Structural Magnetic Resonance Imaging Studies Research Articles

Brain-based correlates of depression and traumatic brain injury: a systematic review of structural and functional magnetic resonance imaging studies

IntroductionDepression is prevalent after traumatic brain injury (TBI). However, there is a lack of understanding of the brain-based correlates of depression post-TBI. This systematic review aimed to synthesize findings of structural and functional magnetic resonance imaging (MRI) studies to identify consistently reported neural correlates of depression post-TBI.MethodsA search for relevant published studies was conducted through OVID (MEDLINE, APA PsycINFO, and Embase), with an end date of August 3rd, 2023. Fourteen published studies were included in this review.ResultsTBI patients with depression exhibited distinct changes in diffusion- based white matter fractional anisotropy, with the direction of change depending on the acuteness or chronicity of TBI. Decreased functional connectivity (FC) of the salience and default mode networks was prominent alongside the decreased volume of gray matter within the insular, dorsomedial prefrontal, and ventromedial prefrontal cortices. Seven studies reported the correlation between observed neuroimaging and depression outcomes. Of these studies, 42% indicated that FC of the bilateral medial temporal lobe subregions was correlated with depression outcomes in TBI.DiscussionThis systematic review summarizes existing neuroimaging evidence and reports brain regions that can be leveraged as potential treatment targets in future studies examining depression post-TBI.

Common and divergent neuroimaging features in major depression, posttraumatic stress disorder and their comorbidity

Abstract Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are common stress-related psychiatric disorders. Genetic and neurobiology research has supported the viewpoint that PTSD and MDD may possess common and disorder-specific underlying mechanisms. In this systematic review, we summarized evidence for the similarities and differences in brain functional and structural features of MDD, PTSD and their comorbidity, as well as the effects of extensively used therapies in patients with comorbid PTSD and MDD (PTSD + MDD). These functional magnetic resonance imaging (MRI) studies highlight the 1) shared hypoactivation in the prefrontal cortex during cognitive and emotional processing in MDD and PTSD, 2) higher activation in fear processing regions including amygdala, hippocampus and insula in PTSD compared to MDD, and 3) distinct functional deficits in brain regions involved in fear and reward processing in patients with PTSD + MDD relative to those with PTSD-alone. These structural MRI studies suggested that PTSD and MDD share features of reduced volume in focal frontal areas. The treatment effects in patients with PTSD + MDD may correlate with the normalization trend of structural alterations. Neuroimaging predictors of repetitive transcranial magnetic stimulation response in patients with PTSD + MDD may differ from the mono-diagnostic groups. In summary, neuroimaging studies to date have provided limited information about the shared and disorder-specific features in MDD and PTSD. Further research is essential to pave the way for developing improved diagnostic markers and eventually targeted treatment approaches for the shared and distinct brain alterations presented in patients with MDD and PTSD.

Adverse childhood experiences and left hippocampal volumetric reductions: A structural magnetic resonance imaging study

BackgroundAdverse childhood experiences (ACEs) have been associated with volume alterations of stress-related brain structures among aging and clinical populations, however, existing studies have predominantly assessed only one type of ACE, with small sample sizes, and it is less clear if these associations exist among a general population of young adults. ObjectiveThe aims were to describe structural hippocampal volumetric differences by ACEs exposure and investigate the association between ACEs exposure and left and right hippocampal volume in a student sample of young adults. Methods959 young adult students (18–24 years old) completed an online questionnaire on ACEs, mental health conditions, and sociodemographic characteristics. Magnetic resonance imaging (MRI) was used to measure left and right hippocampal volume (mm3). We used linear regression to explore the differences of hippocampal volumes in university students with and without ACEs. ResultsTwo thirds of students (65.9%) reported ACEs exposure. As ACEs exposure increased there were significant volumetric reductions in left (p < 0.0001) and right hippocampal volume (p = 0.001) and left (p = 0.0023) and right (p = 0.0013) amygdala volume. After adjusting for intracranial brain volume, sex, age, and depression diagnosis there was a negative association between ACEs exposure and left (β = −22.6, CI = −44.5, −0.7, p = 0.0412) but not right hippocampal volume (β = −18.3, CI = −39.2, 2.6, p = 0.0792). After adjusting for intracranial volume there were no associations between ACEs exposure and left (β = −9.2, CI = −26.2, 7.9 p = 0.2926) or right (β = −5.6, CI = −19.9,8.8 p = 0.4466) amygdala volume. ConclusionsHippocampal volume varied by ACEs exposure in young adult students. ACEs appear to contribute to neuroanatomic differences in young adults from the general population.

