Reduced prefrontal gyrification in obsessive–compulsive disorder

Structural magnetic resonance imaging (MRI) studies reveal evidence for brain abnormalities in obsessive–compulsive disorder (OCD), for instance, reduction of gray matter volume in the prefrontal cortex. Disturbances of gyrification in the prefrontal cortex have been described several times in schizophrenia pointing to a neurodevelopmental etiology, while gyrification has not been studied so far in OCD patients. In 26 OCD patients and 38 healthy control subjects MR-imaging was performed. Prefrontal cortical folding (gyrification) was measured bilaterally by an automated version of the automated-gyrification index (A-GI), a ratio reflecting the extent of folding, from the slice containing the inner genu of the corpus callosum up to the frontal pole. Analysis of covariance (ANCOVA, independent factor diagnosis, covariates age, duration of education) demonstrated that compared with control subjects, patients with OCD displayed a significantly reduced A-GI in the left hemisphere (p = 0.021) and a trend for a decreased A-GI in the right hemisphere (p = 0.076). Significant correlations between prefrontal lobe volume and A-GI were only observed in controls, but not in OCD patients. In conclusion, prefrontal hypogyrification in OCD patients may be a structural correlate of the impairment in executive function of this patient group and may point to a neurodevelopmental origin of this disease.     

Neurodevelopmental alterations of large‐scale structural networks in children with new‐onset epilepsy

Recent neuroimaging and behavioral studies have revealed that children with new onset epilepsy already exhibit brain structural abnormalities and cognitive impairment. How the organization of large‐scale brain structural networks is altered near the time of seizure onset and whether network changes are related to cognitive performances remain unclear. Recent studies also suggest that regional brain volume covariance reflects synchronized brain developmental changes. Here, we test the hypothesis that epilepsy during early‐life is associated with abnormalities in brain network organization and cognition. We used graph theory to study structural brain networks based on regional volume covariance in 39 children with new‐onset seizures and 28 healthy controls. Children with new‐onset epilepsy showed a suboptimal topological structural organization with enhanced network segregation and reduced global integration compared with controls. At the regional level, structural reorganization was evident with redistributed nodes from the posterior to more anterior head regions. The epileptic brain network was more vulnerable to targeted but not random attacks. Finally, a subgroup of children with epilepsy, namely those with lower IQ and poorer executive function, had a reduced balance between network segregation and integration. Taken together, the findings suggest that the neurodevelopmental impact of new onset childhood epilepsies alters large‐scale brain networks, resulting in greater vulnerability to network failure and cognitive impairment. Hum Brain Mapp 35:3661–3672, 2014. © 2014 Wiley Periodicals, Inc .     

Reduced fronto-callosal fiber integrity in unmedicated OCD patients: a diffusion tractography study

It is widely accepted that abnormalities in the frontal area of the brain underpin the pathophysiology of obsessive‐compulsive disorder (OCD). Fundamental to this investigation is the delineation of frontal white matter tracts including dorsal and ventral frontal projections of interhemispheric connections. While previous investigations of OCD have examined the dorsal and ventral frontal regions, the corresponding callosal connections have not been investigated, despite their importance. We recruited twenty patients with OCD (15 drug‐naïve and 5 currently unmedicated) and demographically similar healthy controls, and conducted fiber tractography and post hoc quantitative analysis using diffusion tensor imaging. We extracted fractional anisotropy (FA) of the fronto‐callosal fibers along the entire length of the tract. Function‐specific [by the Brodmann area region‐of‐interest (ROI) approach] and region‐specific (by the length‐parameterization approach) tracts were defined. In addition, we devised a new index of dorsal‐ventral imbalance (DVII) of fiber integrity. Significant FA decreases were observed in orbitofrontal and dorsolateral prefrontal projections of the corpus callosum (P < 0.05, false discovery rate‐corrected) with higher function/region sensitivity than voxel‐based or ROI‐based approaches. Importantly, OCD patients also exhibited significantly higher ventral‐greater‐than‐dorsal asymmetry of FA values than normal controls (P < 0.05, FDR‐corrected). This study is the first to investigate fiber integrity in the dorsal/ventral frontal parts of the callosal tractography in unmedicated OCD patients. Using a more quantitative method in terms of functional and regional specificity than previous studies, we report abnormalities in interhemispheric connectivity of both dorsal and ventral networks in the pathophysiology of OCD. Hum Brain Mapp 33:2441–2452, 2012. © 2011 Wiley Periodicals, Inc.     

