Search results
Found 21078 matches for
Genetic effects on cerebellar structure across mouse models of autism using a magnetic resonance imaging atlas.
Magnetic resonance imaging (MRI) of autism populations is confounded by the inherent heterogeneity in the individuals' genetics and environment, two factors difficult to control for. Imaging genetic animal models that recapitulate a mutation associated with autism quantify the impact of genetics on brain morphology and mitigate the confounding factors in human studies. Here, we used MRI to image three genetic mouse models with single mutations implicated in autism: Neuroligin-3 R451C knock-in, Methyl-CpG binding protein-2 (MECP2) 308-truncation and integrin β3 homozygous knockout. This study identified the morphological differences specific to the cerebellum, a structure repeatedly linked to autism in human neuroimaging and postmortem studies. To accomplish a comparative analysis, a segmented cerebellum template was created and used to segment each study image. This template delineated 39 different cerebellar structures. For Neuroligin-3 R451C male mutants, the gray (effect size (ES) = 1.94, FDR q = 0.03) and white (ES = 1.84, q = 0.037) matter of crus II lobule and the gray matter of the paraflocculus (ES = 1.45, q = 0.045) were larger in volume. The MECP2 mutant mice had cerebellar volume changes that increased in scope depending on the genotype: hemizygous males to homozygous females. The integrin β3 mutant mouse had a drastically smaller cerebellum than controls with 28 out of 39 cerebellar structures smaller. These imaging results are discussed in relation to repetitive behaviors, sociability, and learning in the context of autism. This work further illuminates the cerebellum's role in autism.
Development of short-range white matter in healthy children and adolescents.
Neural communication is facilitated by intricate networks of white matter (WM) comprised of both long and short range connections. The maturation of long range WM connections has been extensively characterized, with projection, commissural, and association tracts showing unique trajectories with age. There, however, remains a limited understanding of age-related changes occurring within short range WM connections, or U-fibers. These connections are important for local connectivity within lobes and facilitate regional cortical function and greater network economy. Recent studies have explored the maturation of U-fibers primarily using cross-sectional study designs. Here, we analyzed diffusion tensor imaging (DTI) data for healthy children and adolescents in both a cross-sectional (n = 78; mean age = 13.04 ± 3.27 years) and a primarily longitudinal (n = 26; mean age = 10.78 ± 2.69 years) cohort. We found significant age-related differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) across the frontal, parietal, and temporal lobes of participants within the cross-sectional cohort. By contrast, we report significant age-related differences in only FA for participants within the longitudinal cohort. Specifically, larger FA values were observed with age in frontal, parietal, and temporal lobes of the left hemisphere. Our results extend previous findings restricted to long range WM to demonstrate regional changes in the microstructure of short range WM during childhood and adolescence. These changes possibly reflect continued myelination and axonal organization of short range WM with increasing age in more anterior regions of the left hemisphere. Hum Brain Mapp 39:204-217, 2018. © 2017 Wiley Periodicals, Inc.
Examining overlap and homogeneity in ASD, ADHD, and OCD: a data-driven, diagnosis-agnostic approach.
The validity of diagnostic labels of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and obsessive compulsive disorder (OCD) is an open question given the mounting evidence that these categories may not correspond to conditions with distinct etiologies, biologies, or phenotypes. The objective of this study was to determine the agreement between existing diagnostic labels and groups discovered based on a data-driven, diagnosis-agnostic approach integrating cortical neuroanatomy and core-domain phenotype features. A machine learning pipeline, called bagged-multiview clustering, was designed to discover homogeneous subgroups by integrating cortical thickness data and measures of core-domain phenotypic features of ASD, ADHD, and OCD. This study was conducted using data from the Province of Ontario Neurodevelopmental Disorders (POND) Network, a multi-center study in Ontario, Canada. Participants (n = 226) included children between the ages of 6 and 18 with a diagnosis of ASD (n = 112, median [IQR] age = 11.7[4.8], 21% female), ADHD (n = 58, median [IQR] age = 10.2[3.3], 14% female), or OCD (n = 34, median [IQR] age = 12.1[4.2], 38% female), as well as typically developing controls (n = 22, median [IQR] age = 11.0[3.8], 55% female). The diagnosis-agnostic groups were significantly different than each other in phenotypic characteristics (SCQ: χ2(9) = 111.21, p < 0.0001; SWAN: χ2(9) = 142.44, p < 0.0001) as well as cortical thickness in 75 regions of the brain. The analyses revealed disagreement between existing diagnostic labels and the diagnosis-agnostic homogeneous groups (normalized mutual information < 0.20). Our results did not support the validity of existing diagnostic labels of ASD, ADHD, and OCD as distinct entities with respect to phenotype and cortical morphology.
