Dorsolateral Prefrontal Cortex Volume Research Articles

Action perception predicts action performance

Everyday action impairments often are observed in demented older adults, and they are common potential barriers to functional independence. We evaluated whether the ability to segment and efficiently encode activities is related to the ability to execute activities. Further, we evaluated whether brain regions important for segmentation also were important for action performance. Cognitively healthy older adults and those with very mild or mild dementia of the Alzheimer's type watched and segmented movies of everyday activities and then completed the Naturalistic Action Test. Structural MRI was used to measure volume in the dorsolateral prefrontal cortex (DLPFC), medial temporal lobes (MTL), posterior cortex, and anterior cingulate cortex (ACC). Dementia status and the ability to segment everyday activities strongly predicted naturalistic action performance, and MTL volume largely accounted for this relationship. In addition, the current results supported the Omission-Commission Model: Different cognitive and neurological mechanisms predicted different types of action error. Segmentation, dementia severity, and MTL volume predicted everyday omission errors, DLPFC volume predicted commission errors, and ACC volume predicted action additions. These findings suggest that event segmentation may be critical for effective action production, and that the segmentation and production of activities may recruit the same event representation system.

A longitudinal study of fronto-limbic brain structures in patients with bipolar I disorder during lithium treatment

In order to assess the association between therapeutic response to lithium treatment and fronto-limbic brain structures’ volumes in bipolar I patients (BPI) 24 BPI and 11 healthy comparisons underwent MRI scans at baseline and 4 weeks later. The BPIs received lithium during the 4 week period with a goal of achieving therapeutic blood levels of >0.5mEq/L (mean level 0.67mEq/L). Mood symptoms were rated with the Hamilton Depression and the Young Mania Rating Scales at baseline and after 4 weeks, and response was defined as >50% decrease on either scale. Hippocampus, amygdala, prefrontal (PFC), dorsolateral prefrontal (DLPFC), and anterior cingulate cortex (ACC) volumes were obtained by Freesurfer image analysis suite. According to baseline symptoms and treatment response, patients were assigned to three groups: euthymics (n=6), responders (n=12) and non-responders (n=6). Taken over both time periods, non-responders had smaller right amygdala than healthy comparisons and euthymic BPI (p=0.035 and p=0.003, respectively). When baseline and after treatment volumes were compared, there was a significant enlargement in left PFC and left DLPFC in BPI who responded to treatment (p=0.002 and p=0.006, respectively). Left hippocampus and right ACC volumes decreased in non-responders (p=0.02 and p=0.0001, respectively). According to the findings decreased left hippocampus and right ACC volumes may be markers of non-response to lithium amongst BPI. Smaller right amygdala may reflect symptomatic remission and be a marker of treatment non-response. Increases in left PFC and left DLPFC as a result of lithium treatment may relate to lithium's neurotrophic effects.

Dorsolateral Prefrontal Cortex Volumes Remained Unchanged in Obsessive Compulsive Disorder

Background: The dorsolateral prefrontal cortex (DLPFC) is an important prefrontal section of cortex, associated with executive functions, attention, nonverbal memory, and visuospatial skills, which have been reported to be disabled in OCD. In addition, neurochemical alterations of the DLPFC have been reported in OCD.Methods: This magnetic resonance imaging (MRI) study used manual tracing to measure DLPFC volumes in OCD patients arelative to healthy controls.Results: The mean DLPFC volumes of the patients with OCD were not statistically different compared to those of healthy control subjects.Conclusion: Based on our finding that DLPFC volumes remained unchanged in patients with OCD, despite some limitating factors, the present study suggests that there may not be an underlying structural basis for neurochemical changes of the DLPFC as well as executive function disorders in OCD.

Atrophy of the left dorsolateral prefrontal cortex is associated with poor performance in verbal fluency in elderly poststroke women.

