Parietal-occipital Cortex Research Articles

Impaired cognitive flexibility in major depressive disorder: Evidences from spatial-temporal ERPs analysis

BackgroundMajor Depressive Disorder (MDD) may exhibit impairments in cognitive flexibility. This study investigated whether the cognitive flexibility deficits in MDD are evident across general stimuli or specific to emotional stimuli, while exploring the underlying neuropsychological mechanism. MethodsA total of 41 MDD patients and 42 healthy controls (HCs) were recruited. Event-related potentials (ERPs) were recorded when participants performed a non-emotional and an emotional task switching paradigm (N-ETSP and ETSP), both of which assessed cognitive flexibility. Microstate and source localization analysis were applied to reflect brain activity among different brain areas during task switching. ResultsIn the N-ETSP, MDD group showed larger P3 difference wave (Pd3) amplitudes and longer P2 difference wave (Pd2) latencies. In the ETSP, MDD group displayed smaller N2 difference wave (Nd2) amplitudes and larger Pd3 amplitudes. The comparison of sLORETA images of emotional switch task and emotional repeat task showed that MDD group had increased activation in the precentral gyrus in microstate2 of the P2 time window and had reduced activation in the middle occipital gyrus in microstate3 of the N2 time window. LimitationsThe cross-sectional design failed to capture dynamic changes in cognitive flexibility in MDD. ConclusionsMDD demonstrated impaired cognitive flexibility respond to both non-emotional and emotional stimuli, with greater impairment for negative emotional stimuli. These deficits are evident in abnormal ERPs component during the early attention stage and the later task preparation stage. Furthermore, abnormal emotional switching cost in MDD appears to be related to early abnormal perceptual control in the parietal-occipital cortex.

Amyloid beta-related angiitis in a patient with light chain systemic Amyloidosis: A rare co-morbidity. (P9-5.013)

<h3>Objective:</h3> To report a rare comorbidity of amyloid beta-related angiitis (ABRA) and systemic light chain amyloidosis (AL) <h3>Background:</h3> ABRA is a rare central nervous system (CNS) disorder with overlapping features of primary angiitis of the CNS and cerebral amyloid angiopathy. ABRA pathophysiology differs from extremely rare CNS involvement in AL. This is the first report of ABRA and AL comorbidity. <h3>Design/Methods:</h3> Case Report <h3>Results:</h3> A 73 year old Caucasian female with AL, prior autologous stem cell transplantation followed by relapse and daratumumab therapy resulting in complete response, presented with subacute development of headaches, global dysphasia and right sided homonymous hemianopia. Brain magnetic resonance imaging (MRI) demonstrated an increased T2/Fluid attenuated inversion recovery signal along the left parietal occipital cortex with mild restricted diffusion and microhemorrhages. Cerebrospinal fluid (CSF) studies showed: pleocytosis (30 nucleated cells/mm3) consisting of mature granulocytes, small mature lymphocytes and rare plasma cells, no monotypic B-cell, overtly aberrant T-cell, or expanded large granular lymphocyte population, no malignant cells; hyperproteinorachia (214 mg/dL); and no markers of intrathecal immunoglobulin G synthesis. Infectious CSF studies, CSF autoimmune encephalopathy panel and rheumatological work up were unremarkable. Steroid treatment (methylprednisolone, 1000 mg/day for 5 days intravenously, followed by a slow oral taper) led to a resolution in visual field deficit and a significant improvement in speech patterns. New microhemorrhages with new foci of restricted diffusion in the left posterior parietal/occipital region and posterior right centrum semiovale were shown on brain MRI three months later. Brain biopsy was performed with no neurological complications and pathology was consistent with ABRA. Liquid chromatography-tandem mass spectrometry of the brain tissue detected a peptide profile consistent with amyloid-beta precursor type amyloid deposition. The patient continued on oral steroid taper and is starting cyclophosphamide. <h3>Conclusions:</h3> Although ABRA is pathophysiologically distinct from and unrelated to AL, those two conditions may rarely co-exist. <b>Disclosure:</b> Dr. Javed has nothing to disclose. The institution of Dr. Jensen has received research support from ASCO / Conquer Cancer Foundation. The institution of Dr. Jensen has received research support from AHRQ. Dr. A Tuchman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Shattuck Labs. Dr. A Tuchman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen. An immediate family member of Dr. Allenzara has received personal compensation for serving as an employee of Atai . An immediate family member of Dr. Allenzara has stock in Atai company stock . An immediate family member of Dr. Ishizawar has received personal compensation for serving as an employee of EMD MilliporeSigma. Dr. Cho has nothing to disclose. Dr. Yap has nothing to disclose. The institution of Dr. Dujmovic Basuroski has received research support from Alexion Pharmaceuticals, Inc. The institution of Dr. Dujmovic Basuroski has received research support from Biogen MA Inc. The institution of Dr. Dujmovic Basuroski has received research support from EMD Serono Research and Development Institute, Inc . The institution of Dr. Dujmovic Basuroski has received research support from Celgene Corporation/Bristol-Myers Squibb. The institution of Dr. Dujmovic Basuroski has received research support from The Bodford Family Transverse Myelitis Center Fund.

