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Rollins CPE, Gallino D, Kong V, Ayranci G, Devenyi GA, Germann J, Chakravarty MM. Contributions of a high-fat diet to Alzheimer's disease-related decline: A longitudinal behavioural and structural neuroimaging study in mouse models. NEUROIMAGE-CLINICAL 2018; 21:101606. [PMID: 30503215 PMCID: PMC6413478 DOI: 10.1016/j.nicl.2018.11.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/26/2018] [Accepted: 11/18/2018] [Indexed: 11/28/2022]
Abstract
Obesity is recognized as a significant risk factor for Alzheimer's disease (AD). Studies have supported that obesity accelerates AD-related pathophysiology and memory impairment in mouse models of AD. However, the nature of the brain structure-behaviour relationship mediating this acceleration remains unclear. In this manuscript we evaluated the impact of adolescent obesity on the brain morphology of the triple transgenic mouse model of AD (3xTg) and a non-transgenic control model of the same background strain (B6129s) using longitudinally acquired structural magnetic resonance imaging (MRI). At 8 weeks of age, animals were placed on a high-fat diet (HFD) or an ingredient-equivalent control diet (CD). Structural images were acquired at 8, 16, and 24 weeks. At 25 weeks, animals underwent the novel object recognition (NOR) task and the Morris water maze (MWM) to assess short-term non-associative memory and spatial memory, respectively. All analyses were carried out across four groups: B6129s-CD and -HFD and 3xTg-CD and -HFD. Neuroanatomical changes in MRI-derived brain morphology were assessed using volumetric and deformation-based analyses. HFD-induced obesity during adolescence exacerbated brain volume alterations by adult life in the 3xTg mouse model in comparison to control-fed mice and mediated volumetric alterations of select brain regions, such as the hippocampus. Further, HFD-induced obesity aggravated memory in all mice, lowering certain memory measures of B6129s control mice to the level of 3xTg mice maintained on a CD. Moreover, decline in the volumetric trajectories of hippocampal regions for all mice were associated with the degree of spatial memory impairments on the MWM. Our results suggest that obesity may interact with the brain changes associated with AD-related pathology in the 3xTg mouse model to aggravate brain atrophy and memory impairments and similarly impair brain structural integrity and memory capacity of non-transgenic mice. Further insight into this process may have significant implications in the development of lifestyle interventions for treatment of AD. Adolescent high-fat diet-induced obesity altered adult brain morphology and memory-related behaviours in a mouse model of AD High-fat feeding exacerbated brain volume changes in a mouse model of AD High-fat feeding mediated volumetric alterations of select brain regions, such as the hippocampus Degree of impairment on a spatial memory task showed linear trends with brain structural changes in AD-related regions High-fat feeding lowered certain memory measures of non-transgenic control mice
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Sengupta SM, Fotopoulos N, Devenyi GA, Fortier MÈ, Ter-Stepanian M, Sagliker S, Karama S, Mallar Chakravarty M, Labbe A, Grizenko N, Joober R. Dissecting genetic cross-talk between ADHD and other neurodevelopmental disorders: Evidence from behavioural, pharmacological and brain imaging investigations. Psychiatry Res 2018; 269:652-657. [PMID: 30216917 DOI: 10.1016/j.psychres.2018.08.080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/01/2018] [Accepted: 08/21/2018] [Indexed: 12/31/2022]
Abstract
Several epidemiological and genetic studies have provided evidence of an overlap between neurodevelopmental disorders. However, the details of the etiological pathways remain to be elucidated. In this study, we garnered the findings of previous GWAS, conducted with schizophrenia and bipolar disorder. We conducted an exploratory study to examine the association between these SNPs and quantitative clinical/ behavioural/ cognitive/ structural brain parameters, as well as response to treatment with a fixed dose of methylphenidate, in a relatively large sample of children with ADHD. Family-based association tests were conducted with nine tag SNPs with 602 nuclear families. In addition, structural magnetic resonance imaging (sMRI) was conducted in a subset of children with ADHD (n = 76). Of the 9 tag SNPs examined, rs1602565 showed a significant association with ADHD, several dimensional measures and response to treatment. An association was also observed between rs1006737 (CACNA1C) and performance IQ. In addition, significant reductions in cortical thickness measurements were observed with the risk allele in rs1006737. These results provide preliminary evidence for putative shared genetic vulnerability between childhood ADHD and other neurodevelopmental disorders.
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Hafizi S, Guma E, Koppel A, Da Silva T, Kiang M, Houle S, Wilson AA, Rusjan PM, Chakravarty MM, Mizrahi R. TSPO expression and brain structure in the psychosis spectrum. Brain Behav Immun 2018; 74:79-85. [PMID: 29906515 PMCID: PMC6289857 DOI: 10.1016/j.bbi.2018.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/06/2018] [Accepted: 06/09/2018] [Indexed: 01/18/2023] Open
Abstract
Psychosis is associated with abnormal structural changes in the brain including decreased regional brain volumes and abnormal brain morphology. However, the underlying causes of these structural abnormalities are less understood. The immune system, including microglial activation, has been implicated in the pathophysiology of psychosis. Although previous studies have suggested a connection between peripheral proinflammatory cytokines and structural brain abnormalities in schizophrenia, no in-vivo studies have investigated whether microglial activation is also linked to brain structure alterations previously observed in schizophrenia and its putative prodrome. In this study, we investigated the link between mitochondrial 18 kDa translocator protein (TSPO) and structural brain characteristics (i.e. regional brain volume, cortical thickness, and hippocampal shape) in key brain regions such as dorsolateral prefrontal cortex and hippocampus of a large group of participants (N = 90) including individuals at clinical high risk (CHR) for psychosis, first-episode psychosis (mostly antipsychotic-naïve) patients, and healthy volunteers. The participants underwent structural brain MRI scan and [18F]FEPPA positron emission tomography (PET) targeting TSPO. A significant [18F]FEPPA binding-by-group interaction was observed in morphological measures across the left hippocampus. In first-episode psychosis, we observed associations between [18F]FEPPA VT (total volume of distribution) and outward and inward morphological alterations, respectively, in the dorsal and ventro-medial portions of the left hippocampus. These associations were not significant in CHR or healthy volunteers. There was no association between [18F]FEPPA VT and other structural brain characteristics. Our findings suggest a link between TSPO expression and alterations in hippocampal morphology in first-episode psychosis.
