MNI Coordinates Research Articles

Dependent Personality Disorder: An Approach Based on fMRI

Background: Dependent Personality Disorder (DPD) is one of the most frequent diagnosed personality disorders. People with DPD become over-dependent on other people and unable to make even everyday decisions. Objective: To detect the neuron network and activation in Brodmann areas (BA 10, BA 11, & BA 47) of the human brain by using Functional Magnetic Resonance Imaging (fMRI) and to identify voxels used in decision making process. Material and Methods: It is an experimental study conducted on a single subject under a controlled observed environment using Functional Magnetic Resonance Imaging (fMRI). The respondent selected was performing a task based on two visual conditions in which two different types of images (easy and hard birds) were displayed to the respondent. The subject was asked for identification of the particular bird image to visualize voxels used in decision making process. Three Brodmann areas (BA 10, BA 11, & BA 47) from prefrontal cortex were selected as a region of interest. The current study analyzed activated brain regions during making ordinary decisions related to two visual conditions. A multivariate technique Multilayer Perceptron (MLP) neural network was applied for the categorization of two ordinary decisions made by respondent while performing visual task. Results: The experimental results show the high classification accuracy 92.9% for ordinary decisions between two visual conditions. Sensitivity and specificity of MLP neural network is represented by ROC curve. The MLP neural network technique also detected some important voxels of Brodmann areas 10, 11 and 47 in prefrontal cortex of brain, which engaged in primary role of ordinary decision making process. The current study tracked down the area of that particular prevailing voxels in prefrontal cortex of brain in context of MNI coordinates. Conclusion: In conclusion, the MLP neural network proficiently classified the voxels which were activated in decision making and provided high classification rates. It also identified significant voxels helping a person in ordinary decision making. The locations of that particular voxels were found in context of MNI coordinates. This study can be helpful in the treatment of patients with DPD by combination of medication and psychotherapy. Advances in Knowledge: This paper explains precise location of dominant voxels discovered in decision making process which can be used in treatment methods among dependent personality disorder patients. At present, the treatment options are limited, and this paper will give psychiatrists and psychologists the knowledge they need to advance their combination therapies.

A voxel-based morphometry investigation of brain structure variations in late-life depression with insomnia.

Late-life depression (LLD) is linked to various medical conditions and influenced by aging-related processes. Sleep disturbances and insomnia symptoms may be early indicators or risk factors for depression. Neuroimaging studies have attempted to understand the neural mechanisms underlying LLD, focusing on different brain networks. This study aims to further delineate discriminative brain structural profiles for LLD with insomnia using MRI. We analyzed 24 cases in the LLD with insomnia group, 26 cases in the LLD group, and 26 in the healthy control (HC) group. Patients were evaluated using the Hamilton Depression Rating Scale (HAMD-17), Hamilton Anxiety Rating Scale (HAMA), Mini-Mental State Examination (MMSE), and Pittsburgh Sleep Quality Index (PSQI). Structural MRI data were gathered and analyzed using voxel-based morphometry (VBM) to identify differences in gray matter volume (GMV) among the groups. Correlation analyses were conducted to explore the relationships between GMV and clinical characteristics. Significant difference in sex distribution was observed across the groups (p = 0.029). However, no significant differences were detected in age and MMSE scores among the groups. LLD with insomnia group exhibited significantly higher HAMA (p = 0.041) and PSQI scores (p < 0.05) compared to the LLD group. ANOVA identified significant difference in GMV of anterior lobe of cerebellum (peak MNI coordinate: x = 52, y = -40, z = -30) among HC, LLD, and LLD with insomnia. Post-hoc two-sample t-tests revealed that the significant difference in GMV was only found between the LLD group and the HC group (p < 0.05). The mean GMV in the cerebellum was positively correlated with HAMA scale in LLD patients (r = 0.47, p < 0.05). There is significant difference in GMV in the LLD group, the association between late-life depression and insomnia may be linked to anxiety. This study provides insights into the discriminative brain structural profiles of LLD and LLD with insomnia, advancing the understanding of the underlying neural mechanisms and potential targets for intervention.

