New resting-state fMRI related studies at PubMed

Abnormal regional homogeneity (ReHo) and fractional amplitude of low frequency fluctuations (fALFF) in first-episode drug-naïve schizophrenia patients comorbid with depression

Wed, 03/31/2021 - 10:00

Brain Imaging Behav. 2021 Mar 31. doi: 10.1007/s11682-021-00465-0. Online ahead of print.

ABSTRACT

The current study aimed to characterize the regional homogeneity (ReHo) or fractional amplitude of low frequency fluctuations (fALFF) alterations in first-episode drug-naïve schizophrenia comorbid with depression. Sixty-nine first-episode drug-naïve schizophrenia patients and 34 healthy controls (HC) were included in the final analysis. Schizophrenia patients were divided into depressive patients (DP) and non-depressive patients (NDP), with 35 and 34 patients respectively, using the Hamilton Rating Scale for Depression -17(HRSD-17). All participants underwent resting-state fMRI (rs-fMRI), the fALFF (slow-4 and slow-5 bands) and ReHo were used to process the data. The results revealed eleven brain regions with altered slow-5 fALFF, eleven brain regions with altered slow-4 fALFF and ten brain regions with altered ReHo among DP, NDP and HC groups. Compared to NDP, the DP group had increased slow-5 fALFF in the Right Inferior Temporal Gyrus, increased ReHo in the Right Superior and Inferior Frontal Gyrus. The altered slow-5 fALFF in the Right Inferior Temporal Gyrus, altered ReHo in the Right Inferior Frontal Gyrus and Superior Frontal Gyrus were all positively correlated with the depressive symptoms in patients. However, there were no significant differences in slow-4 fALFF between DP and NDP groups. Our results indicate that the increased slow-5 fALFF in the Right Inferior Temporal Gyrus, increased ReHo in the Right Superior and Inferior Frontal Gyrus were associated with depressive symptoms in schizophrenia, which may provide preliminary evidence in better understanding the neural mechanisms underlying depressive symptoms in schizophrenia.

PMID:33788124 | DOI:10.1007/s11682-021-00465-0

Ventromedial Prefrontal-Anterior Cingulate Hyperconnectivity and Resilience to Apathy in Traumatic Brain Injury

Wed, 03/31/2021 - 10:00

J Neurotrauma. 2021 Mar 31. doi: 10.1089/neu.2020.7363. Online ahead of print.

ABSTRACT

Apathy is a common and impairing sequela of traumatic brain injury (TBI). Yet, little is known about the neural mechanisms determining which patients do or do not develop apathy post-TBI. Here we aimed to elucidate the impact of TBI on motivational neural circuits, and how this shapes apathy over the course of TBI recovery. Resting-state functional magnetic resonance imaging (rsfMRI) data were collected in patients with subacute mild TBI (N=44), chronic mild-to-moderate TBI (N=26), and non-brain-injured control participants (CTRL; N=28). We measured ventromedial prefrontal cortex (vmPFC) functional connectivity (FC) as a function of apathy, using an a priori vmPFC seed adopted from a motivated decision making study in an independent TBI study cohort. Patients reported apathy using a well-validated tool for assaying apathy in TBI. vmPFC-to-wholebrain FC was contrasted between groups, and we fit regression models with apathy predicting vmPFC FC. Subacute and chronic TBI caused increased apathy relative to CTRL, replicating prior work suggesting that apathy has an enduring impact in TBI. vmPFC was functionally connected to the canonical default network, and this architecture did not differ between subacute TBI, chronic TBI, and CTRL groups. Critically, in TBI, increased apathy scores predicted decreased vmPFC-dorsal anterior cingulate cortex (dACC) FC. Lastly, we subdivided the TBI group based on patients above versus below the threshold for "clinically-significant apathy," finding that TBI patients with clinically-significant apathy demonstrated comparable vmPFC-dACC FC to CTRLs, whereas TBI patients with subthreshold apathy scores demonstrated vmPFC-dACC hyperconnectivity relative to both CTRLs and patients with clinically-significant apathy. Post-TBI vmPFC-dACC hyperconnectivity may represents an adaptive compensatory response, helping to maintain motivation and enabling resilience to the development of apathy after neurotrauma. Given the role of vmPFC-dACC circuits in value-based decision making, rehabilitation strategies designed to improve this ability may help to reduce apathy and improve functional outcomes in TBI.

PMID:33787328 | DOI:10.1089/neu.2020.7363

Functional connectivity of the hippocampus and its subfields in resting-state networks

Wed, 03/31/2021 - 10:00

Eur J Neurosci. 2021 Mar 30. doi: 10.1111/ejn.15213. Online ahead of print.

