Parietal Lobe Structures Research Articles

Abnormal Structure and Function of Parietal Lobe in Individuals With Attention Deficit Hyperactivity Disorder (ADHD): A Systematic Review Study.

Abnormal brain structure and function have been reported in individuals with attention deficit hyperactivity disorder (ADHD). This study investigated the parietal lobe structure and function alteration in individuals with ADHD. In this systematic review, we searched English papers in accordance with the PRISMA (the preferred reporting items for systematic reviews and meta-analyses) approach. Studies were published between January 2010 and May 2021. Our search was conducted in two parts. Our first search was in July 2020, and our final search was in June 2021. A literature search identified 20 empirical experiments. Functional magnetic resonance imaging (MRI) studies generally reported low activity and poor connectivity; structural MRI studies reported less gray matter in this lobe, and an echo study reported atrophy. In addition, electroencephalographic studies reported less connectivity of the parietal lobes in ADHD. Furthermore, the transcranial direct current stimulation intervention has shown that activation of this lobe improves attention and executive functions in children with ADHD. Finally, a deep transcranial magnetic stimulation study has demonstrated that activation of this lobe improves working memory. Functional and structural alteration of the parietal cortex has been reported in ADHD, which has a causal relationship with cognitive impairments. In sum, all included studies reported abnormal structure, function, or connectivity of the parietal lobe or improvement of cognitive functions with parietal lobe stimulation.

Relationship between visuoperceptual functions and parietal structural abnormalities in temporal lobe epilepsy.

Progressive gray matter volume reductions beyond the epileptogenic area has been described in temporal lobe epilepsy. There is less evidence regarding correlations between gray and white matter volume changepres and multi-domain cognitive performance in this setting. We aimed to investigate correlations between volume changes in parietal structures and visuospatial performance in temporal lobe epilepsy patients. we performed a cross-sectional study comparing global and regional brain volume data from 34 temporal lobe epilepsy patients and 30 healthy controls. 3D T1-weighted sequences were obtained on a 3.0 T magnet, and data were analyzed using age and sex-adjusted linear regression models. Global and regional brain volumes and cortical thickness in patients were correlated with standardized visual memory, visuoperceptual, visuospatial, and visuoconstructive parameters obtained in a per-protocol neuropsychological assessment. temporal lobe epilepsy patients had smaller volume fractions of the deep gray matter structures, putamen and nucleus accumbens, and larger cerebrospinal fluid volume fraction than controls. Correlations were found between: 1) visual memory and precuneus and inferior parietal cortical thickness; 2) visuoperceptual performance and precuneus and supramarginal white matter volumes; 3) visuospatial skills and precuneus, postcentral, and inferior and superior parietal white matter volumes; 4) visuoconstructive performance and inferior parietal white matter volume. Brain volume loss is widespread in temporal lobe epilepsy. Volumetric reductions in parietal lobe structures were associated with visuoperceptual cognitive performance.

Elevated lipids are associated with reduced regional brain structure in youth with bipolar disorder.

Abnormal blood lipid levels are common in bipolar disorder (BD) and correlate with mood symptoms and neurocognition. However, studies have not examined the lipid-brain structure association in BD or youth. This study examined low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), triglycerides, and total cholesterol (TC) levels in relation to brain structure utilizing T1-weighted images, among participants ages 13-20 with BD (n=55) and healthy controls (HC; n=47). General linear models investigated group differences in the association of lipids with anterior cingulate cortex (ACC), hippocampus, and inferior parietal lobe structure, controlling for age, sex, body mass index, and intracranial volume. For significant associations, post hoc within-group analyses were undertaken. Exploratory vertex-wise analyses further investigated group differences in the lipid-brain structure association. There were significant group differences in the association of LDL-C (β=-0.29 p=0.001), and TC (β=-0.21 p=0.016), with hippocampal volume, and triglycerides with ACC volume (β=-0.25 p=0.01) and area (β=-0.26 p=0.004). Elevated lipids were associated with smaller brain structure to a significantly greater extent in BD vs HC. Post hoc analyses revealed that elevated LDL-C (β=-0.27 p=0.007) and reduced HDL-C (β=0.24 p=0.01) were associated with smaller hippocampal volume in the BD group. Exclusion of BD second-generation antipsychotic users did not alter these results. Vertex-wise analyses further showed that elevated lipids were associated with smaller brain structure to a significantly greater extent in BD vs HC, across the cortex. Elevated lipids are associated with smaller brain structure in BD. Research evaluating lipid-brain structure associations prospectively and whether lipid optimization has salutary effects on brain structure is necessary.