This study aimed to investigate the association between atrophy in the prefrontal cortex with executive function and verbal fluency in elderly male and female patients poststroke. Thirty elderly female patients with non-aphasic ischemic stroke aged ≥ 60 years and 30 age-matched non-aphasic male patients with ischemic stroke were recruited. Automatic magnetic resonance imaging segmentation was used to assess the volume of the whole prefrontal cortex, along with its subdivisions: anterior cingulate cortex, orbitofrontal cortex and dorsolateral prefrontal cortex. The Semantic Verbal Fluency Test was administered at 3 and 15 months poststroke. At 3 months poststroke, left dorsolateral prefrontal cortex volume was significantly correlated with Verbal Fluency Test score in female patients only (partial coefficient = 0.453, P = 0.045), after controlling for age, education, diabetes, neurological deficit, white matter lesions volume, as well as the location and volume of infarcts. At 15 months poststroke, there remained a significant association between the left dorsolateral prefrontal cortex volume and Verbal Fluency Test (partial coefficient = 0.661, P = 0.001) and between the left prefrontal cortex volume and Verbal Fluency Test (partial coefficient = 0.573, P = 0.004) in female patients after the same adjustments. These findings indicate that atrophy of the left dorsolateral prefrontal cortex contributes to the impairment of verbal fluency in elderly female patients with stroke. Sex differences may be present in the neuropsychological mechanisms of verbal fluency impairment in patients with stroke.

Everyday Cognition in Older Adults: Associations with Neuropsychological Performance and Structural Brain Imaging

The recently developed Everyday Cognition scales (ECog) measure multiple cognitively relevant functional domains (e.g., Everyday Memory, Everyday Language, Everyday Visuospatial abilities, and three everyday executive domains). The present study further evaluated the validity of the ECog by examining its relationship with objective measures of neuropsychological function, and neurobiological markers of disease as reflected by structural neuroimaging. Participants included 474 older adults (244 normals, 142 with MCI, 88 with dementia). The neuropsychological domains measured were episodic memory, semantic memory, spatial ability, and executive functioning. Brain MRI volumes included total brain (BV), hippocampus (HC) and dorsolateral prefrontal cortex (DLPFC). Neuropsychological measures of episodic memory and executive function were most consistently related to the ECog domains; spatial abilities had a specific relationship to the Everyday Visuospatial ECog domain. HC and BV volumes were related to most ECog domains, while DLPFC volume was independently related to two everyday executive domains (Everyday Planning and Everyday Organization). The pattern of associations varied somewhat as a function of diagnosis. Episodic memory and HC had more consistent associations with the ECog domains in older adults with MCI/dementia than in cognitively normal elderly.

Dorsolateral prefrontal lobe volume and neurological soft signs as predictors of clinical social and functional outcome in schizophrenia: A longitudinal study

Schizophrenia is a disorder with variable outcome and the ability to predict the outcome has important clinical utility. Neurological soft signs (NSS) and dorsolateral prefrontal cortex volumes have been described as trait markers for schizophrenia and their relation to long-term outcome in schizophrenia has not been well studied. The aim of this study was to examine the correlation between baseline dorsolateral prefrontal lobe (DLPFL) volume and NSS scores to clinical and functional outcome variables in a cohort of schizophrenia patients who were anti-psychotic naïve at baseline. Fourteen anti-psychotic naive schizophrenia patients whose baseline magnetic resonance imaging scans, NSS scores and positive and negative signs and symptoms scale (PANSS) scores (assessed in drug naïve state) were available were reevaluated after a mean follow-up period of 74.2±24.2 months. The clinical outcome variables measured was PANSS. The social and functional outcome was assessed comprehensively by the socio occupational functioning scale and the Strauss Carpenter outcome scale. The DLPFL, volume was measured from the baseline scans using the region of interest method. Statistical analysis was done using the paired samples t-test and the Pearson's correlation co-efficient. The results showed that smaller left DLPFL volume and greater primitive reflexes at baseline predicted greater negative symptoms and poorer functional outcome on follow-up. This study also demonstrates the clinical utility of NSS as a simple bedside tool in assessing schizophrenia patients.

