Age-related differences in macromolecular resonances observed in ultra-short-TE STEAM MR spectra at 7T

PURPOSE

To understand how macromolecular content varies in the human brain with age in a large cohort of healthy subjects.

METHODS

In-vivo 1H-MR spectra were acquired using ultra-short TE STEAM at 7T in the posterior cingulate cortex. Macromolecular content was studied in 147 datasets from a cohort ranging in age from 19 to 89 y. Three fitting approaches were used to evaluate the macromolecular content: (1) a macromolecular resonances model developed for this study; (2) LCModel-simulated macromolecules; and (3) a combination of measured and LCModel-simulated macromolecules. The effect of age on the macromolecular content was investigated by considering age both as a continuous variable (i.e., linear regressions) and as a categorical variable (i.e., multiple comparisons among sub-groups obtained by stratifying data according to age by decade).

RESULTS

While weak age-related effects were observed for macromolecular peaks at ˜0.9 (MM09), ˜1.2 (MM12), and ˜1.4 (MM14) ppm, moderate to strong effects were observed for peaks at ˜1.7 (MM17), and ˜2.0 (MM20) ppm. Significantly higher MM17 and MM20 content started from 30 to 40 y of age, while for MM09, MM12, and MM14, significantly higher content started from 60 to 70 y of age.

CONCLUSIONS

Our findings provide insights into age-related differences in macromolecular contents and strengthen the necessity of using age-matched measured macromolecules during quantification.

Creatine concentration in the anterior cingulate cortex is associated with greater stress recovery from traumatic events: Preliminary evidence from a US Veteran sample

BACKGROUND

Posttraumatic stress disorder (PTSD) is a psychiatric condition characterized by a prolonged stress response to potentially life-threatening events long after the event has passed. Understanding factors related to recovery from traumatic life events may inform novel targets for intervention. There is emerging preclinical evidence that creatine (Cr), a molecule critical to brain bioenergetics, may be a neurobiological marker of stress reactivity and recovery.

METHOD

25 US Veterans (8 female) completed the Life Events Checklist for DSM-5, which assessed different types of traumatic events. Veterans were also asked to rate the subjective stress of each traumatic event on a 1-10 scale currently (Current Stress) and at the time the event occurred (Past Stress). Stress recovery was quantified as the difference between Current and Past Stress. Current PTSD symptoms were also assessed using the PTSD Checklist for DSM-5. Cr concentrations in the anterior cingulate cortex (ACC) were measured in the anterior cingulate cortex using proton magnetic resonance spectroscopy (1H-MRS).

RESULTS

Higher levels of Cr were associated with self-reported stress recovery from participants' most traumatic life event. Cr was not related to number of different types of traumatic life events or current PTSD symptoms.

LIMITATIONS

The sample size was relatively small. Stress recovery was measured via retrospective self-report. Future experimental work in humans should clarify the protective role of Cr in recovery from trauma.

CONCLUSIONS

ACC concentrations of Cr may be an important neurochemical factor related to stress recovery. Future work should investigate Cr as a possible protective factor against the effects of traumatic stress.

Decreased grey matter volume in dorsolateral prefrontal cortex and thalamus accompanied by compensatory increases in middle cingulate gyrus of premature ejaculation patients

INTRODUCTION

The prefrontal-cingulate-thalamic areas are associated with ejaculation control. Functional abnormalities of these areas and decreased grey matter volume (GMV) in the subcortical areas have been confirmed in premature ejaculation (PE) patients. However, no study has explored the corresponding GMV changes in the prefrontal-cingulate-thalamic areas, which are considered as the important basis for functional abnormalities. This study aimed to investigated whether PE patients exhibited impaired GMV in the brain, especially the prefrontal-cingulate-thalamic areas, and whether these structural deficits were associated with declined ejaculatory control.

METHODS

T1-weighted structural magnetic resonance imaging (MRI) data were acquired from 50 lifelong PE patients and 50 age-, and education-matched healthy controls (HCs). The PE diagnostic tool (PEDT) was applied to assess the subjective symptoms of PE. Based on the method of voxel-based morphometry (VBM), GMV were measured and compared between groups. In addition, the correlations between GMV of brain regions showed differences between groups and PEDT scores were evaluated in the patient group.

RESULTS

PE patients showed decreased GMV in the right dorsolateral superior frontal gyrus (clusters = 13, peak T-values = -4.30) and left thalamus (clusters = 47, T = -4.33), and increased GMV in the left middle cingulate gyrus (clusters = 12, T = 4.02) when compared with HCs. In the patient group, GMV of the left thalamus were negatively associated with PEDT scores (r = -0.35; P = 0.01). Receiver operating characteristic (ROC) analysis showed that GMV of the right dorsolateral superior frontal gyrus (AUC = 0.71, P < 0.01, sensitivity = 60%, specificity = 78%), left thalamus (AUC = 0.72, P < 0.01, sensitivity = 92%, specificity = 46%) and middle cingulate gyrus (AUC = 0.69, P < 0.01, sensitivity = 50%, specificity = 90%), and the combined model (AUC = 0.84, P < 0.01, sensitivity = 78%, specificity = 80%) all had the ability to distinguish PE patients from HCs.

CONCLUSION

Disturbances in GMV were revealed in the prefrontal-cingulate-thalamic areas of PE patients. The findings implied that decreased GMV in the dorsolateral prefrontal cortex and thalamus might be associated with the central pathological neural mechanism underlying the declined ejaculatory control while increased GMV in the middle cingulate gyrus might be the compensatory mechanism underlying PE.

The relationship of neuropsychiatric symptoms with inflammatory markers in the hippocampus and cingulate cortex of bipolar disorder subjects: A post-mortem study

Increased levels of inflammation markers have been found in the peripheral tissue of individuals with bipolar disorder (BD), especially during mood episodes. Previous studies found distinctive inflammatory profiles across different brain regions, but potential associations with clinical symptoms are still lacking. This study aims to evaluate the association of neuropsychiatric symptoms with inflammatory markers in the hippocampus and cingulate of individuals with BD. Levels of IL-1β, IL-6, IL-17A, cortisol, and C-reactive protein (CRP) were measured in the hippocampus and anterior cingulate of 14 BD individuals and their non-psychiatric controls. Neuropsychiatric symptoms present in the three months before death were assessed using the Neuropsychiatric Inventory (NPI). In the BD group, greater NPI scores were associated with higher IL-6 in the hippocampus (p = 0.011) and cingulate (p = 0.038) and higher IL-1β (p = 0.039) in the hippocampus. After adjusting for age, sex and CDR, IL-1β and IL-6 were still associated with higher NPI in the hippocampus. In correlation analysis considering both BD and their controls, moderate positive associations were found between NPI and IL-6 and cortisol in the hippocampus (p < 0.001 and p = 0.006) and cingulate (p = 0.024 and p = 0.016), IL-1β (p < 0.001) and IL-17A in the hippocampus (p = 0.002). No difference in inflammatory markers was found according to type of psychotropic medication used. Hence, in individuals with BD, neuropsychiatric symptoms were differently associated with specific inflammatory cytokines and CRP in the hippocampus and cingulate. These results suggest that the neuroinflammatory changes occurring in BD may be more complex than previously expected and could be associated with clinical manifestations.

Similar imaging changes and their relations to genetic profiles in bipolar disorder across different clinical stages

Bipolar disorder (BD) across different clinical stages may present shared and distinct changes in brain activity. We aimed to reveal the neuroimaging homogeneity and heterogeneity of BD and its relationship with clinical variables and genetic variations. In present study, we conducted fractional amplitude of low-frequency fluctuations (fALFF), functional connectivity (FC) and genetic neuroimaging association analyses with 32 depressed, 26 manic, 35 euthymic BD patients and 87 healthy controls (HCs). Significant differences were found in the bilateral pre/subgenual anterior cingulate cortex (ACC) across the four groups, and all bipolar patients exhibited decreased fALFF values in the ACC when compared to HCs. Furthermore, positive associations were significantly observed between fALFF values in the pre/subgenual ACC and participants' cognitive functioning. No significant changes were found in ACC-based FC. We identified fALFF-alteration-related genes in BD, with enrichment in biological progress including synaptic and ion transmission. Taken together, abnormal activity in ACC is a characteristic change associated with BD, regardless of specific mood stages, serving as a potential neuroimaging feature in BD patients. Our genetic neuroimaging association analysis highlights possible heterogeneity in biological processes that could be responsible for different clinical stages in BD.

Higher-order functional brain networks and anterior cingulate glutamate + glutamine (Glx) in antipsychotic-naïve first episode psychosis patients

Human connectome studies have provided abundant data consistent with the hypothesis that functional dysconnectivity is predominant in psychosis spectrum disorders. Converging lines of evidence also suggest an interaction between dorsal anterior cingulate cortex (dACC) cortical glutamate with higher-order functional brain networks (FC) such as the default mode (DMN), dorsal attention (DAN), and executive control networks (ECN) in healthy controls (HC) and this mechanism may be impaired in psychosis. Data from 70 antipsychotic-medication naïve first-episode psychosis (FEP) and 52 HC were analyzed. 3T Proton magnetic resonance spectroscopy (1H-MRS) data were acquired from a voxel in the dACC and assessed correlations (positive FC) and anticorrelations (negative FC) of the DMN, DAN, and ECN. We then performed regressions to assess associations between glutamate + glutamine (Glx) with positive and negative FC of these same networks and compared them between groups. We found alterations in positive and negative FC in all networks (HC > FEP). A relationship between dACC Glx and positive and negative FC was found in both groups, but when comparing these relationships between groups, we found contrasting associations between these variables in FEP patients compared to HC. We demonstrated that both positive and negative FC in three higher-order resting state networks are already altered in antipsychotic-naïve FEP, underscoring the importance of also considering anticorrelations for optimal characterization of large-scale functional brain networks as these represent biological processes as well. Our data also adds to the growing body of evidence supporting the role of dACC cortical Glx as a mechanism underlying alterations in functional brain network connectivity. Overall, the implications for these findings are imperative as this particular mechanism may differ in untreated or chronic psychotic patients; therefore, understanding this mechanism prior to treatment could better inform clinicians.Clinical trial registration: Trajectories of Treatment Response as Window into the Heterogeneity of Psychosis: A Longitudinal Multimodal Imaging Study, NCT03442101 . Glutamate, Brain Connectivity and Duration of Untreated Psychosis (DUP), NCT02034253 .