S162. MULTI-MODAL ANALYSIS OF THE EFFECTS OF URBAN UPBRINGING ON BRAIN STRUCTURE: THE FOR2107 COHORT

BackgroundUrbanicity has been identified as a major environmental risk factor for schizophrenia as well as other major mental disorders. While initial structural brain imaging studies have pointed to medial and lateral prefrontal cortices being associated with urbanicity during childhood and adolescence, most of these studies have been limited to smaller samples and single analysis methods. The present study used the large ongoing FOR2107 multi-centre study cohort (Kircher et al., 2018) to analyse associations of urban upbringing.MethodsWe analysed a data set of n=625 healthy subjects without a current or previous psychiatric disorder (ascertained through SCID-I interviews), who underwent 3 Tesla MRI scanning, obtaining a high-resolution T1-weighted MPRAGE and a DTI scan. We subsequently also analysed a pilot samples of 42 patients with DSM-IV schizophrenia. We obtained data on urban upbringing (Lederbogen score; Lederbogen et al., 2014) for the first 15 years of life, as well as number of moves. T1 data were pre-processed using CAT12 software, using surface-based morphometric analysis of cortical thickness (CT) with 15 mm smoothing. DTI data were analysed using the TBSS approach in FSL software. We used general linear models to calculate multiple regression analyses using both linear and quadratic (non-linear) associations with urbanicity scores, followed up by analyses of correlations with number of relocations (as unspecific stress factors). Analyses of CT and DTI were each corrected for multiple comparisons using FWE.ResultsIn the healthy subject cohort we identified a significant negative linear correlation (p=0.042 FWE cluster-level; p=0.014 peak-level) between urban upbringing scores and cortical thickness (CT) in a right precuneus / posterior cingulate cluster (x/y/z=35;-88;-15), while non-linear analysis identified an additional trend in the left occipital cortex (p=0.073 FWE cluster-level; -17;-100;15). We did not find significant effects for number of relocations/moves. DTI analysis of fractional anisotropy (FA) showed a significant association (all p<0.05 FWE-corrected) for the uncinate fasciculus and inferior fronto-occipital fasciculus. CT analysis in the schizophrenia pilot cohort showed similar effects, but in a more dorsal precuneus cluster (6;-56;45) only at uncorrected levels.DiscussionOur study identified structural variation in cortical thickness in the precuneus / posterior cingulate cortex of healthy subjects, regions linked to abnormal DMN activity and stress. While the trend-level finding in schizophrenia patients was located in an adjacent cluster, our findings can be interpreted as these medial parietal lobe structure mediating this particular risk factor. Our findings argue against a more wide-spread non-specific effect, as seen in some earlier smaller studies, but points to distinct neuronal network as mediators of this particular risk. The identified brain regions are linked to stress. Unlike previous prefrontal findings, they suggest a new link to the precuneus, a central hub of the default mode network. Given that these effects were observed in clinically healthy subjects, our findings also carry implications for a better understanding of the macro-environment in adolescence.

Neuroinflammation and brain atrophy in former NFL players: An in vivo multimodal imaging pilot study

There are growing concerns about potential delayed, neuropsychiatric consequences (e.g, cognitive decline, mood or anxiety disorders) of sports-related traumatic brain injury (TBI). Autopsy studies of brains from a limited number of former athletes have described characteristic, pathologic changes of chronic traumatic encephalopathy (CTE) leading to questions about the relationship between these pathologic and the neuropsychiatric disturbances seen in former athletes. Research in this area will depend on in vivo methods that characterize molecular changes in the brain, linking CTE and other sports-related pathologies with delayed emergence of neuropsychiatric symptoms. In this pilot project we studied former National Football League (NFL) players using new neuroimaging techniques and clinical measures of cognitive functioning. We hypothesized that former NFL players would show molecular and structural changes in medial temporal and parietal lobe structures as well as specific cognitive deficits, namely those of verbal learning and memory. We observed a significant increase in binding of [11C]DPA-713 to the translocator protein (TSPO), a marker of brain injury and repair, in several brain regions, such as the supramarginal gyrus and right amygdala, in 9 former NFL players compared to 9 age-matched, healthy controls. We also observed significant atrophy of the right hippocampus. Finally, we report that these same former players had varied performance on a test of verbal learning and memory, suggesting that these molecular and pathologic changes may play a role in cognitive decline. These results suggest that localized brain injury and repair, indicated by increased [11C]DPA-713 binding to TSPO, may be linked to history of NFL play. [11C]DPA-713 PET is a promising new tool that can be used in future study design to examine further the relationship between TSPO expression in brain injury and repair, selective regional brain atrophy, and the potential link to deficits in verbal learning and memory after NFL play.