Consortium neuroscience of attention deficit/hyperactivity disorder and autism spectrum disorder: The ENIGMA adventure.
Neuroimaging has been extensively used to study brain structure and function in individuals with attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) over the past decades. Two of the main shortcomings of the neuroimaging literature of these disorders are the small sample sizes employed and the heterogeneity of methods used. In 2013 and 2014, the ENIGMA-ADHD and ENIGMA-ASD working groups were respectively, founded with a common goal to address these limitations. Here, we provide a narrative review of the thus far completed and still ongoing projects of these working groups. Due to an implicitly hierarchical psychiatric diagnostic classification system, the fields of ADHD and ASD have developed largely in isolation, despite the considerable overlap in the occurrence of the disorders. The collaboration between the ENIGMA-ADHD and -ASD working groups seeks to bring the neuroimaging efforts of the two disorders closer together. The outcomes of case-control studies of subcortical and cortical structures showed that subcortical volumes are similarly affected in ASD and ADHD, albeit with small effect sizes. Cortical analyses identified unique differences in each disorder, but also considerable overlap between the two, specifically in cortical thickness. Ongoing work is examining alternative research questions, such as brain laterality, prediction of case-control status, and anatomical heterogeneity. In brief, great strides have been made toward fulfilling the aims of the ENIGMA collaborations, while new ideas and follow-up analyses continue that include more imaging modalities (diffusion MRI and resting-state functional MRI), collaborations with other large databases, and samples with dual diagnoses.
Cyclin D2-knock-out mice with attenuated dentate gyrus neurogenesis have robust deficits in long-term memory formation.
Neurobehavioral studies have produced contradictory findings concerning the function of neurogenesis in the adult dentate gyrus. Previous studies have proved inconsistent across several behavioral endpoints thought to be dependent on dentate neurogenesis, including memory acquisition, short-term and long-term retention of memory, pattern separation, and reversal learning. We hypothesized that the main function of dentate neurogenesis is long-term memory formation because we assumed that a newly formed and integrated neuron would have a long-term impact on the local neural network. We used a cyclin D2-knock-out (cyclin D2-/-) mouse model of endogenously deficient dentate neurogenesis to test this hypothesis. We found that cyclin D2-/- mice had robust and sustained loss of long-term memory in two separate behavioral tasks, Morris water maze (MWM) and touchscreen intermediate pattern separation. Moreover, after adjusting for differences in brain volumes determined by magnetic resonance (MR) imaging, reduced dentate neurogenesis moderately correlated with deficits in memory retention after 24 hours. Importantly, cyclin D2-/- mice did not show deficits in learning acquisition in a touchscreen paradigm of intermediate pattern separation or MWM platform location, indicating intact short-term memory. Further evaluation of cyclin D2-/- mice is necessary to confirm that deficits are specifically linked to dentate gyrus neurogenesis since cyclin D2-/- mice also have a reduced size of the olfactory bulb, hippocampus, cerebellum and cortex besides reduced dentate gyrus neurogenesis.
Effects of Antipsychotic Medication on Brain Structure in Patients With Major Depressive Disorder and Psychotic Features: Neuroimaging Findings in the Context of a Randomized Placebo-Controlled Clinical Trial.