0133 Sleeping Well or Sleeping Poorly: Clues from Brain Neurochemistry

Abstract Introduction Sleep problems are prevalent throughout the population, but little is known about the brain mechanisms that differentiate good and poor sleepers. We studied the association between brain neurochemistry, as measured by proton magnetic resonance spectroscopy (1H-MRS), and sleep quality as measured by actigraphy. We hypothesized that better sleep quality would be predicted by brain metabolites indicative of greater neuronal health, neural inhibition, and reduced levels of excitatory neurotransmitters. Methods 24 healthy adults (12 females25.4±5.6 years) wore an actigraph for seven consecutive days to collect Time in Bed (TIB), Total Sleep Time (TST), Sleep Efficiency (SE), Sleep Onset Latency (SOL), and Wake After Sleep Onset (WASO), and underwent 1H-MRS neuroimaging at 3T. Metabolite data from the medial prefrontal cortex (mPFC), dorsolateral prefrontal cortex (dlPFC), and medial parietal-occipital cortex (P-OCC) were entered stepwise into a series of multiple linear regression models to predict each actigraphic outcome. Results For SE, the regression analysis yielded a significant three predictor model (adjusted R2=.59), p=.0001, including mPFC choline (Cho; β=-.60), P-OCC N-Acetylaspartate (NAA ; β=.56), and P-OCC glutamate+glutamine (Glx; β=-.33). Better SE was associated with a combination of decreased Cho within the mPFC, and increased NAA and decreased Glx within the P-OCC. SOL was predicted by mPFC Cho alone (β =.60; adjusted R2 = .33), p=.002. This suggests that greater Cho within the mPFC was associated with a longer latency to fall asleep. Finally, for WASO, the regression analysis yielded a significant two predictor model, (adjusted R2 = .39), p=.002, including mPFC Cho (β = .56), P-OCC NAA (β = -.41). This suggests that a combination of greater Cho within the mPFC and decreased NAA in the P-OCC was associated with more minutes of wake after sleep onset. Conclusion Sleep quality was predicted from brain metabolites within the medial default mode network (DMN), an interconnected system of cortical regions that is normally deactivated during effortful cognitive processing. Sleep quality was predicted by a combined pattern of metabolites consistent with greater neuronal integrity, reduced cellular turnover, and lower excitatory neurotransmitters. Findings suggest potential metabolic and neuroanatomic targets for enhancing brain health to facilitate sleep quality. Support (If Any)

Dopaminergic medication reduces interhemispheric hyper-synchronization in Parkinson's disease

IntroductionWe previously reported on interhemispheric cortical hyper synchronization in PD. The aim of the present study was to address the hypothesis that increased interhemispheric cortical synchronization in PD is related to dopamine deficiency and is correlated with motor function. MethodsWe studied participants with PD and characterized cortical synchronization with reference to brain regions. Electroencephalography (EEG) was recorded from 20 participants with PD while OFF and ON their dopaminergic medications (two separate visits), during quiet standing and straight-line walking. Cortical interactions in the theta, alpha, beta, and gamma brain wave frequency bands were evaluated using interhemispheric phase synchronization (inter-PS). ResultsInter-PS values were found to be significantly higher during the OFF state as compared to the ON state in standing and walking trials for theta, alpha and beta bands.In addition, inter-PS reduction from OFF to ON was associated with mobility improvement evaluated by the Timed Up and Go test, and with daily levodopa equivalent dose across individuals. Higher differences in inter-PS values between OFF and ON states were evident mainly in the occipital-parietal cortex. ConclusionsPersons with PD have increased inter-PS during the OFF state compared to their ON state, and this increase in inter-PS is associated with the clinical improvement between OFF and ON. We speculate that these findings, together with previous evidence of higher inter-PS in PD as compared to healthy older adults, reflect neuronal processes consequential to asymmetric subcortical dopamine deficiency.