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Shaw P, Ishii-Takahashi A, Park MT, Devenyi GA, Zibman C, Kasparek S, Sudre G, Mangalmurti A, Hoogman M, Tiemeier H, von Polier G, Shook D, Muetzel R, Chakravarty MM, Konrad K, Durston S, White T. A multicohort, longitudinal study of cerebellar development in attention deficit hyperactivity disorder. J Child Psychol Psychiatry 2018; 59:1114-1123. [PMID: 29693267 PMCID: PMC6158081 DOI: 10.1111/jcpp.12920] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/12/2018] [Indexed: 01/19/2023]
Abstract
BACKGROUND The cerebellum supports many cognitive functions disrupted in attention deficit hyperactivity disorder (ADHD). Prior neuroanatomic studies have been often limited by small sample sizes, inconsistent findings, and a reliance on cross-sectional data, limiting inferences about cerebellar development. Here, we conduct a multicohort study using longitudinal data, to characterize cerebellar development. METHODS Growth trajectories of the cerebellar vermis, hemispheres and white matter were estimated using piecewise linear regression from 1,656 youth; of whom 63% had longitudinal data, totaling 2,914 scans. Four cohorts participated, all contained childhood data (age 4-12 years); two had adolescent data (12-25 years). Growth parameters were combined using random-effects meta-analysis. RESULTS Diagnostic differences in growth were confined to the corpus medullare (cerebellar white matter). Here, the ADHD group showed slower growth in early childhood compared to the typically developing group (left corpus medullare z = 2.49, p = .01; right z = 2.03, p = .04). This reversed in late childhood, with faster growth in ADHD in the left corpus medullare (z = 2.06, p = .04). Findings held when gender, intelligence, comorbidity, and psychostimulant medication were considered. DISCUSSION Across four independent cohorts, containing predominately longitudinal data, we found diagnostic differences in the growth of cerebellar white matter. In ADHD, slower white matter growth in early childhood was followed by faster growth in late childhood. The findings are consistent with the concept of ADHD as a disorder of the brain's structural connections, formed partly by developing cortico-cerebellar white matter tracts.
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Nadig A, Reardon PK, Seidlitz J, McDermott CL, Blumenthal JD, Clasen LS, Lalonde F, Lerch JP, Chakravarty MM, Raznahan A. Carriage of Supernumerary Sex Chromosomes Decreases the Volume and Alters the Shape of Limbic Structures. eNeuro 2018; 5:ENEURO.0265-18.2018. [PMID: 30713992 PMCID: PMC6354783 DOI: 10.1523/eneuro.0265-18.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/30/2018] [Accepted: 09/24/2018] [Indexed: 01/10/2023] Open
Abstract
Sex chromosome aneuploidy (SCA) increases risk for several psychiatric disorders associated with the limbic system, including mood and autism spectrum disorders. Thus, SCA offers a genetics-first model for understanding the biological basis of psychopathology. Additionally, the sex-biased prevalence of many psychiatric disorders could potentially reflect sex chromosome dosage effects on brain development. To clarify how limbic anatomy varies across sex and sex chromosome complement, we characterized amygdala and hippocampus structure in a uniquely large sample of patients carrying supernumerary sex chromosomes (n = 132) and typically developing controls (n = 166). After adjustment for sex-differences in brain size, karyotypically normal males (XY) and females (XX) did not differ in volume or shape of either structure. In contrast, all SCAs were associated with lowered amygdala volume relative to gonadally-matched controls. This effect was robust to three different methods for total brain volume adjustment, including an allometric analysis that derived normative scaling rules for these structures in a separate, typically developing population (n = 79). Hippocampal volume was insensitive to SCA after adjustment for total brain volume. However, surface-based analysis revealed that SCA, regardless of specific karyotype, was consistently associated with a spatially specific pattern of shape change in both amygdala and hippocampus. In particular, SCA was accompanied by contraction around the basomedial nucleus of the amygdala and an area crossing the hippocampal tail. These results demonstrate the power of SCA as a model to understand how copy number variation can precipitate changes in brain systems relevant to psychiatric disease.