TMS Targets for Multiple Sclerosis Related Depression Derived Using a Precomputed Functional Connectome (P11-3.014)

TMS Targets for Multiple Sclerosis Related Depression Derived Using a Precomputed Functional Connectome (P11-3.014)

453 Neuromodulation of the Centromedian Nucleus of the Thalamus for the Treatment of Generalized Drug-Resistant Epilepsy: Novel Insights Into the Targeting and the Anti-Seizure Mechanism From a Tractographic Study

INTRODUCTION: Neuromodulation of the centromedian nucleus (CM) has been investigated with promising results for the treatment of generalized drug-resistant epilepsy (gDRE). Recent evidence suggests a more clinically beneficial “sweet-spot” corresponding to the thalamic area between the antero-lateral CM and the posterior subdivision of the ventrolateral nucleus. However, it is unclear if this region can be considered a new target or still a subcomponent of CM. METHODS: We analyzed diffusion and structural MRI scans from 9 DRE patients, who underwent CM-stimulation surgery. CM masks from the THOMAS atlas and 2 spherical ROIs from the MNI coordinates of the sweet-spot and the cold-spot in Warren et al. 2022 were used as seed regions for probabilistic tractography (FSL software). 42 cortical and subcortical areas were selected as target regions and divided in 5 groups: sensorimotor, associative, basal ganglia, infratentorial and limbic structures. Mean structural connectivity was calculated using descriptive statistics and statistical significance was tested with a standard t-test. Statistical comparison among the 3 seed regions was conducted using ANOVA. RESULTS: For each seed, statistically significant (p &lt; 0.05) connections were found for all the 5 groups. When comparing the 3 seeds, the CM and the cold-spot had stronger connections with the postcentral and the superior temporal cortices, the brainstem, the caudate and the amygdala; the sweet-spot with the precentral and the superior frontal cortices, the cerebellum, the putamen and the nucleus accumbens. However, no statistically significant differences resulted among the 3 seeds. CONCLUSIONS: CM has widespread connections with both cortical and subcortical structures. The sweet-spot seems to correspond to the parvocellular part of CM on the border with the ventrolateral nucleus. CM connections with frontal and prefrontal areas and the cerebellum may underlie the beneficial effect against generalized seizures.

Multiple Dipole Source Position and Orientation Estimation Using Non-Invasive EEG-like Signals.

The problem of precisely estimating the position and orientation of multiple dipoles using synthetic EEG signals is considered in this paper. After determining a proper forward model, a nonlinear constrained optimization problem with regularization is solved, and the results are compared with a widely used research code, namely EEGLAB. A thorough sensitivity analysis of the estimation algorithm to the parameters (such as the number of samples and sensors) in the assumed signal measurement model is conducted. To confirm the efficacy of the proposed source identification algorithm on any category of data sets, three different kinds of data-synthetic model data, visually evoked clinical EEG data, and seizure clinical EEG data are used. Furthermore, the algorithm is tested on both the spherical head model and the realistic head model based on the MNI coordinates. The numerical results and comparisons with the EEGLAB show very good agreement, with little pre-processing required for the acquired data.

Source Localization of Somatosensory Neural Generators in Adults with Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder, where differences are often present relating to the performance of motor skills. Our previous work elucidated unique event-related potential patterns of neural activity in those with ADHD when performing visuomotor and force-matching motor paradigms. The purpose of the current study was to identify whether there were unique neural sources related to somatosensory function and motor performance in those with ADHD. Source localization (sLORETA) software identified areas where neural activity differed between those with ADHD and neurotypical controls when performing a visuomotor tracing task and force-matching task. Median nerve somatosensory evoked potentials (SEPs) were elicited, while whole-head electroencephalography (EEG) was performed. sLORETA localized greater neural activity post-FMT in those with ADHD, when compared with their baseline activity (p < 0.05). Specifically, greater activity was exhibited in BA 31, precuneus, parietal lobe (MNI coordinates: X = -5, Y = -75, and Z = 20) at 156 ms post stimulation. No significant differences were found for any other comparisons. Increased activity within BA 31 in those with ADHD at post-FMT measures may reflect increased activation within the default mode network (DMN) or attentional changes, suggesting a unique neural response to the sensory processing of force and proprioceptive afferent input in those with ADHD when performing motor skills. This may have important functional implications for motor tasks dependent on similar proprioceptive afferent input.