Medial prefrontal neuroplasticity during extended-release naltrexone treatment of opioid use disorder – a longitudinal structural magnetic resonance imaging study

Opioid use disorder (OUD) has been linked to macroscopic structural alterations in the brain. The monthly injectable, extended-release formulation of μ-opioid antagonist naltrexone (XR-NTX) is highly effective in reducing opioid craving and preventing opioid relapse. Here, we investigated the neuroanatomical effects of XR-NTX by examining changes in cortical thickness during treatment for OUD. Forty-seven OUD patients underwent structural magnetic resonance imaging and subjectively rated their opioid craving ≤1 day before (pre-treatment) and 11 ± 3 days after (on-treatment) the first XR-NTX injection. A sample of fifty-six non-OUD individuals completed a single imaging session and served as the comparison group. A publicly available [¹¹C]carfentanil positron emission tomography dataset was used to assess the relationship between changes in cortical thickness and μ-opioid receptor (MOR) binding potential across brain regions. We found that the thickness of the medial prefrontal and anterior cingulate cortices (mPFC/aCC; regions with high MOR binding potential) was comparable between the non-OUD individuals and the OUD patients at pre-treatment. However, among the OUD patients, mPFC/aCC thickness significantly decreased from pre-treatment to on-treatment. A greater reduction in mPFC/aCC thickness was associated with a greater reduction in opioid craving. Taken together, our study suggests XR-NTX-induced cortical thickness reduction in the mPFC/aCC regions in OUD patients. The reduction in thickness does not appear to indicate a restoration to the non-OUD level but rather reflects XR-NTX’s distinct therapeutic impact on an MOR-rich brain structure. Our findings highlight the neuroplastic effects of XR-NTX that may inform the development of novel OUD interventions.

Altered Function and Structure of the Cerebellum Associated with Gut-Brain Regulation in Crohn's Disease: a Structural and Functional MRI Study.

This study employed structural and functional magnetic resonance imaging (MRI) to investigate changes in the function and structure of the cerebellum associated with gut-brain axis (GBA) regulation in patients diagnosed with Crohn's disease (CD). The study comprised 20 CD patients, including 12 with active disease (CD-A) and 8 in remission (CD-R), as well as 21 healthy controls. Voxel-based morphometry (VBM) was utilized for structural analysis of cerebellar gray matter volume, while independent component analysis (ICA) was applied for functional analysis of cerebellar functional connectivity (FC). The results showed significant GMV reduction in the left posterior cerebellar lobe across all CD patients compared to HCs, with more pronounced differences in the CD-A subgroup. Additionally, an increase in mean FC of the cerebellar network was observed in all CD patients, particularly in the CD-A subgroup, which demonstrated elevated FC in the vermis and bilateral posterior cerebellum. Correlation analysis revealed a positive relationship between cerebellar FC and the Crohn's Disease Activity Index (CDAI) and a trend toward a negative association with the reciprocal of the Self-rating Depression Scale (SDS) score in CD patients. The study's findings suggest that the cerebellum may play a role in the abnormal regulation of the GBA in CD patients, contributing to a better understanding of the neural mechanisms underlying CD and highlighting the cerebellum's potential role in modulating gut-brain interactions.

Multimodal abnormalities of brain structures in adolescents and young adults with major depressive disorder: An activation likelihood estimation meta-analysis.