Space wandering in the rodent default mode network

The default mode network (DMN) is a large-scale brain network known to be suppressed during a wide range of cognitive tasks. However, our comprehension of its role in naturalistic and unconstrained behaviors has remained elusive because most research on the DMN has been conducted within the restrictive confines of MRI scanners. Here, we use multisite GCaMP (a genetically encoded calcium indicator) fiber photometry with simultaneous videography to probe DMN function in awake, freely exploring rats. We examined neural dynamics in three core DMN nodes-the retrosplenial cortex, cingulate cortex, and prelimbic cortex-as well as the anterior insula node of the salience network, and their association with the rats' spatial exploration behaviors. We found that DMN nodes displayed a hierarchical functional organization during spatial exploration, characterized by stronger coupling with each other than with the anterior insula. Crucially, these DMN nodes encoded the kinematics of spatial exploration, including linear and angular velocity. Additionally, we identified latent brain states that encoded distinct patterns of time-varying exploration behaviors and found that higher linear velocity was associated with enhanced DMN activity, heightened synchronization among DMN nodes, and increased anticorrelation between the DMN and anterior insula. Our findings highlight the involvement of the DMN in collectively and dynamically encoding spatial exploration in a real-world setting. Our findings challenge the notion that the DMN is primarily a "task-negative" network disengaged from the external world. By illuminating the DMN's role in naturalistic behaviors, our study underscores the importance of investigating brain network function in ecologically valid contexts.

White matter tracts adjacent to the human cingulate sulcus visual area (CSv)

Human cingulate sulcus visual area (CSv) was first identified as an area that responds selectively to visual stimulation indicative of self-motion. It was later shown that the area is also sensitive to vestibular stimulation as well as to bodily motion compatible with locomotion. Understanding the anatomical connections of CSv will shed light on how CSv interacts with other parts of the brain to perform information processing related to self-motion and navigation. A previous neuroimaging study (Smith et al. 2018, Cerebral Cortex, 28, 3685-3596) used diffusion-weighted magnetic resonance imaging (dMRI) to examine the structural connectivity of CSv, and demonstrated connections between CSv and the motor and sensorimotor areas in the anterior and posterior cingulate sulcus. The present study aimed to complement this work by investigating the relationship between CSv and adjacent major white matter tracts, and to map CSv's structural connectivity onto known white matter tracts. By re-analysing the dataset from Smith et al. (2018), we identified bundles of fibres (i.e. streamlines) from the whole-brain tractography that terminate near CSv. We then assessed to which white matter tracts those streamlines may belong based on previously established anatomical prescriptions. We found that a significant number of CSv streamlines can be categorised as part of the dorsalmost branch of the superior longitudinal fasciculus (SLF I) and the cingulum. Given current thinking about the functions of these white matter tracts, our results support the proposition that CSv provides an interface between sensory and motor systems in the context of self-motion.

Abnormal functional connectivity within the prefrontal cortex is associated with multiple plasma lipid species in major depressive disorder

BACKGROUND

Abnormalities in functional connectivity (FC) in major depressive disorder (MDD) have been widely reported. Analysis of the relationship between FC and plasma lipid profiles would be meaningful in the exploration of pathophysiological mechanisms and helpful for the identification of biomarkers for MDD.

METHODS

Patients with MDD (n = 49) and healthy controls (HC, n = 87) were recruited. Resting-state functional magnetic resonance imaging (rs-fMRI) data were collected for FC construction. The plasma lipid profiles were acquired using ultra-performance liquid chromatography (UPLC) and mass spectrometry (MS) analysis and clustered as co-expression modules. The differential FC and lipid modules between HCs and patients with MDD were identified, and then the association between FC and lipid co-expression modules was analyzed using correlation analysis. The modules associated molecular function was explored using metabolite set enrichment analysis (MSEA).

RESULTS

MDD-associated FC and lipid co-expression modules were identified. One module was associated with FC values between the right orbital part of the middle frontal gyrus and the opercular part of the left inferior frontal gyrus, which was enriched in lipid sets of diacylglycerols and fatty alcohols; another module was associated with FC values between the right middle frontal gyrus and the right anterior cingulate and paracingulate gyri, which was enriched in lipid sets of glycerophosphocholines and glycerophosphoethanolamines.

CONCLUSION

Our results indicated that abnormal FC in the prefrontal cortex is associated with multiple plasma lipid species, which may provide novel clues for exploring the pathophysiology of MDD.

Distinctive intrinsic functional connectivity alterations of anterior cingulate cortex subdivisions in major depressive disorder: A systematic review and meta-analysis

Evidence of whether the intrinsic functional connectivity of anterior cingulate cortex (ACC) and its subregions is altered in major depressive disorder (MDD) remains inconclusive. A systematic review and meta-analysis were therefore performed on the whole-brain resting-state functional connectivity (rsFC) studies using the ACC and its subregions as seed regions in MDD, in order to draw more reliable conclusions. Forty-four ACC-based rsFC studies were included, comprising 25 subgenual ACC-based studies, 11 pregenual ACC-based studies, and 17 dorsal ACC-based studies. Specific alterations of rsFC were identified for each ACC subregion in patients with MDD, with altered rsFC of subgenual ACC in emotion-related brain regions, of pregenual ACC in sensorimotor-related regions, and of dorsal ACC in cognition-related regions. Furthermore, meta-regression analysis revealed a significant negative correlation between the pgACC-caudate hypoconnectivity and percentage of female patients in the study cohort. This meta-analysis provides robust evidence of altered intrinsic functional connectivity of the ACC subregions in MDD, which may hold relevance to understanding the origin of, and treating, the emotional, sensorimotor and cognitive dysfunctions that are often observed in these patients.

7 T characterization of excitatory and inhibitory systems of acute pain in healthy female participants

Current understanding of the physiological underpinnings of normative pain processing is incomplete. Enhanced knowledge of these systems is necessary to advance our understanding of pain processes as well as to develop effective therapeutic interventions. Previous neuroimaging research suggests a network of interrelated brain regions that seem to be implicated in the processing and experience of pain. Among these, the dorsal anterior cingulate cortex (dACC) plays an important role in the affective aspects of pain signals. The current study leveraged functional MRS to investigate the underlying dynamic shifts in the neurometabolic signature of the human dACC at rest and during acute pain. Results provide support for increased glutamate levels following acute pain administration. Specifically, a 4.6% increase in glutamate was observed during moderate pressure pain compared with baseline. Exploratory analysis also revealed meaningful changes in dACC gamma aminobutyric acid in response to pain stimulation. These data contribute toward the characterization of neurometabolic shifts, which lend insight into the role of the dACC in the pain network. Further research in this area with larger sample sizes could contribute to the development of novel therapeutics or other advances in pain-related outcomes.

Cortical thickness of the posterior cingulate cortex is associated with the ketamine-induced altered sense of self: An ultra-high field MRI study

Subanesthetic doses of ketamine induce an antidepressant effect within hours in individuals with treatment-resistant depression while it furthermore induces immediate but transient psychotomimetic effects. Among these psychotomimetic effects, an altered sense of self has specifically been associated with the antidepressant response to ketamine as well as psychedelics. However, there is plenty of variation in the extent of the drug-induced altered sense of self experience that might be explained by differences in basal morphological characteristics, such as cortical thickness. Regions that have been previously associated with a psychedelics-induced sense of self and with ketamine's mechanism of action, are the posterior cingulate cortex (PCC) and the pregenual anterior cingulate cortex (pgACC). In this randomized, placebo-controlled, double-blind cross-over magnetic resonance imaging study, thirty-five healthy male participants (mean age ± standard deviation (SD) = 25.1 ± 4.2 years) were scanned at 7 T. We investigated whether the cortical thickness of two DMN regions, the PCC and the pgACC, are associated with disembodiment and experience of unity scores, which were used to index the ketamine-induced altered sense of self. We observed a negative correlation between the PCC cortical thickness and the disembodiment scores (R = -0.54, p < 0.001). In contrast, no significant association was found between the pgACC cortical thickness and the ketamine-induced altered sense of self. In the context of the existing literature, our findings highlight the importance of the PCC as a structure involved in the mechanism of ketamine-induced altered sense of self that seems to be shared with different antidepressant agents with psychotomimetic effects operating on different classes of transmitter systems.

Cingulate cortical thickness in cocaine use disorder: mediation effect between early life stress and cocaine consumption

OBJECTIVE

The cingulate gyrus is implicated in the neurobiology of addiction, such as chronic cocaine consumption. Early life stress (ELS) is an important moderator of cocaine use disorder (CUD). Therefore, we investigated the effect of CUD on cingulate cortical thickness and tested whether a history of ELS could influence the effects of CUD.

METHODS

Participants aged 18-50 years (78 with CUD due to crack cocaine consumption and 53 healthy controls) underwent magnetic resonance imaging and the cingulate thickness (rostral anterior, caudal anterior, posterior, and isthmus regions) was analysed. The clinical assessment comprised the Childhood Trauma Questionnaire (CTQ) and the Addiction Severity Index. Group comparisons adjusting by sex, age, and education were performed. Mediation models were generated where lifetime cocaine use, CTQ score, and cortical thickness corresponded to the independent variable, intermediary variable, and outcome, respectively.