Local gyrification index in patients with major depressive disorder and its association with tryptophan hydroxylase‐2 (TPH2) polymorphism

The tryptophan hydroxylase‐2 (TPH2) gene is considered a promising genetic candidate regarding its association with a predisposition to major depressive disorder (MDD). Local gyrification reflects the early neural development of cortical connectivity, and is regarded as a potential neural endophenotype in psychiatric disorders. They aimed to investigate the alterations in the cortical gyrification of the prefrontal cortex and anterior cingulate cortex and their association with the TPH2 rs4570625 polymorphism in patients with MDD. One hundred and thirteen patients with MDD and eighty‐six healthy controls underwent T1‐weighted structural magnetic resonance imaging and genotyping for TPH2 rs4570625. The local gyrification index of 22 cortical regions in the prefrontal cortex and anterior cingulate cortex was analyzed using the FreeSurfer. The patients with MDD showed significant hypergyria in the right rostral anterior cingulate cortex (P = 0.001), medial orbitofrontal cortex (P = 0.003), and frontal pole (P = 0.001). There was a significant genotype‐by‐diagnosis interaction for the local gyrification index in the right rostral anterior cingulate cortex (P = 0.003). Their study revealed significant hypergyria of the anterior cingulate cortex and prefrontal cortex and an interactive effect between the diagnosis of MDD and the genotype in the anterior cingulate cortex. This might be associated with the dysfunction of neural circuits mediating emotion processing, which could contribute to pathophysiology of MDD. Hum Brain Mapp 38:1299–1310, 2017. © 2016 Wiley Periodicals, Inc.     

Large‐scale white matter network reorganization in posttraumatic stress disorder

Recently, graph theoretical approaches applied to neuroimaging data have advanced understanding of the human brain connectome and its abnormalities in psychiatric disorders. However, little is known about the topological organization of brain white matter networks in posttraumatic stress disorder (PTSD). Seventy‐six patients with PTSD and 76 age, gender, and years of education‐matched trauma‐exposed controls were studied after the 2008 Sichuan earthquake using diffusion tensor imaging and graph theoretical approaches. Topological properties of brain networks including global and nodal measurements and modularity were analyzed. At the global level, patients showed lower clustering coefficient (p = .016) and normalized characteristic path length (p = .035) compared with controls. At the nodal level, increased nodal centralities in left middle frontal gyrus, superior and inferior temporal gyrus and right inferior occipital gyrus were observed (p < .05, corrected for false‐discovery rate). Modularity analysis revealed that PTSD patients had significantly increased inter‐modular connections in the fronto‐parietal module, fronto‐striato‐temporal module, and visual and default mode modules. These findings indicate a PTSD‐related shift of white matter network topology toward randomization. This pattern was characterized by an increased global network integration, reflected by increased inter‐modular connections with increased nodal centralities involving fronto‐temporo‐occipital regions. This study suggests that extremely stressful life experiences, when they lead to PTSD, are associated with large‐scale brain white matter network topological reconfiguration at global, nodal, and modular levels.     

Altered cortical gyrification patterns in panic disorder: Deficits and potential compensation

Abnormal gyrification patterns may reflect aberrant cortical connectivity during an early period of brain maturation. We here investigated anatomical distribution of cortical gyrification deficits underlying panic disorder and the relationships of these potential neurodevelopmental markers with panic symptom severity. High-resolution three-dimensional T1-weighted structural images were obtained from 23 patients with panic disorder and 33 matched healthy individuals. Local gyrification indices were measured in each genetically-based parcellated cortical subregion and regional gyrification patterns were compared between groups. Cortical areas in which gyrification patterns were associated with panic symptom severity were also determined. Significant reductions in cortical gyrification were observed in panic patients compared with healthy individuals, which were mainly distributed in the lateral brain extending from the fronto-parietal to the temporal areas. In contrast, hyper-gyrification in the posteromedial cortical regions which exert interconnecting roles in the default mode network, was associated with less severe panic symptoms. Post-hoc analysis for the inter-regional covariance of local gyrification indices revealed that interconnections of the posteromedial cortical regions with other cortical areas which belong to the default mode network were reduced in panic patients with severe symptoms relative to either less severe patients or healthy individuals. Our findings suggest not only substantial perturbation in cortical gyrification patterns in panic disorder but also potential contribution of integrated cortical folding pattern of the default mode network to alleviated panic severity.     