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Bhagwat N, Viviano JD, Voineskos AN, Chakravarty MM. Modeling and prediction of clinical symptom trajectories in Alzheimer's disease using longitudinal data. PLoS Comput Biol 2018; 14:e1006376. [PMID: 30216352 PMCID: PMC6157905 DOI: 10.1371/journal.pcbi.1006376] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 09/26/2018] [Accepted: 07/18/2018] [Indexed: 01/18/2023] Open
Abstract
Computational models predicting symptomatic progression at the individual level can be highly beneficial for early intervention and treatment planning for Alzheimer's disease (AD). Individual prognosis is complicated by many factors including the definition of the prediction objective itself. In this work, we present a computational framework comprising machine-learning techniques for 1) modeling symptom trajectories and 2) prediction of symptom trajectories using multimodal and longitudinal data. We perform primary analyses on three cohorts from Alzheimer's Disease Neuroimaging Initiative (ADNI), and a replication analysis using subjects from Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL). We model the prototypical symptom trajectory classes using clinical assessment scores from mini-mental state exam (MMSE) and Alzheimer's Disease Assessment Scale (ADAS-13) at nine timepoints spanned over six years based on a hierarchical clustering approach. Subsequently we predict these trajectory classes for a given subject using magnetic resonance (MR) imaging, genetic, and clinical variables from two timepoints (baseline + follow-up). For prediction, we present a longitudinal Siamese neural-network (LSN) with novel architectural modules for combining multimodal data from two timepoints. The trajectory modeling yields two (stable and decline) and three (stable, slow-decline, fast-decline) trajectory classes for MMSE and ADAS-13 assessments, respectively. For the predictive tasks, LSN offers highly accurate performance with 0.900 accuracy and 0.968 AUC for binary MMSE task and 0.760 accuracy for 3-way ADAS-13 task on ADNI datasets, as well as, 0.724 accuracy and 0.883 AUC for binary MMSE task on replication AIBL dataset.
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Tullo S, Devenyi GA, Patel R, Park MTM, Collins DL, Chakravarty MM. Warping an atlas derived from serial histology to 5 high-resolution MRIs. Sci Data 2018; 5:180107. [PMID: 29917012 PMCID: PMC6007088 DOI: 10.1038/sdata.2018.107] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 04/06/2018] [Indexed: 11/09/2022] Open
Abstract
Previous work from our group demonstrated the use of multiple input atlases to a modified multi-atlas framework (MAGeT-Brain) to improve subject-based segmentation accuracy. Currently, segmentation of the striatum, globus pallidus and thalamus are generated from a single high-resolution and -contrast MRI atlas derived from annotated serial histological sections. Here, we warp this atlas to five high-resolution MRI templates to create five de novo atlases. The overall goal of this work is to use these newly warped atlases as input to MAGeT-Brain in an effort to consolidate and improve the workflow presented in previous manuscripts from our group, allowing for simultaneous multi-structure segmentation. The work presented details the methodology used for the creation of the atlases using a technique previously proposed, where atlas labels are modified to mimic the intensity and contrast profile of MRI to facilitate atlas-to-template nonlinear transformation estimation. Dice's Kappa metric was used to demonstrate high quality registration and segmentation accuracy of the atlases. The final atlases are available at https://github.com/CobraLab/atlases/tree/master/5-atlas-subcortical.
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Guo T, Chau V, Peyvandi S, Latal B, McQuillen PS, Knirsch W, Synnes A, Feldmann M, Naef N, Chakravarty MM, De Petrillo A, Duerden EG, Barkovich AJ, Miller SP. White matter injury in term neonates with congenital heart diseases: Topology & comparison with preterm newborns. Neuroimage 2018; 185:742-749. [PMID: 29890324 DOI: 10.1016/j.neuroimage.2018.06.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/28/2018] [Accepted: 06/04/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Neonates with congenital heart disease (CHD) are at high risk of punctate white matter injury (WMI) and impaired brain development. We hypothesized that WMI in CHD neonates occurs in a characteristic distribution that shares topology with preterm WMI and that lower birth gestational age (GA) is associated with larger WMI volume. OBJECTIVE (1) To quantitatively assess the volume and location of WMI in CHD neonates across three centres. (2) To compare the volume and spatial distribution of WMI between term CHD neonates and preterm neonates using lesion mapping. METHODS In 216 term born CHD neonates from three prospective cohorts (mean birth GA: 39 weeks), WMI was identified in 86 neonates (UBC: 29; UCSF: 43; UCZ: 14) on pre- and/or post-operative T1 weighted MRI. WMI was manually segmented and volumes were calculated. A standard brain template was generated. Probabilistic WMI maps (total, pre- and post-operative) were developed in this common space. Using these maps, WMI in the term CHD neonates was compared with that in preterm neonates: 58 at early-in-life (mean postmenstrual age at scan 32.2 weeks); 41 at term-equivalent age (mean postmenstrual age at scan 40.1 weeks). RESULTS The total WMI volumes of CHD neonates across centres did not differ (p = 0.068): UBC (median = 84.6 mm3, IQR = 26-174.7 mm3); UCSF (median = 104 mm3, IQR = 44-243 mm3); UCZ (median = 121 mm3, IQR = 68-200.8 mm3). The spatial distribution of WMI in CHD neonates showed strong concordance across centres with predilection for anterior and posterior rather than central lesions. Predominance of anterior lesions was apparent on the post-operative WMI map relative to the pre-operative map. Lower GA at birth predicted an increasing volume of WMI across the full cohort (41.1 mm3 increase of WMI per week decrease in gestational age; 95% CI 11.5-70.8; p = 0.007), when accounting for centre and heart lesion. While WMI in term CHD and preterm neonates occurs most commonly in the intermediate zone/outer subventricular zone there is a paucity of central lesions in the CHD neonates relative to preterms. CONCLUSIONS WMI in term neonates with CHD occurs in a characteristic topology. The spatial distribution of WMI in term neonates with CHD reflects the expected maturation of pre-oligodendrocytes such that the central regions are less vulnerable than in the preterm neonates.
