Anterior Limb Of The Internal Capsule Research Articles

201 Tractography Analysis of Deep Brain Stimulation for Obsessive-Compulsive Disorder

INTRODUCTION: Deep brain stimulation of the anterior limb of the internal capsule (ALIC-DBS) is an effective treatment for refractory obsessive-compulsive disorder (OCD). Animal tracing studies and human tractography suggest that the putative ALIC target for OCD impacts brain circuits for reward, affect and inhibitory control, including projections to orbitofrontal (OFC) and ventromedial (vmPFC) cortex, ventrolateral cortex (vlPFC), dorsal anterior cingulate cortex (dACC), dorsal medial cortex (dmPFC) and dorsolateral prefrontal cortex (dlPFC). The recent development of directional segmented DBS leads may allow for selective stimulation of these ALIC-projections. METHODS: We generated structural connectivity maps of therapeutic stimulation using probabilistic tractography in OCD patients treated with ALIC-DBS. Response was defined as = 35% improvement in YBOCS after routine clinical parameter optimization. We also generated the volume of tissue activation (VTA) based on the stimulation parameters at the last follow-up. We estimated probability of connections between the VTA and each projection to the prefrontal regions (vmPFC/OFC, vlPFC, dlPFC, dmPFC, and dACC) in responders and non-responders. To further explore how connectivity would explain clinical improvement, we correlated connectivity values from stimulation sites to cortical regions to the percentage of change in YBOCS using Spearman correlation. Finally, we developed directional tractography activation models and explored personalized circuit-specific targeting and stimulation for patients with directional DBS-leads. RESULTS: All patients with ALIC DBS displayed stimulation of OFC/vmPFC and dmPFC connections. However, non-responders had incomplete stimulation of vlPFC, dACC and dlPFC compared to responders. Correlation analysis revealed that fibers from the dorsolateral ALIC to vlPFC were positively associated with improvement in Y-BOCS scores, while connections from ventral ALIC to vmPFC were negatively associated. We were able to successfully construct a stimulation tractography model of directional segmented lead configurations along the medial-lateral axis, which we used for personalized DBS targeting and programming in our most recent patients. Early observations suggest that this directional precision-strategy allows for fast improvement in patient-specific symptom domains for reward, affect and inhibitory control. CONCLUSION: Our findings suggest that the therapeutic benefit of ALIC DBS for OCD is associated with stimulation of a subset of specific ALIC WM pathways, which can be selectively targeted using directional DBS-systems.

Association Between Anatomical Location and Hematoma Expansion in Deep Intracerebral Hemorrhage.

ObjectiveTo establish the relationship between hematoma sites of involvement and hematoma expansion (HE) in patients with deep intracerebral hemorrhage (ICH).MethodsEligible patients with deep ICH admitted to hospital within 6 hours of onset between 2018 and 2020 were included in this retrospective multi-center study. Individuals with secondary ICH were excluded. The volume of HE was evaluated based on admission and follow-up computed tomography scans. Associations between deep ICH sites of involvement and HE were examined using multivariable logistic regression analysis while adjusting for confounding covariates of HE.ResultsWe enrolled 583 individuals from three stroke centers. Data from a final total of 460 patients were used in the analysis; of these patients, 159 (34.6%) had HE. In the crude model without adjustment, external capsule, anterior limb of the internal capsule, and posterior limb of the internal capsule (PLIC) involvement were correlated with HE. After fully adjusted models for sex, age, intraventricular hemorrhage, Glasgow Coma Scale admission score, baseline ICH volume, and time from onset to initial computed tomography, multivariable logistic regression revealed that the PLIC is a robust predictor of HE in patients with deep ICH (adjusted odds ratio = 2.73; 95% confidence interval = 1.75–4.26; p < 0.001).ConclusionInvolvement of the posterior limb of the internal capsule in deep hemorrhage could be a promising predictor of HE.