Intrinsic functional and structural connectivity of emotion regulation networks in obsessive‐compulsive disorder

Despite emotion regulation being altered in patients with obsessive‐compulsive disorder (OCD), no studies have investigated its relation to multimodal amygdala connectivity. We compared corticolimbic functional and structural connectivity between OCD patients and healthy controls (HCs), and correlated this with the dispositional use of emotion regulation strategies and with OCD severity. OCD patients (n = 73) and HCs (n = 42) were assessed for suppression and reappraisal strategies using the Emotion Regulation Questionnaire (ERQ) and for OCD severity using the Yale‐Brown Obsessive‐Compulsive Scale. Resting‐state functional magnetic resonance imaging (rs‐fMRI) connectivity maps were generated using subject‐specific left amygdala (LA) and right amygdala (RA) masks. We identified between‐group differences in amygdala whole‐brain connectivity, and evaluated the moderating effect of ERQ strategies. Significant regions and amygdala seeds were used as targets in probabilistic tractography analysis. Patients scored higher in suppression and lower in reappraisal. We observed higher rs‐fMRI RA–right postcentral gyrus (PCG) connectivity in HC, and in patients this was correlated with symptom severity. Reappraisal scores were associated with higher negative LA–left insula connectivity in HC, and suppression scores were negatively associated with LA–precuneus and angular gyri connectivity in OCD. Structurally, patients showed higher mean diffusivity in tracts connecting the amygdala with the other targets. RA–PCG connectivity is diminished in patients, while disrupted emotion regulation is related to altered amygdala connectivity with the insula and posterior brain regions. Our results are the first showing, from a multimodal perspective, the association between amygdala connectivity and specific emotional processing domains, emphasizing the importance of amygdala connectivity in OCD pathophysiology.     

Decreased limbic and increased fronto‐parietal connectivity in unmedicated patients with obsessive‐compulsive disorder

Obsessive‐compulsive disorder (OCD) is characterized by recurrent intrusive thoughts and ritualized, repetitive behaviors, or mental acts. Convergent experimental evidence from neuroimaging and neuropsychological studies supports an orbitofronto‐striato‐thalamo‐cortical dysfunction in OCD. Moreover, an over excitability of the amygdala and over monitoring of thoughts and actions involving the anterior cingulate, frontal and parietal cortex has been proposed as aspects of pathophysiology in OCD. We chose a data driven, graph theoretical approach to investigate brain network organization in 17 unmedicated OCD patients and 19 controls using resting‐state fMRI. OCD patients showed a decreased connectivity of the limbic network to several other brain networks: the basal ganglia network, the default mode network, and the executive/attention network. The connectivity within the limbic network was also found to be decreased in OCD patients compared to healthy controls. Furthermore, we found a stronger connectivity of brain regions within the executive/attention network in OCD patients. This effect was positively correlated with disease severity. The decreased connectivity of limbic regions (amygdala, hippocampus) may be related to several neurocognitive deficits observed in OCD patients involving implicit learning, emotion processing and expectation, and processing of reward and punishment. Limbic disconnection from fronto‐parietal regions relevant for (re)‐appraisal may explain why intrusive thoughts become and/or remain threatening to patients but not to healthy subjects. Hyperconnectivity within the executive/attention network might be related to OCD symptoms such as excessive monitoring of thoughts and behavior as a dysfunctional strategy to cope with threat and uncertainty. Hum Brain Mapp 35:5617–5632, 2014. © 2014 Wiley Periodicals, Inc.     

Altered single‐subject gray matter structural networks in drug‐naïve attention deficit hyperactivity disorder children