Parietal Gamma Band Oscillation Induced by Self-Hand Recognition.

Physiological studies have shown that self-body images receive unique recognition processing in a wide range of brain areas, from the frontal lobe to the parietal-occipital cortex. Event-related potential (ERP) studies have shown that the self-referential effect on the image of a hand increases P300 components, but such studies do not evaluate brain oscillatory activity. In this study, we aimed to discover the self-specific brain electrophysiological activity in relation to hand images. ERPs on the fronto-parietal midline were elicited by a three-stimulus visual oddball task using hand images: the self-hand, another hand (most similar to the self-hand), and another hand (similar to the self-hand). We analyzed ERP waveform and brain oscillatory activity by simple averaging and time-frequency analysis. The simple averaging analysis found no significant differences between the responses for the three stimulus tasks in all time windows. However, time-frequency analysis showed that self-hand stimuli elicited high gamma ERS in 650–900 ms at the Cz electrode compared to other hand stimuli. Our results show that brain activity specific to the self-referential process to the self-hand image was reflected in the long latency gamma band activity in the mid-central region. This high gamma-band activity at the Cz electrode may be similar to the activity of the mirror neuron system, which is involved in hand motion.

Effects of Gaze Fixation on the Performance of a Motor Imagery-Based Brain-Computer Interface.

Motor imagery-based brain-computer interfaces (BCIs) have been studied without controlling subjects’ gaze fixation position previously. The effect of gaze fixation and covert attention on the behavioral performance of BCI is still unknown. This study designed a gaze fixation controlled experiment. Subjects were required to conduct a secondary task of gaze fixation when performing the primary task of motor imagination. Subjects’ performance was analyzed according to the relationship between motor imagery target and the gaze fixation position, resulting in three BCI control conditions, i.e., congruent, incongruent, and center cross trials. A group of fourteen subjects was recruited. The average group performances of three different conditions did not show statistically significant differences in terms of BCI control accuracy, feedback duration, and trajectory length. Further analysis of gaze shift response time revealed a significantly shorter response time for congruent trials compared to incongruent trials. Meanwhile, the parietal occipital cortex also showed active neural activities for congruent and incongruent trials, and this was revealed by a contrast analysis of R-square values and lateralization index. However, the lateralization index computed from the parietal and occipital areas was not correlated with the BCI behavioral performance. Subjects’ BCI behavioral performance was not affected by the position of gaze fixation and covert attention. This indicated that motor imagery-based BCI could be used freely in robotic arm control without sacrificing performance.

Exploration of EEG-Based Depression Biomarkers Identification Techniques and Their Applications: A Systematic Review

Depression is the most common mental illness, which has become the major cause of fear and suicidal mortality or tendencies. Currently, about 10% of the world population has been suffering from depression. The classical approach for detecting depression relies on the clinical questionnaire, which depends on the patients’ responses as well as observing their behavioral activities. However, there is no established method to detect depression from EEG biomarkers. Therefore, exploration of EEG biomarkers for depression assessments is vital and has a great potential to improve our understanding and clinical interventions. In this study, we have conducted a systematic review of 52 research articles using the PRISMA-P systematic review protocol, where we analyzed their research methodologies and outcomes. We categorized the experimentations in these articles according to their physical and psychological aspects scaled by the commonly used clinical questionnaire-based assessments. This study finds that the negative stimuli are the better identification strategies for evaluating depression through EEG signals. From this exploration, researchers observed that the Neural Connectivity Analysis and Brain Topological Mapping have huge potentials for finding depression biomarkers, and it is evident that the right-side hemisphere and frontal and parietal-occipital cortex are distinct regions to detect depression using EEG signals. For this mechanism, researchers are using many signal processing and machine learning approaches. In the case of filtering, Independent Component Analysis (ICA) is commonly used to eliminate physiological and non-physiological artifacts. Among machine learning approaches, Convolutional Neural Network (CNN) and Support Vector Machine (SVM) showed better performance for classifying healthy and depressed brains. The authors hope, this study will create an opportunity to explore more in the future for EEG as diagnostic tool by analyzing brain functional connectivity for focusing on clinical interventions.