Major depressive disorder (MDD) in adolescents and young adults contributes significantly to global morbidity, with inconsistent findings on brain structural changes from structural magnetic resonance imaging studies. Activation likelihood estimation (ALE) offers a method to synthesize these diverse findings and identify consistent brain anomalies. To identify consistent brain structural changes in adolescents and young adults with MDD using ALE meta-analysis. We performed a comprehensive literature search in PubMed, Web of Science, Embase, and Chinese National Knowledge Infrastructure databases for neuroimaging studies on MDD among adolescents and young adults published up to November 19, 2023. Two independent researchers performed the study selection, quality assessment, and data extraction. The ALE technique was employed to synthesize findings on localized brain function anomalies in MDD patients, which was supplemented by sensitivity analyses. Twenty-two studies comprising fourteen diffusion tensor imaging (DTI) studies and eight voxel-based morphometry (VBM) studies, and involving 451 MDD patients and 465 healthy controls (HCs) for DTI and 664 MDD patients and 946 HCs for VBM, were included. DTI-based ALE demonstrated significant reductions in fractional anisotropy (FA) values in the right caudate head, right insula, and right lentiform nucleus putamen in adolescents and young adults with MDD compared to HCs, with no regions exhibiting increased FA values. VBM-based ALE did not demonstrate significant alterations in gray matter volume. Sensitivity analyses highlighted consistent findings in the right caudate head (11 of 14 analyses), right insula (10 of 14 analyses), and right lentiform nucleus putamen (11 of 14 analyses). Structural alterations in the right caudate head, right insula, and right lentiform nucleus putamen in young MDD patients may contribute to its recurrent nature, offering insights for targeted therapies.

Understanding the role of cerebellum in early Parkinson’s disease: a structural and functional MRI study

Increasing evidence suggests that the cerebellum may have a role in the pathophysiology of Parkinson’s disease (PD). Hence, the scope of this study was to investigate whether there are structural and functional alterations of the cerebellum and whether they correlate with motor and non-motor symptoms in early PD patients. Seventy-six patients with early PD and thirty-one age and sex-matched healthy subjects (HS) were enrolled and underwent a 3 T magnetic resonance imaging (MRI) protocol. The following MRI analyses were performed: (1) volumes of 5 cerebellar regions of interest (sensorimotor and cognitive cerebellum, dentate, interposed, and fastigial nuclei); (2) microstructural integrity of the cerebellar white matter connections (inferior, middle, and superior cerebellar peduncles); (3) functional connectivity at rest of the 5 regions of interest already described in point 1 with the rest of brain. Compared to controls, early PD patients showed a significant decrease in gray matter volume of the dentate, interposed and fastigial nuclei, bilaterally. They also showed abnormal, bilateral white matter microstructural integrity in all 3 cerebellar peduncles. Functional connectivity of the 5 cerebellar regions of interest with several areas in the midbrain, basal ganglia and cerebral cortex was altered. Finally, there was a positive correlation between abnormal functional connectivity of the fastigial nucleus with the volume of the nucleus itself and a negative correlation with axial symptoms severity. Our results showed that structural and functional alterations of the cerebellum are present in PD patients and these changes contribute to the pathophysiology of PD in the early phase.

Clinical and neuroimaging aspects of formal thought disorder in schizophrenia: a brief narrative review

Aim. To analyze current sources regarding the clinical and neuroimaging aspects of formal thought disorder (FTD) in patients with schizophrenia to create an up-to-date pathogenetic model of its main forms. Materials and methods. English-language publications in the Medline database (PubMed) were analyzed for this review. We analyzed only structural magnetic resonance imaging (MRI) studies in which a clear clinical assessment of FTD in schizophrenia is provided and the neuroimaging protocol meets generally accepted standards (as in the ENIGMA Schizophrenia Working Group). For the clinical division of FTD, positive and negative FTD were distinguished according to the positive and negative syndrome scale (PANSS). Results. From a clinical point of view, FTD includes at least 30 phenomena. For clinical and neuroimaging studies, division into positive and negative FTD is used according to the PANSS. Positive FTD is manifested by the disorganization of thinking processes and exhibits mainly in violations of its purposeful sequence. Negative FTD is manifested by violations of the abstract-symbolic way of thinking, lack of spontaneity, and stereotyping. According to morphometric MRI data, atrophic changes in brain regions related to neuronal networks of cognition and impulse control (prefrontal and anterior cingulate cortex), emotional processing (amygdala), abstract thinking, and imagination (lateral occipital cortex) are important for the development of both forms of FTD. Negative FTD is mainly associated with damage to the prefronto-cingulate circles, which are the anatomical and functional substrates of executive functions. A unique feature of positive FTD is atrophy of the structures of the left temporal lobe, which leads to language disorders at the semantic level. Using the method of virtual histology, it was established that both forms of FTD are associated with bilateral changes in astrocytes and dendritic spines in the involved anatomical regions. A positive FTD is also associated with pathological changes in microglia in two hemispheres, while with a negative FTD, microglial damages are present only in the right hemisphere. Conclusions. Positive FTD in schizophrenia is mainly associated with atrophic (astroglial-microglial) processes of cognitive control networks, negative – with the atrophy of networks of semantic processing of verbal information. In both forms, networks of emotional processing, abstract thinking, and imagination are involved. Treatment strategies for FTD should include effects on astroglial and microglial dysfunction.