Altered topological organization of brain structural covariance networks has been observed in attention deficit hyperactivity disorder (ADHD). However, results have been inconsistent, potentially related to confounding medication effects. In addition, since structural networks are traditionally constructed at the group level, variabilities in individual structural features remain to be well characterized. Structural brain imaging with MRI was performed on 84 drug‐naïve children with ADHD and 83 age‐matched healthy controls. Single‐subject gray matter (GM) networks were obtained based on areal similarities of GM, and network topological properties were analyzed using graph theory. Group differences in each topological metric were compared using nonparametric permutation testing. Compared with healthy subjects, GM networks in ADHD patients demonstrated significantly altered topological characteristics, including higher global and local efficiency and clustering coefficient, and shorter path length. In addition, ADHD patients exhibited abnormal centrality in corticostriatal circuitry including the superior frontal gyrus, orbitofrontal gyrus, medial superior frontal gyrus, precentral gyrus, middle temporal gyrus, and pallidum (all p < .05, false discovery rate [FDR] corrected). Altered global and nodal topological efficiencies were associated with the severity of hyperactivity symptoms and the performance on the Stroop and Wisconsin Card Sorting Test tests (all p < .05, FDR corrected). ADHD combined and inattention subtypes were differentiated by nodal attributes of amygdala (p < .05, FDR corrected). Alterations in GM network topologies were observed in drug‐naïve ADHD patients, in particular in frontostriatal loops and amygdala. These alterations may contribute to impaired cognitive functioning and impulsive behavior in ADHD.     

MRI study of the cavum septum pellucidum in obsessive–compulsive disorder

The cavum septum pellucidum (CSP), a putative marker of neurodevelopmental anomaly, has been associated with an increased risk of several psychiatric disorders. The purpose of this study was to evaluate the CSP in patients with obsessive–compulsive disorder (OCD) compared with healthy control subjects. Seventy-one patients with OCD and 71 healthy volunteers matched for age and sex were evaluated with magnetic resonance imaging. We evaluated the CSP using criteria employed in previous studies: presence of the CSP, length of the CSP, and overall size of the CSP, measured in five grades, ranging from grades 0 (no CSP) to 4 (severe CSP). We evaluated OCD symptom severity using the Yale–Brown Obsessive–Compulsive Scale (Y-BOCS). The CSP presence was significantly greater in the OCD group (60.6%) than in control subjects (29.6%), and CSP size grade was significantly larger in the OCD group (χ² = 15.609, P = 0.004). CSP length showed no significant group difference. Among patients with OCD, those with a CSP had higher scores on the obsession subscale of the Y-BOCS than those without a CSP (Z = −2.358, P = 0.018), while they did not show significant difference from those without a CSP in the compulsion subscale of the Y-BOCS, age, duration of illness, or age at onset. These results indicate that neurodevelopmental alterations in midline structures might contribute to the pathogenesis of OCD.     

Disrupted brain functional networks in drug‐naïve children with attention deficit hyperactivity disorder assessed using graph theory analysis

Neuroimaging studies have revealed functional brain network abnormalities in attention deficit hyperactivity disorder (ADHD), but the results have been inconsistent, potentially related to confounding medication effects. Furthermore, specific topological alterations in functional networks and their role in behavioral inhibition dysfunction remain to be established. Resting‐state functional magnetic resonance imaging was performed on 51 drug‐naïve children with ADHD and 55 age‐matched healthy controls. Brain functional networks were constructed by thresholding the partial correlation matrices of 90 brain regions, and graph theory was used to analyze network topological properties. The Stroop test was used to assess cognitive inhibitory abilities. Nonparametric permutation tests were used to compare the topological architectures in the two groups. Compared with healthy subjects, brain networks in ADHD patients demonstrated altered topological characteristics, including lower global (FDR q = 0.01) and local efficiency (p = 0.032, uncorrected) and a longer path length (FDR q = 0.01). Lower nodal efficiencies were found in the left inferior frontal gyrus and anterior cingulate cortex in the ADHD group (FDR both q < 0.05). Altered global and nodal topological efficiencies were associated with the severity of inhibitory cognitive control deficits and hyperactivity symptoms in ADHD (p <0 .05). Alterations in network topologies in drug‐naïve ADHD patients indicate weaker small‐worldization with decreased segregation and integration of functional brain networks. Deficits in the cingulo‐fronto‐parietal attention network were associated with inhibitory control deficits.     