Effect of moderate altitude on human cerebral metabolite levels: A preliminary, multi-site, proton magnetic resonance spectroscopy investigation

Epidemiological studies show that altitude-of-residence is an independent risk factor for worsening rates of mood disorders, substance abuse, and suicide. Proton (1H) magnetic resonance spectroscopy (MRS) studies in rodent models of moderate-to-high altitude exposure have documented significant alterations in total creatine, glutamate, and myo-inositol, neurometabolites involved in bioenergetic homeostasis and neuronal/glial cell function. This preliminary study utilized 3 Tesla 1H MRS to study anterior cingulate cortex (ACC) and parietal-occipital cortex (POC) neurochemistry in healthy subjects residing in Utah (n = 19), Massachusetts (n = 10), and South Carolina (n = 10), to test the hypothesis that individuals residing at moderate altitude (Utah; 1,372 m) would show neurometabolite alterations vs. subjects living at sea level. Expressed as ratios to total N-acetyl aspartate (NAA), Utah participants showed lower ACC (p = 0.03) and POC (p < 0.01) total creatine, a trend towards lower ACC glutamate (p = 0.06), and lower POC myo-inositol (p = 0.02). Study limitations include small sample sizes and uncorrected multiple comparisons. To our knowledge, this is the first MRS investigation to identify potential neurochemical differences in individuals residing at moderate altitudes vs. sea level, warranting future 1H MRS studies in larger cohorts and across a range of altitudes-of-residence.

Changes of Metabolic Connectivity in Dementia with Lewy Bodies with Visual Hallucinations: A 18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Study.

Background: Recurrent complex visual hallucinations (VHs) are common in dementia with Lewy bodies (DLB). Previous investigations suggest that VHs are associated with connectivity changes within and between large scale networks involved in visual processing and attention. Aim: To examine more directly whether VH in DLB reflects direct changes in neuronal activity between cortical regions assessing metabolic connectivity with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/magnetic resonance and graph theory. Methods: Twenty-six patients with probable DLB (13 VHs and 13 no-VHs; mean age: 72.9 ± 6.87 years vs. 70.2 ± 7.96 years) were enrolled. T1-weighted 3T-MR images and FDG-PET data were coacquired using an integrated PET/MR scanner. MR images defined cortical parcels of the Shaefer-Yeo atlas for multiple functional networks. We computed in each parcel the regional standardized-uptake-values (SUV) corrected for partial volume and normalized to the cerebellar cortex. Strength degree, clustering coefficient, characteristic path length, and hubs were analyzed with graph analysis. Results: The mean 18F-FDG-PET SUVr of parcels belonging to the visual and dorsal attention networks (DANs) were significantly lower in the VH group (p = 0.01). Metabolism in the right temporoparietal cortex correlated with VH severity (R = -0.58; p < 0.01). VH patients showed weaker metabolic connectivity in the parietal, temporal, and occipital cortex of the default mode network, DAN, and visual networks, but more robust connectivity in the right insula and orbitofrontal cortex. A lower global efficiency characterized the VH group, except for ventral attention network and limbic network. Conclusions: VHs in DLB correlate with lower glucose metabolism and weaker metabolic connectivity in the parietal-occipital cortex, but stronger connectivity in the limbic system. Impact statement This study shows that application of the graph theory to 18F-fluorodeoxyglucose-positron emission tomography data, commonly acquired during the diagnostic workflow in neurodegenerative diseases, could be used to obtain information of functional connectivity at a group level, with results that are consistent with other data commonly used in brain functional investigation (e.g., electroencephalography or functional magnetic resonance). New network-based methods of metabolic image analyses, such as graph analysis, are a recent area of research with a potential capacity to extract information on alterations of metabolic connectivity that may become pharmacological and neuromodulation targets of the physiopathology of recurrent complex visual hallucinations.

Investigating Parietal and Premotor Influence on Motor Cortical Excitability Associated with Visuomotor Associative Plasticity.

The brain changes in response to sensory signals it is exposed to. It has been shown that long term potentiation-like neuroplasticity can be experimentally induced via visual paired-associative stimulation (V-PAS). V-PAS combines afferent visual stimuli with a transcranial magnetic stimulation pulse to induce plasticity. Preparation of a reaching movement to generate activity in superior parietal occipital cortex (SPOC) was used in this study as an additional afferent contributor to modulate the resultant plasticity. We hypothesized that V-PAS with a reaching movement would induce greater cortical excitability than V-PAS alone and would exhibit facilitated SPOC to M1 projections. All four experiments enrolled groups of 10 participants to complete variations of V-PAS in a repeated measures design. SPOC to M1 projections facilitated motor cortex excitability following V-PAS regardless of intervention received. We did not observe evidence indicating extra afferent information provided an additive effect to participants. Investigation of PMd to M1 projections confirmed disinhibition and suggested interneuronal populations within M1 may be mechanistically involved. Future research should look to rule out the existence of an upper limit for effective afference during V-PAS and investigate the average influence of V-PAS on cortical excitability in the larger population.