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Reardon PK, Seidlitz J, Vandekar S, Liu S, Patel R, Park MTM, Alexander-Bloch A, Clasen LS, Blumenthal JD, Lalonde FM, Giedd JN, Gur RC, Gur RE, Lerch JP, Chakravarty MM, Satterthwaite TD, Shinohara RT, Raznahan A. Normative brain size variation and brain shape diversity in humans. Science 2018; 360:1222-1227. [PMID: 29853553 PMCID: PMC7485526 DOI: 10.1126/science.aar2578] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 04/09/2018] [Indexed: 01/09/2023]
Abstract
Brain size variation over primate evolution and human development is associated with shifts in the proportions of different brain regions. Individual brain size can vary almost twofold among typically developing humans, but the consequences of this for brain organization remain poorly understood. Using in vivo neuroimaging data from more than 3000 individuals, we find that larger human brains show greater areal expansion in distributed frontoparietal cortical networks and related subcortical regions than in limbic, sensory, and motor systems. This areal redistribution recapitulates cortical remodeling across evolution, manifests by early childhood in humans, and is linked to multiple markers of heightened metabolic cost and neuronal connectivity. Thus, human brain shape is systematically coupled to naturally occurring variations in brain size through a scaling map that integrates spatiotemporally diverse aspects of neurobiology.
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Kong V, Devenyi GA, Gallino D, Ayranci G, Germann J, Rollins C, Chakravarty MM. Early-in-life neuroanatomical and behavioural trajectories in a triple transgenic model of Alzheimer’s disease. Brain Struct Funct 2018; 223:3365-3382. [DOI: 10.1007/s00429-018-1691-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/26/2018] [Indexed: 11/29/2022]
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Patel S, Patel R, Park MTM, Masellis M, Knight J, Chakravarty MM. Heritability estimates of cortical anatomy: The influence and reliability of different estimation strategies. Neuroimage 2018; 178:78-91. [PMID: 29742386 DOI: 10.1016/j.neuroimage.2018.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 04/23/2018] [Accepted: 05/03/2018] [Indexed: 12/20/2022] Open
Abstract
Twin study designs have been previously used to investigate the heritability of neuroanatomical measures, such as regional cortical volumes. Volume can be fractionated into surface area and cortical thickness, where both measures are considered to have independent genetic and environmental bases. Region of interest (ROI) and vertex-wise approaches have been used to calculate heritability of cortical thickness and surface area in twin studies. In our study, we estimate heritability using the Human Connectome Project magnetic resonance imaging dataset composed of healthy young twin and non-twin siblings (mean age of 29, sample size of 757). Both ROI and vertex-wise methods were used to compare regional heritability of cortical thickness and surface area. Heritability estimates were controlled for age, sex, and total ipsilateral surface area or mean cortical thickness. In both approaches, heritability estimates of cortical thickness and surface area were lower when accounting for average ipsilateral cortical thickness and total surface area respectively. When comparing both approaches at a regional level, the vertex-wise approach showed higher surface area and lower cortical thickness heritability estimates compared to the ROI approach. The calcarine fissure had the highest surface area heritability estimate (ROI: 44%, vertex-wise: 50%) and posterior cingulate gyrus had the highest cortical thickness heritability (ROI: 50%, vertex-wise 40%). We also observed that limitations in image processing and variability in spatial averaging errors based on regional size may make obtaining true estimates of cortical thickness and surface area challenging in smaller regions. It is important to identify which approach is best suited to estimate heritability based on the research hypothesis and the size of the regions being investigated.
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Guma E, Rocchetti J, Devenyi GA, Tanti A, Mathieu A, Lerch JP, Elgbeili G, Courcot B, Mechawar N, Chakravarty MM, Giros B. Regional brain volume changes following chronic antipsychotic administration are mediated by the dopamine D2 receptor. Neuroimage 2018; 176:226-238. [PMID: 29704613 DOI: 10.1016/j.neuroimage.2018.04.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/17/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Neuroanatomical alterations are well established in patients suffering from schizophrenia, however the extent to which these changes are attributable to illness, antipsychotic drugs (APDs), or their interaction is unclear. APDs have been extremely effective for treatment of positive symptoms in major psychotic disorders. Their therapeutic effects are mediated, in part, through blockade of D2-like dopamine (DA) receptors, i.e. the D2, D3 and D4 dopamine receptors. Furthermore, the dependency of neuroanatomical change on DA system function and D2-like receptors has yet to be explored. METHODS We undertook a preclinical longitudinal study to examine the effects of typical (haloperidol (HAL)) and atypical (clozapine (CLZ)) APDs in wild type (WT) and dopamine D2 knockout (D2KO) mice over 9-weeks using structural magnetic resonance imaging (MRI). RESULTS Chronic typical APD administration in WT mice was associated with reductions in total brain (p = 0.009) and prelimbic area (PL) (p = 0.02) volumes following 9-weeks, and an increase in striatal volume (p = 0.04) after six weeks. These APD-induced changes were not present in D2KOs, where, at baseline, we observed significantly smaller overall brain volume (p < 0.01), thinner cortices (q < 0.05), and enlarged striata (q < 0.05). Stereological assessment revealed increased glial density in PL area of HAL treated wild types. Interestingly, in WT and D2KO mice, chronic CLZ administration caused more limited changes in brain structure. CONCLUSIONS Our results present evidence for the role of D2 DA receptors in structural alterations induced by the administration of the typical APD HAL and that chronic administration of CLZ has a limited influence on brain structure.