The Association Between Chronic Tobacco Smoking and Brain Alterations in Schizophrenia: A Systematic Review of Magnetic Resonance Imaging Studies.

The high co-occurrence of tobacco smoking in patients with schizophrenia spectrum disorders (SSD) poses a serious health concern, linked to increased mortality and worse clinical outcomes. The mechanisms underlying this co-occurrence are not fully understood. Addressing the need for a comprehensive overview of the impact of tobacco use on SSD neurobiology, we conducted a systematic review of neuroimaging studies (including structural, functional, and neurochemical magnetic resonance imaging studies) that investigate the association between chronic tobacco smoking and brain alterations in patients with SSD. Eight structural and fourteen functional studies were included. Structural studies show widespread independent and additive reductions in gray matter in relation to smoking and SSD. The majority of functional studies suggest that smoking might be associated with improvements in connectivity deficits linked to SSD. However, the limited number of and high amount of cross-sectional studies, and high between-studies sample overlap prevent a conclusive determination of the nature and extent of the impact of smoking on brain functioning in patients with SSD. Overall, functional results imply a distinct neurobiological mechanism for tobacco addiction in patients with SSD, possibly attributed to differences at the nicotinic acetylcholine receptor level. Our findings highlight the need for more longitudinal and exposure-dependent studies to differentiate between inherent neurobiological differences and the (long-term) effects of smoking in SSD, and to unravel the complex interaction between smoking and schizophrenia at various disease stages. This could inform more effective strategies addressing smoking susceptibility in SSD, potentially improving clinical outcomes.

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.

Effects of electroconvulsive therapy on cortical thickness in depression: a systematic review.

Electroconvulsive therapy (ECT) is one of the most studied and validated available treatments for severe or treatment-resistant depression. However, little is known about the neural mechanisms underlying ECT. This systematic review aims to critically review all structural magnetic resonance imaging studies investigating longitudinal cortical thickness (CT) changes after ECT in patients with unipolar or bipolar depression. We performed a search on PubMed, Medline, and Embase to identify all available studies published before April 20, 2023. A total of 10 studies were included. The investigations showed widespread increases in CT after ECT in depressed patients, involving mainly the temporal, insular, and frontal regions. In five studies, CT increases in a non-overlapping set of brain areas correlated with the clinical efficacy of ECT. The small sample size, heterogeneity in terms of populations, comorbidities, and ECT protocols, and the lack of a control group in some investigations limit the generalisability of the results. Our findings support the idea that ECT can increase CT in patients with unipolar and bipolar depression. It remains unclear whether these changes are related to the clinical response. Future larger studies with longer follow-up are warranted to thoroughly address the potential role of CT as a biomarker of clinical response after ECT.

Aging, cingulate cortex, and cognition: insights from structural MRI, emotional recognition, and theory of mind.

The cingulate cortex is a limbic structure involved in multiple functions, including emotionalprocessing, pain, cognition, memory, and spatial orientation. The main goal of this structural Magnetic Resonance Imaging (MRI) study was to investigate whether age affects the cingulate cortex uniformly across its anteroposterior dimensions and determine if the effects of age differ based on sex, hemisphere, and regional cingulate anatomy, in a large cohort of healthy individuals across the adult lifespan. The second objective aimed to explore whether the decline in emotional recognition accuracy and Theory of Mind (ToM) is linked to the potential age-related reductions in the pregenual anterior cingulate (ACC) and anterior midcingulate (MCC) cortices. We recruited 126 healthy participants (18-85years) for this study. MRI datasets were acquired on a 4.7T system. The cingulate cortex was manually segmented into the pregenual ACC, anterior MCC, posterior MCC, and posterior cingulate cortex (PCC). We observed negative relationships between the presence and length of the superior cingulate gyrus and bilateral volumes of pregenual ACC and anterior MCC. Age showed negative effects on the volume of all cingulate cortical subregions bilaterally except for the right anterior MCC. Most of the associations between age and the cingulate subregional volumes were linear. We did not find a significant effect of sex on cingulate cortical volumes. However, stronger effects of age were observed in men compared to women. This study also demonstrated that performance on an emotional recognition task was linked to pregenual ACC volume, whist the ToM capabilities were related to the size of pregenual ACC and anterior MCC. These results suggest that the cingulate cortex contributes to emotional recognition ability and ToM across the adult lifespan.