Brain Structural Correlates of Reward Sensitivity and Impulsivity in Adolescents with Normal and Excess Weight

IntroductionNeuroscience evidence suggests that adolescent obesity is linked to brain dysfunctions associated with enhanced reward and somatosensory processing and reduced impulse control during food processing. Comparatively less is known about the role of more stable brain structural measures and their link to personality traits and neuropsychological factors on the presentation of adolescent obesity. Here we aimed to investigate regional brain anatomy in adolescents with excess weight vs. lean controls. We also aimed to contrast the associations between brain structure and personality and cognitive measures in both groups.MethodsFifty-two adolescents (16 with normal weight and 36 with excess weight) were scanned using magnetic resonance imaging and completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the UPPS-P scale, and the Stroop task. Voxel-based morphometry (VBM) was used to assess possible between-group differences in regional gray matter (GM) and to measure the putative differences in the way reward and punishment sensitivity, impulsivity and inhibitory control relate to regional GM volumes, which were analyzed using both region of interest (ROI) and whole brain analyses. The ROIs included areas involved in reward/somatosensory processing (striatum, somatosensory cortices) and motivation/impulse control (hippocampus, prefrontal cortex).ResultsExcess weight adolescents showed increased GM volume in the right hippocampus. Voxel-wise volumes of the second somatosensory cortex (SII) were correlated with reward sensitivity and positive urgency in lean controls, but this association was missed in excess weight adolescents. Moreover, Stroop performance correlated with dorsolateral prefrontal cortex volumes in controls but not in excess weight adolescents.ConclusionAdolescents with excess weight have structural abnormalities in brain regions associated with somatosensory processing and motivation.

Injury to the Premature Cerebellum: Outcome is Related to Remote Cortical Development

Cerebellar injury is an important complication of preterm birth with far-reaching neuropsychiatric sequelae. We have previously shown a significant association between isolated injury to the premature cerebellum and subsequent impairment of regional volumetric growth in the contralateral cerebrum. In the current study, we examine the relationship between these remote regional impairments of cerebral volumetric growth and domain-specific functional deficits in these children. In 40 ex-preterm infants with isolated cerebellar injury, we performed neurodevelopmental evaluations and quantitative magnetic resonance imaging (MRI) studies at a mean age of 34 months. We measured cortical gray matter volumes in 8 parcellated regions of each cerebral hemisphere, as well as right and left cerebellar volumes. We show highly significant associations between early signs of autism and dorsolateral prefrontal cortex volume (P < 0.001); gross motor scores and sensorimotor cortical volumes (P < 0.001); and cognitive and expressive language scores and premotor and mid-temporal cortical volumes (P < 0.001). By multivariate analyses, each unit increase in the corresponding regional cerebral volume was associated with lower odds of abnormal outcome score, adjusted for age at MRI and contralateral cerebellar volume. This is the first report linking secondary impairment of remote cerebral cortical growth and functional disabilities in survivors of prematurity-related cerebellar brain injury.

Brain structure abnormalities in adolescent girls with conduct disorder

BackgroundConduct disorder (CD) in female adolescents is associated with a range of negative outcomes, including teenage pregnancy and antisocial personality disorder. Although recent studies have documented changes in brain structure and function in male adolescents with CD, there have been no neuroimaging studies of female adolescents with CD. Our primary objective was to investigate whether female adolescents with CD show changes in grey matter volume. Our secondary aim was to assess for sex differences in the relationship between CD and brain structure.MethodsFemale adolescents with CD (n = 22) and healthy control participants matched in age, performance IQ and handedness (n = 20) underwent structural magnetic resonance imaging. Group comparisons of grey matter volume were performed using voxel-based morphometry. We also tested for sex differences using archive data obtained from male CD and control participants.ResultsFemale adolescents with CD showed reduced bilateral anterior insula and right striatal grey matter volumes compared with healthy controls. Aggressive CD symptoms were negatively correlated with right dorsolateral prefrontal cortex volume, whereas callous-unemotional traits were positively correlated with bilateral orbitofrontal cortex volume. The sex differences analyses revealed a main effect of diagnosis on right amygdala volume (reflecting reduced amygdala volume in the combined CD group relative to controls) and sex-by-diagnosis interactions in bilateral anterior insula.ConclusionsWe observed structural abnormalities in brain regions involved in emotion processing, reward and empathy in female adolescents with CD, which broadly overlap with those reported in previous studies of CD in male adolescents.