Evaluating the neural substrates of effort-expenditure for reward in adults with major depressive disorder and obesity

Converging evidence has suggested that disturbances in monetary reward processing may subserve the shared biosignature between major depressive disorder (MDD) and obesity. However, there remains a paucity of studies that have evaluated the deficits in specific subcomponents of reward functioning in populations with MDD and obesity comorbidity. We evaluated the association between effort-expenditure for monetary reward and neural activation in regions associated with reward-based decision making (i.e., the caudate nucleus, anterior cingulate cortex (ACC) and hippocampus) in people with MDD and obesity comorbidity. We acquired structural and functional magnetic resonance imaging (fMRI) in 12 participants and performed a spherical region-of-interest analysis (ROI) using previously defined peak MNI coordinates. A one-sample t-test was employed to compare ROI-specific blood-oxygen-level-dependent (BOLD) signal change during the task choice selection window (i.e., high-effort vs. low-effort task) of the effort-expenditure for reward task (EEfRT). We observed no change in activation of the caudate nucleus, ACC or hippocampus in participants with increased BMI when contrasting the high effort > low effort reward magnitude condition for the EEfRT. The findings from our exploratory study evaluated the disturbances in fundamental reward processes, including cost-benefit decision making, in people MDD and obesity. Future studies should further investigate this relationship with a larger sample size.

Probabilistic mapping of deep brain stimulation in childhood dystonia

ObjectivesIn adults with dystonia Probabilistic Stimulation Mapping (PSM) has identified putative “sweet spots” for stimulation. We aimed to apply PSM to a cohort of Children and Young People (CYP) following DBS surgery. MethodsPre-operative MRI and post-operative CT images were co-registered for 52 CYP undergoing bilateral pallidal DBS (n = 31 genetic/idiopathic dystonia, and n = 21 Cerebral Palsy (CP)). DBS electrodes (n = 104) were automatically detected, and Volumes of Tissue Activation (VTA) derived from individual patient stimulation settings. VTAs were normalised to the MNI105 space, weighted by percentage improvement in Burke-Fahn-Marsden Dystonia Rating scale (BFMDRS) at one-year post surgery and mean improvement was calculated for each voxel. ResultsFor the genetic/idiopathic dystonia group, BFMDRS improvement was associated with stimulation across a broad volume of the GPi. A spatial clustering of the upper 25th percentile of voxels corresponded with a more delineated volume within the posterior ventrolateral GPi. The MNI coordinates of the centroid of this volume (X = −23.0, Y = −10.5 and Z = −3.5) were posterior and superior to the typical target for electrode placement. Volume of VTA overlap with a previously published “sweet spots” correlated with improvement following surgery. In contrast, there was minimal BFMDRS improvement for the CP group, no spatial clustering of efficacious clusters and a correlation between established “sweet spots” could not be established. ConclusionsPSM in CYP with genetic/idiopathic dystonia suggests the presence of a “sweet spot” for electrode placement within the GPi, consistent with previous studies. Further work is required to identify and validate putative “sweet spots” across different cohorts of patients.