RESULTS

Group comparisons revealed significant differences in six out of eight cingulate cortices, showing lower thickness in the CUD group. Furthermore, years of regular cocaine use was the variable most associated with cingulate thickness. Negative correlations were found between CTQ scores and the isthmus cingulate (right hemisphere), as well as with the rostral anterior cingulate (left hemisphere). In the mediation analysis, we observed a significant negative direct effect of lifetime cocaine use on the isthmus cingulate and an indirect effect of cocaine use mediated by CTQ score.

CONCLUSION

Our findings suggest that a history of ELS could aggravate the negative effects of chronic cocaine use on the cingulate gyrus, particularly in the right isthmus cingulate cortex.

Glutamatergic basis of antipsychotic response in first-episode psychosis: a dual voxel study of the anterior cingulate cortex

A subgroup of patients with schizophrenia is believed to have aberrant excess of glutamate in the frontal cortex; this subgroup is thought to show poor response to first-line antipsychotic treatments that focus on dopamine blockade. If we can identify this subgroup early in the course of illness, we can reduce the repeated use of first-line antipsychotics and potentially stratify first-episode patients to intervene early with second-line treatments such as clozapine. The use of proton magnetic resonance spectroscopy (1H-MRS) to measure glutamate and Glx (glutamate plus glutamine) may provide a means for such a stratification. We must first establish if there is robust evidence linking elevations in anterior cingulate cortex (ACC) glutamate metabolites to poor response, and determine if the use of antipsychotics worsens the glutamatergic excess in eventual nonresponders. In this study, we estimated glutamate levels at baseline in 42 drug-naive patients with schizophrenia. We then treated them all with risperidone at a standard dose range of 2-6 mg/day and followed them up for 3 months to categorize their response status. We expected to see baseline "hyperglutamatergia" in nonresponders, and expected this to worsen over time at the follow-up. In line with our predictions, nonresponders had higher glutamate than responders, but patients as a group did not differ in glutamate and Glx from the healthy control (HC) group before treatment-onset (F1,79 = 3.20, p = 0.046, partial η2 = 0.075). Glutamatergic metabolites did not change significantly over time in both nonresponders and responders over the 3 months of antipsychotic exposure (F1,31 = 1.26, p = 0.270, partial η2 = 0.039). We conclude that the use of antipsychotics without prior knowledge of later response delays symptom relief in a subgroup of first-episode patients, but does not worsen the glutamatergic excess seen at the baseline. Given the current practice of nonstratified use of antipsychotics, longer-time follow-up MRS studies are required to see if improvement in symptoms accompanies a dynamic shift in glutamate profile.

Motor performance and functional connectivity between the posterior cingulate cortex and supplementary motor cortex in bipolar and unipolar depression

Although implicated in unsuccessful treatment, psychomotor deficits and their neurobiological underpinnings in bipolar (BD) and unipolar (UD) depression remain poorly investigated. Here, we hypothesized that motor performance deficits in depressed patients would relate to basal functional coupling of the hand primary motor cortex (M1) and the posterior cingulate cortex (PCC) with the supplementary motor area (SMA). We performed a longitudinal, naturalistic study in BD, UD and matched healthy controls comprising of two resting-state functional MRI measurements five weeks apart and accompanying assessments of motor performance using a finger tapping task (FTT). A subject-specific seed-based analysis describing functional connectivity between PCC-SMA as well as M1-SMA was conducted. The basal relationships with motor performance were investigated using linear regression models and all measures were compared across groups. Performance in FTT was impaired in BD in comparison to HC in both sessions. Behavioral performance across groups correlated significantly with resting state functional coupling of PCC-SMA, but not of M1-SMA regions. This relationship was partially reflected in a reduced PCC-SMA connectivity in BD vs HC in the second session. Exploratory evaluation of large-scale networks coupling (SMN-DMN) exhibited no correlation to motor performance. Our results shed new light on the association between the degree of disruption in the SMA-PCC anticorrelation and the level of motor impairment in BD.

Enhanced amygdala-anterior cingulate white matter structural connectivity in Sahaja Yoga Meditators

OBJECTIVE

To study the white matter connections between anterior cingulate cortex, anterior insula and amygdala as key regions of the frontal-limbic network that have been related to meditation.

DESIGN

Twenty experienced practitioners of Sahaja Yoga Meditation and twenty nonmeditators matched on age, gender and education level, were scanned using Diffusion Weighted Imaging, using a 3T scanner, and their white matter connectivity was compared using diffusion tensor imaging analyses.

RESULTS

There were five white matter fiber paths in which meditators showed a larger number of tracts, two of them connecting the same area in both hemispheres: the left and right amygdalae and the left and right anterior insula; and the other three connecting left anterior cingulate with the right anterior insula, the right amygdala and the left amygdala. On the other hand, non-meditators showed larger number of tracts in two paths connecting the left anterior insula with the left amygdala, and the left anterior insula with the left anterior cingulate.

CONCLUSIONS

The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger white matter tracts strengthening interhemispheric connections between limbic regions and connections between cingulo-amygdalar and cingulo-insular brain regions related to top-down attentional and emotional processes as well as between top-down control functions that could potentially be related to the witness state perceived through the state of mental silence promoted with this meditation. On the other hand, reduced connectivity strength in left anterior insula in the meditation group could be associated to reduced emotional processing affecting top-down processes.

Toll-Like Receptor mRNA Levels in Schizophrenia: Association With Complement Factors and Cingulate Gyrus Cortical Thinning

BACKGROUND AND HYPOTHESES

Previous studies revealed innate immune system activation in people with schizophrenia (SZ), potentially mediated by endogenous pathogen recognition receptors, notably Toll-like receptors (TLR). TLRs are activated by pathogenic molecules like bacterial lipopolysaccharides (TLR1 and TLR4), viral RNA (TLR3), or both (TLR8). Furthermore, the complement system, another key component of innate immunity, has previously been linked to SZ.

STUDY DESIGN

Peripheral mRNA levels of TLR1, TLR3, TLR4, and TLR8 were compared between SZ and healthy controls (HC). We investigated their relationship with immune activation through complement expression and cortical thickness of the cingulate gyrus, a region susceptible to immunological hits. TLR mRNA levels and peripheral complement receptor mRNA were extracted from 86 SZ and 77 HC white blood cells; structural MRI scans were conducted on a subset.

STUDY RESULTS

We found significantly higher TLR4 and TLR8 mRNA levels and lower TLR3 mRNA levels in SZ compared to HC. TLRs and complemental factors were significantly associated in SZ and HC, with the strongest deviations of TLR mRNA levels in the SZ subgroup having elevated complement expression. Cortical thickness of the cingulate gyrus was inversely associated with TLR8 mRNA levels in SZ, and with TLR4 and TLR8 levels in HC.

CONCLUSIONS

The study underscores the role of innate immune activation in schizophrenia, indicating a coordinated immune response of TLRs and the complement system. Our results suggest there could be more bacterial influence (based on TLR 4 levels) as opposed to viral influence (based on TLR3 levels) in schizophrenia. Specific TLRs were associated with brain cortical thickness reductions of limbic brain structures.

GABA in the anterior cingulate cortex mediates the association of white matter hyperintensities with executive function: a magnetic resonance spectroscopy study

White matter hyperintensities (WMH) and gamma-aminobutyric acid (GABA) are associated with executive function. Multiple studies suggested cortical alterations mediate WMH-related cognitive decline. The aim of this study was to investigate the crucial role of cortical GABA in the WMH patients. In the 87 WMH patients (46 mild and 41 moderate to severe) examined in this study, GABA levels in the anterior cingulate cortex (ACC) and posterior cingulate cortex (PCC) assessed by the Meshcher-Garwood point resolved spectroscopy (MEGA-PRESS) sequence, WMH volume and executive function were compared between the two groups. Partial correlation and mediation analyses were carried out to examine the GABA levels in mediating the association between WMH volume and executive function. Patients with moderate to severe WMH had lower GABA+/Cr in the ACC (p = 0.034) and worse executive function (p = 0.004) than mild WMH patients. In all WMH cases, the GABA+/Cr levels in the ACC mediated the negative correlation between WMH and executive function (ab: effect = -0.020, BootSE = 0.010, 95% CI: -0.042 to -0.004). This finding suggested GABA+/Cr levels in the ACC might serve as a protective factor or potential target for preventing the occurrence and progression of executive function decline in WMH people.

Anterior cingulate and medial prefrontal cortex alcohol cue reactivity varies as a function of drink preference in alcohol use disorder

BACKGROUND

Functional MRI visual cue reactivity studies have not considered that brain responses to various alcohol-containing beverage types may vary as a function of an individual's drinking patterns and preferences. This study tested whether the brain's reward system responds differently to visual cues associated with an individuals' most commonly consumed ("preferred") alcohol beverage compared with less commonly consumed ("non-preferred") alcohol beverages in individuals with alcohol use disorder (AUD).

METHODS

Participants (N=70) with current AUD completed a standard visual alcohol cue reactivity procedure during fMRI and reported recent alcohol use through the Timeline Followback interview. Alcohol use patterns were used to infer drink preference. Repeated measure ANCOVAs were used to evaluate differences in subjective craving (alcohol urge) and neural reactivity to cues of individual's "preferred" versus "non-preferred" alcohol beverages.

RESULTS

Fifty-four (77%) participants were determined to have a "preferred" alcohol beverage, as defined by their pattern of alcohol use. These participants reported greater subjective alcohol urge (p=0.02) and activation in the anterior cingulate cortex (ACC) (p=0.005) and medial prefrontal cortex (mPFC) (p=0.001)) in response to visual cues associated with their "preferred" versus "non-preferred" alcohol beverage. Individuals with an alcohol preference did not differ from those with no alcohol preference on subjective or neural responses to their "preferred" and "non-preferred" alcohol cues.

DISCUSSION

Results suggest alcohol cue-elicited subjective and neural responses vary as a function of alcohol beverage preference in individuals with AUD and a behaviorally defined alcohol preference. Stronger ACC and mPFC activation may reflect greater subjective value of an individual's "preferred" alcohol beverage cue.

