Biology subjects

Nerland, S.

Publications and source records attributed to Nerland, S..

5 recordsLinked to original sources

bioRxiv2025

Thalamic Nuclei Volumes Across Psychiatric and Neurological Disorders: A Multi-Site Magnetic Resonance Imaging Study

The human thalamus is an integrative hub for multiple cortical and subcortical circuits involved in sensory processing and higher cognitive functions. Thalamic volume differences have been reported across multiple psychiatric and neurological disorders, but previous studies have typically relied on small samples, focused on one or a limited number of disorders, or investigated the thalamus as a whole without considering its functional subdivisions. In this multi-site study, we compared thalamic nuclei volumes across mild cognitive impairment (MCI), dementia (DEM), major depressive disorder, schizophrenia spectrum disorder (SCZ), clinical high risk for schizophrenia, bipolar spectrum disorder, autism spectrum disorder, attention-deficit/hyperactivity disorder, Parkinsons disease, multiple sclerosis (MS), and healthy controls (N > 8 000). Using structural MRI, we segmented 25 bilateral thalamic nuclei, corresponding to six anatomical groups. Linear models revealed that anterior, medial and lateral regions of the thalamus were significantly smaller in several conditions, with largest effects observed for MCI, DEM, SCZ and MS. In contrast, the ventral and intralaminar groups were relatively normal. This pattern of effects largely corresponds to the canonical functional subdivision of the thalamus into higher-order and sensory regions. At the level of individual nuclei, the clinical conditions were associated with distinct patterns of alterations, while left and right lateral geniculate nuclei were implicated in six of the disorders, suggesting a possible relation with circadian and sleep disturbances. Together, the results highlight a role for the higher-order thalamus in common brain disorders and a differential involvement at the nuclei level, refining our understanding of thalamic pathology across common brain disorders.

neuroscience↗

bioRxiv2024

The within-subject stability of cortical thickness, surface area, and brain volumes across one year

T1-weighted (T1w) imaging is widely used to examine brain structure based on image-derived phenotypes (IDPs) such as cortical thickness, surface area, and brain volumes. The reliability of these IDPs has been extensively explored, mainly focusing on the inter-subject variations, whereas the stability of the within-subject variations has often been overlooked. Additionally, how environmental factors such as time of day and daylight hours impact the structural brain is poorly understood. Therefore, we aimed to address the stability of T1w-derived phenotypes and explore the effecting factors including processing stream, brain region size, time of day, daylight hours, and head movement. Three subjects in their late 20s, early 30s, and early 40s were scanned repeatedly on the same scanner over one year, from which a densely sampled dataset was acquired with 38, 40, and 25 sessions for subjects 1, 2, and 3, respectively. The temporal stability was evaluated using within-subject percentage change and coefficients of variation (CV). The effects of time of day and daylight hours were assessed by fitting general linear models, aggregating the effect size with meta-analysis, and equivalent analysis. The longitudinal processing stream generates more stable results than the cross-sectional processing stream, hence the following results are all derived from the longitudinal processing stream. First and foremost, most IDPs demonstrated percentage changes within 5% and CVs within 2% for almost all brain regions, indicating high stability. Interestingly, we found that the brain region size negatively correlates with the CVs. Specifically, several small brain regions, including the temporal pole, frontal pole, pericalcarine, entorhinal cortex, and accumbens area, showed low stability. In addition, cortical thickness change was strongly and positively correlated with that of volume change while being negatively correlated with change in surface area, illustrating their distinct roles in brain anatomy. Moreover, the time of day could be ignored when evaluating the total surface area and total cortical brain volume but not the average cortical thickness and total subcortical brain volume. Furthermore, daylight hours could be left out when evaluating IDPs since there was no appreciable effect of daylight hours on the IDPs stability. Lastly, apparent head motion causes cortical thickness and volume underestimated and surface area overestimated.