ABSTRACT

Many neuro-imaging studies have shown that the hippocampus participates in a resting-state network called the default mode network. However, how the hippocampus connects to the default mode network, whether the hippocampus connects to any other resting-state network, and how the different hippocampal subfields take part in resting-state networks remains poorly understood. Here we examined these issues using the high spatial-resolution 7T resting-state fMRI dataset from the Human Connectome Project. We used data-driven techniques that relied on spatially-restricted Independent Component Analysis, Dual Regression, and linear mixed-effect group-analyses based on participant-specific brain morphology. The results revealed two main activity hotspots inside the hippocampus. The first hotspot was located in an anterior location and was correlated with the somatomotor network. This network was subserved by co-activity in the CA1, CA3, CA4 and Dentate Gyrus fields. In addition, there was an activity hotspot that extended from middle to posterior locations along the hippocampal long-axis and correlated with the default mode network. This network reflected activity in the Subiculum, CA4 and Dentate Gyrus fields. These results show how different sections of the hippocampus participate in two known resting-state networks, and how these two resting-state networks depend on different configurations of hippocampal subfield co-activity.

PMID:33786931 | DOI:10.1111/ejn.15213

MRI correlates of cognitive improvement after home-based EEG neurofeedback training in patients with multiple sclerosis: a pilot study

Wed, 03/31/2021 - 10:00

J Neurol. 2021 Mar 30. doi: 10.1007/s00415-021-10530-9. Online ahead of print.

ABSTRACT

OBJECTIVE: Neurofeedback training may improve cognitive function in patients with neurological disorders. However, the underlying cerebral mechanisms of such improvements are poorly understood. Therefore, we aimed to investigate MRI correlates of cognitive improvement after EEG-based neurofeedback training in patients with MS (pwMS).

METHODS: Fourteen pwMS underwent ten neurofeedback training sessions within 3-4 weeks at home using a tele-rehabilitation system. Half of the pwMS (N = 7, responders) learned to self-regulate sensorimotor rhythm (SMR, 12-15 Hz) by visual feedback and improved cognitively after training, whereas the remainder (non-responders, n = 7) did not. Diffusion-tensor imaging and resting-state fMRI of the brain was performed before and after training. We analyzed fractional anisotropy (FA) and functional connectivity (FC) of the default-mode, sensorimotor (SMN) and salience network (SAL).

RESULTS: At baseline, responders and non-responders were comparable regarding sex, age, education, disease duration, physical and cognitive impairment, and MRI parameters. After training, compared to non-responders, responders showed increased FA and FC within the SAL and SMN. Cognitive improvement correlated with increased FC in SAL and a correlation trend with increased FA was observed.

CONCLUSIONS: This exploratory study suggests that successful neurofeedback training may not only lead to cognitive improvement, but also to increases in brain microstructure and functional connectivity.

PMID:33786666 | DOI:10.1007/s00415-021-10530-9

Characterizing resting-state networks in Parkinson's disease: A multi-aspect functional connectivity study

Tue, 03/30/2021 - 10:00

Brain Behav. 2021 Mar 30:e02101. doi: 10.1002/brb3.2101. Online ahead of print.

ABSTRACT

PURPOSE: Resting-state functional magnetic resonance imaging (Rs-fMRI) can be used to investigate the alteration of resting-state brain networks (RSNs) in patients with Parkinson's disease (PD) when compared with healthy controls (HCs). The aim of this study was to identify the differences between individual RSNs and reveal the most important discriminatory characteristic of RSNs between the HCs and PDs.

METHODS: This study used Rs-fMRI data of 23 patients with PD and 18 HCs. Group independent component analysis (ICA) was performed, and 23 components were extracted by spatially overlapping the components with a template RSN. The extracted components were used in the following three methods to compare RSNs of PD patients and HCs: (1) a subject-specific score based on group RSNs and a dual-regression approach (namely RSN scores); (2) voxel-wise comparison of the RSNs in the PD patient and HC groups using a nonparametric permutation test; and (3) a hierarchical clustering analysis of RSNs in the PD patient and HC groups.

RESULTS: The results of RSN scores showed a significant decrease in connectivity in seven ICs in patients with PD compared with HCs, and this decrease was particularly striking on the lateral and medial posterior occipital cortices. The results of hierarchical clustering of the RSNs revealed that the cluster of the default mode network breaks down into the three other clusters in PD patients.

CONCLUSION: We found various characteristics of the alteration of the RSNs in PD patients compared with HCs. Our results suggest that different characteristics of RSNs provide insights into the biological mechanism of PD.

PMID:33784022 | DOI:10.1002/brb3.2101

Cerebellar involvement in olfaction: An fMRI Study

Tue, 03/30/2021 - 10:00

J Neuroimaging. 2021 Mar 30. doi: 10.1111/jon.12843. Online ahead of print.