Cerebral glucose hypometabolism and hypoperfusion of cingulate gyrus: an imaging biomarker of autoimmune encephalitis with psychiatric symptoms

BACKGROUND

About 60% of autoimmune encephalitis (AE) patients present psychiatric symptoms, but the underlying mechanism remains unknown. This study examined the role of the cingulate cortex in such patients to identify predictive poor psychiatric factors.

METHODS

In this study, 49 AE patients and 39 healthy controls were enrolled. AE patients were further divided into two groups based on the presence/absence of psychiatric symptoms. The ratio of the standardized uptake value (SUVR) and relative cerebral blood flow (rCBF) in different regions of the cingulate cortex were calculated through positron emission tomography-computed tomography (PET/CT) and arterial spin labeling (ASL) MRI, and the results were compared among the three groups. In addition, we followed-up on the psychiatric outcomes and identified the risk factors for poor psychiatric prognosis, focusing on the cingulate cortex.

RESULTS

More than half of the AE patients (27/49) exhibited psychiatric symptoms. Agitation and thought blocking were typical psychiatric phenotypes, except for anti-glutamic acid decarboxylase 65 (GAD65) encephalitis, which mainly presented with catatonia and a depressed mood. AE patients with psychiatric symptoms experienced reduced metabolism and perfusion of the anterior cingulate cortex (ACC), midcingulate cortex (MCC), and posterior cingulate cortex (PCC). The SUVR of ACC can be used as an independent risk factor of poor psychiatric outcomes, which had an area under the ROC curve (AUC) of 0.865.

CONCLUSION

Impaired cingulate cortex function in AE may be the potential mechanism of psychiatric symptoms. Hypometabolism of ACC is an independent prognostic factor predicting an unfavorable psychiatric prognosis in AE.

Low-Intensity Focused Ultrasound to the Human Dorsal Anterior Cingulate Attenuates Acute Pain Perception and Autonomic Responses

The dorsal anterior cingulate cortex (dACC) is a critical brain area for pain and autonomic processing, making it a promising noninvasive therapeutic target. We leverage the high spatial resolution and deep focal lengths of low-intensity focused ultrasound (LIFU) to noninvasively modulate the dACC for effects on behavioral and cardiac autonomic responses using transient heat pain stimuli. A N = 16 healthy human volunteers (6 M/10 F) received transient contact heat pain during either LIFU to the dACC or Sham stimulation. Continuous electroencephalogram (EEG), electrocardiogram (ECG), and electrodermal response (EDR) were recorded. Outcome measures included pain ratings, heart rate variability, EDR response, blood pressure, and the amplitude of the contact heat-evoked potential (CHEP).LIFU reduced pain ratings by 1.09 ± 0.20 points relative to Sham. LIFU increased heart rate variability indexed by the standard deviation of normal sinus beats (SDNN), low-frequency (LF) power, and the low-frequency/high-frequency (LF/HF) ratio. There were no effects on the blood pressure or EDR. LIFU resulted in a 38.1% reduction in the P2 CHEP amplitude. Results demonstrate LIFU to the dACC reduces pain and alters autonomic responses to acute heat pain stimuli. This has implications for the causal understanding of human pain and autonomic processing in the dACC and potential future therapeutic options for pain relief and modulation of homeostatic signals.

The role of the thalamic subregions in major depressive disorder with childhood maltreatment: Evidences from dynamic and static functional connectivity

BACKGROUND

Major depressive disorder (MDD) with a history of childhood maltreatment represents a highly prevalent clinical phenotype. Previous studies have demonstrated functional alterations of the thalamus among MDD. However, no study has investigated the static and dynamic changes in functional connectivity (FC) within thalamic subregions among MDD with childhood maltreatment.

METHODS

This study included four groups: MDD with childhood maltreatment (n = 48), MDD without childhood maltreatment (n = 30), healthy controls with childhood maltreatment (n = 57), and healthy controls without childhood maltreatment (n = 46). Sixteen thalamic subregions were selected as seed to investigate group-differences in dynamic FC (dFC) and static FC (sFC). Correlation analyses were performed to assess the associations between abnormal FC and maltreatment severity. Eventually, moderation analyses were employed to explore the moderating role of abnormal FC in the relationship between maltreatment and depressive severity.

RESULTS

MDD with childhood maltreatment exhibit abnormal thalamic subregions FC compared to MDD without childhood maltreatment, characterized by abnormalities with the sFC of the rostral anterior cingulate cortex, with the dFC of the calcarine, middle cingulate cortex, precuneus cortex and superior temporal gyrus. Furthermore, sFC with the rostral anterior cingulate cortex and dFC with the middle cingulate cortex were correlated with the severity of maltreatment. Additionally, dFC with the superior temporal gyrus moderates the relationship between maltreatment and depression severity.

LIMITATIONS

The cross-sectional designs fail to infer causality.

CONCLUSIONS

Our findings support thalamic dysfunction as neurobiological features of childhood maltreatment as well as vulnerability to MDD.

Glucose metabolism in posterior cingulate cortex has supplementary value to predict the progression of cognitively unimpaired to dementia due to Alzheimer's disease: an exploratory study of 18F-FDG-PET

Amyloid-β (Aβ) and tau are important biomarkers to predict the progression of cognitively unimpaired (CU) to dementia due to Alzheimer's disease (AD), according to the diagnosis framework from the US National Institute on Aging and the Alzheimer's Association (NIA-AA). However, it is clinically difficult to predict those subjects who were already with Aβ positive (A +) or tau positive (T +). As a typical characteristic of neurodegeneration in the diagnosis framework, the hypometabolism of the posterior cingulate cortex (PCC) has significant clinical value in the early prediction and prevention of AD. In this paper, we proposed the glucose metabolism in the PCC as a biomarker supplement to Aβ and tau biomarkers. First, we calculated the standard uptake value ratio (SUVR) of PCC based on fluorodeoxyglucose positron emission computed tomography (FDG PET) imaging. Secondly, we performed Kaplan-Meier (KM) survival analyses to explore the predictive performance of PCC SUVR, and the hazard ratio (HR) was calculated. Finally, we performed Pearson correlation analyses to explore the physiological significance of PCC SUVR. As a result, the PCC SUVR showed a consistent downward trend along the AD continuum. KM analyses showed better predictive performance when we combined PCC SUVR with cerebro-spinal fluid (CSF) Aβ42 (from HR = 2.56 to 3.00 within 5 years; from HR = 2.76 to 4.20 within 10 years) and ptau-181 (from 2.83 to 3.91 within 5 years; from HR = 2.32 to 4.17 within 10 years). There was a slight correlation between Aβ42/Aβ40 and PCC SUVR (r = 0.14, p = 0.02). In addition, several cognition scales were also correlated to PCC SUVR (from r = -0.407 to 0.383, p < 0.05). Our results showed that glucose metabolism in PCC may be a potential biomarker supplement to the Aβ and tau biomarkers to predict the progression of CU to AD.

Abnormal causal connectivity of anterior cingulate cortex-visual cortex circuit related to nonsteroidal anti-inflammatory drug efficacy in migraine

The anterior cingulate cortex (ACC) and visual cortex are integral components of the neurophysiological mechanisms underlying migraine, yet the impact of altered connectivity patterns between these regions on migraine treatment remains unknown. To elucidate this issue, we investigated the abnormal causal connectivity between the ACC and visual cortex in patients with migraine without aura (MwoA), based on the resting-state functional magnetic resonance imaging data, and its predictive ability for the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs). The results revealed increased causal connectivity from the bilateral ACC to the lingual gyrus (LG) and decreased connectivity in the opposite direction in nonresponders compared with the responders. Moreover, compared with the healthy controls, nonresponders exhibited heightened causal connectivity from the ACC to the LG, right inferior occipital gyrus (IOG) and left superior occipital gyrus, while connectivity patterns from the LG and right IOG to the ACC were diminished. Based on the observed abnormal connectivity patterns, the support vector machine (SVM) models showed that the area under the receiver operator characteristic curves for the ACC to LG, LG to ACC and bidirectional models were 0.857, 0.898, and 0.939, respectively. These findings indicate that neuroimaging markers of abnormal causal connectivity in the ACC-visual cortex circuit may facilitate clinical decision-making regarding NSAIDs administration for migraine management.

Glutamate and GABA levels in the anterior cingulate cortex in treatment resistant first episode psychosis patients

BACKGROUND

Around 30 % of schizophrenia patients do not respond sufficiently to conventional antipsychotic treatment. Glutamate and γ-aminobutyric acid (GABA) may be implicated in treatment resistant (TR) patients. Some data indicate that TR patients show increased glutamate levels compared to responders, but findings are inconclusive and limited in the early disease stage. Furthermore, the two neurotransmitters have rarely been assessed in conjunction. We therefore aimed to investigate the role of GABA+ and glutamate in first episode TR patients and explore whether these neurometabolites could be potential predictive markers for TR schizophrenia.

STUDY DESIGN

We used proton magnetic resonance spectroscopy (MRS) to assess glutamate + glutamine (Glx) and GABA including macromolecules (GABA+) in the anterior cingulate cortex (ACC) of 58 first episode psychosis patients. At six months follow-up treatment response was determined and in a subgroup of 33 patients a follow-up MRS scan was acquired.

STUDY RESULTS

Glx and GABA+ levels were not significantly different between TR patients and responders at baseline and the levels did not change at six months follow-up. The groups differed in voxel fractions, which could have influenced our results even though we corrected for these differences.

CONCLUSIONS

Our findings do not provide evidence that ACC Glx or GABA+ levels are potential biomarkers for TR in first episode psychosis. Future research needs to take in to account voxel fractions and report potential differences. Comparison with previous literature suggests that illness duration, clozapine responsiveness and medication effects may partly explain the heterogeneous results on Glx and GABA+ levels in TR.