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Plitman E, Chavez S, Nakajima S, Iwata Y, Chung JK, Caravaggio F, Kim J, Alshehri Y, Chakravarty MM, De Luca V, Remington G, Gerretsen P, Graff-Guerrero A. Striatal neurometabolite levels in patients with schizophrenia undergoing long-term antipsychotic treatment: A proton magnetic resonance spectroscopy and reliability study. Psychiatry Res Neuroimaging 2018; 273:16-24. [PMID: 29414127 DOI: 10.1016/j.pscychresns.2018.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/14/2017] [Accepted: 01/22/2018] [Indexed: 12/13/2022]
Abstract
Previous proton magnetic resonance spectroscopy (1H-MRS) studies have reported disrupted levels of various neurometabolites in patients with schizophrenia. An area of particular interest within this patient population is the striatum, which is highly implicated in the pathophysiology of schizophrenia. The present study examined neurometabolite levels in the striatum of 12 patients with schizophrenia receiving antipsychotic treatment for at least 1 year and 11 healthy controls using 3-Tesla 1H-MRS (PRESS, TE = 35 ms). Glutamate, glutamate+glutamine (Glx), myo-inositol, choline, N-acetylaspartate, and creatine levels were estimated using LCModel, and corrected for fraction of cerebrospinal fluid in the 1H-MRS voxel. Striatal neurometabolite levels were compared between groups. Multiple study visits permitted a reliability assessment for neurometabolite levels (days between paired 1H-MRS acquisitions: average = 90.33; range = 7-306). Striatal neurometabolite levels did not differ between groups. Within the whole sample, intraclass correlation coefficients for glutamate, Glx, myo-inositol, choline, and N-acetylaspartate were fair to excellent (0.576-0.847). The similarity in striatal neurometabolite levels between groups implies a marked difference from the antipsychotic-naïve first-episode state, especially in terms of glutamatergic neurometabolites, and might provide insight regarding illness progression and the influence of antipsychotic medication.
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Chung JK, Plitman E, Nakajima S, Caravaggio F, Iwata Y, Gerretsen P, Kim J, Takeuchi H, Shinagawa S, Patel R, Chakravarty MM, Graff-Guerrero A. Hippocampal and Clinical Trajectories of Mild Cognitive Impairment with Suspected Non-Alzheimer's Disease Pathology. J Alzheimers Dis 2018; 58:747-762. [PMID: 28505977 DOI: 10.3233/jad-170201] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Suspected non-Alzheimer's disease pathology (SNAP) characterizes individuals showing neurodegeneration (e.g., hypometabolism) without amyloid-β (Aβ). Findings from previous studies regarding clinical and structural trajectories of SNAP are inconsistent. Using data from the Alzheimer's Disease Neuroimaging Initiative, patients with amnestic mild cognitive impairment (MCI) were categorized into four groups: amyloid positive with hypometabolism (Aβ+ND+), amyloid only (Aβ+ND-), neither amyloid nor hypometabolism (Aβ-ND-), and SNAP (Aβ-ND+). Aβ+ND+(n = 33), Aβ+ND-(n = 32), and Aβ-ND-(n = 36) were matched to SNAP for age, gender, apolipoprotein E4 (apoE4) genotype, and scores on the Montreal Cognitive Assessment. Elderly controls (n = 40) were also matched to SNAP for age, gender, and apoE4 genotype. Longitudinal changes were compared across groups in terms of hippocampal volume, clinical symptoms, daily functioning, and cognitive functioning over a 2-year period. At baseline, no difference in cognition and functioning was observed between SNAP and Aβ+groups. SNAP showed worse clinical symptoms and impaired functioning at baseline compared to Aβ-ND-and controls. Two years of follow-up showed no differences in hippocampal volume changes between SNAP and any of the comparison groups. SNAP showed worse functional deterioration in comparison to Aβ-ND-and controls. However, Aβ+ND+ showed more severe changes in clinical symptoms in comparison to SNAP. Thus, patients with MCI and SNAP showed 1) more severe functional deterioration compared to Aβ-ND-and controls, 2) no differences with Aβ+ND-, and 3) less cognitive deterioration than Aβ+ND+. Future studies should investigate what causes SNAP, which is different from typical AD pathology and biomarker cascades.
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Schneider J, Fischer Fumeaux CJ, Duerden EG, Guo T, Foong J, Graz MB, Hagmann P, Chakravarty MM, Hüppi PS, Beauport L, Truttmann AC, Miller SP. Nutrient Intake in the First Two Weeks of Life and Brain Growth in Preterm Neonates. Pediatrics 2018; 141:peds.2017-2169. [PMID: 29440285 DOI: 10.1542/peds.2017-2169] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/12/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Optimizing early nutritional intake in preterm neonates may promote brain health and neurodevelopment through enhanced brain maturation. Our objectives were (1) to determine the association of energy and macronutrient intake in the first 2 weeks of life with regional and total brain growth and white matter (WM) maturation, assessed by 3 serial MRI scans in preterm neonates; (2) to examine how critical illness modifies this association; and (3) to investigate the relationship with neurodevelopmental outcomes. METHODS Forty-nine preterm neonates (21 boys, median [interquartile range] gestational age: 27.6 [2.3] weeks) were scanned serially at the following median postmenstrual weeks: 29.4, 31.7, and 41. The total brain, basal nuclei, and cerebellum were semiautomatically segmented. Fractional anisotropy was extracted from diffusion tensor imaging data. Nutritional intake from day of life 1 to 14 was monitored and clinical factors were collected. RESULTS Greater energy and lipid intake predicted increased total brain and basal nuclei volumes over the course of neonatal care to term-equivalent age. Similarly, energy and lipid intake were significantly associated with fractional anisotropy values in selected WM tracts. The association of ventilation duration with smaller brain volumes was attenuated by higher energy intake. Brain growth predicted psychomotor outcome at 18 months' corrected age. CONCLUSIONS In preterm neonates, greater energy and enteral feeding during the first 2 weeks of life predicted more robust brain growth and accelerated WM maturation. The long-lasting effect of early nutrition on neurodevelopment may be mediated by enhanced brain growth. Optimizing nutrition in preterm neonates may represent a potential avenue to mitigate the adverse brain health consequences of critical illness.