Functional connectivity maps of theta/alpha and beta coherence within the subthalamic nucleus region

The subthalamic nucleus (STN) is a primary target for deep brain stimulation in Parkinson's disease (PD). Although small in size, the STN is commonly partitioned into sensorimotor, cognitive/associative, and limbic subregions based on its structural connectivity profile to cortical areas. We investigated whether such a regional specialization is also supported by functional connectivity between local field potential recordings and simultaneous magnetoencephalography. Using a novel data set of 21 PD patients, we replicated previously reported cortico-STN coherence networks in the theta/alpha and beta frequency ranges, and looked for the spatial distribution of these networks within the STN region. Although theta/alpha and beta coherence peaks were both observed in on-medication recordings from electrode contacts at several locations within and around the STN, sites with theta/alpha coherence peaks were situated at significantly more inferior MNI coordinates than beta coherence peaks. Sites with only theta/alpha coherence peaks, i.e. without distinct beta coherence, were mostly located near the border of sensorimotor and cognitive/associative subregions as defined by a tractography-based atlas of the STN. Peak coherence values were largely unaltered by the medication state of the subject, however, theta/alpha peaks were more often identified in recordings obtained after administration of dopaminergic medication. Our findings suggest the existence of a frequency-specific topography of cortico-STN coherence within the STN, albeit with considerable spatial overlap between functional networks. Consequently, optimization of deep brain stimulation targeting might remain a trade-off between alleviating motor symptoms and avoiding adverse neuropsychiatric side effects.

451 Unique Gray Matter Volume Differences in Bilingual Children with Reading Disability

OBJECTIVES/GOALS: Developmental dyslexia is a common reading disability (RD) which negatively impacts academic success. To address the role of early language experience on RD, we tested if the reported differences in gray matter volume (GMV) in RD also manifests in poor readers with a bilingual language background. METHODS/STUDY POPULATION: We studied 54 Spanish-English Bilingual Typical Readers with Oral Reading Recognition Test (ORRT) scores above 100 (avg. =113 ± 10), 51 Spanish-English Bilinguals with RD with ORRT scores below 92 (avg. =84 ± 7), 54 English Monolingual Typical Readers with ORRT scores above 100 (avg. =113 ± 10) and 51 English Monolinguals with RD with ORRT scores below 92 (avg. =84 ± 7) from the Adolescent Brain &amp; Cognitive Development Study. All groups had an average age of 12 ± 0.7 years and were matched for sex and self-ratings of English ability. Structural magnetic resonance images were analyzed using Voxel-Based Morphometry and the bilingual and monolingual groups were separately compared in two-sample t-tests (p &lt; 0.05). RESULTS/ANTICIPATED RESULTS: Monolinguals with RD had less GMV than the Monolingual Typical Readers in the right supramarginal gyrus (Brodmanns Area (BA) 40; MNI Coordinates: 69, -27, 39) (p=0.011) similar to the right superior temporal finding reported in the existing literature. However, a comparison of Bilinguals with RD and Bilingual Typical Readers did not show any GMV differences in superior temporal regions. Instead, our Bilinguals with RD had less GMV compared to the Spanish-English Bilingual Typical Readers in the right superior frontal gyrus (BA 11; MNI Coordinates: 21, 44, -24) extending to the middle frontal gyrus (BA 10) (p = 0.014). DISCUSSION/SIGNIFICANCE: Our findings suggest that the neuroanatomical bases of RD in Spanish-English Bilingual children are not the same as those observed for monolinguals, and biological models developed in monolinguals cannot be generalized. This has implications for diagnoses and treatment of RD in bilinguals.

Intranasal oxytocin modulates the salience network in aging

Growing evidence supports a role of the neuropeptide oxytocin in promoting social cognition and prosocial behavior, possibly via modulation of the salience of social information. The effect of intranasal oxytocin administration on the salience network, however, is not well understood, including in the aging brain. To address this research gap, 42 young (22.52 ± 3.02 years; 24 in the oxytocin group) and 43 older (71.12 ± 5.25 years; 21 in the oxytocin group) participants were randomized to either self-administer intranasal oxytocin or placebo prior to resting-state functional imaging. The salience network was identified using independent component analysis (ICA). Independent t-tests showed that individuals in the oxytocin compared to the placebo group had lower within-network resting-state functional connectivity, both for left amygdala (MNI coordinates: x = -18, y = 0, z = -15; corrected p < 0.05) within a more ventral salience network and for right insula (MNI coordinates: x = 39, y = 6, z = -6; corrected p < 0.05) within a more dorsal salience network. Age moderation analysis furthermore demonstrated that the oxytocin-reduced functional connectivity between the ventral salience network and the left amygdala was only present in older participants. These findings suggest a modulatory role of exogenous oxytocin on resting-state functional connectivity within the salience network and support age-differential effects of acute intranasal oxytocin administration on this network.