Structural and functional changes of anterior cingulate cortex subregions in migraine without aura: relationships with pain sensation and pain emotion

Migraine without aura is a multidimensional neurological disorder characterized by sensory, emotional, and cognitive symptoms linked to structural and functional abnormalities in the anterior cingulate cortex. Anterior cingulate cortex subregions play differential roles in the clinical symptoms of migraine without aura; however, the specific patterns and mechanisms remain unclear. In this study, voxel-based morphometry and seed-based functional connectivity were used to investigate structural and functional alterations in the anterior cingulate cortex subdivisions in 50 patients with migraine without aura and 50 matched healthy controls. Compared with healthy controls, patients exhibited (1) decreased gray matter volume in the subgenual anterior cingulate cortex, (2) increased functional connectivity between the bilateral subgenual anterior cingulate cortex and right middle frontal gyrus, and between the posterior part of anterior cingulate cortex and right middle frontal gyrus, orbital part, and (3) decreased functional connectivity between the anterior cingulate cortex and left anterior cingulate and paracingulate gyri. Notably, left subgenual anterior cingulate cortex was correlated with the duration of each attack, whereas the right subgenual anterior cingulate cortex was associated with migraine-specific quality-of-life questionnaire (emotion) and self-rating anxiety scale scores. Our findings provide new evidence supporting the hypothesis of abnormal anterior cingulate cortex subcircuitry, revealing structural and functional abnormalities in its subregions and emphasizing the potential involvement of the left subgenual anterior cingulate cortex-related pain sensation subcircuit and right subgenual anterior cingulate cortex -related pain emotion subcircuit in migraine.

Differences in Functional Activity and Connectivity in the Right Frontoparietal Network between Nurses Working Long-Term Shifts and Fixed Day Shifts

OBJECTIVES

To investigate the differences in functional brain activity and connectivity between nurses working long-term shifts and fixed day shift and explore their correlations with work-related psychological conditions.

METHODS

Thirty-five nurses working long-term shifts and 35 nurses working fixed day shifts were recruited. After assessing work-related psychological conditions, such as burnout and perceived stress of these two groups of nurses, amplitude of low-frequency fluctuations (ALFF) and functional connectivity (FC) analyses were performed to investigate the between-group differences in brain functional activity and connectivity. Furthermore, correlation analysis between the ALFF/FC metrics and psychological conditions was conducted.

RESULTS

Compared with nurses working fixed day shifts, nurses working long-term shifts showed higher levels of burnout, perceived stress, and depression scores; lower z-transformed ALFF (zALFF) values in the right dorsolateral prefrontal cortex (dlPFC), right superior parietal lobule (SPL), and right anterior cingulate cortex (ACC); and higher zALFF values in the right middle temporal gyrus (voxel-level p < 0.001, cluster-level p < 0.05, gaussian random field (GRF) correction), as well as lower FC values in the right dlPFC-right SPL and right dlPFC-right ACC (p < 0.05, false discovery rate (FDR) corrected). Moreover, the FC values in the right dlPFC-right SPL were negatively correlated with the perceived stress score in nurses working long-term shifts (p < 0.05, FDR corrected).

CONCLUSIONS

This study demonstrated that nurses working long-term shifts had lower functional activity and weaker functional connectivity in the right frontoparietal network, which mainly includes the right dlPFC and right SPL, than those working on regular day shift. The current findings provide new insights into the impacts of long-term shift work on nurses' mental health from a functional neuroimaging perspective.

Altered task-related decoupling of the rostral anterior cingulate cortex in depression

Dysfunctional activity of the rostral anterior cingulate cortex (rACC) - an extensively connected hub region of the default mode network - has been broadly linked to cognitive and affective impairments in depression. However, the nature of aberrant task-related rACC suppression in depression is incompletely understood. In this study, we sought to characterize functional connectivity of rACC activity suppression ('deactivation') - an essential feature of rACC function - during external task engagement in depression. Specifically, we aimed to explore neural patterns of functional decoupling and coupling with the rACC during its task-driven suppression. We enrolled 81 15- to 25-year-old young people with moderate-to-severe major depressive disorder (MDD) before they commenced a 12-week clinical trial that assessed the effectiveness of cognitive behavioral therapy plus either fluoxetine or placebo. Ninety-four matched healthy controls were also recruited. Participants completed a functional magnetic resonance imaging face matching task known to elicit rACC suppression. To identify brain regions associated with the rACC during its task-driven suppression, we employed a seed-based functional connectivity analysis. We found MDD participants, compared to controls, showed significantly reduced 'decoupling' of the rACC with extended task-specific regions during task performance. Specifically, less decoupling was observed in the occipital and fusiform gyrus, dorsal ACC, medial prefrontal cortex, cuneus, amygdala, thalamus, and hippocampus. Notably, impaired decoupling was apparent in participants who did not remit to treatment, but not treatment remitters. Further, we found MDD participants showed significant increased coupling with the anterior insula cortex during task engagement. Our findings indicate that aberrant task-related rACC suppression is associated with disruptions in adaptive neural communication and dynamic switching between internal and external cognitive modes that may underpin maladaptive cognitions and biased emotional processing in depression.

Reduced functional connectivity of the right dorsolateral prefrontal cortex at rest in obsessive-compulsive disorder

BACKGROUND

Neuroimaging studies have revealed the role of the right dorsolateral prefrontal cortex (DLPFC) in the neurobiological mechanism of obsessive-compulsive disorder (OCD). However, only a few studies have examined the functional connectivity (FC) pattern of the right DLPFC at rest in OCD.

OBJECTIVE

The aim of this research is to examine the FC patterns of the right DLPFC at rest in OCD.

METHODS

Twenty-eight medication-free patients with OCD and 20 healthy controls underwent resting-state functional magnetic resonance imaging. Seed-based FC and support vector machine (SVM) were used to analyze the imaging data.

RESULTS

The patients with OCD showed reduced FC values in the right middle temporal gyrus (MTG), right superior temporal gyrus, right ventral anterior cingulate cortex (vACC), and left Crus II. No brain regions showed a remarkable difference in FC values in patients with OCD after 8 weeks of medication treatment. The reduced right DLPFC-right MTG and right DLPFC-right vACC connectivities were correlated with the clinical symptoms of OCD. SVM results showed that reduced right DLPFC-right MTG connectivity at rest could predict the therapeutic response to OCD medication.

CONCLUSIONS

The findings highlight the important role of the right DLPFC in the pathophysiological mechanism of OCD.

Task fMRI studies investigating inhibitory control in patients with obsessive-compulsive disorder and eating disorders: A comparative meta-analysis

BACKGROUND

Obsessive-compulsive disorder (OCD) and eating disorders (EDs) share similarities in terms of clinical characteristics and deficits in inhibitory control.

OBJECTIVE

To investigate whether inhibitory control could serve as a common behavioural phenotype between OCD and EDs and whether it might be underpinned by shared and/or distinct neural signatures.

METHOD

We performed a quantitative meta-analysis of brain function abnormalities during the inhibitory control task-based functional Magnetic Resonance Imaging (fMRI) scan across patients with OCD and EDs using seed-based d mapping (SDM).

RESULTS

The meta-analysis included sixteen OCD fMRI studies and ten EDs fMRI studies. And findings revealed that patients with OCD showed hypoactivation relative to healthy controls and patients with EDs in the anterior cingulate cortex, while compared to healthy controls and patients with OCD, patients with EDs showed hypoactivation in the right insula.

CONCLUSIONS

Patients with OCD and EDs are inclined to exhibit impaired inhibitory control, which may be attributed to different abnormal patterns of neural activation.

The intra-individual reliability of 1 H-MRS measurement in the anterior cingulate cortex across 1 year

Magnetic resonance spectroscopy (MRS) is the primary method that can measure the levels of metabolites in the brain in vivo. To achieve its potential in clinical usage, the reliability of the measurement requires further articulation. Although there are many studies that investigate the reliability of gamma-aminobutyric acid (GABA), comparatively few studies have investigated the reliability of other brain metabolites, such as glutamate (Glu), N-acetyl-aspartate (NAA), creatine (Cr), phosphocreatine (PCr), or myo-inositol (mI), which all play a significant role in brain development and functions. In addition, previous studies which predominately used only two measurements (two data points) failed to provide the details of the time effect (e.g., time-of-day) on MRS measurement within subjects. Therefore, in this study, MRS data located in the anterior cingulate cortex (ACC) were repeatedly recorded across 1 year leading to at least 25 sessions for each subject with the aim of exploring the variability of other metabolites by using the index coefficient of variability (CV); the smaller the CV, the more reliable the measurements. We found that the metabolites of NAA, tNAA, and tCr showed the smallest CVs (between 1.43% and 4.90%), and the metabolites of Glu, Glx, mI, and tCho showed modest CVs (between 4.26% and 7.89%). Furthermore, we found that the concentration reference of the ratio to water results in smaller CVs compared to the ratio to tCr. In addition, we did not find any time-of-day effect on the MRS measurements. Collectively, the results of this study indicate that the MRS measurement is reasonably reliable in quantifying the levels of metabolites.

Children with maltreatment exposure exhibit rumination-like spontaneous thought patterns: association with symptoms of depression, subcallosal cingulate cortex thickness, and cortisol levels

BACKGROUND

Childhood maltreatment is associated with pervasive risk for depression. However, the immediate cognitive and neural mechanisms that mediate this risk during development are unknown. We here studied the impact of maltreatment on self-generated thought (SGT) patterns and their association with depressive symptoms, subcallosal cingulate cortex (SCC) thickness, and cortisol levels in children.

METHODS

We recruited 183 children aged 6-12 years, 96 of which were exposed to maltreatment. Children performed a mind wandering task to elicit SGTs. A subgroup of children underwent structural magnetic resonance imaging (N = 155) for SCC thickness analyses and saliva collection for quantification of free cortisol concentrations (N = 126) was collected. Using network analysis, we assessed thought networks and compared these networks between children with and without maltreatment exposure. Using multilevel analyses, we then tested the association between thought networks of children with maltreatment exposure with depressive symptoms, SCC thickness, and cortisol levels.