Importance: Prescriptions for antipsychotic medications continue to increase across many brain disorders, including off-label use in children and elderly individuals. Concerning animal and uncontrolled human data suggest antipsychotics are associated with change in brain structure, but to our knowledge, there are no controlled human studies that have yet addressed this question. Objective: To assess the effects of antipsychotics on brain structure in humans. Design, Setting, and Participants: Prespecified secondary analysis of a double-blind, randomized, placebo-controlled trial over a 36-week period at 5 academic centers. All participants, aged 18 to 85 years, were recruited from the multicenter Study of the Pharmacotherapy of Psychotic Depression II (STOP-PD II). All participants had major depressive disorder with psychotic features (psychotic depression) and were prescribed olanzapine and sertraline for a period of 12 to 20 weeks, which included 8 weeks of remission of psychosis and remission/near remission of depression. Participants were then were randomized to continue receiving this regimen or to be switched to placebo and sertraline for a subsequent 36-week period. Data were analyzed between October 2018 and February 2019. Interventions: Those who consented to the imaging study completed a magnetic resonance imaging (MRI) scan at the time of randomization and a second MRI scan at the end of the 36-week period or at time of relapse. Main Outcomes and Measures: The primary outcome measure was cortical thickness in gray matter and the secondary outcome measure was microstructural integrity of white matter. Results: Eighty-eight participants (age range, 18-85 years) completed a baseline scan; 75 completed a follow-up scan, of which 72 (32 men and 40 women) were useable for final analyses. There was a significant treatment-group by time interaction in cortical thickness (left, t = 3.3; P = .001; right, t = 3.6; P < .001) but not surface area. No significant interaction was found for fractional anisotropy, but one for mean diffusivity of the white matter skeleton was present (t = -2.6, P = .01). When the analysis was restricted to those who sustained remission, exposure to olanzapine compared with placebo was associated with significant decreases in cortical thickness in the left hemisphere (β [SE], 0.04 [0.009]; t34.4 = 4.7; P <.001), and the right hemisphere (β [SE], 0.03 [0.009]; t35.1 = 3.6; P <.001). Post hoc analyses showed that those who relapsed receiving placebo experienced decreases in cortical thickness compared with those who sustained remission. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, antipsychotic medication was shown to change brain structure. This information is important for prescribing in psychiatric conditions where alternatives are present. However, adverse effects of relapse on brain structure support antipsychotic treatment during active illness. Trial Registration: ClinicalTrials.gov Identifier: NCT01427608.
Altered structural brain asymmetry in autism spectrum disorder in a study of 54 datasets.
Altered structural brain asymmetry in autism spectrum disorder (ASD) has been reported. However, findings have been inconsistent, likely due to limited sample sizes. Here we investigated 1,774 individuals with ASD and 1,809 controls, from 54 independent data sets of the ENIGMA consortium. ASD was significantly associated with alterations of cortical thickness asymmetry in mostly medial frontal, orbitofrontal, cingulate and inferior temporal areas, and also with asymmetry of orbitofrontal surface area. These differences generally involved reduced asymmetry in individuals with ASD compared to controls. Furthermore, putamen volume asymmetry was significantly increased in ASD. The largest case-control effect size was Cohen's d = -0.13, for asymmetry of superior frontal cortical thickness. Most effects did not depend on age, sex, IQ, severity or medication use. Altered lateralized neurodevelopment may therefore be a feature of ASD, affecting widespread brain regions with diverse functions. Large-scale analysis was necessary to quantify subtle alterations of brain structural asymmetry in ASD.
Cortical thickness in children receiving intensive therapy for idiopathic apraxia of speech.
Children with idiopathic apraxia experience difficulties planning the movements necessary for intelligible speech. There is increasing evidence that targeted early interventions, such as Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT), can be effective in treating these disorders. In this study, we investigate possible cortical thickness correlates of idiopathic apraxia of speech in childhood, and changes associated with participation in an 8-week block of PROMPT therapy. We found that children with idiopathic apraxia (n = 11), aged 3-6 years, had significantly thicker left supramarginal gyri than a group of typically-developing age-matched controls (n = 11), t(20) = 2.84, p ≤ 0.05. Over the course of therapy, the children with apraxia (n = 9) experienced significant thinning of the left posterior superior temporal gyrus (canonical Wernicke's area), t(8) = 2.42, p ≤ 0.05. This is the first study to demonstrate experience-dependent structural plasticity in children receiving therapy for speech sound disorders.
Neuroanatomical consequences of very preterm birth in middle childhood.