Altered iron and myelin in premanifest Huntington's Disease more than 20 years before clinical onset: Evidence from the cross-sectional HD Young Adult Study.

BackgroundPathological processes in Huntington's disease (HD) begin many years prior to symptom onset. Recently we demonstrated that in a premanifest cohort approximately 24 years from predicted disease onset, despite intact function, there was evidence of subtle neurodegeneration. Here, we use novel imaging techniques to determine whether macro- and micro-structural changes can be detected across the whole-brain in the same cohort.Methods62 premanifest HD (PreHD) and 61 controls from the HD Young Adult Study (HD-YAS) were included. Grey and white matter volume, diffusion weighted imaging (DWI) measures of white matter microstructure, multiparametric maps (MPM) estimating myelin and iron content from magnetization transfer (MT), proton density (PD), longitudinal relaxation (R1) and effective transverse relaxation (R2*), and myelin g-ratio were examined. Group differences between PreHD and controls were assessed; associations between all imaging metrics and disease burden and CSF neurofilament light (NfL) were also performed. Volumetric and MPM results were corrected at a cluster-wise value of familywise error (FWE) 0.05. Diffusion and g-ratio results were corrected via threshold-free cluster enhancement at FWE 0.05.FindingsWe showed significantly increased R1 and R2*, suggestive of increased iron, in the putamen, globus pallidum and external capsule of PreHD participants. There was also a significant association between lower cortical R2*, suggestive of reduced myelin or iron, and higher CSF NfL in the frontal lobe and the parieto-occipital cortices. No other results were significant at corrected levels.InterpretationIncreased iron in subcortical structures and the surrounding white matter is a feature of very early PreHD. Furthermore, increases in CSF NfL were linked to microstructural changes in the posterior parietal-occipital cortex, a region previously shown to undergo some of the earliest cortical changes in HD. These findings suggest that disease related process are occurring in both subcortical and cortical regions more than 20 years from predicted disease onset.

Clinico-radiological Profile of Posterior Reversible Encephalopathy Syndrome and Its Associated Risk Factors in PICU: A Single-center Experience from a Tertiary Care Hospital in Bhubaneswar, Odisha.

ObjectivePosterior reversible encephalopathy syndrome (PRES) is a clinico-radiographic entity of heterogeneous etiologies having similar clinical and neuroimaging features. Pediatric data are sparse, making early diagnosis challenging, which needs a high index of suspicion. So, we conducted this study to evaluate clinico-radiological features, associated risk factors, etiology, and outcome in children.Materials and methodsThis is a retrospective case series of patients, diagnosed as having PRES and followed up at a tertiary care hospital in Eastern India between September 2016 and December 2019.ResultsAmong 16 patients with a median age of 9.5 years [interquartile range (IQR) 8–13.75] and a male preponderance (75%), common underlying diseases were post-streptococcal glomerulonephritis (56.3%) and renovascular hypertension (12.5%). Acute elevation of blood pressure was found in all patients (n = 16). The neurological symptom was seizure (87.5%), mental changes (68.75%), headache (43.8%), vomiting (31.3%), and visual disturbances (31.3%). The most common triggering factor was hypertension (100%), use of mycophenolate mofetil and prednisolone (12.5%), and hemodialysis (12.5%). Anemia was present in 15 (93.4%) patients at the time of admission. All showed abnormal neuroimaging with 55% having atypical involvement. The most common site was the parietal-occipital cortex (88%), frontal and temporal lobe (44% cases each), and the cerebellum (13%). Clinical recovery was followed by a radiological resolution in all survived except in one, who developed visual impairment.ConclusionPosterior reversible encephalopathy syndrome should be considered in the differential diagnosis of patients who present with acute neurological disturbances and underlying diseases such as renal disorders, vasculitis, malignancy, and use of immunosuppressant accompanied by hypertension. Early diagnosis and treatment of comorbid conditions are of paramount importance for the early reversal of the syndrome.How to cite this articleBehera CK, Jain MK, Mishra R, Jena PK, Dash SK, Sahoo RK. Clinico-radiological Profile of Posterior Reversible Encephalopathy Syndrome and Its Associated Risk Factors in PICU: A Single-center Experience from a Tertiary Care Hospital in Bhubaneswar, Odisha. Indian J Crit Care Med 2020;24(12):1223–1229.