RESULTS

Children exposed to maltreatment generated fewer positively valenced thoughts. Network analysis revealed rumination-like thought patterns in children with maltreatment exposure, which were associated with depressive symptoms, SCC thickness, and cortisol levels. Children with maltreatment exposure further exhibited decreased future-self thought coupling, which was associated with depressive symptoms, while other-related and past-oriented thoughts had the greatest importance within the network.

CONCLUSIONS

Using a novel network analytic approach, we provide evidence that children exposed to maltreatment exhibit ruminative clustering of thoughts, which is associated with depressive symptoms and neurobiological correlates of depression. Our results provide a specific target for clinical translation to design early interventions for middle childhood. Targeting thought patterns in children with maltreatment exposure may be an effective strategy to effectively mitigate depression risk early in life.

Neural mechanisms of acceptance-commitment therapy for obsessive-compulsive disorder: a resting-state and task-based fMRI study

BACKGROUND

There is growing evidence for the use of acceptance-commitment therapy (ACT) for the treatment of obsessive-compulsive disorder (OCD). However, few fully implemented ACT have been conducted on the neural mechanisms underlying its effect on OCD. Thus, this study aimed to elucidate the neural correlates of ACT in patients with OCD using task-based and resting-state functional magnetic resonance imaging (fMRI).

METHODS

Patients with OCD were randomly assigned to the ACT (n = 21) or the wait-list control group (n = 21). An 8-week group-format ACT program was provided to the ACT group. All participants underwent an fMRI scan and psychological measurements before and after 8 weeks.

RESULTS

Patients with OCD showed significantly increased activation in the bilateral insula and superior temporal gyri (STG), induced by the thought-action fusion task after ACT intervention. Further psycho-physiological interaction analyses with these regions as seeds revealed that the left insular-left inferior frontal gyrus (IFG) connectivity was strengthened in the ACT group after treatment. Increased resting-state functional connectivity was also found in the posterior cingulate cortex (PCC), precuneus, and lingual gyrus after ACT intervention Most of these regions showed significant correlations with ACT process measures while only the right insula was correlated with the obsessive-compulsive symptom measure.

CONCLUSIONS

These findings suggest that the therapeutic effect of ACT on OCD may involve the salience and interoception processes (i.e. insula), multisensory integration (i.e. STG), language (i.e. IFG), and self-referential processes (i.e. PCC and precuneus). These areas or their interactions could be important for understanding how ACT works psychologically.

Empathy-related differences in the anterior cingulate functional connectivity of regular cannabis users when compared to controls

It has been reported that cannabis consumption affects the anterior cingulate cortex (ACC), a structure with a central role in mediating the empathic response. In this study, we compared psychometric scores of empathy subscales, between a group of regular cannabis users (85, users) and a group of non-consumers (51, controls). We found that users have a greater Emotional Comprehension, a cognitive empathy trait involving the understanding of the "other" emotional state. Resting state functional MRI in a smaller sample (users = 46, controls = 34) allowed to identify greater functional connectivity (FC) of the ACC with the left somatomotor cortex (SMC), in users when compared to controls. These differences were also evident within the empathy core network, where users showed greater within network FC. The greater FC showed by the users is associated with emotional representational areas and empathy-related regions. In addition, the differences in psychometric scores suggest that users have more empathic comprehension. These findings suggest a potential association between cannabis use, a greater comprehension of the other's affective state and the functional brain organization of the users. However, further research is needed to explore such association, since many other factors may be at play.

Pain-preferential thalamocortical neural dynamics across species

Searching for pain-preferential neural activity is essential for understanding and managing pain. Here, we investigated the preferential role of thalamocortical neural dynamics in encoding pain using human neuroimaging and rat electrophysiology across three studies. In study 1, we found that painful stimuli preferentially activated the medial-dorsal (MD) thalamic nucleus and its functional connectivity with the dorsal anterior cingulate cortex (dACC) and insula in two human functional magnetic resonance imaging (fMRI) datasets (n = 399 and n = 25). In study 2, human fMRI and electroencephalography fusion analyses (n = 220) revealed that pain-preferential MD responses were identified 89-295 ms after painful stimuli. In study 3, rat electrophysiology further showed that painful stimuli preferentially activated MD neurons and MD-ACC connectivity. These converging cross-species findings provided evidence for pain-preferential thalamocortical neural dynamics, which could guide future pain evaluation and management strategies.

Sleep Deficits Inter-Link Lower Basal Forebrain-Posterior Cingulate Connectivity and Perceived Stress and Anxiety Bidirectionally in Young Men

BACKGROUND

The basal nucleus of Meynert (BNM), a primary source of cholinergic projections to the cortex, plays key roles in regulating the sleep-wake cycle and attention. Sleep deficit is associated with impairment in cognitive and emotional functions. However, whether or how cholinergic circuit, sleep, and cognitive/emotional dysfunction are inter-related remains unclear.

METHODS

We curated the Human Connectome Project data and explored BNM resting state functional connectivities (rsFC) in relation to sleep deficit, based on the Pittsburgh Sleep Quality Index (PSQI), cognitive performance, and subjective reports of emotional states in 687 young adults (342 women). Imaging data were processed with published routines and evaluated at a corrected threshold. We assessed the correlation between BNM rsFC, PSQI, and clinical measurements with Pearson regressions and their inter-relationships with mediation analyses.

RESULTS

In whole-brain regressions with age and alcohol use severity as covariates, men showed lower BNM rsFC with the posterior cingulate cortex (PCC) in correlation with PSQI score. No clusters were identified in women at the same threshold. Both BNM-PCC rsFC and PSQI score were significantly correlated with anxiety, perceived stress, and neuroticism scores in men. Moreover, mediation analyses showed that PSQI score mediated the relationship between BNM-PCC rsFC and these measures of negative emotions bidirectionally in men.

CONCLUSIONS

Sleep deficit is associated with negative emotions and lower BNM rsFC with the PCC. Negative emotional states and BNM-PCC rsFC are bidirectionally related through poor sleep quality. These findings are specific to men, suggesting potential sex differences in the neural circuits regulating sleep and emotional states.

Proof-of-concept recall-by-genotype study of extremely low and high Alzheimer's polygenic risk reveals autobiographical deficits and cingulate cortex correlates

BACKGROUND

Genome-wide association studies demonstrate that Alzheimer's disease (AD) has a highly polygenic architecture, where thousands of independent genetic variants explain risk with high classification accuracy. This AD polygenic risk score (AD-PRS) has been previously linked to preclinical cognitive and neuroimaging features observed in asymptomatic individuals. However, shared variance between AD-PRS and neurocognitive features are small, suggesting limited preclinical utility.

METHODS

Here, we recruited sixteen clinically asymptomatic individuals (mean age 67; range 58-76) with either extremely low / high AD-PRS (defined as at least 2 standard deviations from the wider sample mean (N = 4504; N EFFECTIVE = 90)) with comparable age sex and education level. We assessed group differences in autobiographical memory and T1-weighted structural neuroimaging features.

RESULTS

We observed marked reductions in autobiographical recollection (Cohen's d =  - 1.66; P FDR = 0.014) and midline structure (cingulate) thickness (Cohen's d =  - 1.55, P FDR = 0.05), with no difference in hippocampal volume (P > 0.3). We further confirm the negative association between AD-PRS and cingulate thickness in a larger study with a comparable age (N = 31,966, β =  - 0.002, P = 0.011), supporting the validity of our approach.

CONCLUSIONS

These observations conform with multiple streams of prior evidence suggesting alterations in cingulate structures may occur in individuals with higher AD genetic risk. We were able to use a genetically informed research design strategy that significantly improved the efficiency and power of the study. Thus, we further demonstrate that the recall-by-genotype of AD-PRS from wider samples is a promising approach for the detection, assessment, and intervention in specific individuals with increased AD genetic risk.

Early-in-life isoflurane exposure alters resting-state functional connectivity in juvenile non-human primates

BACKGROUND

Clinical studies suggest that anaesthesia exposure early in life affects neurobehavioural development. We designed a non-human primate (NHP) study to evaluate cognitive, behavioural, and brain functional and structural alterations after isoflurane exposure during infancy. These NHPs displayed decreased close social behaviour and increased astrogliosis in specific brain regions, most notably in the amygdala. Here we hypothesise that resting-state functional connectivity MRI can detect alterations in connectivity of brain areas that relate to these social behaviours and astrogliosis.

METHODS

Imaging was performed in 2-yr-old NHPs under light anaesthesia, after early-in-life (postnatal days 6-12) exposure to 5 h of isoflurane either one or three times, or to room air. Brain images were segmented into 82 regions of interest; the amygdala and the posterior cingulate cortex were chosen for a seed-based resting-state functional connectivity MRI analysis.

RESULTS

We found differences between groups in resting-state functional connectivity of the amygdala and the auditory cortices, medial premotor cortex, and posterior cingulate cortex. There were also alterations in resting-state functional connectivity between the posterior cingulate cortex and secondary auditory, polar prefrontal, and temporal cortices, and the anterior insula. Relationships were identified between resting-state functional connectivity alterations and the decrease in close social behaviour and increased astrogliosis.

CONCLUSIONS

Early-in-life anaesthesia exposure in NHPs is associated with resting-state functional connectivity alterations of the amygdala and the posterior cingulate cortex with other brain regions, evident at the juvenile age of 2 yr. These changes in resting-state functional connectivity correlate with the decrease in close social behaviour and increased astrogliosis. Using resting-state functional connectivity MRI to study the neuronal underpinnings of early-in-life anaesthesia-induced behavioural alterations could facilitate development of a biomarker for anaesthesia-induced developmental neurotoxicity.

Structural and functional connectivity alteration patterns of the cingulate gyrus in Type 2 diabetes

OBJECTIVE

We aimed to reveal the role of structural and functional alterations of cingulate gyrus in early cognitive impairment in Type 2 diabetes mellitus (T2DM) patients.