Deep Brain Stimulation Reduces Conflict-Related Theta and Error-Related Negativity in Patients With Obsessive–Compulsive Disorder

ObjectivesObsessive–compulsive disorder (OCD) is a psychiatric disorder with alterations of cortico-striato-thalamo-cortical loops and impaired performance monitoring. Electrophysiological markers such as conflict-related medial frontal theta (MFT) and error-related negativity (ERN) may be altered by clinically effective deep brain stimulation (DBS) of the anterior limb of the internal capsule and nucleus accumbens (ALIC/NAc). We hypothesized that ALIC/NAc DBS modulates electrophysiological performance monitoring markers. Materials and MethodsFifteen patients (six male) with otherwise treatment-refractory OCD receiving ALIC/NAc DBS performed a flanker task with EEG recordings at three sessions: presurgery and at follow-up with DBS on and off. We examined MFT, ERN, and task performance. Furthermore, we investigated interrelations with clinical efficacy and then explored the influence of the location of individual stimulation volumes on EEG modulations. ResultsMFT and ERN were significantly attenuated by DBS with differences most pronounced between presurgery and DBS-on states. Also, we observed reaction time slowing for erroneous responses during DBS-off. Larger presurgery ERN amplitudes were associated with decreased clinical efficacy. Exploratory anatomical analyses suggested that stimulation volumes encompassing the NAc were associated with MFT modulation, whereas ALIC stimulation was associated with modulation of the ERN and clinical efficacy. ConclusionALIC/NAc DBS diminished MFT and ERN, demonstrating modulation of the medial frontal performance monitoring system in OCD. Furthermore, our findings encourage further studies to explore the ERN as a potential predictor for clinical efficacy.

Thermocoagulation Treatment of a Patient with Obsessive Compulsive Disorder and Substance Use Disorder: Case Report

AbstractObsessive compulsive disorder (OCD) is a possible cause associated with substance use disorder (SUD), a set of physical, psychological, behavioral, and cognitive phenomena related to the use of one or more chemical substances as a priority in a person's life that compromises quality of life. Since they can share the same neuronal network, this serves as a basis for neurosurgical procedures in cases refractory to conventional therapies. A 31-year-old male patient with a history of OCD and SUD refractory to conventional therapies underwent bilateral ablative stereotactic neurosurgery of the anterior limb of the internal capsule, the subgenual cingulate region, the nucleus accumbens, and the cingulate gyrus. Up to 33 months after the the procedure, the patient showed an absolute improvement in OCD and SUD and reported lack of withdrawal signs or symptoms and/or need to use drugs. In recent years, ablative neurosurgery has proven to be an alternative to OCD refractoriness, with long-term benefits. In the case analyzed, ablative stereotactic neurosurgery was effective in controlling both the signs and symptoms triggered by OCD, as well as those of anxiety and stress.

Abnormal white matter structure in hoarding disorder

Although preliminary neuroimaging research suggests that patients with hoarding disorder (HD) show widespread abnormal task-related activity in the brain, there has been no research on alterations in the white matter tracts in these patients. The aim of this study was to investigate the characteristics of the major white matter tracts in patients with HD. Tract-based spatial statistics were used to search for white matter tract abnormalities throughout the brain in 25 patients with HD and 36 healthy controls. Post hoc analysis of regions of interest was performed to detect correlations with clinical features. Compared with the controls, patients with HD showed decreased fractional anisotropy and increased radial diffusivity in anatomically widespread white matter tracts. Post hoc analysis of regions of interest revealed a significant negative correlation between the severity of hoarding symptoms and fractional anisotropy in the left anterior limb of the internal capsule and a positive correlation between the severity of these symptoms and radial diffusivity in the right anterior thalamic radiation. Patients with HD showed a broad range of alterations in the frontal white matter tracts, including the frontothalamic circuit, frontoparietal network, and frontolimbic pathway. The findings of this study indicate associations between frontal white matter abnormalities related to the severity of hoarding symptoms in HD and the cortical regions involved in cognitive dysfunction. The insights provided would be useful for understanding the neurobiological basis of HD.