Antidepressant effects of sertraline associated with volume increases in dorsolateral prefrontal cortex

BackgroundStructural brain imaging has revealed differences in gray matter volume between depressed individuals and control subjects in key structures related to emotion. The aim of the present study was to assess within subjects whether regional changes in gray matter volume were observed over time in depressed patients treated with sertraline. MethodsThirteen depressed patients were assigned to selective serotonin reuptake inhibitor (SSRI) treatment with sertraline. Structural magnetic resonance imaging (MRI) was performed at four time points over 12 weeks of treatment. Depressed individuals were compared to a control group of 10 subjects scanned at the same time points using voxel based morphometry and a statistical growth modeling technique. ResultsSSRI-treated patients showed a region of significantly increasing gray matter volume over time within the left dorsolateral prefrontal cortex (DLPFC) that specifically correlated with decreases in self-reported depression levels. No statistically significant changes were observed related to time in controls. LimitationsThis study included a small sample size and the method of analysis was capable of detecting only linear changes in volume. ConclusionsEffective antidepressant treatment with sertraline is associated with left DLPFC volume increases. These volume increases may reflect cortical architectural changes associated with top-down neuronal modulation of emotion.

Dorsolateral prefrontal cortex volume in patients with deficit or nondeficit schizophrenia

Deficit schizophrenia (DS) represents a promising putative clinical subtype of schizophrenia and is characterized by the presence of primary and enduring negative symptoms. Previous studies have often reported a reduced amount of gray matter within prefrontal and temporal cortices in schizophrenia subjects with prevailing negative symptoms; however, the evidence concerning brain structural abnormalities in patients with DS remains controversial. The aim of the present study was to investigate whether patients with DS differed from those with nondeficit schizophrenia (NDS) with respect to the volume of the dorsolateral prefrontal cortex (DLPFC) and hippocampus, two brain areas considered as key regions in the pathogenesis of schizophrenia. In the present study a 3D-T1w MR imaging procedure and an extensive clinical assessment was carried out in 18 patients with schizophrenia, (10 DS and 8 NDS). 3D MPRAGE images were preprocessed with SPM software and two regions of interest (hippocampus and DLPFC) were manually traced to obtain their gray matter volumes. We found a significant reduction of DLPFC in the entire schizophrenia group, with respect to healthy subjects. Although the subgroup of patients with DS had a more severe clinical picture and more impaired social functioning, the DLPFC volume reduction was greater in NDS than in DS patients. In conclusion, according to our structural neuroimaging findings, DS patients, although characterized by a more severe clinical picture and a worse outcome, show less neurobiological abnormalities.

Restraint of appetite and reduced regional brain volumes in anorexia nervosa: a voxel-based morphometric study

BackgroundPrevious Magnetic Resonance Imaging (MRI) studies of people with anorexia nervosa (AN) have shown differences in brain structure. This study aimed to provide preliminary extensions of this data by examining how different levels of appetitive restraint impact on brain volume.MethodsVoxel based morphometry (VBM), corrected for total intracranial volume, age, BMI, years of education in 14 women with AN (8 RAN and 6 BPAN) and 21 women (HC) was performed. Correlations between brain volume and dietary restraint were done using Statistical Package for the Social Sciences (SPSS).ResultsIncreased right dorsolateral prefrontal cortex (DLPFC) and reduced right anterior insular cortex, bilateral parahippocampal gyrus, left fusiform gyrus, left cerebellum and right posterior cingulate volumes in AN compared to HC. RAN compared to BPAN had reduced left orbitofrontal cortex, right anterior insular cortex, bilateral parahippocampal gyrus and left cerebellum. Age negatively correlated with right DLPFC volume in HC but not in AN; dietary restraint and BMI predicted 57% of variance in right DLPFC volume in AN.ConclusionsIn AN, brain volume differences were found in appetitive, somatosensory and top-down control brain regions. Differences in regional GMV may be linked to levels of appetitive restraint, but whether they are state or trait is unclear. Nevertheless, these discrete brain volume differences provide candidate brain regions for further structural and functional study in people with eating disorders.