ABSTRACT

BACKGROUND AND PURPOSE: The role of the cerebellum in olfactory function is not fully understood. In this study, we tried to combine resting state and task functional MRI (fMRI) to improve the understanding of the cerebellum during olfactory processing.

METHODS: A resting state and a block paradigm of olfactory stimulation fMRI were scanned in 50 subjects. The olfactory stimuli, including phenylethyl alcohol and isovaleric acid, were alternately delivered to the subject using a custom-built olfactometer through air flow. The cerebellar activations elicited by isovaleric acid were subsequently used in the seed-based resting-state functional connectivity study.

RESULTS: Phenylethyl alcohol did not induce any cerebellum activation, while isovaleric acid with a more unpleasant smell elicited significant cerebellum activations, primarily in the bilateral posterior lateral hemispheres (bilateral lobule crus I and right lobule VI). Seed-based functional connectivity analysis revealed significant within-cerebellum and corticocerebellar connections.

CONCLUSIONS: The results imply that the cerebellum is probably involved in olfactory-related responses caused by unpleasant odor but does not directly participate in olfactory perception. Our results may further improve the understanding of the cerebellum in olfactory function.

PMID:33783911 | DOI:10.1111/jon.12843

Maternal parenting behavior and functional connectivity development in children: A longitudinal fMRI study

Mon, 03/29/2021 - 10:00

Dev Cogn Neurosci. 2021 Mar 22;48:100946. doi: 10.1016/j.dcn.2021.100946. Online ahead of print.

ABSTRACT

Parenting behavior is associated with internalizing symptoms in children, and cross-sectional research suggests that this association may be mediated by the influence of parenting on the development of frontoamygdala circuitry. However, longitudinal studies are lacking. Moreover, there is a paucity of studies that have investigated parenting and large-scale networks implicated in affective functioning. In this longitudinal study, data from 95 (52 female) children and their mothers were included. Children underwent magnetic resonance imaging that included a 6 min resting state sequence at wave 1 (mean age = 8.4 years) and wave 2 (mean age = 9.9 years). At wave 1, observational measures of positive and negative maternal behavior were collected during mother-child interactions. Region-of-interest analysis of the amygdala, and independent component and dual-regression analyses of the Default Mode Network (DMN), Executive Control Network (ECN) and the Salience Network (SN) were carried out. We identified developmental effects as a function of parenting: positive parenting was associated with decreased coactivation of the superior parietal lobule with the ECN at wave 2 compared to wave 1. Thus our findings provide preliminary longitudinal evidence that positive maternal behavior is associated with maturation of the connectivity between higher-order control networks.

PMID:33780733 | DOI:10.1016/j.dcn.2021.100946

Relationship between GABA levels and task-dependent cortical excitability in children with attention-deficit/hyperactivity disorder

Mon, 03/29/2021 - 10:00

Clin Neurophysiol. 2021 Mar 10;132(5):1163-1172. doi: 10.1016/j.clinph.2021.01.023. Online ahead of print.

ABSTRACT

OBJECTIVE: Compared to typically developing (TD) peers, children with attention deficit hyperactivity disorder (ADHD) manifest reduced short interval cortical inhibition (SICI) in the dominant motor cortex measured with transcranial magnetic stimulation (TMS). This multimodal study investigates the inhibitory neurophysiology and neurochemistry by evaluating the relationship between SICI and γ-amino butyric acid (GABA+) levels, measured with magnetic resonance spectroscopy (MRS).

METHODS: Across two sites, 37 children with ADHD and 45 TD children, ages 8-12 years, participated. Single and paired pulse TMS to left motor cortex quantified SICI during REST and at times of action selection (GO) and inhibition (STOP) during a modified Slater-Hammel stop signal reaction task. MRS quantified GABA+ levels in the left sensorimotor cortex. Relationships between SICI and GABA+, as well as stopping efficiency and clinical symptoms, were analyzed with correlations and repeated-measure, mixed-models.

RESULTS: In both groups, higher GABA+ levels correlated with less SICI. In TD children only, higher GABA+ levels correlated with larger TMS motor evoked potentials (MEPs) at REST. In GO and STOP trials, higher GABA+ was associated with smaller MEP amplitudes, for both groups. Overall, GABA+ levels did not differ between groups or correlate with ADHD clinical symptoms.

CONCLUSIONS: In children with higher motor cortex GABA+, motor cortex is less responsive to inhibitory TMS (SICI). Comparing the relationships between MRS-GABA+ levels and responses to TMS at REST vs. GO/STOP trials suggests differences in inhibitory neurophysiology and neurotransmitters in children with ADHD. These differences are more prominent at rest than during response inhibition task engagement.

SIGNIFICANCE: Evaluating relationships between GABA+ and SICI may provide a biomarker useful for understanding behavioral diagnoses.