Sex‐specific contribution of DHEA‐cortisol ratio to prefrontal‐hippocampal structural development,cognitive abilities and personality traits

Although dehydroepiandrosterone (DHEA) may exert neuroprotective effects in the developing brain, prolonged or excessive elevations in cortisol may exert neurotoxic effects. The ratio between DHEA and cortisol (DC ratio) has been linked to internalising and externalising disorders, as well as cognitive performance, supporting the clinical relevance of this hormonal ratio during development. However, the brain mechanisms by which these effects may be mediated have not yet been identified. Furthermore, although there is evidence that the effects of cortisol in the central nervous system may be sexually dimorphic in humans, the opposite is true for DHEA, with human studies showing no sex‐specific associations in cortical thickness, cortico‐amygdalar or cortico‐hippocampal structural covariance. Therefore, it remains unclear whether sex moderates the developmental associations between DC ratio, brain structure, cognition and behaviour. In the present study, we examined the associations between DC ratio, structural covariance of the hippocampus with whole‐brain cortical thickness, and measures of personality, behaviour and cognition in a longitudinal sample of typically developing children, adolescents and young adults aged 6‐22 years (N = 225 participants [F = 128]; 355 scans [F = 208]), using mixed effects models that accounted for both within‐ and between‐subject variances. We found sex‐specific interactions between DC ratio and anterior cingulate cortex‐hippocampal structural covariance, with higher DC ratios being associated with a more negative covariance between these structures in girls, and a more positive covariance in boys. Furthermore, the negative prefrontal‐hippocampal structural covariance found in girls was associated with higher verbal memory and mathematical ability, whereas the positive covariance found in boys was associated with lower cooperativeness and reward dependence personality traits. These findings support the notion that the ratio between DHEA and cortisol levels may contribute, at least in part, to the development of sex differences in cognitive abilities, as well as risk for internalising/externalising disorders, via an alteration in prefrontal‐hippocampal structure during the transition from childhood to adulthood.     

Reduced functional connectivity within the limbic cortico‐striato‐thalamo‐cortical loop in unmedicated adults with obsessive‐compulsive disorder

Cortico‐striato‐thalamo‐cortical (CSTC) loops project from the cortex to the striatum, then from the striatum to the thalamus via the globus pallidus, and finally from the thalamus back to the cortex again. These loops have been implicated in Obsessive‐Compulsive Disorder (OCD) with particular focus on the limbic CSTC loop, which encompasses the orbitofrontal and anterior cingulate cortices, as well as the ventral striatum. Resting state functional‐connectivity MRI (rs‐fcMRI) studies, which examine temporal correlations in neural activity across brain regions at rest, have examined CSTC loop connectivity in patients with OCD and suggest hyperconnectivity within these loops in medicated adults with OCD. We used rs‐fcMRI to examine functional connectivity within CSTC loops in unmedicated adults with OCD (n = 23) versus healthy controls (HCs) (n = 20). Contrary to prior rs‐fcMRI studies in OCD patients on medications that report hyperconnectivity in the limbic CSTC loop, we found that compared with HCs, unmedicated OCD participants had reduced connectivity within the limbic CSTC loop. Exploratory analyses revealed that reduced connectivity within the limbic CSTC loop correlated with OCD symptom severity in the OCD group. Our finding of limbic loop hypoconnectivity in unmedicted OCD patients highlights the potential confounding effects of antidepressants on connectivity measures and the value of future examinations of the effects of pharmacological and/or behavioral treatments on limbic CSTC loop connectivity. Hum Brain Mapp 35:2852–2860, 2014. © 2013 Wiley Periodicals, Inc .     

White matter tract network disruption explains reduced conscientiousness in multiple sclerosis

Quantifying white matter (WM) tract disruption in people with multiple sclerosis (PwMS) provides a novel means for investigating the relationship between defective network connectivity and clinical markers. PwMS exhibit perturbations in personality, where decreased Conscientiousness is particularly prominent. This trait deficit influences disease trajectory and functional outcomes such as work capacity. We aimed to identify patterns of WM tract disruption related to decreased Conscientiousness in PwMS. Personality assessment and brain MRI were obtained in 133 PwMS and 49 age‐ and sex‐matched healthy controls (HC). Lesion maps were applied to determine the severity of WM tract disruption between pairs of gray matter regions. Next, the Network‐Based‐Statistics tool was applied to identify structural networks whose disruption negatively correlates with Conscientiousness. Finally, to determine whether these networks explain unique variance above conventional MRI measures and cognition, regression models were applied controlling for age, sex, brain volume, T2‐lesion volume, and cognition. Relative to HCs, PwMS exhibited lower Conscientiousness and slowed cognitive processing speed (p = .025, p = .006). Lower Conscientiousness in PwMS was significantly associated with WM tract disruption between frontal, frontal‐parietal, and frontal‐cingulate pathways in the left (p = .02) and right (p = .01) hemisphere. The mean disruption of these pathways explained unique additive variance in Conscientiousness, after accounting for conventional MRI markers of pathology and cognition (ΔR² = .049, p = .029). Damage to WM tracts between frontal, frontal‐parietal, and frontal‐cingulate cortical regions is significantly correlated with reduced Conscientiousness in PwMS. Tract disruption within these networks explains decreased Conscientiousness observed in PwMS as compared with HCs.     