neuroscience↗

bioRxiv2022

A new cortical parcellation based on systematic review of primate anatomical tracing studies on corticostriatal projections

Corticostriatal projections form the input level of a circuitry that connects the cerebral cortex, basal ganglia, and thalamus. Three distinct, functional subcircuits exist according to the tripartite model: Sensorimotor cortices projecting mainly to the dorsolateral striatum; associative cortices projecting to the dorsomedial striatum and limbic cortices projecting to the ventral striatum. However, there is to date no atlas that allows researchers to label cortical projection areas belonging to each of these subcircuits separately. To address this research gap, the aim of this study was threefold: First, to systematically review anatomical tracing studies that focused on corticostriatal projections in non-human primates, and to classify their findings according to the tripartite model. Second, to develop an atlas of the human cerebral cortex based on this classification. Third, to test the hypothesis that labels in this atlas show structural connectivity with specific striatal subregions in humans using diffusion-based tractography in a sample of 24 healthy participants. In total, 98 studies met the inclusion criteria for our systematic review. Information about projections from the cortex to the striatum was systematically extracted by Brodmann area, and cortical areas were classified by their dominant efferent projections. Taking known homological and functional similarities and differences between non-human primate and human cortical regions into account, a new human corticostriatal projection (CSP) atlas was developed. Using human diffusion-based tractography analyses, we found that the limbic and sensorimotor atlas labels showed preferential structural connectivity with the ventral and dorsolateral striatum, respectively. However, the pattern of structural connectivity for the associative label showed the greatest degree of overlap with other labels. We provide this new atlas as a freely available tool for neuroimaging studies, where it allows for the first-time delineation of anatomically informed regions-of-interest to study functional subcircuits within the corticostriatal circuitry. This tool will enable specific investigations of subcircuits involved in the pathogenesis of neuropsychiatric illness such as schizophrenia and bipolar disorders. Highlights- Systematic review of anatomical projections from the cerebral cortex to the striatum in non-human primates. - Development of a novel cortical atlas for use in neuroimaging studies focusing on the corticostriatal brain circuitry. - Tractography in human diffusion-weighted imaging data to test if associative, limbic, and sensorimotor cortical atlas labels show preferential connectivity to regions within the striatum.

neuroscience↗

bioRxiv2022

A comparison of intracranial volume estimation methods and their cross-sectional and longitudinal associations with age

Intracranial volume (ICV) is frequently used in volumetric brain magnetic resonance imaging (MRI) studies, both as an adjustment factor for head size and as a variable of interest. Associations with age have been reported in both longitudinal and cross-sectional studies, but results have varied, potentially due to differences in ICV estimation methods. Here, we compared five commonly used ICV estimation methods and their cross-sectional and longitudinal associations with age. T1-weighted cross-sectional MRI data was included for 651 healthy individuals recruited through the NORMENT Centre (mean age = 46.1 years, range = 12.0-85.8 years) and 2,410 healthy individuals recruited through the UK Biobank study (UKB, mean age = 63.2 years, range = 47.0-80.3 years), where follow-up data was also available with a mean follow-up interval of 2.3 years. ICV was estimated with FreeSurfer (eTIV and sbTIV), SPM12, CAT12, and FSL. We assessed Pearson correlations, performed Bland-Altman analysis, and tested the explained variance of sex, height, body weight, and age on pairwise differences between ICV estimation methods. We fitted regression models to test linear and non-linear cross-sectional associations between age and ICV. For the UKB dataset, we further assessed longitudinal ICV change using linear mixed-effects (LME) models. We found overall high correlations across ICV estimation method, with the lowest correlations between FSL and eTIV (r=0.87) and between FSL and CAT12 (r=0.89). Widespread proportional bias was found in the Bland-Altman analyses, i.e., agreement between methods varying as a function of head size. Body weight, age, and sex explained the most variance in the differences between ICV estimation methods, indicating possible confounding by these variables for some estimation methods. In the NORMENT dataset, cross-sectional associations with age were found only for FSL and SPM12, indicating a positive association. For the UKB dataset, we observed negative cross-sectional associations with age for all ICV estimation methods. Longitudinal associations with age were found for all ICV estimation methods, with estimated annual percentage change ranging from -0.291 % to -0.416 % across the sampled age range. This convergence of longitudinal results across ICV estimation methods, in the largest dataset to date, offers strong evidence for age-related ICV reductions in mid- to late adulthood. HighlightsO_LICorrelations between the five assessed estimation methods were very high (r>0.90) with the exception of FSL and eTIV (r=0.87), and FSL and CAT12 (r=0.89). C_LIO_LIExplained variance of estimated ICV differences by body weight, age, and sex indicate possible confounding for some ICV estimation methods. C_LIO_LIPositive cross-sectional associations with age, from adolescence to old age, were observed for the SPM12 and FSL estimation methods in one dataset. C_LIO_LIIn the other dataset, negative cross-sectional associations with age, from mid- to late adulthood, were found for all estimation methods. C_LIO_LILongitudinal ICV changes were observed for all estimation methods, indicating an annual percentage ICV reduction of -0.29 % to -0.42 % in mid- to late adulthood. C_LI