PMID:33780723 | DOI:10.1016/j.clinph.2021.01.023

Asthma-Specific Temporal Variability Reveals the Effect of Group Cognitive Behavior Therapy in Asthmatic Patients

Mon, 03/29/2021 - 10:00

Front Neurol. 2021 Mar 12;12:615820. doi: 10.3389/fneur.2021.615820. eCollection 2021.

ABSTRACT

Background: Group cognitive behavior therapy (GCBT) is a successful therapy for asthma. However, the neural biomarker of GCBT which could be used in clinic remains unclear. The temporal variability is a novel concept to characterize the dynamic functional connectivity (FC), which has many advantages as biomarker. Therefore, the aim of this study is to explore the potential difference of temporal variability between asthmatic patients and healthy controls, then determine the different patterns of temporal variability between pre- and post-treatment group and reveal the relationship between the variability and the symptoms improvement reduced by GCBT. Methods: At baseline, 40 asthmatic patients and 40 matched controls received resting-state functional magnetic resonance imaging (fMRI) scans and clinical assessments. After 8 weeks of GCBT treatment, 17 patients received fMRI scans, and assessments again. Temporal variability at baseline and post-treatment were calculated for further analysis. Results: Compared with controls, asthmatic patients showed widespread decreases in temporal variability. Moreover, the variability in both right caudate and left putamen were positively correlated with asthma control level. After GCBT, asthma control level and depression of patients were improved. Meanwhile, compared with pre-GCBT, patients after treatment showed lower variability in left opercular of Rolandic, right parahippocampal gyrus and right lingual gyrus, as well as higher variability in left temporal pole. Variability in regions which were found abnormal at baseline did not exhibit significant differences between post-GCBT and controls. Conclusions: Asthma-specific changes of dynamic functional connectivity may serve as promising underpinnings of GCBT for asthma. Clinical Trial Registration: http://www.chictr.org.cn/index.aspx, identifier: Chi-CTR-15007442.

PMID:33776882 | PMC:PMC7994749 | DOI:10.3389/fneur.2021.615820

Altered Functional Connectivity Within and Between Salience and Sensorimotor Networks in Patients With Functional Constipation

Mon, 03/29/2021 - 10:00

Front Neurosci. 2021 Mar 11;15:628880. doi: 10.3389/fnins.2021.628880. eCollection 2021.

ABSTRACT

Functional constipation (FCon) is a common functional gastrointestinal disorder. A considerable portion of patients with FCon is associated with anxiety/depressive status (FCAD). Previous neuroimaging studies mainly focused on patients with FCon without distinguishing FCAD from FCon patients without anxiety/depressive status (FCNAD). Differences in brain functions between these two subtypes remain unclear. Thus, we employed resting-state functional magnetic resonance imaging (RS-fMRI) and graph theory method to investigate differences in brain network connectivity and topology in 41 FCAD, 42 FCNAD, and 43 age- and gender-matched healthy controls (HCs). FCAD/FCNAD showed significantly lower normalized clustering coefficient and small-world-ness. Both groups showed altered nodal degree/efficiency mainly in the rostral anterior cingulate cortex (rACC), precentral gyrus (PreCen), supplementary motor area (SMA), and thalamus. In the FCAD group, nodal degree in the SMA was negatively correlated with difficulty of defecation, and abdominal pain was positively correlated with nodal degree/efficiency in the rACC, which had a lower within-module nodal degree. The salience network (SN) exhibited higher functional connectivity (FC) with the sensorimotor network (SMN) in FCAD/FCNAD, and FC between these two networks was negatively correlated with anxiety ratings in FCAD group. Additionally, FC of anterior insula (aINS)-rACC was only correlated with constipation symptom (i.e., abdominal pain) in the FCNAD group. In the FCAD group, FCs of dorsomedial prefrontal cortex-rACC, PreCen-aINS showed correlations with both constipation symptom (i.e., difficulty of defecation) and depressive status. These findings indicate the differences in FC of the SN-SMN between FCAD and FCNAD and provide neuroimaging evidence based on brain function, which portrays important clues for improving new treatment strategies.

PMID:33776637 | PMC:PMC7991789 | DOI:10.3389/fnins.2021.628880

The Instant and Sustained Effect of Electroacupuncture in Postgraduate Students with Depression: An fMRI Study

Mon, 03/29/2021 - 10:00

Neuropsychiatr Dis Treat. 2021 Mar 19;17:873-883. doi: 10.2147/NDT.S307083. eCollection 2021.

ABSTRACT

OBJECTION: This study was a primary study to evaluate the instant and sustained effect of electroacupuncture (EA) at GV20 (Baihui) in postgraduate students with mild depression by using a special flexible head coil.