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Caravaggio F, Fervaha G, Iwata Y, Plitman E, Chung JK, Nakajima S, Mar W, Gerretsen P, Kim J, Chakravarty MM, Mulsant B, Pollock B, Mamo D, Remington G, Graff-Guerrero A. Amotivation is associated with smaller ventral striatum volumes in older patients with schizophrenia. Int J Geriatr Psychiatry 2018; 33:523-530. [PMID: 29110353 PMCID: PMC5807115 DOI: 10.1002/gps.4818] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/08/2017] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Motivational deficits are prevalent in patients with schizophrenia, persist despite antipsychotic treatment, and predict long-term outcomes. Evidence suggests that patients with greater amotivation have smaller ventral striatum (VS) volumes. We wished to replicate this finding in a sample of older, chronically medicated patients with schizophrenia. Using structural imaging and positron emission tomography, we examined whether amotivation uniquely predicted VS volumes beyond the effects of striatal dopamine D2/3 receptor (D2/3 R) blockade by antipsychotics. METHODS Data from 41 older schizophrenia patients (mean age: 60.2 ± 6.7; 11 female) were reanalysed from previously published imaging data. We constructed multivariate linear stepwise regression models with VS volumes as the dependent variable and various sociodemographic and clinical variables as the initial predictors: age, gender, total brain volume, and antipsychotic striatal D2/3 R occupancy. Amotivation was included as a subsequent step to determine any unique relationships with VS volumes beyond the contribution of the covariates. In a reduced sample (n = 36), general cognition was also included as a covariate. RESULTS Amotivation uniquely explained 8% and 6% of the variance in right and left VS volumes, respectively (right: β = -.38, t = -2.48, P = .01; left: β = -.31, t = -2.17, P = .03). Considering cognition, amotivation levels uniquely explained 9% of the variance in right VS volumes (β = -.43, t = -0.26, P = .03). CONCLUSION We replicate and extend the finding of reduced VS volumes with greater amotivation. We demonstrate this relationship uniquely beyond the potential contributions of striatal D2/3 R blockade by antipsychotics. Elucidating the structural correlates of amotivation in schizophrenia may help develop treatments for this presently irremediable deficit.
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Schoemaker D, Buss C, Head K, Sandman CA, Davis EP, Chakravarty MM, Gauthier S, Pruessner JC. Corrigendum to "Hippocampus and amygdala volumes from magnetic resonance images in children: Assessing accuracy of FreeSurfer and FSL against manual segmentation"[NeuroImage 129 (2016) 1-14]. Neuroimage 2018; 173:1-2. [PMID: 29477029 DOI: 10.1016/j.neuroimage.2018.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Park MTM, Raznahan A, Shaw P, Gogtay N, Lerch JP, Chakravarty MM. Neuroanatomical phenotypes in mental illness: identifying convergent and divergent cortical phenotypes across autism, ADHD and schizophrenia. J Psychiatry Neurosci 2018; 43:170094. [PMID: 29402375 PMCID: PMC5915241 DOI: 10.1503/jpn.170094] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/01/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND There is evidence suggesting neuropsychiatric disorders share genomic, cognitive and clinical features. Here, we ask if autism-spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD) and schizophrenia share neuroanatomical variations. METHODS First, we used measures of cortical anatomy to estimate spatial overlap of neuroanatomical variation using univariate methods. Next, we developed a novel methodology to determine whether cortical deficits specifically target or are "enriched" within functional resting-state networks. RESULTS We found cortical anomalies were preferentially enriched across functional networks rather than clustering spatially. Specifically, cortical thickness showed significant enrichment between patients with ASD and those with ADHD in the default mode network, between patients with ASD and those with schizophrenia in the frontoparietal and limbic networks, and between patients with ADHD and those with schizophrenia in the ventral attention network. Networks enriched in cortical thickness anomalies were also strongly represented in functional MRI results (Neurosynth; r = 0.64, p = 0.032). LIMITATIONS We did not account for variable symptom dimensions and severity in patient populations, and our cross-sectional design prevented longitudinal analyses of developmental trajectories. CONCLUSION These findings suggest that common deficits across neuropsychiatric disorders cannot simply be characterized as arising out of local changes in cortical grey matter, but rather as entities of both local and systemic alterations targeting brain networks.
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Tardif CL, Devenyi GA, Amaral RSC, Pelleieux S, Poirier J, Rosa‐Neto P, Breitner J, Chakravarty MM. Regionally specific changes in the hippocampal circuitry accompany progression of cerebrospinal fluid biomarkers in preclinical Alzheimer's disease. Hum Brain Mapp 2018; 39:971-984. [PMID: 29164798 PMCID: PMC6866392 DOI: 10.1002/hbm.23897] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 11/10/2017] [Accepted: 11/13/2017] [Indexed: 01/18/2023] Open
Abstract
Neuropathological and in vivo brain imaging studies agree that the cornu ammonis 1 and subiculum subfields of the hippocampus are most vulnerable to atrophy in the prodromal phases of Alzheimer's disease (AD). However, there has been limited investigation of the structural integrity of the components of the hippocampal circuit, including subfields and extra-hippocampal white matter structure, in relation to the progression of well-accepted cerebrospinal fluid (CSF) biomarkers of AD, amyloid-β 1-42 (Aβ) and total-tau (tau). We investigated these relationships in 88 aging asymptomatic individuals with a parental or multiple-sibling familial history of AD. Apolipoprotein (APOE) ɛ4 risk allele carriers were identified, and all participants underwent cognitive testing, structural magnetic resonance imaging, and lumbar puncture for CSF assays of tau, phosphorylated-tau (p-tau) and Aβ. Individuals with a reduction in CSF Aβ levels (an indicator of amyloid accretion into neuritic plaques) as well as evident tau pathology (believed to be linked to neurodegeneration) exhibited lower subiculum volume, lower fornix microstructural integrity, and a trend towards lower cognitive score than individuals who showed only reduction in CSF Aβ. In contrast, persons with normal levels of tau showed an increase in structural MR markers in relation to declining levels of CSF Aβ. These results suggest that hippocampal subfield volume and extra-hippocampal white matter microstructure demonstrate a complex pattern where an initial volume increase is followed by decline among asymptomatic individuals who, in some instances, may be a decade or more away from onset of cognitive or functional impairment.