Updated scalp heuristics for localizing the dorsolateral prefrontal cortex based on convergent evidence of lesion and brain stimulation studies in depression

BackgroundRepetitive transcranial magnetic stimulation (rTMS) is entering wider use as a therapeutic intervention for many psychiatric illnesses. The efficacy of this therapeutic intervention may depend on accurately localizing target brain regions. Recent work investigating whole-brain maps of circuits associated with depression and its successful treatment has identified foci of interest within the dorsolateral prefrontal cortex (DLPFC). ObjectiveTo create an updated scalp heuristic for localizing the DLPFC based on convergent evidence of lesion and brain stimulation studies in depression. MethodsUsing the standard MNI ICBM152 anatomical template, we localized the scalp sites at minimum Euclidean distance from target MNI coordinates and performed nasion-inion, tragus-tragus, and head-circumference measurements on the anatomical template. We then derived equations to localize these scalp sites. ResultsThe derived equations to calculate the arc length X and Y for these new targets are as follows: [Y=((NI+TrTr)/2)×0.3167 ; X=HC×0.1359] for the left anterior DLPFC[ Y=((NI+TrTr)/2)×0.2884; X=HC×0.1352] for the right anterior DLPFC[ Y=((NI+TrTr)/2)×0.2480; X=HC×0.1847] for the left posterior DLPFC[ Y=((NI+TrTr)/2)×0.2316 ; X=HC×0.1968] for the right posterior DLPFC ConclusionsThis heuristic may help localize DLPFC targets identified in previous lesion-/stimulation-mapping work. A spreadsheet calculation tool is offered to support use of this heuristic.

Variability of EEG electrode positions and their underlying brain regions: visualizing gel artifacts from a simultaneous EEG-fMRI dataset.

IntroductionWe investigated the between‐subject variability of EEG (electroencephalography) electrode placement from a simultaneously recorded EEG‐fMRI (functional magnetic resonance imaging) dataset.MethodsNeuro‐navigation software was used to localize electrode positions, made possible by the gel artifacts present in the structural magnetic resonance images. To assess variation in the brain regions directly underneath electrodes we used MNI coordinates, their associated Brodmann areas, and labels from the Harvard‐Oxford Cortical Atlas. We outline this relatively simple pipeline with accompanying analysis code.ResultsIn a sample of 20 participants, the mean standard deviation of electrode placement was 3.94 mm in x, 5.55 mm in y, and 7.17 mm in z, with the largest variation in parietal and occipital electrodes. In addition, the brain regions covered by electrode pairs were not always consistent; for example, the mean location of electrode PO7 was mapped to BA18 (secondary visual cortex), whereas PO8 was closer to BA19 (visual association cortex). Further, electrode C1 was mapped to BA4 (primary motor cortex), whereas C2 was closer to BA6 (premotor cortex).ConclusionsOverall, the results emphasize the variation in electrode positioning that can be found even in a fixed cap. This may be particularly important to consider when using EEG positioning systems to inform non‐invasive neurostimulation.

Differences in functional connectivity amongst older adults with mild cognitive impairment, subjective cognitive decline or normal cognition