METHODS: A total of 20 postgraduate students with mild depression underwent EA stimulation at GV20 and 3 phases of resting-state functional magnetic resonance imaging (rs-fMRI) scanning. Phase I: Preparation (before needle insertion); Phase II: during EA; Phase III: 15 minutes after needle removal. The Rs-fMRI data were processed using DPABI and SPSS 25.

RESULTS: 1) ReHo values showed significantly differences in the right posterior cingulate cortex, right calcarine gyrus, right angular gyrus, right precuneus, right cuneus, and bilateral postcentral gyri among Phase I, Phase II and Phase III; 2) Relative to the Phase I, increased brain activity in the Phase II was observed in the bilateral postcentral gyri, right calcarine gyrus, right cuneus. Compared with the Phase II, decreased brain activity in the Phase III was observed in the right precuneus, right posterior cingulate cortex, right angular gyrus. Relative to the Phase I, Significantly increased brain activity in the Phase III was observed in the right calcarine gyrus, right cuneus, and bilateral postcentral gyri. While decreased ReHo values were found in the right posterior cingulate cortex, right angular gyrus, right precuneus; and 3) Correlation analysis showed that the ReHo values of multiple brain regions in Phase I and Phase III were significantly correlated with the VAS and HRSD-17 scores.

CONCLUSION: This study focuses on the instant and sustained effect in postgraduate students with depression. Our study showed that instant effect produced by EA stimulation at GV20 firstly induced changes in somatosensory and visual area, and then, sustained effect (Phase III) have a higher intensity and more extensive than instant effects. Meanwhile, we provide a visualization way to study the instant effects of head acupoints by using a flexible head coil.

PMID:33776442 | PMC:PMC7989050 | DOI:10.2147/NDT.S307083

Influence of anhedonic symptom severity on reward circuit connectivity in PTSD

Mon, 03/29/2021 - 10:00

Behav Brain Res. 2021 Mar 25:113258. doi: 10.1016/j.bbr.2021.113258. Online ahead of print.

ABSTRACT

Anhedonia, marked by deficits in reward processing, is a prominent symptom of several psychiatric conditions and has been shown to influence functional connectivity between reward-related regions. However, the unique influence of anhedonia severity on reward circuit connectivity in posttraumatic stress disorder (PTSD) remains unclear. To address this, we examined resting-state functional connectivity (rsFC) of the ventral striatum as a function of anhedonia for individuals with PTSD. Resting-state functional MRI scans and behavioral assessments were collected for 71 women diagnosed with PTSD. Seed-based voxelwise rsFC analyses for left and right nucleus accumbens (NAcc) seed regions of interest were performed. Voxelwise regression analyses were conducted to examine the relationship between anhedonia severity and rsFC of left and right NAcc. Results indicated that greater anhedonia severity was associated with reduced rsFC between the left NAcc and a cluster in the left caudate extending to the thalamus. This relationship between anhedonia and rsFC remained significant after controlling for PTSD symptom severity or depression severity. Our findings suggest that reward circuit dysfunction at rest is associated with anhedonia in PTSD. These results further contribute to our understanding of the neural correlates of anhedonia in psychiatric conditions.

PMID:33775774 | DOI:10.1016/j.bbr.2021.113258

Whole-Brain Functional Dynamics Track Depressive Symptom Severity

Sun, 03/28/2021 - 10:00

Cereb Cortex. 2021 Mar 29:bhab047. doi: 10.1093/cercor/bhab047. Online ahead of print.

ABSTRACT

Depressive symptoms are reported by 20% of the population and are related to altered functional integrity of large-scale brain networks. The link between moment-to-moment brain function and depressive symptomatology, and the implications of these relationships for clinical and community populations alike, remain understudied. The present study examined relationships between functional brain dynamics and subclinical-to-mild depressive symptomatology in a large community sample of adults with and without psychiatric diagnoses. This study used data made available through the Enhanced Nathan Kline Institute-Rockland Sample; 445 participants between 18 and 65 years of age completed a 10-min resting-state functional MRI scan. Coactivation pattern analysis was used to examine the dimensional relationship between depressive symptoms and whole-brain states. Elevated levels of depressive symptoms were associated with increased frequency and dwell time of the default mode network, a brain network associated with self-referential thought, evaluative judgment, and social cognition. Furthermore, increased depressive symptom severity was associated with less frequent occurrences of a hybrid brain network implicated in cognitive control and goal-directed behavior, which may impair the inhibition of negative thinking patterns in depressed individuals. These findings demonstrate how temporally dynamic techniques offer novel insights into time-varying neural processes underlying subclinical and clinically meaningful depressive symptomatology.