ADHD prevalence and association with hoarding behaviors in childhood‐onset OCD

Background: It has been suggested that attention‐deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD), both neurodevelopmental disorders with onset in childhood, are highly comorbid, but previous studies examining ADHD and OCD comorbidity have been quite variable, partly because of inconsistency in excluding individuals with tic disorders. Similarly, ADHD has been postulated to be associated with hoarding although this potential relationship is largely methodologically unexplored. This study aimed to examine the prevalence of ADHD among individuals with childhood‐onset OCD but without comorbid tic disorders, as well as to examine the relationship between clinically significant hoarding behaviors (hoarding) and ADHD. Method: ADHD prevalence rates and the relationship between ADHD and hoarding were examined in 155 OCD‐affected individuals (114 probands and 41 relatives, age range 4–82 years) recruited for genetic studies and compared to pooled prevalence rates derived from previously published studies. Results: In total, 11.8% met criteria for definite ADHD, whereas an additional 8.6% had probable or definite ADHD (total=20.4%). In total, 41.9% of participants with ADHD also had hoarding compared to 29.2% of participants without ADHD. Hoarding was the only demographic or clinical variable independently associated with ADHD (odds ratio=9.54, P<0.0001). Conclusion: ADHD rates were elevated in this sample of individuals with childhood‐onset OCD compared to the general population rate of ADHD, and there was a strong association between ADHD and clinically significant hoarding behavior. This association is consistent with recent studies suggesting that individuals with hoarding may exhibit substantial executive functioning impairments and/or abnormalities, including attentional problems. Depression and Anxiety, 2010. © 2010 Wiley‐Liss, Inc.     

Associations of gestational age with gyrification and neurocognition in healthy adults

Epidemiological studies have shown that gestational age and birth weight are linked to cognitive performance in adults. On a neurobiological level, this effect is hypothesized to be related to cortical gyrification, which is determined primarily during fetal development. The relationships between gestational age, gyrification and specific cognitive abilities in adults are still poorly understood. In 542 healthy participants, gyrification indices were calculated from structural magnetic resonance imaging T1 data at 3 T using CAT12. After applying a battery of neuropsychological tests, neuropsychological factors were extracted with a factor analysis. We conducted regressions to test associations between gyrification and gestational age as well as birth weight. Moderation analyses explored the relationships between gestational age, gyrification and neuropsychological factors. Gestational age is significantly positively associated with cortical folding in the left supramarginal, bilaterally in the superior frontal and the lingual cortex. We extracted two neuropsychological factors that describe language abilities and working memory/attention. The association between gyrification in the left superior frontal gyrus and working memory/attention was moderated by gestational age. Further, the association between gyrification in the left supramarginal cortex and both, working memory/attention as well as language, were moderated by gestational age. Gyrification is associated with gestational age and related to specific neuropsychological outcomes in healthy adulthood. Implications from these findings for the cortical neurodevelopment of cognitive domains and mental health are discussed.

     

A voxel‐based morphometric MRI study in men with borderline personality disorder: preliminary findings

Objective There is increasing evidence for subtle changes in brain morphology and function in patients with borderline personality disorder (BPD). Structural brain imaging studies show lower volume in frontal, temporal and parietal brain regions than in healthy controls. The aim of our preliminary study of men with BPD was to investigate structural brain changes and their relationship with a measure of impulsivity. Methods We examined seven male patients with BPD and six control men using voxel‐based morphometry. Analysis of covariance was carried out to assess regionally specific differences in grey and white matter (WM) volumes. Correlations between trait impulsivity as measured using the Impulsiveness‐Venturesomeness‐Empathy scale and brain volumes were studied. Results Compared with healthy men, men with BPD had similar WM volumes but smaller grey matter (GM) volumes in frontal, temporal and parietal cortices. The latter were negatively correlated with trait impulsivity. Conclusions Our findings fit with previous reports of smaller regional GM volumes reported in women with BPD, and suggest that in men there may be an association between smaller GM volumes and impulsivity. Copyright © 2009 John Wiley & Sons, Ltd.     

