Cortical thickness changes after computerized working memory training in patients with mild cognitive impairment

Background: Adaptive computerized working memory (WM) training has shown favorable effects on cerebral cortical thickness as compared to non-adaptive training in healthy individuals. However, knowledge of WM training-related morphological changes in mild cognitive impairment (MCI) is limited. Objective: The primary objective of this double-blind randomized study was to investigate differences in longitudinal cortical thickness trajectories after adaptive and non-adaptive WM training in patients with MCI. We also investigated the genotype effects on cortical thickness trajectories after WM training combining these two training groups using longitudinal structural magnetic resonance imaging (MRI) analysis in Freesurfer. Method: Magnetic resonance imaging acquisition at 1.5 T were performed at baseline, and after four- and 16-weeks post training. A total of 81 individuals with MCI accepted invitations to undergo 25 training sessions over 5 weeks. Longitudinal Linear Mixed effect models investigated the effect of adaptive vs. non-adaptive WM training. The LME model was fitted for each location (vertex). On all statistical analyzes, a threshold was applied to yield an expected false discovery rate (FDR) of 5%. A secondary LME model investigated the effects of LMX1A and APOE-ε4 on cortical thickness trajectories after WM training. Results: A total of 62 participants/patients completed the 25 training sessions. Structural MRI showed no group difference between the two training regimes in our MCI patients, contrary to previous reports in cognitively healthy adults. No significant structural cortical changes were found after training, regardless of training type, across all participants. However, LMX1A-AA carriers displayed increased cortical thickness trajectories or lack of decrease in two regions post-training compared to those with LMX1A-GG/GA. No training or training type effects were found in relation to the APOE-ε4 gene variants. Conclusion: The MCI patients in our study, did not have improved cortical thickness after WM training with either adaptive or non-adaptive training. These results were derived from a heterogeneous population of MCI participants. The lack of changes in the cortical thickness trajectory after WM training may also suggest the lack of atrophy during this follow-up period. Our promising results of increased cortical thickness trajectory, suggesting greater neuroplasticity, in those with LMX1A-AA genotype need to be validated in future trials.publishedVersio

Association of the Big Five Personality Traits with Training Effectiveness, Sense of Presence, and Cybersickness in Virtual Reality

Virtual reality (VR) presents numerous opportunities for training skills and abilities through the technology’s capacity to simulate realistic training scenarios and environments. This can be seen in how newer research has emphasized how VR can be used for creating adaptable training scenarios. Nevertheless, a limited number of studies have examined how personality traits can influence the training effectiveness of participants within VR. To assess individual preferences in a virtual environment, the current study examines the associations of Big Five personality traits with training effectiveness from VR, as well as sense of presence and cybersickness. Our results show that traits of high agreeableness and low conscientiousness are predictors of training transferability in the VR environment in relation to the real world. Furthermore, the results also showed that trainees experiencing higher levels of cybersickness incurred worse training outcomes

Association of the Big Five Personality Traits with Training Effectiveness, Sense of Presence, and Cybersickness in Virtual Reality

Virtual reality (VR) presents numerous opportunities for training skills and abilities through the technology’s capacity to simulate realistic training scenarios and environments. This can be seen in how newer research has emphasized how VR can be used for creating adaptable training scenarios. Nevertheless, a limited number of studies have examined how personality traits can influence the training effectiveness of participants within VR. To assess individual preferences in a virtual environment, the current study examines the associations of Big Five personality traits with training effectiveness from VR, as well as sense of presence and cybersickness. Our results show that traits of high agreeableness and low conscientiousness are predictors of training transferability in the VR environment in relation to the real world. Furthermore, the results also showed that trainees experiencing higher levels of cybersickness incurred worse training outcomes

Comparative analysis of spatial ability in immersive and non-immersive virtual reality: the role of sense of presence, simulation sickness and cognitive load

This study investigates the effects of immersion on spatial ability in virtual reality (VR) and the influence of sense of presence, simulation sickness, and cognitive load. Participants performed a spatial ability task using a head-mounted display in an immersive or non-immersive VR condition. Contrary to expectations, immersive VR did not enhance spatial performance compared to non-immersive VR. Interestingly, cognitive load was positively associated with spatial ability in immersive VR but negatively associated with it in non-immersive VR. A higher sense of presence was associated with increased spatial ability for both conditions. Predictably, simulation sickness negatively impacted spatial ability in the more immersive condition. Sense of presence and simulation sickness correlated in the immersive condition but not in the non-immersive condition, indicating the importance of immersion as a covariate. These findings highlight a complex interplay of factors in immersive environments, challenging existing assumptions and providing insights for designing spatial environments in immersive and non-immersive virtual environments