Treatment Outcomes of Gamma-Knife Radio Surgery in Refractory Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is a common disease that has negative effects on functionality, and 10% of the patients do not respond to first-line treatments. Gamma-knife radiosurgery (GKRS) has been used in patients with treatment-resistant OCD, but the data on long-term outcomes are still unsatisfactory. In this study, 12 patients who underwent GKRS between 2005 and 2020 were evaluated retrospectively. Anterior capsulotomy was performed using two 4-mm isocenters at the midputaminal point of the anterior limb of the internal capsule on each side with a maximum radiation dose of 140-180 Gy. Patients were followed up with the Yale-Brown Obsession and Compulsion Scale (Y-BOCS), Montgomery-Asberg Depression Rating Scale (MADRS), and Brief Psychiatric Rating Scale (BPRS) on the first, third, and sixth months. After the procedure, a 35% reduction was observed in the overall Y-BOCS scores, and full response rate was 50%. There was a 49.5% decrease in the MADRS scores and a 57.8% decrease in the BPRS. GKRS is an effective and non-invasive procedure with favorable side effects in treatment-resistant OCD with selected patients.

Effectiveness and safety of deep brain stimulation for patients with refractory obsessive compulsive disorder and comorbid autism spectrum disorder; A case series

Background: Deep brain stimulation (DBS) is effective for patients with treatment refractory obsessive-compulsive disorder (OCD). Autism spectrum disorder (ASD) is present in up to a third of all patients with OCD, but it is unknown whether effectiveness of DBS for OCD also applies for patients with comorbid ASD. The present case series is the first to examine effectiveness on OCD symptoms and safety of DBS in patients with OCD and ASD specifically.Methods: Six consecutive patients with treatment-refractory OCD and comorbid ASD received DBS of the ventral anterior limb of the internal capsule (vALIC) or medial forebrain bundle (MFB). We examined effectiveness of DBS on symptoms of OCD and depression with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and Hamilton Depression Rating Scale (HAM-D), respectively. We included qualitative data to describe the course of treatment in individual patients with OCD and ASD.Results: We found that DBS significantly decreased symptoms of OCD (p < .001) and depression (p = .007). Four out of six patients with OCD and comorbid ASD were responders (decrease ≥ 35% in Y-BOCS), one patient was partial-responder (decrease 25–35% in Y-BOCS) and one patient did not respond (decrease ≤ 25% in Y-BOCS). Serious adverse events were an infection of the DBS system, and a suicide attempt.Conclusions: Though present results are preliminary, DBS reduced symptoms of OCD and depression in patients with OCD and comorbid ASD. Comorbid ASD should therefore not be seen as a contra-indication for DBS in OCD.

Diffusion Tensor Imaging Correlates of Resilience Following Adolescent Traumatic Brain Injury.

Traumatic brain injury (TBI) is associated with considerable mortality and morbidity in adolescents, but positive outcomes are possible. Resilience is the concept that some individuals flourish despite significant adversity. To determine if there is a relationship between resilience-promoting factors that are known to promote resilience and white matter (WM) microstructure 1 year after complicated mild TBI or moderate or severe TBI that is sustained by adolescents. We examined the relationship between performance on a self-report measure of resilience-promoting factors and WM integrity assessed by diffusion tensor imaging in a group of adolescents who had sustained either a TBI (n = 38) or an orthopedic injury (OI) (n = 23). Immediately following injury, the individuals with TBI and the OI controls had comparable levels of resilience-promoting factors; however, at 1 year post injury, the TBI group endorsed fewer resilience-promoting factors and exhibited WM disruption compared with the OI controls. The individuals with TBI who had more resilience-promoting factors at 1 year post injury exhibited increased WM integrity, but the OI controls did not. Findings were particularly strong for the following structures: anterior corona radiata, anterior limb of the internal capsule, and genu of the corpus callosum-structures that are implicated in social cognition and are frequently disrupted after TBI. Relationships were notable for caregiver and community-level resilience-promoting factors. The current findings are some of the first to indicate neurobiological evidence of previously noted buffering effects of resilience-promoting factors in individuals with TBI.