AbstractBackgroundSubjective cognitive decline (SCD), hypothesized as a preclinical stage of Alzheimer’s disease (AD), describes individuals with subjective cognitive concerns despite normal performance on cognitive tests (Jessen et al., 2014). The reduced ability of the salience network (SN) to control switching between the central executive network (CEN) and the default mode network (DMN) has been linked to deterioration of cognitive functioning in normal aging, mild cognitive impairment (MCI) and AD dementia (He et al., 2014). Since alterations in functional connectivity between these networks have been implicated in MCI and AD, we compared connectivity of the SN with CEN and DMN amongst SCD, MCI and older adults who were cognitively unimpaired (CU). We predicted that SCD would show reduced SN connectivity between CEN and DMN networks compared to CU, but greater connectivity compared to MCI.MethodParticipants were 72 older adults [39 females, mean age=71.5] who were classified as either CU (n=26), SCD (n=29), or MCI (n=17). CU reported no memory concerns and performed within normal limits on neuropsychological (NP) assessments. SCD was established by affirmative responses to “Do you feel like your memory is becoming worse?” “If so, are you worried?” and normal NP test performance. MCI was based on the presence of subjective cognitive concerns and impairment on ≥ 2 NP measures within a cognitive domain, and functional independence. Participants underwent resting state functional magnetic resonance imaging (rs‐fMRI) for 6 minutes in an awake state with their eyes closed using gradient‐echo EPI BOLD at 3T (TR=2000ms, TE=30ms). Imaging data were processed using CONN toolbox. Seed‐based analysis using left and right frontoinsular cortices as seeds, which are key nodes in the SN network (MNI coordinates: ‐34,24‐,6 and 38,16,6, respectively), was conducted to measure connectivity between SN and the other two networks, CEN and DMN, within each group.ResultGroups did not differ in age, years of education, or sex distribution [F(2,69)=0.415, p=0.66;F(2,69)=2.20, p=0.12;X2(2, N=72)=1.89, p=0.39, respectively]. Results from imaging data analyses will be presented.ConclusionExamination of functional connectivity in SCD can be conducted using rs‐fMRI and may provide a window to the neurobiology of SCD.

Analysis of abnormal dynamic functional connectivity of the raphe nucleus in adolescent patients with first-episode depression on resting-state functional magnetic resonance imaging

Objective: To investigate the dynamic functional connectivity (dFC) abnormalities of the raphe nucleus in adolescent patients with first-episode depression and its correlation with clinical characteristics and cognitive function. Methods: A total of 30 adolescent patients with untreated depression [Depression Groups, 17 males and 13 females, median age 16.5 (15.0, 17.0) years] and 29 age-, gender-and education-[Healthy Controls, 17 males and 12 females, median age 17.0 (16.0, 18.0) years] matched healthy controls underwent resting functional MRI examinations and their clinical data were obtained in the First Affiliated Hospital of Zhengzhou University.The raphe nuclei was subdivided into dorsal raphe nuclei (DRN) and median raphe nuclei (MRN). Seed-based dFC of the raphe nucleus was conducted to analyze the abnormal dFC between DRN and whole brain gray matter as well as MRN. Clinical characteristics and cognitive function were evaluated using HAMD-17 and Wisconsin card sorting (WSCT), respectively. The difference of dFC between the two groups was compared. The variance values of dFC in the different brain regions were extracted and subsequently used for evaluating the correlation between the scores of HAMD-17 as well as cognitive tests. Results: Compared with HC, the depression group had an significantly increased variance of dFC in the right superior temporal gyrus (MNI coordinate:33,-12,-12; voxel size 468; t=4.715), extending to the right insula, lentiform nucleus, putamen and Rolandic_Oper_R (aal) (GRF correction, voxel-P<0.005,cluster-P<0.05). Significant negative correlations were observed between the variance in the different brain regions and the total scores andthe factor of retardation scores of HAMD-17 as well the total time, the time of correct thinking, the time of mistake thinking and the number of non-persistent errors of WSCT in depression groups (r=-0.388, -0.365, -0.488, -0.470, -0.412, -0.390, respectively, all P<0.05). Conclusion: The variability of the dFC between the DRN and the temporal insula regions as well as striatum was increased in adolescent patients with untreated depression and associated with the severity and cognitive abnormality.

Cognitive Neural Mechanism of Social Anxiety Disorder: A Meta-Analysis Based on fMRI Studies.