Cerebral cortical dimensions in headache sufferers aged 50-66 years: a population-based imaging study in the Nord-Trondelag Health Study (HUNT-MRI)

Based on previous clinic-based magnetic resonance imaging studies showing regional differences in the cerebral cortex between those with and without headache, we hypothesized that headache sufferers have a decrease in volume, thickness, or surface area in the anterior cingulate cortex, prefrontal cortex, and insula. In addition, exploratory analyses on volume, thickness, and surface area across the cerebral cortical mantle were performed. A total of 1006 participants (aged 50-66 years) from the general population were selected to an imaging study of the head at 1.5 T (HUNT-MRI). Two hundred eighty-three individuals suffered from headache, 80 with migraine, and 87 with tension-type headache, whereas 309 individuals did not suffer from headache and were used as controls. T1-weighted 3D scans of the brain were analysed with voxel-based morphometry and FreeSurfer. The association between cortical volume, thickness, and surface area and questionnaire-based headache diagnoses was evaluated, taking into consideration evolution of headache and frequency of attacks. There were no significant differences in cortical volume, thickness, or surface area between headache sufferers and nonsufferers in the anterior cingulate cortex, prefrontal cortex, or insula. Similarly, the exploratory analyses across the cortical mantle demonstrated no significant differences in volume, thickness, or surface area between any of the headache groups and the nonsufferers. Maps of effect sizes showed small differences in the cortical measures between headache sufferers and nonsufferers. Hence, there are probably no or only very small differences in volume, thickness, or surface area of the cerebral cortex between those with and without headache in the general population

Impaired verbal learning is associated with larger caudate volumes in early onset schizophrenia spectrum disorders

Background Both brain structural abnormalities and neurocognitive impairments are core features of schizophrenia. We have previously reported enlargements in subcortical brain structure volumes and impairment of neurocognitive functioning as measured by the MATRICS Cognitive Consensus Battery (MCCB) in early onset schizophrenia spectrum disorders (EOS). To our knowledge, no previous study has investigated whether neurocognitive performance and volumetric abnormalities in subcortical brain structures are related in EOS. Methods Twenty-four patients with EOS and 33 healthy controls (HC) were included in the study. Relationships between the caudate nucleus, the lateral and fourth ventricles volumes and neurocognitive performance were investigated with multivariate linear regression analyses. Intracranial volume, age, antipsychotic medication and IQ were included as independent predictor-variables. Results The caudate volume was negatively correlated with verbal learning performance uniquely in the EOS group (r=-.454, p=.034). There were comparable positive correlations between the lateral ventricular volume and the processing speed, attention and reasoning and problem solving domains for both the EOS patients and the healthy controls. Antipsychotic medication was related to ventricular enlargements, but did not affect the brain structure-function relationship. Conclusion Enlargement of the caudate volume was related to poorer verbal learning performance in patients with EOS. Despite a 32% enlargement of the lateral ventricles in the EOS group, associations to processing speed, attention and reasoning and problem solving were similar for both the EOS and the HC groups

Visual-motor deficits relate to altered gray and white matter in young adults born preterm with very low birth weight

Individuals born preterm and at very low birth weight (birth weight ≤ 1500 g) are at an increased risk of perinatal brain injury and neurodevelopmental deficits over the long term. This study examined whether this clinical group has more problems with visual–motor integration, motor coordination, and visual perception compared to term-born controls, and related these findings to cortical surface area and thickness and white matter fractional anisotropy. Forty-seven preterm-born very low birth weight individuals and 56 term-born controls were examined at 18–22 years of age with a combined cognitive, morphometric MRI, and diffusion tensor imaging evaluation in Trondheim, Norway. Visual–motor skills were evaluated with the Beery–Buktenica Developmental Test of Visual–Motor Integration—V (VMI) copying test and its supplemental tests of motor coordination and visual perception. 3D T1-weighted MPRAGE images and diffusion tensor imaging were done at 1.5 T. Cortical reconstruction generated in FreeSurfer and voxelwise maps of fractional anisotropy calculated with Tract-Based Spatial Statistics were used to explore the relationship between MRI findings and cognitive results. Very low birth weight individuals had significantly lower scores on the copying and motor coordination tests compared with controls. In the very low birth weight group, VMI scores showed significant positive relationships with cortical surface area in widespread regions, with reductions of the superior temporal gyrus, insula, and medial occipital lobe in conjunction with the posterior ventral temporal lobe. Visual perception scores also showed positive relationships with cortical thickness in the very low birth weight group, primarily in the lateral occipito-temporo-parietal junction, the superior temporal gyrus, insula, and superior parietal regions. In the very low birth weight group, visual–motor performance correlated positively with fractional anisotropy especially in the corpus callosum, inferior fronto-occipital fasciculus bilaterally, and anterior thalamic radiation bilaterally, driven primarily by an increase in radial diffusivity. VMI scores did not demonstrate a significant relationship to cortical surface area, cortical thickness, or diffusion measures in the control group. Our results indicate that visual–motor integration problems persist into adulthood for very low birth weight individuals, which may be due to structural alterations in several specific gray–white matter networks. Visual–motor deficits appear related to reduced surface area of motor and visual cortices and disturbed connectivity in long association tracts containing visual and motor information. We conjecture that these outcomes may be due to perinatal brain injury or aberrant cortical development secondary to injury or due to very preterm birth