Classification of schizophrenia using feature-based morphometry

The objective of this study was to use a combined local descriptor, namely scale invariance feature transform (SIFT), and a non linear support vector machine (SVM) technique to automatically classify patients with schizophrenia. The dorsolateral prefrontal cortex (DLPFC), considered a reliable neuroanatomical marker of the disease, was chosen as region of interest (ROI). Fifty-four schizophrenia patients and 54 age- and gender-matched normal controls were studied with a 1.5T MRI (slice thickness 1.25mm). Three steps were conducted: (1) landmark detection and description of the DLPFC, (2) feature vocabulary construction and Bag-of-Words (BoW) computation for brain representation, (3) SVM classification which adopted the local kernel to implicitly implement the feature matching. Moreover, a new weighting approach was proposed to take into account the discriminant relevance of the detected groups of features. Substantial results were obtained for the classification of the whole dataset (left side 75%, right side 66.38%). The performances were higher when females (left side 84.09%, right side 77.27%) and seniors (left side 81.25%, right side 70.83%) were considered separately. In general, the supervised weighed functions increased the efficacy in all the analyses. No effects of age, gender, antipsychotic treatment and chronicity were shown on DLPFC volumes. This integrated innovative ROI-SVM approach allows to reliably detect subjects with schizophrenia, based on a structural brain marker for the disease such as the DLPFC. Such classification should be performed in first-episode patients in future studies, by considering males and females separately.

Cognition and dorsolateral prefrontal cortex volume in corticosteroid‐treated patients given lamotrigine

AbstractIn addition to changes in declarative memory and the hippocampus, corticosteroid excess is associated with prefrontal cortex changes. We previously reported that patients receiving exogenous corticosteroid therapy had impaired performance on prefrontal cortex‐related tasks, including working memory and executive functioning tasks. Glutamate release inhibitors attenuate corticosteroid‐effects on the hippocampus in both animal and human models. Twenty‐eight outpatients receiving chronic prednisone therapy for transplant rejection or other medical conditions were randomized to lamotrigine (a glutamate release inhibitor) or placebo for 24 weeks. Dorsolateral prefrontal cortex (DLPFC) volume was manually traced from MRI scans by trained staff members. Cognition was examined using the Stroop Color Word Test (SCWT), Delis‐Kaplan Executive Function System (D‐KEFS) and the Trail Making Test. Groups were compared using analysis of covariance. Consistent with prior findings in corticosteroid‐treated patients, baseline cognitive function was in the low normal range. At baseline, prednisone duration showed a trend towards negative correlation with SCWT and D‐KEFS inhibition switching time error scores, and DLPFC volume showed a trend towards a positive correlation with SCWT scores. No significant between‐group differences in outcomes were observed following lamotrigine therapy. Thus, this study found lamotrigine to not be associated with either positive or negative effects on cognition or DLPFC volume. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Dorso- and ventro-lateral prefrontal volume and spatial working memory in schizotypal personality disorder

Schizotypal personality disorder (SPD) individuals and borderline personality disorder (BPD) individuals have been reported to show neuropsychological impairments and abnormalities in brain structure. However, relationships between neuropsychological function and brain structure in these groups are not well understood. This study compared visual–spatial working memory (SWM) and its associations with dorsolateral prefrontal cortex (DLPFC) and ventrolateral prefrontal cortex (VLPFC) gray matter volume in 18 unmedicated SPD patients with no BPD traits, 18 unmedicated BPD patients with no SPD traits, and 16 healthy controls (HC). Results showed impaired SWM in SPD but not BPD, compared with HC. Moreover, among the HC group, but not SPD patients, better SWM performance was associated with larger VLPFC (BA44/45) gray matter volume (Fisher's Z p-values <0.05). Findings suggest spatial working memory impairments may be a core neuropsychological deficit specific to SPD patients and highlight the role of VLPFC subcomponents in normal and dysfunctional memory performance.