PMID:33774654 | DOI:10.1093/cercor/bhab047

Association between functional brain alterations and neuropsychological scales in male chronic smokers using resting-state fMRI

Sat, 03/27/2021 - 10:00

Psychopharmacology (Berl). 2021 Mar 27. doi: 10.1007/s00213-021-05819-6. Online ahead of print.

ABSTRACT

RATIONALE: Recent studies have demonstrated that cigarette smoking is related to changes in brain structure and function. However, few studies focus on functional brain differences between male chronic smokers and nonsmokers in both local spontaneous activity and whole-brain functional networks.

OBJECTIVES: Our study recruited 67 chronic smokers and 43 nonsmokers who underwent functional magnetic resonance imaging (fMRI) scans to investigate functional activity and connectivity alterations in chronic smokers.

METHODS: We used the mean fractional amplitude of the low-frequency fluctuation (mfALFF) and mean regional homogeneity (mReHo) methods to investigate resting-state spontaneous activity in chronic smokers and nonsmokers. The graph theoretical analysis (GTA) and network-based statistical (NBS) analysis were also used to investigate functional connectivity alterations.

RESULTS: Compared with nonsmokers, chronic smokers exhibited higher activation in the reward system and portions of the prefrontal cortex but lower activation in the default mode networks (DMN) and visual-related regions. In addition, correlation analysis was conducted to assess the associations between neuroimaging findings and the severity of nicotine dependence or expectations of smoking effects. Our results showed that certain brain regions correlated with the Fagerström Test for Nicotine Dependence (FTND), the positive aspect of the Drug Use Disorders Identification Test Extended (DUDIT-E), and the negative aspect of the DUDIT-E, especially in the attentional control networks and hippocampus. The graph theoretical analysis (GTA) results indicated chronic smokers exhibited a trend toward increased assortativity. Our network-based statistical (NBS) analysis revealed reduced functional connections between the subnetwork in the prefrontal cortex, olfactory cortex, angular gyrus, and cingulate gyrus of chronic smokers.

CONCLUSIONS: We concluded that chronic smokers have neural adaptations in local spontaneous activity but remain healthy brain functional networks.

PMID:33772331 | DOI:10.1007/s00213-021-05819-6

Using carpet plots to analyze transit times of low frequency oscillations in resting state fMRI

Sat, 03/27/2021 - 10:00

Sci Rep. 2021 Mar 26;11(1):7011. doi: 10.1038/s41598-021-86402-z.

ABSTRACT

A "carpet plot" is a 2-dimensional plot (time vs. voxel) of scaled fMRI voxel intensity values. Low frequency oscillations (LFOs) can be successfully identified from BOLD fMRI and used to study characteristics of neuronal and physiological activity. Here, we evaluate the use of carpet plots paired with a developed slope-detection algorithm as a means to study LFOs in resting state fMRI (rs-fMRI) data with the help of dynamic susceptibility contrast (DSC) MRI data. Carpet plots were constructed by ordering voxels according to signal delay time for each voxel. The slope-detection algorithm was used to identify and calculate propagation times, or "transit times", of tilted vertical edges across which a sudden signal change was observed. We aim to show that this metric has applications in understanding LFOs in fMRI data, possibly reflecting changes in blood flow speed during the scan, and for evaluating alternative blood-tracking contrast agents such as inhaled CO2. We demonstrate that the propagations of LFOs can be visualized and automatically identified in a carpet plot as tilted lines of sudden intensity change. Resting state carpet plots produce edges with transit times similar to those of DSC carpet plots. Additionally, resting state carpet plots indicate that edge transit times vary at different time points during the scan.

PMID:33772060 | DOI:10.1038/s41598-021-86402-z

Associations between neighborhood disadvantage, resting-state functional connectivity, and behavior in the Adolescent Brain Cognitive Development (ABCD) Study(R): Moderating role of positive family and school environments

Sat, 03/27/2021 - 10:00

Biol Psychiatry Cogn Neurosci Neuroimaging. 2021 Mar 23:S2451-9022(21)00085-9. doi: 10.1016/j.bpsc.2021.03.008. Online ahead of print.

ABSTRACT

OBJECTIVE: Neighborhood disadvantage has consistently been associated with mental health and cognitive function, in addition to alterations in brain function and connectivity. However, positive environmental influences may buffer these effects. The aim of the present study was to examine the association between neighborhood disadvantage and resting-state functional connectivity (rsFC), the moderating role of positive parenting and school environment, and relationships between disadvantage-associated rsFC patterns and mental health and cognition.

METHODS: In this pre-registered study, we tested this hypothesis in a large sample of 7618 children (aged 9-10 years) from the Adolescent Brain Cognitive Development (ABCD) Study. Specifically, we analyzed the relationship between neighborhood disadvantage and system-level FC. We also tested whether positive family and school environmental factors, and sex, moderated effects. Finally, we investigated multivariate relationships between disadvantage-associated rsFC patterns and cognition and mental health.