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Leoutsakos JMS, Yan H, Anderson WS, Asaad WF, Baltuch G, Burke A, Chakravarty MM, Drake KE, Foote KD, Fosdick L, Giacobbe P, Mari Z, McAndrews MP, Munro CA, Oh ES, Okun MS, Pendergrass JC, Ponce FA, Rosenberg PB, Sabbagh MN, Salloway S, Tang-Wai DF, Targum SD, Wolk D, Lozano AM, Smith GS, Lyketsos CG. Deep Brain Stimulation Targeting the Fornix for Mild Alzheimer Dementia (the ADvance Trial): A Two Year Follow-up Including Results of Delayed Activation. J Alzheimers Dis 2018; 64:597-606. [PMID: 29914028 PMCID: PMC6518401 DOI: 10.3233/jad-180121] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Given recent challenges in developing new treatments for Alzheimer dementia (AD), it is vital to explore alternate treatment targets, such as neuromodulation for circuit dysfunction. We previously reported an exploratory Phase IIb double-blind trial of deep brain stimulation targeting the fornix (DBS-f) in mild AD (the ADvance trial). We reported safety but no clinical benefits of DBS-f versus the delayed-on (sham) treatment in 42 participants after one year. However, secondary post hoc analyses of the one-year data suggested a possible DBS-f benefit for participants≥65 years. OBJECTIVE To examine the long-term safety and clinical effects of sustained and delayed-on DBS-f treatment of mild AD after two years. METHODS 42 participants underwent implantation of DBS-f electrodes, with half randomized to active DBS-f stimulation (early on) for two years and half to delayed-on (sham) stimulation after 1 year to provide 1 year of active DBS-f stimulation (delayed on). We evaluated safety and clinical outcomes over the two years of the trial. RESULTS DBS-f had a favorable safety profile with similar rates of adverse events across both trial phases (years 1 and 2) and between treatment arms. There were no differences between treatment arms on any primary clinical outcomes. However, post-hoc age group analyses suggested a possible benefit among older (>65) participants. CONCLUSION DBS-f was safe. Additional study of mechanisms of action and methods for titrating stimulation parameters will be needed to determine if DBS has potential as an AD treatment. Future efficacy studies should focus on patients over age 65.
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Nasseef MT, Devenyi GA, Mechling AE, Harsan LA, Chakravarty MM, Kieffer BL, Darcq E. Deformation-based Morphometry MRI Reveals Brain Structural Modifications in Living Mu Opioid Receptor Knockout Mice. Front Psychiatry 2018; 9:643. [PMID: 30559685 PMCID: PMC6287113 DOI: 10.3389/fpsyt.2018.00643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 11/15/2018] [Indexed: 12/12/2022] Open
Abstract
Mu opioid receptor (MOR) activation facilitates reward processing and reduces pain, and brain networks underlying these effects are under intense investigation. Mice lacking the MOR gene (MOR KO mice) show lower drug and social reward, enhanced pain sensitivity and altered emotional responses. Our previous neuroimaging analysis using Resting-state (Rs) functional Magnetic Resonance Imaging (fMRI) showed significant alterations of functional connectivity (FC) within reward/aversion networks in these mice, in agreement with their behavioral deficits. Here we further used a structural MRI approach to determine whether volumetric alterations also occur in MOR KO mice. We acquired anatomical images using a 7-Tesla MRI scanner and measured deformation-based morphometry (DBM) for each voxel in subjects from MOR KO and control groups. Our analysis shows marked anatomical differences in mutant animals. We observed both local volumetric contraction (striatum, nucleus accumbens, bed nucleus of the stria terminalis, hippocampus, hypothalamus and periacqueducal gray) and expansion (prefrontal cortex, amygdala, habenula, and periacqueducal gray) at voxel level. Volumetric modifications occurred mainly in MOR-enriched regions and across reward/aversion centers, consistent with our prior FC findings. Specifically, several regions with volume differences corresponded to components showing highest FC changes in our previous Rs-fMRI study, suggesting a possible function-structure relationship in MOR KO-related brain differences. In conclusion, both Rs-fMRI and volumetric MRI in live MOR KO mice concur to disclose functional and structural whole-brain level mechanisms that likely drive MOR-controlled behaviors in animals, and may translate to MOR-associated endophenotypes or disease in humans.