White matter microstructure differences in individuals with dependence on cocaine, methamphetamine, and nicotine: Findings from the ENIGMA-Addiction working group

BackgroundNicotine and illicit stimulants are very addictive substances. Although associations between grey matter and dependence on stimulants have been frequently reported, white matter correlates have received less attention. MethodsEleven international sites ascribed to the ENIGMA-Addiction consortium contributed data from individuals with dependence on cocaine (n = 147), methamphetamine (n = 132) and nicotine (n = 189), as well as non-dependent controls (n = 333). We compared the fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) of 20 bilateral tracts. Also, we compared the performance of various machine learning algorithms in deriving brain-based classifications on stimulant dependence. ResultsThe cocaine and methamphetamine groups had lower regional FA and higher RD in several association, commissural, and projection white matter tracts. The methamphetamine dependent group additionally showed lower regional AD. The nicotine group had lower FA and higher RD limited to the anterior limb of the internal capsule. The best performing machine learning algorithm was the support vector machine (SVM). The SVM successfully classified individuals with dependence on cocaine (AUC = 0.70, p < 0.001) and methamphetamine (AUC = 0.71, p < 0.001) relative to non-dependent controls. Classifications related to nicotine dependence proved modest (AUC = 0.62, p = 0.014). ConclusionsStimulant dependence was related to FA disturbances within tracts consistent with a role in addiction. The multivariate pattern of white matter differences proved sufficient to identify individuals with stimulant dependence, particularly for cocaine and methamphetamine.

The role of white matter abnormality in the left anterior corona radiata: In relation to formal thought disorder in patients with schizophrenia

White matter abnormality has been widely reported in patients with schizophrenia (Sz). However, few studies have focused on the relationship between the white matter deficit and formal thought disorder (FTD). Moreover, the role of genetic high risk in FTD-related white matter deficit remains unclear. The present study recruited 46 Sz patients, 18 unaffected first-degree relatives of Sz patients, and 29 healthy controls. There was a widespread fractional anisotropy (FA) reduction in Sz. In addition, reduced FA in the left anterior corona radiata was related to more severe FTD symptoms in Sz. However, the genetic high-risk group only showed lower mean FA in the left anterior limb of the internal capsule than healthy controls. Our findings suggest that abnormality in the left anterior corona radiata may only occur in Sz but not in the genetic high-risk group. Such an abnormality might be associated with the severity of FTD symptoms. Meanwhile, genetic vulnerability may contribute to the abnormality in the left anterior limb of the internal capsule. Better analytical methods are needed to validate our results.

Impact of Pretreatment Ischemic Location on Functional Outcome after Thrombectomy.

Pretreatment ischemic location may be an important determinant for functional outcome prediction in acute ischemic stroke. In total, 143 anterior circulation ischemic stroke patients in the THRACE study were included. Ischemic lesions were semi-automatically segmented on pretreatment diffusion-weighted imaging and registered on brain atlases. The percentage of ischemic tissue in each atlas-segmented region was calculated. Statistical models with logistic regression and support vector machine were built to analyze the predictors of functional outcome. The investigated parameters included: age, baseline National Institutes of Health Stroke Scale score, and lesional volume (three-parameter model), together with the ischemic percentage in each atlas-segmented region (four-parameter model). The support vector machine with radial basis functions outperformed logistic regression in prediction accuracy. The support vector machine three-parameter model demonstrated an area under the curve of 0.77, while the four-parameter model achieved a higher area under the curve (0.82). Regions with marked impacts on outcome prediction were the uncinate fasciculus, postcentral gyrus, putamen, middle occipital gyrus, supramarginal gyrus, and posterior corona radiata in the left hemisphere; and the uncinate fasciculus, paracentral lobule, temporal pole, hippocampus, inferior occipital gyrus, middle temporal gyrus, pallidum, and anterior limb of the internal capsule in the right hemisphere. In conclusion, pretreatment ischemic location provided significant prognostic information for functional outcome in ischemic stroke.