RESULTS: Disadvantage was associated with widespread alterations in FC across both higher-order (e.g., default mode network and dorsal attention network) and sensorimotor functional systems; some of which were moderated by positive environments. Implicated connections showed multivariate associations with behavior, whereby disadvantage-associated rsFC was generally associated with worse cognition and mental health. Disadvantage-associated connections also predicted variation in cognitive scores using machine learning models.

CONCLUSIONS: Our findings shed light on potential mechanisms (i.e., alteration of neural circuitry) through which neighborhood disadvantage may affect youth cognition and mental wellbeing. This work highlights the importance of positive family and school environments in mitigating some of these effects.

PMID:33771727 | DOI:10.1016/j.bpsc.2021.03.008

The NIMH Intramural Longitudinal Study of the Endocrine and Neurobiological Events Accompanying Puberty: Protocol and Rationale for Methods and Measures

Sat, 03/27/2021 - 10:00

Neuroimage. 2021 Mar 23:117970. doi: 10.1016/j.neuroimage.2021.117970. Online ahead of print.

ABSTRACT

Delineating the relationship between human neurodevelopment and the maturation of the hypothalamic-pituitary-gonadal (HPG) axis during puberty is critical for investigating the increase in vulnerability to neuropsychiatric disorders that is well documented during this period. Preclinical research demonstrates a clear association between gonadal production of sex steroids and neurodevelopment; however, identifying similar associations in humans has been complicated by confounding variables (such as age) and the coactivation of two additional endocrine systems (the adrenal androgenic system and the somatotropic growth axis) and requires further elucidation. In this paper, we present the design of, and preliminary observations from, the ongoing NIMH Intramural Longitudinal Study of the Endocrine and Neurobiological Events Accompanying Puberty. The aim of this study is to directly examine how the increase in sex steroid hormone production following activation of the HPG-axis (i.e., gonadarche) impacts neurodevelopment, and, additionally, to determine how gonadal development and maturation is associated with longitudinal changes in brain structure and function in boys and girls. To disentangle the effects of sex steroids from those of age and other endocrine events on brain development, our study design includes 1) selection criteria that establish a well-characterized baseline cohort of healthy 8-year-old children prior to the onset of puberty (e.g., prior to puberty-related sex steroid hormone production); 2) temporally dense longitudinal, repeated-measures sampling of typically developing children at 8-10 month intervals over a 10-year period between the ages of eight and 18; 3) contemporaneous collection of endocrine and other measures of gonadal, adrenal, and growth axis function at each timepoint; and 4) collection of multimodal neuroimaging measures at these same timepoints, including brain structure (gray and white matter volume, cortical thickness and area, white matter integrity, myelination) and function (reward processing, emotional processing, inhibition/impulsivity, working memory, resting-state network connectivity, regional cerebral blood flow). This report of our ongoing longitudinal study 1) provides a comprehensive review of the endocrine events of puberty; 2) details our overall study design; 3) presents our selection criteria for study entry (e.g., well-characterized prepubertal baseline) along with the endocrinological considerations and guiding principles that underlie these criteria; 4) describes our longitudinal outcome measures and how they specifically relate to investigating the effects of gonadal development on brain development; and 5) documents patterns of fMRI activation and resting-state networks from an early, representative subsample of our cohort of prepubertal 8-year-old children.

PMID:33771694 | DOI:10.1016/j.neuroimage.2021.117970

Dysmaturation Observed as Altered Hippocampal Functional Connectivity at Rest Is Associated With the Emergence of Positive Psychotic Symptoms in Patients With 22q11 Deletion Syndrome

Sat, 03/27/2021 - 10:00

Biol Psychiatry. 2021 Jan 18:S0006-3223(21)00045-7. doi: 10.1016/j.biopsych.2020.12.033. Online ahead of print.

ABSTRACT

BACKGROUND: Hippocampal alterations are among the most replicated neuroimaging findings across the psychosis spectrum. Moreover, there is strong translational evidence that preserving the maturation of hippocampal networks in mice models prevents the progression of cognitive deficits. However, the developmental trajectory of hippocampal functional connectivity (HFC) and its contribution to psychosis is not well characterized in the human population. 22q11 deletion syndrome (22q11DS) offers a unique model for characterizing early neural correlates of schizophrenia.

METHODS: We acquired resting-state functional magnetic resonance imaging in 242 longitudinally repeated scans from 84 patients with 22q11DS (30 with moderate to severe positive psychotic symptoms) and 94 healthy control subjects in the age span of 6 to 32 years. We obtained bilateral hippocampus to whole-brain functional connectivity and employed a novel longitudinal multivariate approach by means of partial least squares correlation to evaluate the developmental trajectory of HFC across groups.