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Chung JK, Plitman E, Nakajima S, Caravaggio F, Shinagawa S, Iwata Y, Gerretsen P, Kim J, Takeuchi H, Patel R, Chakravarty MM, Strafella A, Graff-Guerrero A. The Effects of Cortical Hypometabolism and Hippocampal Atrophy on Clinical Trajectories in Mild Cognitive Impairment with Suspected Non-Alzheimer's Pathology: A Brief Report. J Alzheimers Dis 2017; 60:341-347. [PMID: 28826178 DOI: 10.3233/jad-170098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The clinical and structural trajectories of suspected non-Alzheimer' pathology (SNAP) remain elusive due to its heterogeneous etiology. Baseline and longitudinal clinical (global cognition, daily functioning, symptoms of dementia, and learning memory) and hippocampal volume trajectories over two years were compared between patients with amnestic mild cognitive impairment (aMCI) with SNAP with reduced hippocampal volumes (SNAP+HIPPO) and aMCI patients with SNAP without reduced hippocampal volumes. SNAP+HIPPO showed overall worse baseline cognitive functions. Longitudinally, SNAP+HIPPO showed faster deterioration of clinical symptoms of dementia. Having both hippocampal atrophy and cortical hypometabolism without amyloid pathology may exacerbate symptoms of dementia in aMCI.
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Hawco C, Armony JL, Daskalakis ZJ, Berlim MT, Chakravarty MM, Pike GB, Lepage M. Differing Time of Onset of Concurrent TMS-fMRI during Associative Memory Encoding: A Measure of Dynamic Connectivity. Front Hum Neurosci 2017; 11:404. [PMID: 28855865 PMCID: PMC5557775 DOI: 10.3389/fnhum.2017.00404] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 07/21/2017] [Indexed: 02/02/2023] Open
Abstract
There has been a distinct shift in neuroimaging from localization of function into a more network based approach focused on connectivity. While fMRI has proven very fruitful for this, the hemodynamic signal is inherently slow which limits the temporal resolution of fMRI-only connectivity measures. The brain, however, works on a time scale of milliseconds. This study utilized concurrent transcranial magnetic stimulation (TMS)-fMRI in a novel way to obtain measures of dynamic connectivity by measuring changes in fMRI signal amplitude in regions distal to the site of stimulation following differing TMS onset times. Seventeen healthy subjects completed an associative memory encoding task known to involve the DLPFC, viewing pairs of objects which could be semantically related or unrelated. Three pulses of 10 Hz repetitive TMS were applied over the left DLPFC starting either at 200, 600, or 1000 ms after stimulus onset. Associations for related pairs were better remembered than unrelated pairs in a post-scan cued recall test. Differences in neural activity were assessed across different TMS onsets, separately for related and unrelated pairs. Time specific TMS effects were observed in several regions, including those associated with higher-level processing (lateral frontal, anterior cingulate), visual areas (occipital), and regions involved in semantic processing (e.g., left mid-temporal and medial frontal). Activity in the frontal cortex was decreased at 200 ms post-stimulus for unrelated pairs, and 1000 ms post-stimulus for related pairs. This suggests differences in the timing across conditions in which the DLFPC interacts with other PFC regions, consistent with the notion that the DLPFC is facilitating extended semantic processing for related items. This study demonstrates that time-varying TMS onset inside the MRI can be used to reliably measure fast dynamic connectivity with a temporal resolution in the hundreds of milliseconds.
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Caravaggio F, Ku Chung J, Plitman E, Boileau I, Gerretsen P, Kim J, Iwata Y, Patel R, Chakravarty MM, Remington G, Graff-Guerrero A. The relationship between subcortical brain volume and striatal dopamine D 2/3 receptor availability in healthy humans assessed with [ 11 C]-raclopride and [ 11 C]-(+)-PHNO PET. Hum Brain Mapp 2017; 38:5519-5534. [PMID: 28752565 DOI: 10.1002/hbm.23744] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 07/16/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Abnormalities in dopamine (DA) and brain morphology are observed in several neuropsychiatric disorders. However, it is not fully understood how these abnormalities may relate to one another. For such in vivo findings to be used as biomarkers for neuropsychiatric disease, it must be understood how variability in DA relates to brain structure under healthy conditions. We explored how the availability of striatal DA D2/3 receptors (D2/3 R) is related to the volume of subcortical brain structures in a sample of healthy humans. Differences in D2/3 R availability measured with an antagonist radiotracer ([11 C]-raclopride) versus an agonist radiotracer ([11 C]-(+)-PHNO) were examined. METHODS Data from 62 subjects scanned with [11 C]-raclopride (mean age = 38.98 ± 14.45; 23 female) and 68 subjects scanned with [11 C]-(+)-PHNO (mean age = 38.54 ± 14.59; 25 female) were used. Subcortical volumes were extracted from T1-weighted images using the Multiple Automatically Generated Templates (MAGeT-Brain) algorithm. Partial correlations were used controlling for age, gender, and total brain volume. RESULTS For [11 C]-(+)-PHNO, ventral caudate volumes were positively correlated with BPND in the dorsal caudate and globus pallidus (GP). Ventral striatum (VS) volumes were positively correlated with BPND in the VS. With [11 C]-raclopride, BPND in the VS was negatively correlated with subiculum volume of the hippocampus. Moreover, BPND in the GP was negatively correlated with the volume of the lateral posterior nucleus of the thalamus. CONCLUSION Findings are purely exploratory and presented corrected and uncorrected for multiple comparisons. We hope they will help inform the interpretation of future PET studies where concurrent changes in D2/3 R and brain morphology are observed. Hum Brain Mapp 38:5519-5534, 2017. © 2017 Wiley Periodicals, Inc.
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Decker AL, Szulc KU, Bouffet E, Laughlin S, Chakravarty MM, Skocic J, de Medeiros CB, Mabbott DJ. Smaller hippocampal subfield volumes predict verbal associative memory in pediatric brain tumor survivors. Hippocampus 2017; 27:1140-1154. [DOI: 10.1002/hipo.22758] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 11/06/2022]
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