METHODS

Fifty-six T2DM patients and 60 healthy controls (HCs) underwent a neuropsychological assessment and sagittal three-dimensional T1-weighted and resting-state functional MRI. Differences in the cortical thickness of the cingulate cortex and the functional connectivity (FC) of the nine subregions of the cingulate gyrus and the whole brain were compared between T2DM patients and HCs. Correlation analysis was performed between cortex thickness and FC and the participants' clinical/cognitive variables.

RESULTS

The cortical thickness of the cingulate gyrus was not significantly different between T2DM patients and HCs. However, the T2DM patients showed significantly lower FC between the pregenual ACC (pACC) and the bilateral hippocampus, significantly higher FC between the pACC and bilateral lateral prefrontal cortex (LPFC) and left precentral gyrus, and significantly lower FC between the retrosplenial cortex (RSC) and right cerebellar Crus I. The FC between the pACC and the left hippocampus was negatively correlated with the FC between the pACC and LPFC (r = -0.306, p = 0.022).

INTERPRETATION

The pACC and the RSC show dysfunctional connectivity before the appearance of structural abnormalities in T2DM patients. Abnormal FC of the pACC with the bilateral hippocampus and LPFC may imply a neural compensatory mechanism for memory function. These findings provide valuable information and new directions for possible interventions for the T2DM-related cognitive impairment.

Dynamic evolution of the anterior cingulate-insula network during seizures

OBJECTIVES

In physiological situations, the anterior cingulate cortex (ACC) and anterior insular cortex (AIC) are prone to coactivation. The functional connectivity and interaction between ACC and AIC in the context of epilepsy remain unclear. This study aimed to investigate the dynamic coupling between these two brain regions during seizures.

METHODS

Patients who underwent stereoelectroencephalography (SEEG) recording were included in this study. The SEEG data were visually inspected and quantitatively analyzed. The narrowband oscillations and aperiodic components at seizure onset were parameterized. The frequency-specific non-linear correlation analysis was applied to the functional connectivity. The excitation/inhibition ratio (E:I ratio) reflected by the aperiodic slope was performed to evaluate the excitability.

RESULTS

Twenty patients were included in the study, with 10 diagnosed with anterior cingulate epilepsy and 10 with anterior insular epilepsy. In both types of epilepsy, the correlation coefficient (h2 ) between the ACC and AIC at seizure onset exhibited a significantly higher value than that during interictal and preictal periods (p < 0.05). The direction index (D) showed a significant increase at seizure onset, serving as an indicator for the direction of information flow between these two brain regions with up to 90% accuracy. The E:I ratio increased significantly at seizure onset, with the seizure-onset zone (SOZ) demonstrating a more pronounced increase compared to non-SOZ (p < 0.05). For seizures originating from AIC, the E:I ratio was significantly higher in the AIC than in the ACC (p = 0.0364).

CONCLUSIONS

In the context of epilepsy, the ACC and AIC are dynamically coupled during seizures. The functional connectivity and excitability exhibit a significant increase at seizure onset. By analyzing connectivity and excitability, the SOZ in ACC and AIC can be identified. The direction index (D) serves as an indicator for the direction of information flow from SOZ to non-SOZ. Notably, the excitability of SOZ changes more significantly than that of non-SOZ.

Decreased cortical gyrification in major depressive disorder

BACKGROUND

Early neurodevelopmental deviations, such as abnormal cortical folding patterns, are candidate biomarkers of major depressive disorder (MDD). We aimed to investigate the association of MDD with the local gyrification index (LGI) in each cortical region at the whole-brain level, and the association of the LGI with clinical characteristics of MDD.

METHODS

We obtained T1-weighted images from 234 patients with MDD and 215 healthy controls (HCs). The LGI values from 66 cortical regions in the bilateral hemispheres were automatically calculated according to the Desikan-Killiany atlas. We compared the LGI values between the MDD and HC groups using analysis of covariance, including age, sex, and years of education as covariates. The association between the clinical characteristics and LGI values was investigated in the MDD group.

RESULTS

Compared with HCs, patients with MDD showed significantly decreased LGI values in the cortical regions, including the bilateral ventrolateral and dorsolateral prefrontal cortices, medial and lateral orbitofrontal cortices, insula, right rostral anterior cingulate cortex, and several temporal and parietal regions, with the largest effect size in the left pars triangularis (Cohen's f2 = 0.361; p = 1.78 × 10-13). Regarding the association of clinical characteristics with LGIs within the MDD group, recurrence and longer illness duration were associated with increased gyrification in several occipital and temporal regions, which showed no significant difference in LGIs between the MDD and HC groups.

CONCLUSIONS

These findings suggest that the LGI may be a relatively stable neuroimaging marker associated with MDD predisposition.

Resting-State Functional Connectivity of the Anterior Cingulate Cortex Among Persons With Mood Disorders and Suicidal Behaviors

OBJECTIVE

To assess whether anterior cingulate cortex (ACC) abnormalities contribute to suicide risk in major depressive disorder and bipolar disorder, the investigators compared resting-state functional connectivity (rsFC) of ACC subdivisions between individuals with major depressive or bipolar disorder with and without a lifetime history of suicidal behavior.

METHODS

Forty-two inpatients with and 26 inpatients without a history of suicidal behavior (SB+ and SB-, respectively) associated with major depressive or bipolar disorder and 40 healthy control (HC) participants underwent rsFC neuroimaging. RsFC of the subgenual, perigenual, rostral, dorsal, and caudal subdivisions of the ACC was calculated. Possible confounders, such as psychosis and severity of depression, were controlled for, seed-to-voxel and post hoc region of interest (ROI)-to-ROI analyses were performed, and the accuracy of rsFC in classifying suicidal behavior was studied.

RESULTS

Compared with individuals in the SB- and HC groups, patients in the SB+ group had higher rsFC between the left rostral and right dorsal ACC seeds and visual cortex clusters. Conversely, rsFC between the left rostral and right dorsal ACC seeds and cingulate and frontal clusters was lower in the SB+ group than in the HC group. Left rostral ACC to left Brodmann's area 18 connectivity showed up to 75% discriminative accuracy in distinguishing SB+ from SB- patients.

CONCLUSIONS

A history of suicidal behavior among individuals with major depressive disorder or bipolar disorder was associated with altered rsFC of the rostral and caudal ACC, regions involved in conflict detection and error monitoring. Replication of these findings is needed to further explore the involvement of the ACC in the neurobiology of suicidal behavior and suicidal ideation.

Anterior cingulate metabolite levels, memory, and inhibitory control in abstinent men and women with alcohol use disorder

Alcohol use disorder (AUD) has been shown to have harmful cognitive and physiological effects, including altered brain chemistry. Further, although men and women may differ in vulnerability to the neurobiological effects of AUD, the results of existing studies have been conflicting. We examined brain metabolite levels and cognitive functions in a cross-section of men with AUD (AUDm) and women with AUD (AUDw) to determine the degree of abnormalities after extended periods of abstinence (mean, 6 years) and to evaluate gender differences in neuropsychological and metabolite measures. Participants were 40 abstinent individuals with AUD (22 AUDw, 18 AUDm) and 50 age-equivalent non-AUD comparison participants (26 NCw, 24 NCm). Proton magnetic resonance spectroscopy (MRS) was employed at 3 Tesla to acquire metabolite spectra from the dorsal anterior cingulate cortex (dACC). Brain metabolites N-acetyl aspartate (NAA), choline (Cho), myo-Inositol (mI), and glutamate & glutamine (Glx) were examined relative to measures of memory and inhibitory control. Metabolite levels did not differ significantly between AUD and NC groups. Memory and inhibitory-control impairments were observed in the AUD group. There also were significant group-specific associations between metabolite ratios and measures of inhibitory control. There were no group-by-gender interactions for the four metabolite ratios. These findings demonstrate that brain metabolite levels in men and women with AUD, following long-term abstinence, do not differ from individuals without AUD. The data also provide preliminary evidence of sustained associations between metabolite levels and measures of inhibitory control, a functional domain important for curtailing harmful drinking.

Circadian misalignment alters resting-state functional connectivity of the salience network in rotating shift workers

STUDY OBJECTIVES

This study compared resting-state functional connectivity (rsFC) of the salience network (SN) between rotating shift workers (RSWs) and controls. Furthermore, we examined whether rsFC of the SN was correlated with sleep, emotion, cognition, and attention.

METHODS

The 60 RSWs and 57 controls enrolled in this study completed self-report questionnaires and sleep diaries to assess subjective sleep quality, and polysomnography and actigraphy to evaluate objective sleep and 24-hour rest-activity rhythm parameters. The participants also underwent resting-state functional magnetic resonance imaging and structural T1 scans. We performed a seed-based rsFC analysis of the SN using the anterior cingulate cortex (ACC) and anterior insula (AI) as seed regions. Furthermore, AI and ACC rsFC were compared in RSWs and controls, and we analyzed correlations between rsFC and variables of interest showing significant group differences.

RESULTS

Compared with controls, RSWs showed reduced rsFC between the ACC and right insula, and increased rsFC of the ACC with the left occipital lobe and right superior frontal gyrus extending to the supplementary motor area (SFG/SMA). Moreover, RSWs showed reduced rsFC between the right AI and right superior parietal lobule (SPL). Finally, rsFC between the ACC and right AI was correlated with 24-hour rest-activity rhythmicity.

CONCLUSIONS

Although RSWs did not show sleep disturbance, emotional distress, cognitive impairment, or attention deficits, alterations of right insula, left occipital lobe, right SFG/SMA, and right SPL rsFC in the SN indicate that impairments in salience detection and top-down attentional control may emerge in shift workers over time.

Social Regulation of the Neural Threat Response Predicts Subsequent Markers of Physical Health

OBJECTIVE

Social support has been linked to a vast range of beneficial health outcomes. However, the physiological mechanisms of social support are not well characterized. Drawing on functional magnetic resonance imaging and health-related outcome data, this study aimed to understand how neural measures of "yielding"-the reduction of brain activity during social support-moderate the link between social support and health.