neuroscience↗

bioRxiv2019

Trajectories of brain volume change over 13 years in chronic schizophrenia.

ImportanceSchizophrenia is a leading cause of disability worldwide, with an illness course that putatively deteriorates over time. Whether the notion of a progressive brain disease holds in its chronic stage is debated. ObjectiveTo investigate brain volume change and the impact of iatrogenic factors in chronic schizophrenia patients (duration of illness at baseline 16.17 {+/-} 8.14 years) and controls over 13 years. DesignParticipants were recruited as part of the Human Brain Informatics study. Data acquisition took place between 1999 and 2018, including baseline, 5- and 13-years follow-up. SettingNaturalistic longitudinal case-control study. ParticipantsThe sample consisted of 143 participants, of whom 64 were patients with chronic schizophrenia (20% female, mean age at baseline 40.5 {+/-} 7.7 years) and 79 healthy controls (37% female, mean age at baseline 42.8 {+/-} 8.4 years). T1-weighted structural imaging and information about medication use were obtained at each time point. ExposureAntipsychotic medication and other prescribed drugs. Main Outcome(s) and Measure(s)Individual total and tissue-specific brain volumes, as well as two-time point percentage brain and ventricle volume change. ResultsPatients had lower total brain volume at baseline. Yet, trajectories in total brain volume and gray matter volume loss as well as ventricular enlargement did not differ relative to controls. White matter volume was similar between groups at baseline and 5-year but diverged between 5-year and 13-year follow-up, with accelerated loss in patients. While antipsychotic exposure did not show an association with brain volume loss over time, higher medication load was associated with lower brain volume across time points. Patients on second-generation antipsychotics alone showed lowest total brain volume, only after accounting for add-on drug use. Conclusion and RelevanceWe found limited evidence for progressive brain volume loss in chronic schizophrenia, beyond normal aging. Stable differences in patient brain volumes relative to controls may primarily occur during the first years of illness. All prescribed drugs need to be considered when examining the impact of antipsychotic medication on brain structure. Key PointsO_ST_ABSQuestionC_ST_ABSIs chronic schizophrenia associated with progressive brain volume loss beyond normal aging? FindingsWhile brain volume was lower at baseline, patient trajectories of brain volume change over a 13-year follow-up period differed little from healthy individuals. Small effects indicated greater white matter volume loss in patients during the late phase of follow-up. Stable differences in patient brain volumes seem explicable by antipsychotic medication class and respective add-on drugs. MeaningWe found limited evidence of progressive brain volume loss, beyond normal aging, in chronic schizophrenia over 13 years.

neuroscience↗