Individuals born preterm can demonstrate reductions in brain volume, cortical surface area and thickness. However, the extent of these neuroanatomical deficits and the relation among these measures in middle childhood, a critical developmental period, have not been determined. We assessed differences in brain structure by acquiring high-resolution T(1)-weighted scans in 25 children born very preterm (<32 weeks gestational age) without significant post-natal neurological sequelae and 32 age-matched term-born children (7-10 years). Children born very preterm had decreased brain volume, surface area and cortical thickness compared to term-born children. Furthermore, children born preterm did not display the robust relation between total brain volume and basal ganglia and thalamic volume apparent in the term-born children. Cortical thickness analyses revealed that the cortex was thinner for children born preterm than term-born children in the anterior cingulate cortex/supplementary motor area, isthmus of the cingulate gyrus, right superior temporal sulcus, right anterior insula, postcentral gyrus and precuneus. Follow-up analyses revealed that right precuneus thickness was correlated with gestational age. Thus, even without significant postnatal medical sequelae, very preterm-born children showed atypical brain structure and developmental patterns in areas related to higher cognitive function. Disruptions of the typical neurodevelopmental trajectory in the third trimester of pregnancy likely underlie these differences persisting into middle childhood.
Measures of cortical grey matter structure and development in children with autism spectrum disorder.
The current study examined group differences in cortical volume, surface area, and thickness with age, in a group of typically developing children and a group of children with ASD aged 6-15 years. Results showed evidence of age by group interactions, suggesting atypicalities in the relation between these measures and age in the ASD group. Additional vertex-based analyses of cortical thickness revealed that specific regions in the left inferior frontal gyrus (BA 44) and left precuneus showed thicker cortex for the ASD group at younger ages only. These data support the hypothesis of an abnormal developmental trajectory of the cortex in ASD, which could have profound effects on other aspects of neural development in children with ASD.
Mental flexibility: An MEG investigation in typically developing children.
Mental flexibility is a core property of cognitive executive functions, relying on an extended frontoparietal network in the brain. fMRI research comparing typically developing children and adults has found that children from an early age recruit the same "classic" brain areas associated with mental flexibility as adults; however, there is evidence that the timing of activation may be different. To investigate the temporal dynamics of brain activity associated with mental flexibility in children, we recruited 22 typically developing children (8-15 years) to complete a set-shifting task in the MEG. Our results showed that while the children relied on the same frontoparietal network of mental flexibility, there was a different emphasis on active brain regions, with children preferentially using their posterior parietal cortices. Additional areas such as the temporal pole and the premotor areas were also recruited, potentially playing a supporting role. Although children shared the same window of peak activity as adults, 75-350ms, we found a significant decrease in activation latency with increasing age, suggesting the presence of developmental differences in timing of brain activity in areas supporting mental flexibility during childhood.
Abnormal Brain Dynamics Underlie Speech Production in Children with Autism Spectrum Disorder.
A large proportion of children with autism spectrum disorder (ASD) have speech and/or language difficulties. While a number of structural and functional neuroimaging methods have been used to explore the brain differences in ASD with regards to speech and language comprehension and production, the neurobiology of basic speech function in ASD has not been examined. Magnetoencephalography (MEG) is a neuroimaging modality with high spatial and temporal resolution that can be applied to the examination of brain dynamics underlying speech as it can capture the fast responses fundamental to this function. We acquired MEG from 21 children with high-functioning autism (mean age: 11.43 years) and 21 age- and sex-matched controls as they performed a simple oromotor task, a phoneme production task and a phonemic sequencing task. Results showed significant differences in activation magnitude and peak latencies in primary motor cortex (Brodmann Area 4), motor planning areas (BA 6), temporal sequencing and sensorimotor integration areas (BA 22/13) and executive control areas (BA 9). Our findings of significant functional brain differences between these two groups on these simple oromotor and phonemic tasks suggest that these deficits may be foundational and could underlie the language deficits seen in ASD.
Subcortical and cortical morphological anomalies as an endophenotype in obsessive-compulsive disorder.
Endophentoypes, quantifiable traits lying on the causal chain between a clinical phenotype and etiology, can be used to accelerate genomic discovery in obsessive-compulsive disorder (OCD). Here we identify the neuroanatomic changes that are shared by 22 OCD adult and adolescent patients and 25 of their unaffected siblings who are at genetic risk for the disorder. Comparisons were made against 47 age and sex matched healthy controls. We defined the surface morphology of the striatum, globus pallidus and thalamus, and thickness of the cerebral cortex. Patients with OCD show significant surface expansion compared with healthy controls, following adjustment for multiple comparisons, in interconnected regions of the caudate, thalamus and right orbitofrontal cortex. Their unaffected siblings show similar, significant expansion, most marked in the ventromedial caudate bilaterally, the right pulvinar thalamic nucleus and the right orbitofrontal cortex. These regions define a network that has been consistently implicated in OCD. In addition, both patients with OCD and unaffected siblings showed similar increased thickness of the right precuneus, which receives rich input from the thalamic pulvinar nuclei and the left medial temporal cortex. Anatomic change within the orbitofrontostriatal and posterior brain circuitry thus emerges as a promising endophenotype for OCD.