Predicting Response to vALIC Deep Brain Stimulation for Refractory Obsessive-Compulsive Disorder.

Background: Deep brain stimulation (DBS) for treatment-refractory obsessive-compulsive disorder (OCD) is effective in half of patients, but also is invasive and labor-intensive.Objective: Selecting probable responders beforehand would more optimally allocate treatment resources and prevent patients' disappointment. Some centers use clinical and demographic predictors to exclude patients from DBS treatment, but the evidence base remains uncertain.Methods: This observational cohort study examined the association of baseline demographic and disease characteristics with a 1-year prospective course of OCD and depressive symptoms in a cohort of 70 consecutive patients who received DBS of the ventral anterior limb of the internal capsule (vALIC-DBS) for OCD according to DSM-IV or DSM-5 criteria between April 2005 and October 2017. Baseline characteristics and symptom decrease were analyzed using Fisher exact tests and binary logistic regression to examine whether they could predict individual response (> 35% reduction in Yale-Brown Obsessive Compulsive Scale score and 50% reduction in Hamilton Depression Rating Scale score, respectively).Results: Insight into illness was the only significant predictor of individual response, with a positive predictive value of 84.4%, while the negative predictive value was 44.0% (b = 0.247, χ21 = 5.259, P = .022). Late-onset OCD was associated with more symptom decrease (β = -0.29; 95% CI, -0.53 to -0.04; P = .023) and comorbid personality disorder with less symptom decrease over time (β = 0.88; 95% CI -0.29 to 1.47; P = .004), but they could not significantly predict vALIC-DBS response. A later age at onset, comorbid personality disorder, and insight into illness were associated with clinical outcomes after vALIC-DBS, but predictive values were not large enough to facilitate clinical patient selection.Conclusions: Clinical and demographic factors cannot yet predict outcome and should not be used to exclude patients from treatment with vALIC-DBS. These first individual prediction analyses for vALIC-DBS response in OCD are important, given that some centers up until now still exclude patients based on clinical characteristics such as comorbid personality disorders.

Interstitial laser anterior capsulotomy for obsessive–compulsive disorder: lesion size and tractography correlate with outcome

BackgroundAnterior capsulotomy is a well-established treatment for refractory obsessive–compulsive disorder (OCD). MRI-guided laser interstitial thermal therapy (LITT) allows creation of large, sharply demarcated lesions with the safeguard of real-time imaging.ObjectiveTo...

Nucleus accumbens as a stereotactic target for the treatment of addictions in humans: a literature review.

Deep brain stimulation (DBS) has achieved substantial success as a treatment for movement disorders such as Parkinson's Disease (PD), essential tremor (ET), and dystonia. More recently, a limited number of basic and clinical studies have indicated that DBS of the nucleus accumbens (NAc) and other neighbouring structures of the reward circuit may be an effective intervention for patients with treatment-refractory addiction. We performed a structured literature review of human studies of DBS for addiction outlining the clinical efficacy and adverse events. We found 14 human studies targeting mostly the NAc with neighbouring structures such as anterior limb of the internal capsule (ALIC). Five studies including 12 patients reported the outcomes for alcohol dependence. Nine studies including 18 patients reported the outcomes for addictions to various psychoactive substances. The most common indication was addiction to heroin, found in 13 patients, followed by methamphetamine, 3 patients, cocaine, one patient, and polysubstance drug abuse in one patient. The limited clinical data available indicates that DBS may be a promising therapeutic modality for the treatment of intractable addiction. In general, the safety profile of DBS in patients with addiction is good. Based on the data published in the literature, the NAc is the most often targeted, and is probably the most effective, structure of the reward circuit in the treatment of addiction in humans. Given the ever-expanding understanding of the psychosurgery of addiction, DBS could in the future be a treatment option for patients suffering from intractable addictive disorders.