Lateralized alpha activity and slow potential shifts over visual cortex track the time course of both endogenous and exogenous orienting of attention

Spatial attention can be oriented endogenously, based on current task goals, or exogenously, triggered by salient events in the environment. Based upon literature demonstrating differences in the time course and neural substrates of each type of orienting, these two attention systems are often treated as fundamentally distinct. However, recent studies suggest that rhythmic neural activity in the alpha band (8–13 Hz) and slow waves in the event-related potential (ERP) may emerge over parietal-occipital cortex following both endogenous and exogenous attention cues. To assess whether these neural changes index common processes of spatial attention, we conducted two within-subject experiments varying the two main dimensions over which endogenous and exogenous attention tasks typically differ: cue informativity (spatially predictive vs. non-predictive) and cue format (centrally vs. peripherally presented). This task design allowed us to tease apart neural changes related to top-down goals and those driven by the reflexive orienting of spatial attention, and examine their interactions in a novel hybrid cross-modal attention task. Our data demonstrate that both central and peripheral cues elicit lateralized ERPs over parietal-occipital cortex, though at different points in time, consistent with these ERPs reflecting the orienting of spatial attention. Lateralized alpha activity was also present across all tasks, emerging rapidly for peripheral cues and sustaining longer for spatially informative cues. Overall, these data indicate that distinct slow-wave ERPs index the spatial orienting of endogenous and exogenous attention, while lateralized alpha activity represents a common signature of visual-cortical biasing in anticipation of potential targets across both types of attention.

Coexistence of Tic Disorders and Combined Type of Attention Deficit/Hyperactivity Disorder: Features of Specific Cognitive Deficit

The state of cognitive deficit in subjects with combination of attention deficit hyperactivity disorder and tic hyperkinesis is among the least studied issues. Identification of the cognitive development features in children with these disorders comorbidity will help to develop and build an adequate model of rehabilitation.Purpose of the study.To study cognitive deficits in children with tic hyperkinesis (TH) in cases of comorbidity with the combined type of attention deficit disorder (ADHD).Materials and methods.404 children aged 6–10 years with a combined type of ADHD were divided into three subgroups according to the state of monoamine activity: 1st subgroup with a combination of hypofunction of dopaminergic and hyperfunction of noradrenergic systems — 120 people, 2nd subgroup with a combination of hyperfunction of noradrenergic system with a relative dopamine balance — 136 people, 3rd subgroup with indicators of monoamines within the reference values — 148 children. The control group comprised of 90 children (54 boys and 36 girls). To diagnose the level of intellectual development, Wechsler Intelligence Scale for Children was used. In each subgroup, with the known direction of monoamine activity, the Wexler test parameters were compared among ADHD groups, both with or without TG.Results.Subtests “Picture Arrangement”, “Picture Completion” and “Block Design” turned out to be sensitive to concomitant combined type of ADHD and tics in children, reflecting, respectively, enumeration, the ability to logical thinking, visual attention and hand-eye coordination. In a case of dopamine system hypofunction in children with ADHD, the addition of tics leads to the smoothing of the biochemical imbalance by increasing the activity of dopamine and thus, results in a more effective realization of logical thinking ability. The level of visual attention in children with ADHD with the addition of TH also increases, probably due to a growth of the intensity of serotonin system activity. Finally, hand-eye coordination improves with the addition of tics in cases of a shift in the balance of dopamine and noradrenergic systems.Conclusion.The data obtained are consistent with the “frontal lobe compensation hypothesis” in the part, which describes the presence of a compensatory process when tics emerge in children with combined type of ADHD. Besides, our results expand it, suggesting that not only the prefrontal cortex but also the parietal-occipital cortex participates in the adaptive process associated with spatial synthesis and analysis of information, as well as hand-eye coordination.