Distinct neuroanatomical substrates and cognitive mechanisms of figure copy performance in Alzheimer's disease and behavioral variant frontotemporal dementia

Figure copy is the most common method of visual spatial assessment in dementia evaluations, but performance on this test may be multifactorial. We examined the neuroanatomical substrates of figure copy performance in 46 patients with Alzheimer's disease (AD) and 48 patients with the behavioral variant of Frontotemporal dementia (bvFTD). A group of 94 neurologically healthy controls were studied for comparison. In AD, poor figure copy correlated significantly with right parietal cortex volumes but not with right dorsolateral prefrontal cortex volumes, whereas in bvFTD, figure copy performance correlated significantly with right dorsolateral prefrontal cortex volumes and there was only a trend with right parietal cortex volumes. The cognitive processes associated with figure copy performance also differed by diagnostic group such that figure copy was associated with spatial perception and attention in AD and with spatial planning and working memory in bvFTD. Spatial planning accounted for unique variance in the figure copy performance of bvFTD even after accounting for spatial perception, attention, and working memory. These results suggest that figure copy performance in AD and bvFTD is not anatomically specific and is differentially impacted by bottom-up and top-down aspects of visual spatial processing. Alternative methods of visual spatial assessment for dementia evaluations are proposed.

Dorsolateral Prefrontal Cortex Magnetic Resonance Imaging Measurements and Cognitive Performance in Autism

This study examined the relationships between volumetric measurements of frontal lobe structures and performance on executive function tasks in individuals with autism. Magnetic resonance imaging (MRI) scans were obtained from 38 individuals with autism and 40 matched controls between the ages of 8 and 45 years. Executive function was assessed using neuropsychological measures including the Wisconsin Card Sorting Test and Tower of Hanoi. Differences in performance on the neuropsychological tests were found between the 2 groups. However, no differences in dorsolateral prefrontal cortex volumes were observed between groups. No correlations between volumetric measurements and performance on the neuropsychological tests were found. Findings from this study suggest that executive function deficits observed in autism are related to functional but not anatomical abnormalities of the frontal lobe. The absence of correlations suggests that executive dysfunction is not the result of focal brain alterations but, rather, is the result of a distributed neural network dysfunction.

Individual Differences in Right Dorsolateral Prefrontal Cortex Volumes, Whole Brain Activity and Memory Performance in Healthy Young and Older Adults

Event Abstract Back to Event Individual Differences in Right Dorsolateral Prefrontal Cortex Volumes, Whole Brain Activity and Memory Performance in Healthy Young and Older Adults Y. Czechowska1, C L Grady1, 2, R. Languay1, J C Pruessner1, M N Rajah1* and L. Valiquette1 1 McGill University, Douglas Mental Health University Institute, Canada 2 University of Toronto, Rotman Research Institute at Baycrest, Canada We conducted an fMRI study on 25 young and 26 older healthy adults and reported deficits in right dorsolateral PFC (DLPFC) activity that were linked to context memory reductions deficits in older adults (Rajah et al 2010). To extend this result we conducted semi-automatic volume segmentation of left and right DLFPC in this cohort and found a near significant (p = .055) group-by-hemispheric difference in DLPFC volume, due to older adults exhibiting smaller right versus left DLPFC volumes compared to young adults. To determine if this age-difference in right DLPFC volume was linked with changes in right DLPFC structure-function associations, we conducted a multivariate partial least squares (ST-PLS) seed analysis, using right DLPFC volumes and accuracy scores. One significant effect (p<.001) was indentified, which reflected group differences in the network of brain regions activated in association with correct context retrieval and larger right DLPFC volumes. In young adults improved retrieval accuracy and larger right DLPFC volumes was associated with increased bilateral DLPFC activity and right hippocampal activity. In contrast, in older adults retrieval accuracy and larger right DLPFC volumes was associated with increased activity in left, but not right, DLPFC, bilateral ventrolateral PFC and caudate. This supports the argument that age-related deficits in context memory retrieval may be due to changes in right DLPFC structure, function and its structure-function associations with the retrieval network, including right hippocampus. Conference: The 20th Annual Rotman Research Institute Conference, The frontal lobes, Toronto, Canada, 22 Mar - 26 Mar, 2010. Presentation Type: Poster Presentation Topic: Cognitive Neuroscience Citation: Czechowska Y, Grady C, Languay R, Pruessner J, Rajah M and Valiquette L (2010). Individual Differences in Right Dorsolateral Prefrontal Cortex Volumes, Whole Brain Activity and Memory Performance in Healthy Young and Older Adults. Conference Abstract: The 20th Annual Rotman Research Institute Conference, The frontal lobes. doi: 10.3389/conf.fnins.2010.14.00116 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Jun 2010; Published Online: 30 Jun 2010. * Correspondence: M N Rajah, McGill University, Douglas Mental Health University Institute, Montreal, QC, Canada, maria.rajah@mcgill.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Y. Czechowska C L Grady R. Languay J C Pruessner M N Rajah L. Valiquette Google Y. Czechowska C L Grady R. Languay J C Pruessner M N Rajah L. Valiquette Google Scholar Y. Czechowska C L Grady R. Languay J C Pruessner M N Rajah L. Valiquette PubMed Y. Czechowska C L Grady R. Languay J C Pruessner M N Rajah L. Valiquette Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Anterior hippocampal and orbitofrontal cortical structural brain abnormalities in association with cognitive deficits in schizophrenia