Возрастные особенности показателей структурной МРТ головного мозга и методы их квантификации

Understanding the formation of the trajectories of the brain structural development in relation to emotional and cognitive functions is an important scientific task for identifying and predicting the stages of brain maturation. This review systematically examines structural magnetic resonance imaging studies of the brain anatomical development in children and adolescents. The literature reveals inconsistency due to the difference in participants demographic groups and methodological approaches. Nevertheless, some patterns have been identified, such as age-related changes in the ratios of white and gray matter, thickness and area of the cerebral cortex both total and regional. The most observable results underline that the brain maturation is a heterochronous processes. For instance, the frontal region of the cerebral cortex has a longer maturation trajectory compared to the occipital region. Gender differences reflected in higher values of volume indicators have been identified in many studies. This article also describes the methods of quantification of structural magnetic resonance imaging, which allowed us to determine the value of more than two hundred parameters. There are some explanations of the advantage of the surface-based morphometry by using the FreeSurfer software, developed by the Computational Neuroimaging Laboratory at the A. A. Martinos Biomedical Imaging Center at Harvard University. The authors substantiate the necessity of further experimental studies of age-related changes in surface-based morphometry parameters in relation to emotional and cognitive functions in children from 7 to 20 years old.

Psychomotor slowing in schizophrenia is associated with cortical thinning of primary motor cortex: A three cohort structural magnetic resonance imaging study

Psychomotor slowing (PS) is characterized by slowed movements and lower activity levels. PS is frequently observed in schizophrenia (SZ) and distressing because it impairs performance of everyday tasks and social activities. Studying brain topography contributing to PS in SZ can help to understand the underlying neurobiological mechanisms as well as help to develop more effective treatments that specifically target affected brain areas. Here, we conducted structural magnetic resonance imaging (sMRI) of three independent cohorts of right-handed SZ patients (SZ#1: n = 72, SZ#2: n = 37, SZ#3: n = 25) and age, gender and education matched healthy controls (HC) (HC#1: n = 40, HC#2: n = 37, HC#3: n = 38). PS severity in the three SZ cohorts was determined using the Positive and Negative Syndrome Scale (PANSS) item #G7 (motor retardation) and Trail-Making-Test B (TMT-B). FreeSurfer v7.2 was used for automated parcellation and segmentation of cortical and subcortical regions. SZ#1 patients showed reduced cortical thickness in right precentral gyrus (M1; p = 0.04; Benjamini-Hochberg [BH] corr.). In SZ#1, cortical thinning in right M1 was associated with PANSS item #G7 (p = 0.04; BH corr.) and TMT-B performance (p = 0.002; BH corr.). In SZ#1, we found a significant correlation between PANSS item #G7 and TMT-B (p = 0.005, ρ=0.326). In conclusion, PANSS G#7 and TMT-B might have a surrogate value for predicting PS in SZ. Cortical thinning of M1 rather than alterations of subcortical structures may point towards cortical pathomechanism underlying PS in SZ.

Internalizing and externalizing behaviors in school-aged children are related to state anxiety during magnetic resonance imaging