Deep Brain Stimulation for Obsessive-Compulsive Disorder: Why Anatomy Matters

It has now been 21 years since the first publication discussed deep brain stimulation (DBS) for obsessive-compulsive disorder (OCD) (1), which targeted a well-established ablation site, the anterior limb of the internal capsule (ALIC). Building on the hypothesis that high-frequency stimulation equals ablation, first introduced for tremor in Parkinson’s disease in the late 1980s, the application of DBS for a variety of neuropsychiatry disorders has been evolving ever since. The initial and somewhat naïve hypothesis was that DBS merely provided a safer, adjustable, and reversible lesion.

Distribution of electric field in patients with obsessive compulsive disorder treated with deep brain stimulation of the bed nucleus of stria terminalis

BackgroundDeep brain stimulation (DBS) is being investigated as a treatment for therapy-refractory obsessive compulsive disorder (OCD). Many different brain targets are being trialled. Several of these targets such as the ventral striatum (including the nucleus accumbens (NAc)), the ventral capsule, the inferior thalamic peduncle, and the bed nucleus of stria terminalis (BNST)) belong to the same network, are anatomically very close to one another, or even overlap. Data is still missing on how various stimulation parameters in a given target will affect surrounding anatomical areas and impact the clinical outcome of DBS.MethodsIn a pilot study of eleven participants with DBS of the BNST, we investigate through patient-specific simulation of electric field, which anatomical areas are affected by the electric field, and if this can be related to the clinical results. Our study combined individual patient’s stimulation parameters at 12- and 24-month follow-up with image data from the preoperative MRI and postoperative CT. These data were used to calculate the distribution of electric field and create individual anatomical models of the field of stimulation.ResultsThe individual electric stimulation fields by stimulation in the BNST were similar at both the 12- and 24-month follow-up, involving mainly anterior limb of the internal capsule (ALIC), genu of the internal capsule (IC), BNST, fornix, anteromedial globus pallidus externa (GPe), and the anterior commissure. A statistical significant correlation (p < 0.05) between clinical effect measured by the Yale-Brown Obsessive Compulsive Scale and stimulation was found at the 12-month follow-up in the ventral ALIC and anteromedial GPe.ConclusionsMany of the targets under investigation for OCD are in anatomical proximity. As seen in our study, off-target effects are overlapping. Therefore, DBS in the region of ALIC, NAc, and BNST may perhaps be considered to be stimulation of the same target.

White Matter Abnormalities in Patients With Typhoon-Related Posttraumatic Stress Disorder.

Patients with posttraumatic stress disorder (PTSD) might have white matter abnormalities. However, less is known about white matter changes after exposing a specific traumatic event. The purpose of this study was to explore the abnormalities of diffusion in cerebral white matter and its relationship with the clinical symptoms in patients with PTSD by using diffusion tensor imaging (DTI). Diffusion-weighted imaging of the cerebrum was performed in typhoon survivors with (n = 27) and without PTSD (n = 33) and healthy controls (HCs) (n = 30). Differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated among groups using voxel-based analysis of the DTI data. Correlations between diffusion indices and clinical symptoms in patients with PTSD were also assessed. Both patients with PTSD and trauma-exposed control (TEC) group showed increased FA in the anterior limb of the internal capsule, forceps of the corpus callosum, and corona radiata relative to the HC group. Additionally, there was a negative correlation between FA values in the white matter and the clinical symptoms. Trauma exposure may result in disruption of cerebral white matter in individuals with or without PTSD, particularly in the frontal fibers. Aberrant white matter alterations may be associated with the severity of PTSD symptoms.