Objective Numerous studies have implicated the hippocampus and prefrontal cortex in schizophrenia. However, precisely which subregions of the hippocampus and prefrontal cortex are abnormal remain unknown. Our study goal was to investigate the structure of the anterior hippocampus, posterior hippocampus, dorsolateral prefrontal cortex (DLPFC), and orbitofrontal cortex (OFC) simultaneously in thirty-eight patients with schizophrenia and twenty-nine controls to determine which of these subregions are abnormal in schizophrenia. As an exploratory study goal, we investigated the relation of neurocognition to brain structure in schizophrenia patients. Method We generated detailed structural magnetic resonance imaging data and compared hippocampal and prefrontal subregional structural brain volumes between schizophrenia and control groups. We obtained a neurocognitive test battery in schizophrenia patients and studied the association of abnormal brain structures to neurocognition. Results Structural brain abnormalities were pinpointed to the left anterior hippocampus and left OFC in schizophrenia patients, which were both significantly reduced in volume. The DLPFC and posterior hippocampus, though numerically decreased in volume, were not significantly decreased. Anterior hippocampal volumes were more strongly associated with OFC volumes in schizophrenia patients compared to controls. By contrast, DLPFC volume was unrelated to anterior or posterior hippocampal volume. Both the anterior hippocampus and OFC were independently related to cognitive abnormalities common in schizophrenia, including indices of verbal, language, and executive functions. The DLPFC and posterior hippocampal volumes were unrelated to cognitive measures. Conclusions These findings highlight related abnormalities of the anterior hippocampus and OFC in schizophrenia, which may shed light on the pathophysiology of the disorder.

Neuroanatomic Alterations and Social and Communication Deficits in Monozygotic Twins Discordant for Autism Disorder

Investigating neuroanatomic differences in monozygotic twins who are discordant for autism can help unravel the relative contributions of genetics and environment to this pervasive developmental disorder. The authors used magnetic resonance imaging (MRI) to investigate several brain regions of interest in monozygotic twins who varied in degree of phenotypic discordance for narrowly defined autism. The subjects were 14 pairs of monozygotic twins between the ages of 5 and 14 years old and 14 singleton age- and gender-matched typically developing comparison subjects. The monozygotic twin group was a cohort of children with narrowly defined autistic deficits and their co-twins who presented with varying levels of autistic deficits. High-resolution MRIs were acquired and volumetric/area measurements obtained for the frontal lobe, amygdala, and hippocampus and subregions of the prefrontal cortex, corpus callosum, and cerebellar vermis. No neurovolumetric/area differences were found between twin pairs. Relative to typically developing comparison subjects, dorsolateral prefrontal cortex volumes and anterior areas of the corpus callosum were significantly altered in autistic twins, and volumes of the posterior vermis were altered in both autistic twins and co-twins. Intraclass correlation analysis of brain volumes between children with autism and their co-twins indicated that the degree of within-pair neuroanatomic concordance varied with brain region. In the group of subjects with narrowly defined autism only, dorsolateral prefrontal cortex, amygdala, and posterior vermis volumes were significantly associated with the severity of autism based on scores from the Autism Diagnostic Observation Schedule-Generic. These findings support previous research demonstrating alterations in the prefrontal cortex, corpus callosum, and posterior vermis in children with autism and further suggest that alterations are associated with the severity of the autism phenotype. Continued research involving twins who are concordant and discordant for autism is essential to disentangle the genetic and environmental contributions to autism.