Magnetic resonance imaging (MRI) procedures often evoke anxiety in children. Further, anxious children may be less likely to participate in MRI research, leading to a possible selection bias, and may be more likely to move during image acquisition, resulting in lower image quality and possible information bias. Therefore, state anxiety is problematic for functional and structural MRI studies. Children with behavioral problems, such as internalizing and externalizing behaviors, may be more likely to experience state anxiety prior to and during MRI scanning. Therefore, our first aim was to investigate the relationship between internalizing/externalizing behavior and children’s MRI-related state anxiety. Our second aim was to investigate the relationship between internalizing and externalizing behaviors and MRI research participation. Our final aim was to investigate the effect of internalizing and externalizing behaviors as well as MRI-related anxiety on image quality in children. We included 1,241 six- to ten-year-old children who underwent a mock MRI. Afterward, if not too anxious, these children were scanned using a 3-Tesla GE Discovery MRI system (n = 1,070). Internalizing and externalizing behaviors were assessed with the child behavior checklist. State anxiety was assessed with a visual analog scale. Internalizing behaviors were positively associated with child state anxiety, as reported by the child, parent, and researcher. For state anxiety reported by the parent and researcher, this relationship was independent of externalizing behaviors. Externalizing behaviors were related to state anxiety as reported by the child, parent, and researcher, but this difference was not independent of internalizing behaviors, pointing toward a relationship via the shared variance with internalizing behaviors. Further, children with more internalizing and externalizing behaviors were less likely to participate in the actual MRI-scanning procedure. Lastly, MRI-related state anxiety, reported by the child and the researcher, was associated with worse image quality. These results underscore the potential for biases and methodological issues related to MRI-related state anxiety in children.

APOEε4 genotype boosts neurodegenerative structural changes in medial temporal lobe areas in adults with Mild Cognitive Impairment

AbstractBackgroundApolipoprotein E ε4 allele (APOEε4) is considered the major genetic risk factor of Alzheimer´s Disease (AD). Structural magnetic resonance imaging (sMRI) studies demonstrated that, compared to APOEε4 non‐carriers, APOEε4 carriers display structural changes in lateral and medial temporal lobe (MTL). However, the knowledge about the impact of this genotype on hippocampal subfields is still limited. The present sMRI study aimed to evaluate volumetric and cortical thickness differences between adults with mild cognitive impairment (MCI) APOEε4 non‐carriers compared with MCI‐APOEε4 carriers.MethodTwelve MCI‐APOEε4 non‐carriers (mean age: 70.33 years, SD: 5.12) and ten MCI‐APOEε4 carriers (mean age: 72.70 years, SD: 6.38), diagnosed as MCI according Petersen criteria (Petersen, 2004; Albert et al., 2011), underwent neuropsychological assessment, cerebrospinal fluid, genetic and MRI examinations. MRI surface‐based morphometry analyses was conducted with the FreeSurfer software to evaluate volumetric and thickness differences in the hippocampal subfields and its surrounding MTL areas.ResultCompared with MCI‐APOEε4 non‐carriers, the MCI‐APOEε4 carriers group showed a significant reduced volume in several areas of the left hemisphere. Specifically, in this hemisphere volumetric changes were found in the entorhinal cortex, the whole hippocampus and in its head, body and tail; the head of presubiculum, the head and body of subiculum, the CA1, CA3, CA4 subfields, the granulate cell of the molecular layer of dentate gyrus and the molecular layer of the hippocampus. This group also displayed a significant reduced volume in the right body of CA3 subfield.ConclusionThese results suggest that, in MCI adults, the presence of the APOEε4 genotype may have an additional neuropathological impact on the structure of brain regions of the MTL with a critical functional role in episodic memory, the most affected neurocognitive system in Alzheimer’s disease (AD). Particularly, the left MTL would show higher vulnerability to neurodegenerative changes in the prodromal stage of AD.

Behavioral and neural underpinnings of empathic characteristics in a Humanitude-care expert.

Humanitude approaches have shown positive effects in elderly care. However, the behavioral and neural underpinnings of empathic characteristics in Humanitude-care experts remain unknown. We investigated the empathic characteristics of a Humanitude-care expert (YG) and those of age-, sex-, and race-matched controls (n = 13). In a behavioral study, we measured subjective valence and arousal ratings and facial electromyography (EMG) of the corrugator supercilii and zygomatic major muscles while participants passively observed dynamic facial expressions associated with anger and happiness and their randomized mosaic patterns. In a functional magnetic resonance imaging (MRI) study, we measured brain activity while participants passively observed the same dynamic facial expressions and mosaics. In a structural MRI study, we acquired structural MRI data and analyzed gray matter volume. Our behavioral data showed that YG experienced higher subjective arousal and showed stronger facial EMG activity congruent with stimulus facial expressions compared with controls. The functional MRI data demonstrated that YG showed stronger activity in the ventral premotor cortex (PMv; covering the precentral gyrus and inferior frontal gyrus) and posterior middle temporal gyrus in the right hemisphere in response to dynamic facial expressions versus dynamic mosaics compared with controls. The structural MRI data revealed higher regional gray matter volume in the right PMv in YG than in controls. These results suggest that Humanitude-care experts have behavioral and neural characteristics associated with empathic social interactions.