Altered brain development in an early-onset murine model of Alzheimer's disease.
Murine models of Alzheimer's disease (AD) have been used to draw associations between atrophy of neural tissue and underlying pathology. In this study, the early-onset TgCRND8 mouse model of AD and littermate controls were scanned longitudinally with in vivo manganese-enhanced MRI (MEMRI) before and after the onset of amyloid plaque deposition at 12 weeks of age. Separate cohorts of mice were scanned at 1 week (ex vivo imaging) and 4 weeks (MEMRI) of age to investigate early life alterations in the brain. Contrary to our expectations, differences in neuroanatomy were found in early post-natal life, preceding plaque deposition by as much as 11 weeks. Many of these differences remained at all imaging time points, suggesting that they were programmed early in life and were unaffected by the onset of pathology. Furthermore, rather than showing atrophy, many regions of the TgCRND8 brain grew at a faster rate compared to controls. These regions contained the greatest density of amyloid plaques and reactive astrocytes. Our findings suggest that pathological processes as well as an alteration in brain development influence the TgCRND8 neuroanatomy throughout the lifespan.
Clustering autism: using neuroanatomical differences in 26 mouse models to gain insight into the heterogeneity.
Autism is a heritable disorder, with over 250 associated genes identified to date, yet no single gene accounts for >1-2% of cases. The clinical presentation, behavioural symptoms, imaging and histopathology findings are strikingly heterogeneous. A more complete understanding of autism can be obtained by examining multiple genetic or behavioural mouse models of autism using magnetic resonance imaging (MRI)-based neuroanatomical phenotyping. Twenty-six different mouse models were examined and the consistently found abnormal brain regions across models were parieto-temporal lobe, cerebellar cortex, frontal lobe, hypothalamus and striatum. These models separated into three distinct clusters, two of which can be linked to the under and over-connectivity found in autism. These clusters also identified previously unknown connections between Nrxn1α, En2 and Fmr1; Nlgn3, BTBR and Slc6A4; and also between X monosomy and Mecp2. With no single treatment for autism found, clustering autism using neuroanatomy and identifying these strong connections may prove to be a crucial step in predicting treatment response.
The brain-derived neurotrophic factor Val66Met polymorphism and prediction of neural risk for Alzheimer disease.
CONTEXT: The brain-derived neurotrophic factor (BDNF) Val66Met (rs6265) polymorphism may predict the risk of Alzheimer disease (AD). However, genetic association studies of the BDNF gene with AD have produced equivocal results. Imaging-genetics strategies may clarify the manner in which BDNF gene variation predicts the risk of AD via characterization of its effects on at-risk structures or neural networks susceptible in this disorder. OBJECTIVE: To determine whether the BDNF Val66Met gene variant interacts with age to predict brain and cognitive measures in healthy volunteers across the adult lifespan in an intermediate phenotype pattern related to AD by examining (1) cortical thickness, (2) fractional anisotropy of white matter tracts (ie, white matter integrity), and (3) episodic memory performance. DESIGN: A cross-sectional study using genetics, high-resolution magnetic resonance imaging, diffusion tensor imaging, and cognitive testing in healthy individuals spanning the adult lifespan. SETTING: University hospital. PARTICIPANTS: A total of 69 healthy volunteers ranging from 19 to 82 years of age. MAIN OUTCOME MEASURES: The BDNF Val66Met genotype, apolipoprotein E genotype, cortical thickness, microstructural integrity of white matter tracts, and episodic memory performance were evaluated. RESULTS: The BDNF Val66Met polymorphism interacted with age to predict (1) cortical thickness (prominently at the entorhinal cortex and temporal gyri), (2) fractional anisotropy of white matter tracts (prominently at white matter tracts connecting to the medial temporal lobe), and (3) episodic memory performance. For each of these findings, the pattern was similar: valine/valine individuals in late life were susceptible, and in early adult life, methionine allele carriers demonstrated susceptibility. CONCLUSIONS: The BDNF gene confers risk in an age-dependent manner on the brain structures and cognitive functions that are consistent with the neural circuitry vulnerable in the earliest stages of AD. Our novel findings provide convergent evidence in vivo for a BDNF genetic mechanism of susceptibility in an intermediate phenotype related to AD.