Covariation between Childhood-Trauma Related Resting-State Functional Connectivity and Affective Temperaments is Impaired in Individuals with Major Depressive Disorder

Affective temperaments and childhood-trauma experiences are associated with major depressive disorder (MDD). So far, how the covariation between distinct affective temperaments and childhood-trauma insulted brain functional connectivities (FCs) contribute to MDD remains unclear. Here, we aimed to investigate whether certain brain FC patterns are related to certain affective temperaments and whether the FCs contribute to depressive symptom dimensions of MDD patients. Twenty-nine medication-free MDD patients and 58 healthy controls underwent magnetic resonance imaging scanning and completed the Hamilton Depression Rating Scale (HDRS), the Hamilton Anxiety Rating Scale (HARS), the Childhood Trauma Questionnaire-Short Form (CTQ-SF), and the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS). Two multivariate analyses of partial least squares (PLS) regression were used to explore the associations among childhood-trauma related resting-state FCs, affective temperaments and depressive symptom dimensions. In all participants, a linear combination of 81 FCs (involving parahippocampus, amygdala, cingulate cortex, insula, frontal–temporal–parietal–occipital cortex, pallidum, and cerebellum) were associated with a linear combination of increased depressive, irritable, anxious, and cyclothymic temperaments. Moreover, the covariation between the PLS FC profile and the PLS affective-temperament profile were enhanced in the MDD patients compared to healthy controls. In MDD participants alone, the affective-temperament modulated FC profile (mainly of the lingual and temporal cortex) was associated with the somatization symptom dimension when age, sex, ill-duration, age-of-onset, and HARS scores were adjusted. The findings imply possible neural correlates of affective temperaments and may find applications in intervention of the somatization-depression symptoms by stimulation of the related neural correlates.

A semi-LASER, single-voxel spectroscopic sequence with a minimal echo time of 20.1 ms in the human brain at 3 T.

An optimized semi-LASER sequence that is capable of acquiring artefact-free data with an echo time (TE) of 20.1 ms on a standard clinical 3 T MR system was developed. Simulations were performed to determine the optimal TEs that minimize the expected Cramér-Rao lower bound (CRLB) as proxy for quantification accuracy of metabolites. Optimized RF pulses, crusher gradients and phase cycling were used to achieve the shortest TE in a semi-LASER sequence to date on a clinical system. Synthetic spectra were simulated using the density matrix formalism for TEs spanning from 20.1 to 220.1 ms. These simulations were used to calculate the expected CRLB for each of the 18 metabolites typically considered in 1 H MRS. High quality spectra were obtained in six healthy volunteers in the prefrontal cortex, which is known for spurious echoes due to its proximity to the paranasal sinuses, and in the parietal-occipital cortex. Spectral transients were sufficient in quality to enable phase and frequency alignment prior to summation over all repetitions. Automated high-quality water suppression was obtained for all voxels without manual adjustment. The shortest TE minimized the CRLB for all brain metabolites except glycine due to its overlap with myo-inositol at this TE. It is also demonstrated that the CRLBs increase rapidly with TE for certain coupled metabolites.

Prompting future events: Effects of temporal cueing and time on task on brain preparation to action

Prediction about event timing plays a leading role in organizing and optimizing behavior. We recorded anticipatory brain activities and evaluated whether temporal orienting processes are reflected by the novel prefrontal negative (pN) component, as already shown for the contingent negative variation (CNV). Fourteen young healthy participants underwent EEG and fMRI recordings in separate sessions; they were asked to perform a Go/No-Go task in which temporal orienting was manipulated: the external condition (a visual display indicating the time of stimulus onset) and the internal condition (time information not provided). In both conditions, the source of the pN was localized in the pars opercularis of the iFg; the source of the CNV was localized in the supplementary motor area and cingulate motor area, as expected. Anticipatory activity was also found in the occipital-parietal cortex. Time on task EEG analysis showed a marked learning effect in the internal condition, while the effect was minor in the external condition. In fMRI, the two conditions had a similar pattern; similarities and differences of results obtained with the two techniques are discussed. Overall, data are consistent with the view that the pN reflects a proactive cognitive control, including temporal orienting.

Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression

Psilocybin has shown promise as a treatment for depression but its therapeutic mechanisms are not properly understood. In contrast to the presumed actions of antidepressants, we recently found increased amygdala responsiveness to fearful faces one day after open-label treatment with psilocybin (25 mg) in 19 patients with treatment-resistant depression, which correlated with treatment efficacy. Aiming to further unravel the therapeutic mechanisms of psilocybin, the present study extends this basic activation analysis. We hypothesised changed amygdala functional connectivity, more precisely decreased amygdala-ventromedial prefrontal cortex functional connectivity, during face processing after treatment with psilocybin. Psychophysiological interaction analyses were conducted on functional magnetic resonance imaging data from a classic face/emotion perception task, with the bilateral amygdala and ventromedial prefrontal cortex time-series as physiological regressors. Average parameter estimates (beta weights) of significant clusters were correlated with clinical outcomes at one week. Results showed decreased ventromedial prefrontal cortex-right amygdala functional connectivity during face processing post- (versus pre-) treatment; this decrease was associated with levels of rumination at one week. This effect was driven by connectivity changes in response to fearful and neutral (but not happy) faces. Independent whole-brain analyses also revealed a post-treatment increase in functional connectivity between the amygdala and ventromedial prefrontal cortex to occipital-parietal cortices during face processing. These results are consistent with the idea that psilocybin therapy revives emotional responsiveness on a neural and psychological level, which may be a key treatment mechanism for psychedelic therapy. Future larger placebo-controlled studies are needed to examine the replicability of the current findings.

Retinal thickness as potential biomarker in posterior cortical atrophy and typical Alzheimer\u2019s disease

BackgroundRetinal thickness can be measured non-invasively with optical coherence tomography (OCT) and may offer compelling potential as a biomarker for Alzheimer’s disease (AD). Retinal thinning is hypothesized to be a result of retrograde atrophy and/or parallel neurodegenerative processes. Changes in the visual pathway are of particular interest in posterior cortical atrophy (PCA), the most common atypical AD phenotype predominantly affecting the parietal-occipital cortices. We therefore evaluated retinal thickness as non-invasive biomarker of neurodegeneration in well-characterized participants with posterior cortical atrophy (PCA) and typical Alzheimer’s disease (tAD).MethodsRetinal thickness measures were acquired from 48 patient participants (N = 25 PCA; N = 23 tAD) fulfilling consensus diagnostic criteria and 70 age-matched controls. Participants were recruited between 2014 and 2016. All participants underwent optical coherence tomography (OCT) imaging, including measurement of peripapillary retinal nerve fiber layer (pRNFL) thickness and total macular thickness (mRT). Participants did not show evidence of any significant ophthalmological conditions. Subgroup analyses were performed in participants with available MRI and CSF measures, providing evidence of neurodegeneration and underlying AD pathology respectively.ResultsThere was no evidence of overall between-group differences in pRNFL thickness (mean PCA 98.7 ± 12.2; tAD 99.9 ± 8.7; controls 99.6 ± 10.0 μm, one-way analysis of variance (ANOVA) p = 0.92) or total mRT (mean PCA 266.9 ± 16.3; tAD 267.8 ± 13.6; controls 269.3 ± 13.6 μm, one-way ANOVA p = 0.75). Similarly, subgroup analysis with MRI biomarkers (PCA = 18, tAD = 17, controls = 31) showing neurodegeneration, and CSF biomarkers (PCA = 18, tAD = 14, controls = 13) supporting underlying AD pathology did not provide evidence of overall between-group differences in pRNFL or mRT measures (all p > 0.3).ConclusionsRetinal thickness did not discriminate tAD and PCA from controls or from one another despite unequivocal differences on standard clinical, neuro-imaging and CSF measures. Findings from this well-characterized sample, including cases with PCA, do not support the hypothesis that retinal neurodegeneration, measured using conventional OCT, is a useful biomarker for AD or PCA.

Altered Brain Structure in Infants with Turner Syndrome.

Turner syndrome (TS) is a genetic disorder affecting approximately 1:2000 live-born females. It results from partial or complete X monosomy and is associated with a range of clinical issues including a unique cognitive profile and increased risk for certain behavioral problems. Structural neuroimaging studies in adolescents, adults, and older children with TS have revealed altered neuroanatomy but are unable to identify when in development differences arise. In addition, older children and adults have often been exposed to years of growth hormone and/or exogenous estrogen therapy with potential implications for neurodevelopment. The study presented here is the first to test whether brain structure is altered in infants with TS. Twenty-six infants with TS received high-resolution structural MRI scans of the brain at 1year of age and were compared to 47 typically developing female and 39 typically developing male infants. Results indicate that the typical neuroanatomical profile seen in older individuals with TS, characterized by decreased gray matter volumes in premotor, somatosensory, and parietal-occipital cortex, is already present at 1year of age, suggesting a stable phenotype with origins in the prenatal or early postnatal period.