Neural correlates of self-awareness of cognitive deficits in non-demented patients with Parkinson's disease.

The aim was to investigate the neural correlates of impaired self-awareness of cognitive deficits (IACd) in non-demented patients with Parkinson's disease (PD). This cross-sectional study enrolled 153 drug-naïve and non-demented PD patients who underwent brain magnetic resonance imaging, dopamine transporter (DAT) positron emission tomography, detailed neuropsychological testing, and the Cognitive Complaints Interview at baseline. Based on the presence of mild cognitive impairment and subjective cognitive complaints, patients were grouped into those with IACd (PD-IACd+, n=33) and those with normal recognition of cognitive function (n=82) or underestimation of cognitive function (n=38). Cortical thickness, white matter (WM) integrity, DAT availability and cognitive function were compared between the groups. The prevalence of IACd was 21.6% in drug-naïve patients with PD. The PD-IACd+ group had a lower z-score in the Stroop color reading test than the other groups. Patients in the PD-IACd+ group had WM disintegrity, especially in the genu of the corpus callosum and anterior limb of the internal capsule, compared to those without IACd, whilst cortical thickness or striatal DAT availability was comparable regardless of the presence of IACd. Amongst patients with mild cognitive impairment, those with IACd had more severe WM disintegrity than those without IACd. Structural connectivity between and from the frontal lobes is closely associated with self-awareness of cognitive deficits in PD. Evaluating frontal structural connectivity from the early stages of PD will be important in assessing the actual cognitive and daily life performance of patients with PD.

The influence of NRXN1 on systemizing and the brain structure in healthy adults.

Certain behavioral characteristics of autism spectrum disorder can be found in otherwise healthy people. Individuals with difficulties in social adaptation may have subclinical autistic traits; however, effective biomarkers of these traits have not yet been established. There is a dire need for objective indices of these traits that combine behavior, brain images, and genetic information. In this study, we examined the association among a single nucleotide polymorphism of NRXN1 (rs858932; C/G), autistic traits, and brain structure in 311 healthy adults. We found that carriers of minor alleles (carriers of the G-allele) had significantly higher systemizing scores than major-allele (C-allele) homozygotes. Furthermore, the regional white matter volume in the right anterior limb of the internal capsule was significantly greater in carriers of the G-allele than in C-allele homozygotes. To the best of our knowledge, this is the first report of NRXN1 rs858932 being involved in systemizing and the brain structure of healthy adults. Our findings provide insight into the effects of genetics on autistic traits and their respective neural substrates.

Prospective study on microstructure in medication-naïve adolescents with first-episode major depressive disorder

Background: Major depressive disorder (MDD) is one of the most prevalent mental disorders during adolescence, and early diagnosis and treatment are important. We aimed to characterize the microstructure of the brain in medication-naïve adolescents with first-episode MDD. Methods: Patients with MDD (N = 31) and healthy controls (N = 27) participated in this study and severity of depressive symptoms, duration of untreated depressive episode, demographic data, and diffuse tensor imaging data were collected. A comparative analysis of patients and healthy controls was performed, and the effect of medication on the brain`s integrity was investigated through comparison before and after 3 months of treatment in the patient group. Tract-based spatial statistics was used for diffusion tensor image analysis. Results: In the patient group, functional anisotropy (FA) values were significantly higher at the genu of the corpus callosum, body of the corpus callosum, and right anterior corona radiata than in healthy controls. After 3 months of treatment, FA values were significantly decreased in the left anterior limb of the internal capsule, left posterior limb of the internal capsule, and left superior longitudinal fasciculus. Limitations: The sample size is relatively small and 3-month treatment period was relatively short. Conclusion: FA values of patients with MDD were increased compared to healthy controls and decreased after treatment. These results suggested that pharmacological treatments in the early stages of MDD might restore the brain`s integrity.