Co-twin design in brain imaging-review on biomarkers of Alzheimer's disease.

Twin samples allow to conduct a quasi-experimental co-twin case-control approach that can control for genetic and environmental confounding in brain-cognition associations, being more informative on causality compared with studies in unrelated individuals. We conducted a review of studies that have utilized discordant co-twin design to investigate the associations of brain imaging markers of Alzheimer's disease and cognition. Inclusion criteria encompassed twin pairs discordant for cognition or Alzheimer's disease imaging markers and reporting of within-twin pair comparison on the association between cognition and brain measures. Our PubMed search (2022 April 23, updated 2023 March 9) resulted in 18 studies matching these criteria. Alzheimer's disease imaging markers have been addressed only by few studies, most with small sample size. Structural magnetic resonance imaging studies have indicated greater hippocampal volume and thicker cortex in co-twins with better cognitive performance compared with their co-twins with poorer cognitive performance. No studies have looked at cortical surface area. Positron emission tomography imaging studies have suggested that lower cortical glucose metabolism rate and higher cortical neuroinflammation, amyloid, and tau accumulations are related to poorer episodic memory in within-twin pair comparisons. Thus far, only cross-sectional within-twin pair associations of cortical amyloid and hippocampal volume with cognition have been replicated.

Unraveling the pathophysiology of schizophrenia: insights from structural magnetic resonance imaging studies.

Schizophrenia affects about 1% of the global population. In addition to the complex etiology, linking this illness to genetic, environmental, and neurobiological factors, the dynamic experiences associated with this disease, such as experiences of delusions, hallucinations, disorganized thinking, and abnormal behaviors, limit neurological consensuses regarding mechanisms underlying this disease. In this study, we recruited 72 patients with schizophrenia and 74 healthy individuals matched by age and sex to investigate the structural brain changes that may serve as prognostic biomarkers, indicating evidence of neural dysfunction underlying schizophrenia and subsequent cognitive and behavioral deficits. We used voxel-based morphometry (VBM) to determine these changes in the three tissue structures: the gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). For both image processing and statistical analysis, we used statistical parametric mapping (SPM). Our results show that patients with schizophrenia exhibited a significant volume reduction in both GM and WM. In particular, GM volume reductions were more evident in the frontal, temporal, limbic, and parietal lobe, similarly the WM volume reductions were predominantly in the frontal, temporal, and limbic lobe. In addition, patients with schizophrenia demonstrated a significant increase in the CSF volume in the left third and lateral ventricle regions. This VBM study supports existing research showing that schizophrenia is associated with alterations in brain structure, including gray and white matter, and cerebrospinal fluid volume. These findings provide insights into the neurobiology of schizophrenia and may inform the development of more effective diagnostic and therapeutic approaches.

Abnormal Brain Structure Is Associated with Social and Communication Deficits in Children with Autism Spectrum Disorder: A Voxel-Based Morphometry Analysis.

Structural magnetic resonance imaging (sMRI) studies have shown abnormalities in the brain structure of ASD patients, but the relationship between structural changes and social communication problems is still unclear. This study aims to explore the structural mechanisms of clinical dysfunction in the brain of ASD children through voxel-based morphometry (VBM). After screening T1 structural images from the Autism Brain Imaging Data Exchange (ABIDE) database, 98 children aged 8-12 years old with ASD were matched with 105 children aged 8-12 years old with typical development (TD). Firstly, this study compared the differences in gray matter volume (GMV) between the two groups. Then, this study evaluated the relationship between GMV and the subtotal score of communications and social interaction on the Autism Diagnostic Observation Schedule (ADOS) in ASD children. Research has found that abnormal brain structures in ASD include the midbrain, pontine, bilateral hippocampus, left parahippocampal gyrus, left superior temporal gyrus, left temporal pole, left middle temporal gyrus and left superior occipital gyrus. In addition, in ASD children, the subtotal score of communications and social interaction on the ADOS were only significantly positively correlated with GMV in the left hippocampus, left superior temporal gyrus and left middle temporal gyrus. In summary, the gray matter structure of ASD children is abnormal, and different clinical dysfunction in ASD children is related to structural abnormalities in specific regions.