Selective deficit of mental visual imagery with intact primary visual cortex and visual perception.
There is a vigorous debate as to whether visual perception and imagery share the same neuronal networks, whether the primary visual cortex is necessarily involved in visual imagery, and whether visual imagery functions are lateralized in the brain. Two patients with brain damage from closed head injury were submitted to tests of mental imagery in the visual, tactile, auditory, gustatory, olfactory and motor domains, as well as to an extensive testing of cognitive functions. A computerized mapping procedure was used to localize the site and to assess the extent of the lesions. One patient showed pure visual mental imagery deficits in the absence of imagery deficits in other sensory domains as well as in the motor domain, while the other patient showed both visual and tactile imagery deficits. Perceptual, language, and memory deficits were conspicuously absent. Computerized analysis of the lesions showed a massive involvement of the left temporal lobe in both patients and a bilateral parietal lesion in one patient. In both patients the calcarine cortex with the primary visual area was bilaterally intact. Our study indicates that: (i) visual imagery deficits can occur independently from deficits of visual perception; (ii) visual imagery deficits can occur when the primary visual cortex is intact and (iii) the left temporal lobe plays an important role in visual mental imagery.
MEMRI-based imaging pipeline for guiding preclinical studies in mouse models of sporadic medulloblastoma.
PURPOSE: Genetically engineered mouse models of sporadic cancers are critical for studying tumor biology and for preclinical testing of therapeutics. We present an MRI-based pipeline designed to produce high resolution, quantitative information about tumor progression and response to novel therapies in mouse models of medulloblastoma (MB). METHODS: Sporadic MB was modeled in mice by inducing expression of an activated form of the Smoothened gene (aSmo) in a small number of cerebellar granule cell precursors. aSmo mice were imaged and analyzed at defined time-points using a 3D manganese-enhanced MRI-based pipeline optimized for high-throughput. RESULTS: A semi-automated segmentation protocol was established that estimates tumor volume in a time-frame compatible with a high-throughput pipeline. Both an empirical, volume-based classifier and a linear discriminant analysis-based classifier were tested to distinguish progressing from nonprogressing lesions at early stages of tumorigenesis. Tumor centroids measured at early stages revealed that there is a very specific location of the probable origin of the aSmo MB tumors. The efficacy of the manganese-enhanced MRI pipeline was demonstrated with a small-scale experimental drug trial designed to reduce the number of tumor associated macrophages and microglia. CONCLUSION: Our results revealed a high level of heterogeneity between tumors within and between aSmo MB models, indicating that meaningful studies of sporadic tumor progression and response to therapy could not be conducted without an imaging-based pipeline approach.
Illness denial in schizophrenia spectrum disorders: a function of left hemisphere dominance.
Impaired illness awareness or anosognosia is a common, but poorly understood feature of schizophrenia that contributes to medication nonadherence and poor treatment outcomes. Here we present a functional imaging study to measure brain activity at the moment of illness denial. To accomplish this, participants with schizophrenia (n = 18) with varying degrees of illness awareness were confronted with their illness beliefs while undergoing functional MRI. To link structure with function, we explored the relationships among impaired illness awareness and brain activity during the illness denial task with cortical thickness. Impaired illness awareness was associated with increased brain activity in the left temporoparieto-occipital junction (TPO) and left medial prefrontal cortex (mPFC) at the moment of illness denial. Brain activity in the left mPFC appeared to be a function of participants' degree of self-reflectiveness, while the activity in the left TPO was associated with cortical thinning in this region and more specific to illness denial. Participants with impaired illness awareness had slower response times to illness related stimuli than those with good illness awareness. Increased left hemisphere brain activity in association with illness denial is consistent with the literature in other neuropsychiatric conditions attributing anosognosia or impaired illness awareness to left hemisphere dominance. The TPO and mPFC may represent putative targets for noninvasive treatment interventions, such as transcranial magnetic or direct current stimulation.