Objective: The present meta-analysis aimed to explore the cognitive and neural mechanism of social anxiety disorder (SAD) from a whole-brain view, and compare the differences in brain activations under different task paradigms. Methods: We searched Web of Science Core Collection and other databases with the keywords related to social anxiety, social phobia, and functional magnetic resonance imaging (fMRI) for comparing persons with SAD to healthy controls and used the activation likelihood estimation method. Thirty-seven papers met the inclusion criteria, including 15 with emotional faces as stimuli, 8 presenting specific situations as stimuli, and 14 using other types of tasks as stimuli. Among these papers, 654 participants were in the SAD group and 594 participants were in the control group with 335 activation increase points and 115 activation decrease points. Results: Whole-brain analysis showed that compared with healthy controls, persons with SAD showed significantly lower activation of the left anterior cingulate gyrus (MNI coordinate: x = −6, y = 22, z = 38; p 0.001). Sub-group analysis based on task indicated that when performing tasks with emotional faces as stimuli, persons with SAD showed significantly lower activation of the left cerebellar slope and fusiform gyrus (MNI coordinate: x = −26, y = −68, z = −12; p 0.001), and significantly higher activation of the right supramarginal gyrus and angular gyrus, than healthy controls (MNI coordinate: x = 58, y = −52, z = 30; p 0.001). Conclusion: Individuals with social anxiety disorder show abnormal activation in the cingulate gyrus, which is responsible for the process of attention control, and task type can influence the activation pattern.

483 Neuroanatomical and Neurofunctional Correlates of Unexplained Excessive Daytime Sleepiness

Abstract Introduction Excessive daytime sleepiness (EDS) frequently presents as a secondary symptom, but some experience EDS in the absence of an explanatory medical condition, psychiatric illness, sleep disorder, or medication/substance use. The neurobiology underlying unexplained EDS (uEDS) is poorly understood, which contributes to the existing limitations in uEDS classification, assessment, and treatment. This investigation was designed to identify potential neuroanatomical and neurofunctional correlates of uEDS. Methods Data were acquired from the open-access Stockholm Sleepy Brain (SSB) Project, which included either young (20–30 years old) or older (65–75 years old) adults. SSB criteria ruled out common EDS explanations. A uEDS sample (N = 18; Percentage Female = 33%; Percentage Young = 33%) was established using Epworth Sleepiness Scale (ESS) ≥ 11. Age-and-sex matched controls without EDS (noEDS) were identified. T1-weighted MRI and resting-state fMRI (rs-fMRI) data were compiled for each subject, as well as depression, anxiety, and global health self-ratings. Processing pipelines were performed on T1-weighted and rs-fMRI data. Neuroanatomical analyses compared groups using voxel-based morphometry and across gray matter (GM), white matter (WM), and cerebral spinal fluid volume. Threshold free cluster enhancement was used across all neuroanatomical comparisons. For neurofunctional analyses, seed-based connectivity analysis was performed with a seed placed in the left hemisphere of the medial prefrontal cortex (MNI coordinates: 2 -46 12). Fischer Z-transformed functional connectivity maps were compared across groups. Depression, anxiety, and global health scores were included as covariates and corrections were applied for multiple comparisons, across all analyses. Results Group characteristics were comparable, except for ESS. Significantly increased GM volume (middle occipital gyrus and precuneus) was associated with uEDS, relative to noEDS. Robust, bilateral increases in WM matter (thalamus, cerebellum, and middle frontal gyrus) were observed for uEDS, relative to noEDS. No significant group differences were observed in rs-fMRI. Conclusion Significant neuroanatomical alterations were associated with uEDS that included increases in both GM and WM. These findings converge on previous research associating anatomical differences within the default mode network with uEDS. Future research using more sensitive quantitative measures of WM is warranted. Support (if any) This project was supported by a National Institute Nursing Research grant (NR018288).