Sex Differences in Parietal Lobe Structure and Development

Structural magnetic resonance imaging studies provide evidence for sex differences in the human brain. Differences in surface area and the proportion of gray to white matter volume are observed, in particular in the parietal lobe. To our knowledge, no studies have examined sex differences in parietal lobe structure in younger populations or in the context of development. The present study evaluated sex differences in the structure of the parietal lobe in children aged 7 to 17 years. In addition, by adding a cohort of previously studied adults aged 18 to 50 years, sex differences in parietal lobe structure were examined across the age span of 7 to 50 years. Compared with the adult sample, the younger sample showed that the ratio of parietal lobe cortex to white matter was greater in female brains, but no sex differences in surface area. When examining the effects of age, surface area exhibited a significant sex-age interaction. In male brains, there was essentially no decrease in surfaces area over time, whereas in female brains, there was a significant decrease in surface area over time. These findings support the notion of structural sex differences in the parietal lobe, not only in the context of cross-sectional assessment but also in terms of differences in developmental trajectories.

Perceptual illusions provide clues to excitatory–inhibitory balance in migraine neocortex

Perceptual illusions provide clues to excitatory–inhibitory balance in migraine neocortex

Sex differences in parietal lobe morphology: Relationship to mental rotation performance

Structural magnetic resonance imaging (MRI) studies of the human brain have reported evidence for sexual dimorphism. In addition to sex differences in overall cerebral volume, differences in the proportion of gray matter (GM) to white matter (WM) volume have been observed, particularly in the parietal lobe. To our knowledge there have been no studies examining the relationship between the sex differences in parietal lobe structure and function. The parietal lobe is thought to be involved in spatial ability, and particularly involved in mental rotation. The purpose of this study is to examine whether sex differences in parietal lobe structure are present, and if present to relate these differences to performance on the mental rotations test (MRT). We found that women had proportionately greater gray matter volume in the parietal lobe compared to men, and this morphologic difference was disadvantageous for women in terms of performance on the MRT. In contrast, we found that men compared to women had proportionately greater parietal lobe surface area, and this morphologic difference was associated with a performance advantage for men on mental rotation. These findings support the possibility that the sexual dimorphism in the structure of the parietal lobe is a neurobiological substrate for the sex difference in performance on the mental rotations test.

Effects of Semantic Impairment on Language Processing in Semantic Dementia

Semantic dementia is a neurodegenerative disease characterized by progressive loss of conceptual and lexical knowledge. Cortical atrophy remains relatively isolated to anterior and inferior portions of the temporal lobe early in semantic dementia, later affecting more extensive regions of temporal cortex. Throughout much of the disease course, frontal and parietal lobe structures remain relatively intact. This distribution of cortical damage produces a unique language profile. Patients with semantic dementia typically experience profound deficits in language comprehension and production in the context of relatively well-preserved functioning in domains such as phonology, executive function, visuospatial processing, and speech perception. We discuss the effects of semantic impairment on language processing in semantic dementia within the context of an interactive theory of semantic cognition that assumes the active coordination of modality-neutral and modality-specific components. Finally, we argue the need for an etiology-specific language intervention for this population.

Gaze palsy and visual hemineglect in acute hemisphere lesions

Forty-eight acute stroke patients with CT lesions were studied for horizontal gaze paresis (GP) and visual hemineglect (VN). In 24 GP-patients a clear relationship between stroke extent and GP was found, not revealing, however, specific neural substrates. Visual hemineglect in 12 cases was closely related with (right) inferior parietal lobe structures. Eye movements and VN are intertwined with separable underlying mechanisms.