Altered brain network integrity after childhood maltreatment: A structural connectomic DTI‐study

Childhood maltreatment is associated with alterations in neural architecture that potentially put these children at increased risk for psychopathology. Alterations in white matter (WM) tracts have been reported, however no study to date has investigated WM connectivity in brain networks in maltreated children to quantify global and local abnormalities through graph theoretical analyses of DTI data. We aimed for a multilevel investigation examining the DTI‐based structural connectome and its associations with basal cortisol levels of 25 children with documented maltreatment experiences before age 3, and 24 matched controls (age: 10.6 ± 1.75 years). On the global and lobar level, maltreated children showed significant reductions in global connectivity strength, local connectivity and increased path length, suggesting deviations from the small‐world network architecture previously associated with psychopathology. Reductions in global connectivity were associated with placement instability, attenuated cortisol secretion and higher levels of internalizing and externalizing behaviours. Regional measures revealed lower connectivity strength especially in regions within the ventromedial prefrontal cortex (vMPFC) in maltreated children. These findings show that childhood maltreatment is associated with systemic global neurodevelopmental alterations in WM networks next to regional alterations in areas involved in the regulation of affect. These alterations in WM organization could underlie global functional deficits and multi‐symptom patterns frequently observed in children with maltreatment experiences. Hum Brain Mapp 38:855–868, 2017. © 2016 Wiley Periodicals, Inc.     

Abnormalities of hippocampal shape and subfield volumes in medication‐free patients with obsessive–compulsive disorder

In this study, we sought to identify alterations of hippocampal shape and subfield volumes in a relatively large sample of medication‐free obsessive–compulsive disorder (OCD) patients without comorbid depression. 3D T1‐weighted Magnetic Resonance Imaging scans were collected from 81 medication‐free OCD patients and 95 age‐ and sex‐matched healthy controls (HC). Total hippocampal volume and volume of eight bilateral subfields were measured using FreeSurfer software. Subregional shape deformity was examined via FSL software. Volumetric and shape differences between groups and correlations with OCD symptoms were examined. The volume of right hippocampus was significantly reduced in OCD patients (p = .001, η² = 0.065). Follow‐up analysis of right hemisphere subfields showed reduced volume in right subiculum (p < .001, η² = 0.081), presubiculum (p < .001, η² = 0.125), CA2/3 (p = .001, η² = 0.06), and hippocampal tail (p < 0.001, η² = 0.105), while the volume of right fimbria was increased (p = .001, η² = 0.058). Shape analysis revealed a bilateral outward bending in the hippocampal body related to a lateral displacement of hippocampus from the body to the tail. Symptom severity was correlated with volumes of presubiculum (with compulsions, r = ?0.25, p = .024) and fimbria (with obsessions, r = ?0.28, p = .012), and with the lateral shift of middle and posterior hippocampus (with obsessions). Alterations across hippocampal subfields and overall shape may contribute to the distinctive cognitive and affective abnormalities associated with OCD.     

Gray matter volume covariance networks associated with dual‐task cost during walking‐while‐talking

We studied gray matter volume covariance networks associated with normal pace walking (NPW) speed and dual‐task costs (DTCs) during walking‐while‐talking (WWT)—a mobility stress test that involves walking while reciting alternate letters of the alphabet. Using a multivariate covariance‐based analytic approach, we identified gray matter networks associated with NPW speed (mean 102.1 cm/s ±22.5 cm/s) and DTC (percent difference in gait speed between NPW and WWT, mean 25.9% ± 18.8%) in 139 older adults without dementia (M = 75.3 ± 6.1 years). The gray matter network associated with NPW was primarily composed of supplementary motor area, precuneus cortex, and the middle frontal gyrus. Greater expression of this NPW network was associated with better processing speed (trail‐making test A [r = ?0.30, p = 0.005]) and executive function (trail‐making test B ? A [r = ?0.43, p < 0.0001]). The gray matter network associated with DTC was primarily composed of medial prefrontal, cingulate, and thalamic regions. Greater expression of this DTC network was associated with better episodic memory performance on the free and cued selective reminding test (r = 0.30, p = 0.007). These results suggest that NPW speed and DTC are supported by different networks, and are associated with different cognitive domains.