Allocentric representation in the human amygdala and ventral visual stream

The hippocampus and the entorhinal cortex are considered the main brain structures for allocentric representation of the external environment. Here, we show that the amygdala and the ventral visual stream are involved in allocentric representation. Thirty-one young men explored 35 virtual environments during high-resolution functional magnetic resonance imaging (fMRI) of the medial temporal lobe (MTL) and were subsequently tested on recall of the allocentric pattern of the objects in each environment—in other words, the positions of the objects relative to each other and to the outer perimeter. We find increasingly unique brain activation patterns associated with increasing allocentric accuracy in distinct neural populations in the perirhinal cortex, parahippocampal cortex, fusiform cortex, amygdala, hippocampus, and entorhinal cortex. In contrast to the traditional view of a hierarchical MTL network with the hippocampus at the top, we demonstrate, using recently developed graph analyses, a hierarchical allocentric MTL network without a main connector hub

Joint Analysis of Cortical Area and Thickness as a Replacement for the Analysis of the Volume of the Cerebral Cortex

Cortical surface area is an increasingly used brain morphology metric that is ontogenetically and phylogenetically distinct from cortical thickness and offers a separate index of neurodevelopment and disease. However, the various existing methods for assessment of cortical surface area from magnetic resonance images have never been systematically compared. We show that the surface area method implemented in FreeSurfer corresponds closely to the exact, but computationally more demanding, mass-conservative (pycnophylactic) method, provided that images are smoothed. Thus, the data produced by this method can be interpreted as estimates of cortical surface area, as opposed to areal expansion. In addition, focusing on the joint analysis of thickness and area, we compare an improved, analytic method for measuring cortical volume to a permutation-based nonparametric combination (NPC) method. We use the methods to analyze area, thickness and volume in young adults born preterm with very low birth weight, and show that NPC analysis is a more sensitive option for studying joint effects on area and thickness, giving equal weight to variation in both of these 2 morphological features

Trajectories of brain development in school-age children born preterm with very low birth weight

Preterm birth (gestational age < 37 weeks) with very low birth weight (VLBW, birth weight ≤ 1500 g) is associated with lifelong cognitive deficits, including in executive function, and persistent alterations in cortical and subcortical structures. However, it remains unclear whether “catch-up” growth is possible in the preterm/VLBW brain. Longitudinal structural MRI was conducted with children born preterm with VLBW (n = 41) and term-born peers participating in the Norwegian Mother and Child Cohort Study (MoBa) (n = 128) at two timepoints in early school age (mean ages 8.0 and 9.3 years). Images were analyzed with the FreeSurfer 5.3.0 longitudinal stream to assess differences in development of cortical thickness, surface area, and brain structure volumes, as well as associations with executive function development (NEPSY Statue and WMS-III Spatial Span scores) and perinatal health markers. No longitudinal group × time effects in cortical thickness, surface area, or subcortical volumes were seen, indicating similar brain growth trajectories in the groups over an approximately 16-month period in middle childhood. Higher IQ scores within the VLBW group were associated with greater surface area in left parieto-occipital and inferior temporal regions. Among VLBW preterm-born children, cortical surface area was smaller across the cortical mantle, and cortical thickness was thicker occipitally and frontally and thinner in lateral parietal and posterior temporal areas. Smaller volumes of corpus callosum, right globus pallidus, and right thalamus persisted in the VLBW group from timepoint 1 to 2. VLBW children had on average IQ 1 SD below term-born MoBa peers and significantly worse scores on WMS-III Spatial Span. Executive function scores did not show differential associations with morphometry between groups cross-sectionally or longitudinally. This study investigated divergent or “catch-up” growth in terms of cortical thickness, surface area, and volumes of subcortical gray matter structures and corpus callosum in children born preterm/VLBW and did not find group × time interactions. Greater surface area at mean age 9.3 in left parieto-occipital and inferior temporal cortex was associated with higher IQ in the VLBW group. These results suggest that preterm VLBW children may have altered cognitive networks, yet have structural growth trajectories that appear generally similar to their term-born peers in this early school age window.publishedVersion© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/