Pure Agraphia Associated with a Frontal Meningioma on Left Superior Frontal Gyrus

<i>Background</i>: The existence of cerebral area specifically involved in coding for writing movements in the left middle frontal gyrus is a matter of debate. We present a rare case of pure agraphia associated with a left frontal meningioma. The location of the lesion associated with this disorder could help to feed this debate. <i>Method</i>: We report a case of pure agraphia in a 69-year-old man. The patient had a writing disorder evolving over several months with a dominant, left frontal lesion. On neuropsychological evaluation, the writing difficulties were present whatever the nature of the writing (spontaneous, dictation, coping). The writing disorder was isolated, with no features of aphasia, alexia or limb apraxia. Phonological and lexical processing was preserved. The imaging showed a probable frontal meningioma restricted to the foot of the first and second left frontal circumvolutions (MNI coordinates /barycenter of the lesion: x=-19.8, y=1.5, z=52.2). <i>Results</i>: The patient was operated and the whole lesion was removed. After surgical resection, the patient’s writing disorder improved. Other components of language assessed were the same as before the surgery and showed no disturbances. The pathological study concluded on an OMS grade II atypical meningioma. <i>Conclusion</i>: We think that the disorder presented by our patient was related to the disturbance of the frontal graphemic center located in the Exner area. Here, we describe and analyze his condition through a neuro-anatomical and a cognitive approach.

Network of ictal head version in mesial temporal lobe epilepsy.

ObjectiveIctal head version is a common clinical manifestation of mesial temporal lobe epilepsy (MTLE). Nevertheless, the location of the symptomatogenic zone and the network involved in head version remains unclear. We attempt to explain these problems by analyzing interictal 18FDG‐PET imaging and ictal stereo‐electroencephalography (SEEG) recordings in MTLE patients.MethodsFifty‐eight patients with MTLE were retrospectively analyzed. The patients were divided into version (+) and (−) groups according to the occurrence of versive head movements. The interictal PET data were compared among 18 healthy controls and the (+) and (−) groups. Furthermore, epileptogenicity index (EI) values and correlations with the onset time of head version were analyzed with SEEG.ResultsIntergroup comparisons showed that PET differences were observed in the middle temporal neocortex (MTN), posterior temporal neocortex (PTN), supramarginal gyrus (SMG), and inferior parietal lobe (IPL). The EI values in the SMG, MTN, and PTN were significantly higher in the version (+) group than in the version (−) group. A linear relationship was observed between head version onset and ipsilateral onset time in the SMG, orbitofrontal cortex (OFC), MTN, and PTN. A linear relationship was observed between EI, the difference between version onset and temporal neocortex onset, and the y‐axis of the MNI coordinate.ConclusionThe generation of ictal head version contributes to the propagation of ictal discharges to the intraparietal sulcus (IPS) area. The network of version originates from a mesial temporal lobe structure, passes through the MTN, PTN, and SMG, and likely ends at the IPS.

The ventral attention network: the mirror of the language network in the right brain hemisphere.

Resting-state functional MRI (RfMRI) analyses have identified two anatomically separable fronto-parietal attention networks in the human brain: a bilateral dorsal attention network and a right-lateralised ventral attention network (VAN). The VAN has been implicated in visuospatial cognition and, thus, potentially in the unilateral spatial neglect associated with right hemisphere lesions. Its parietal, frontal and temporal endpoints are thought to be structurally supported by undefined white matter tracts. We investigated the white matter tract connecting the VAN. We used three approaches to study the structural anatomy of the VAN: (a) independent component analysis on RfMRI (50 subjects), defining the endpoints of the VAN, (b) tractography in the same 50 healthy volunteers, with regions of interest defined by the MNI coordinates of cortical areas involved in the VAN used in a seed-based approach and (c) dissection, by Klingler's method, of 20 right hemispheres, for ex vivo studies of the fibre tracts connecting VAN endpoints. The VAN includes the temporoparietal junction and the ventral frontal cortex. The endpoints of the superior longitudinal fasciculus in its third portion (SLF III) and the arcuate fasciculus (AF) overlap with the VAN endpoints. The SLF III connects the supramarginal gyrus to the ventral portion of the precentral gyrus and the pars opercularis. The AF connects the middle and inferior temporal gyrus and the middle and inferior frontal gyrus. We reconstructed the structural connectivity of the VAN and considered it in the context if the pathophysiology of unilateral neglect and right hemisphere awake brain surgery.