RESULTS: Relative to control subjects, patients with 22q11DS failed to increase HFC with frontal regions such as the dorsal part of the anterior cingulate cortex, prefrontal cortex, and supplementary motor area. Concurrently, carriers of the deletion had abnormally higher HFC with subcortical dopaminergic areas. Remarkably, this aberrant maturation of HFC was more prominent during midadolescence and was mainly driven by patients exhibiting subthreshold positive psychotic symptoms.

CONCLUSIONS: Our findings suggest a critical period of prefrontal cortex-hippocampal-striatal circuit dysmaturation, particularly during late adolescence, which in light of current translation evidence could be a target for short-term interventions to potentially achieve long-lasting rescue of circuit dysfunctions associated with psychosis.

PMID:33771350 | DOI:10.1016/j.biopsych.2020.12.033

A literature review of magnetic resonance imaging sequence advancements in visualizing functional neurosurgery targets

Fri, 03/26/2021 - 10:00

J Neurosurg. 2021 Mar 26:1-14. doi: 10.3171/2020.8.JNS201125. Online ahead of print.

ABSTRACT

OBJECTIVE: Historically, preoperative planning for functional neurosurgery has depended on the indirect localization of target brain structures using visible anatomical landmarks. However, recent technological advances in neuroimaging have permitted marked improvements in MRI-based direct target visualization, allowing for refinement of "first-pass" targeting. The authors reviewed studies relating to direct MRI visualization of the most common functional neurosurgery targets (subthalamic nucleus, globus pallidus, and thalamus) and summarize sequence specifications for the various approaches described in this literature.

METHODS: The peer-reviewed literature on MRI visualization of the subthalamic nucleus, globus pallidus, and thalamus was obtained by searching MEDLINE. Publications examining direct MRI visualization of these deep brain stimulation targets were included for review.

RESULTS: A variety of specialized sequences and postprocessing methods for enhanced MRI visualization are in current use. These include susceptibility-based techniques such as quantitative susceptibility mapping, which exploit the amount of tissue iron in target structures, and white matter attenuated inversion recovery, which suppresses the signal from white matter to improve the distinction between gray matter nuclei. However, evidence confirming the superiority of these sequences over indirect targeting with respect to clinical outcome is sparse. Future targeting may utilize information about functional and structural networks, necessitating the use of resting-state functional MRI and diffusion-weighted imaging.

CONCLUSIONS: Specialized MRI sequences have enabled considerable improvement in the visualization of common deep brain stimulation targets. With further validation of their ability to improve clinical outcomes and advances in imaging techniques, direct visualization of targets may play an increasingly important role in preoperative planning.

PMID:33770759 | DOI:10.3171/2020.8.JNS201125

A neurodevelopmental signature of parkinsonism in schizophrenia

Fri, 03/26/2021 - 10:00

Schizophr Res. 2021 Mar 23;231:54-60. doi: 10.1016/j.schres.2021.03.004. Online ahead of print.

ABSTRACT

While sensorimotor abnormalities in schizophrenia (SZ) are of increasing scientific interest, little is known about structural changes and their developmental origins that may underlie parkinsonism. This multimodal magnetic resonance imaging (MRI) study examined healthy controls (HC, n = 20) and SZ patients with (SZ-P, n = 38) and without (SZ-nonP, n = 35) parkinsonism, as defined by Simpson-Angus Scale total scores of ≥4 or ≤1, respectively. Using the Computational Anatomy Toolbox (CAT12), voxel- and surface-based morphometry were applied to investigate cortical and subcortical gray matter volume (GMV) and three cortical surface markers of distinct neurodevelopmental origin: cortical thickness (CTh), complexity of cortical folding (CCF) and sulcus depth. In a subgroup of patients (29 SZ-nonP, 25 SZ-P), resting-state fMRI data were also analyzed using a regions-of-interest approach based on fractional amplitude of low frequency fluctuations (fALFF). SZ-P patients showed increased CCF in the left supplementary motor cortex (SMC) and decreased left postcentral sulcus (PCS) depth compared to SZ-nonP patients (p < 0.05, FWE-corrected at cluster level). In SMC, CCF was associated negatively with activity, which also differed significantly between the patient groups and between patients and HC. In regression models, severity of parkinsonism was associated negatively with left middle frontal CCF and left anterior cingulate CTh. These data provide novel insights into altered trajectories of cortical development in SZ patients with parkinsonism. These cortical surface changes involve the sensorimotor system, suggesting abnormal neurodevelopmental processes tightly coupled with cortical activity and subcortical morphology that convey increased risk for sensorimotor abnormalities in SZ.

PMID:33770626 | DOI:10.1016/j.schres.2021.03.004

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