheric maps were produced (e.g. Kikinis et al, 2019). This approach was deemed appropriate due to, a) the bilateral lesioning of the ipsilaterally-projecting mammillothalamic tract (Vann & Albasser, 2009) symmetrical to the midline and, b) the assumption that lesion-induced and training-induced changes would not show laterality (e.g.…”

Fractional Anisotropy of Thalamic Nuclei Is Associated With Verticality Misperception After Extra-Thalamic Stroke

“…DTI studies using fractional anisotropy (FA) can quantify microstructural characteristics of brain tissue, reflecting axonal properties in the white matter and cytoarchitecture in the gray matter (11, 12). The FA of the thalamic nuclei has been investigated in several studies because it is composed of both gray matter and myelinated fibers (9, 13).…”