METHODS

We used a data set where 78 participants around the age of 24 years were exposed to the threat of shock when holding the hand of a partner. At ages 28 to 30 years, participants returned for a health visit where inflammatory activity and heart rate variability were recorded.

RESULTS

Findings showed a significant interaction between dorsal anterior cingulate cortex-related yielding and perceived social support on C-reactive protein levels ( β = -0.95, SE = 0.42, z = -2.24, p = .025, 95% confidence interval = -1.77 to -0.12). We also found a significant interaction between hypothalamus-related yielding and perceived social support on baseline heart rate variability ( β = 0.51, SE = 0.23, z = 2.19, p = .028, 95% confidence interval = 0.05 to 0.97).

CONCLUSIONS

Greater perceived social support was associated with lower C-reactive protein levels and greater baseline heart rate variability among individuals who were more likely to yield to social support in the dorsal anterior cingulate cortex and hypothalamus years earlier. The current study highlights the construct of yielding in the link between social support and physical health.

Neuroimaging Insights: Kava's (Piper methysticum) Effect on Dorsal Anterior Cingulate Cortex GABA in Generalized Anxiety Disorder

Generalised Anxiety Disorder (GAD) is a prevalent, chronic mental health disorder. The measurement of regional brain gamma-aminobutyric acid (GABA) offers insight into its role in anxiety and is a potential biomarker for treatment response. Research literature suggests Piper methysticum (Kava) is efficacious as an anxiety treatment, but no study has assessed its effects on central GABA levels. This study investigated dorsal anterior cingulate (dACC) GABA levels in 37 adult participants with GAD. GABA was measured using proton magnetic resonance spectroscopy (1H-MRS) at baseline and following an eight-week administration of Kava (standardised to 120 mg kavalactones twice daily) (n = 20) or placebo (n = 17). This study was part of the Kava for the Treatment of GAD (KGAD; ClinicalTrials.gov: NCT02219880), a 16-week intervention study. Compared with the placebo group, the Kava group had a significant reduction in dACC GABA (p = 0.049) at eight weeks. Baseline anxiety scores on the HAM-A were positively correlated with GABA levels but were not significantly related to treatment. Central GABA reductions following Kava treatment may signal an inhibitory effect, which, if considered efficacious, suggests that GABA levels are modulated by Kava, independent of reported anxiety symptoms. dACC GABA patterns suggest a functional role of higher levels in clinical anxiety but warrants further research for symptom benefit. Findings suggest that dACC GABA levels previously un-examined in GAD could serve as a biomarker for diagnosis and treatment response.

Mindfulness-based real-time fMRI neurofeedback: a randomized controlled trial to optimize dosing for depressed adolescents

BACKGROUND

Adolescence is characterized by a heightened vulnerability for Major Depressive Disorder (MDD) onset, and currently, treatments are only effective for roughly half of adolescents with MDD. Accordingly, novel interventions are urgently needed. This study aims to establish mindfulness-based real-time fMRI neurofeedback (mbNF) as a non-invasive approach to downregulate the default mode network (DMN) in order to decrease ruminatory processes and depressive symptoms.

METHODS

Adolescents (N = 90) with a current diagnosis of MDD ages 13-18-years-old will be randomized in a parallel group, two-arm, superiority trial to receive either 15 or 30 min of mbNF with a 1:1 allocation ratio. Real-time neurofeedback based on activation of the frontoparietal network (FPN) relative to the DMN will be displayed to participants via the movement of a ball on a computer screen while participants practice mindfulness in the scanner. We hypothesize that within-DMN (medial prefrontal cortex [mPFC] with posterior cingulate cortex [PCC]) functional connectivity will be reduced following mbNF (Aim 1: Target Engagement). Additionally, we hypothesize that participants in the 30-min mbNF condition will show greater reductions in within-DMN functional connectivity (Aim 2: Dosing Impact on Target Engagement). Aim 1 will analyze data from all participants as a single-group, and Aim 2 will leverage the randomized assignment to analyze data as a parallel-group trial. Secondary analyses will probe changes in depressive symptoms and rumination.

DISCUSSION

Results of this study will determine whether mbNF reduces functional connectivity within the DMN among adolescents with MDD, and critically, will identify the optimal dosing with respect to DMN modulation as well as reduction in depressive symptoms and rumination.

TRIAL REGISTRATION

This study has been registered with clinicaltrials.gov, most recently updated on July 6, 2023 (trial identifier: NCT05617495).

Spectroscopic abnormalities in the pregenual anterior cingulate cortex in obsessive-compulsive disorder using proton magnetic resonance spectroscopy: a controlled study

BACKGROUND

The main aim of the present study is to determine the role of metabolites observed using proton magnetic resonance spectroscopy (1H-MRS) in obsessive-compulsive disorder (OCD). As the literature describing biochemical changes in OCD yields conflicting results, we focused on accurate metabolite quantification of total N-acetyl aspartate (tNAA), total creatine (tCr), total choline-containing compounds (tCh), and myo-inositol (mI) in the anterior cingulate cortex (ACC) to capture the small metabolic changes between OCD patients and controls and between OCD patients with and without medication.

METHODS

In total 46 patients with OCD and 46 healthy controls (HC) matched for age and sex were included in the study. The severity of symptoms in the OCD was evaluated on the day of magnetic resonance imaging (MRI) using the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Subjects underwent 1H-MRS from the pregenual ACC (pgACC) region to calculate concentrations of tNAA, tCr, tCho, and mI. Twenty-eight OCD and 28 HC subjects were included in the statistical analysis. We compared differences between groups for all selected metabolites and in OCD patients we analyzed the relationship between metabolite levels and symptom severity, medication status, age, and the duration of illness.

RESULTS

Significant decreases in tCr (U = 253.00, p = 0.022) and mI (U = 197.00, p = 0.001) in the pgACC were observed in the OCD group. No statistically significant differences were found in tNAA and tCho levels; however, tCho revealed a trend towards lower concentrations in OCD patients (U = 278.00, p = 0.062). Metabolic concentrations showed no significant correlations with the age and duration of illness. The correlation statistics found a significant negative correlation between tCr levels and YBOCS compulsions subscale (cor = -0.380, p = 0.046). tCho and YBOCS compulsions subscale showed a trend towards a negative correlation (cor = -0.351, p = 0.067). Analysis of subgroups with or without medication showed no differences.

CONCLUSIONS

Patients with OCD present metabolic disruption in the pgACC. The decrease in tCr shows an important relationship with OCD symptomatology. tCr as a marker of cerebral bioenergetics may also be considered as a biomarker of the severity of compulsions. The study failed to prove that metabolic changes correlate with the medication status or the duration of illness. It seems that a disruption in the balance between these metabolites and their transmission may play a role in the pathophysiology of OCD.

Assessment of neurotransmitter imbalances within the anterior cingulate cortex in women with primary dysmenorrhea: An initial proton magnetic resonance spectroscopy study

PURPOSE

The neural pathophysiology underlying primary dysmenorrhea (PDM), which leads to poor mode and changes in central pain modulatory systems, remains largely unknown. The objective of this study was to investigate the changes in glutamate/glutamine (Glx) and gamma-aminobutyric acid (GABA+) levels within anterior cingulate cortex (ACC), and their associations with clinical indicators in PDM women.

METHODS

Using 3 T proton magnetic resonance spectroscopy (1H-MRS), we acquired and compared ACC-Glx and ACC-GABA+ levels in PDMs (N = 41) and age- and education-matched healthy controls (HCs) (N = 39) during both the menstrual and periovulatory phases, and between menstrual and periovulatory phases within each group. Total creatine (Cr referencing) level was used as an endogenous reference. The correlations of ACC-neurotransmitter levels with clinical characteristics and the correlations of ACC-Glx with ACC-GABA+ levels in the two groups were analyzed.

RESULTS

Compared to HCs or the periovulatory phase, PDMs exhibited significantly increased ACC-Glx levels (p < 0.05) during the menstrual phase. Positive correlations between GABA+ and Glx levels (r = 0.385, p = 0.025) were found in PDMs during the menstrual phase. ACC-GABA+ levels were associated with self-rating distress scale (SDS) scores (GABA+/Cr: r = 0.369, p = 0.045) and pain catastrophizing scale (PCS) scores (GABA+/Cr: r = 0.373, p = 0.042) in PDM group in only the menstrual phase.

CONCLUSION

Our study represents the first report of ACC-GABA+/Glx imbalances in PDMs during the menstrual phase, which may underlie the mechanisms mediating depression and painful catastrophic symptoms.

Cortical gyrification differences between early- and late-onset obsessive-compulsive disorder: neurobiological evidence for neurodevelopmentally distinct subtypes

BACKGROUND

Identifying more homogenous subtypes of patients with obsessive-compulsive disorder (OCD) using biological evidence is critical for understanding complexities of the disorder in this heterogeneous population. Age of onset serves as a useful subtyping scheme for distinguishing OCD into two subgroups that aligns with neurodevelopmental perspectives. The underlying neurobiological markers for these distinct neurodevelopmental differences can be identified by investigating gyrification changes to establish biological evidence-based homogeneous subtypes.

METHODS

We compared whole-brain cortical gyrification in 84 patients with early-onset OCD, 84 patients with late-onset OCD, and 152 healthy controls (HCs) to identify potential markers for early neurodevelopmental deficits using the local gyrification index (lGI). Then, the relationships between lGI in clusters showing significant differences and performance in visuospatial memory and verbal fluency, which are considered trait-related neurocognitive impairments in OCD, were further examined in early-onset OCD patients.

RESULTS

The early-onset OCD patients exhibited significantly greater gyrification than those with late-onset OCD patients and HCs in frontoparietal and cingulate regions, including the bilateral precentral, postcentral, precuneus, paracentral, posterior cingulate, superior frontal, and caudal anterior cingulate gyri. Moreover, impaired neurocognitive functions in early-onset OCD patients were correlated with increased gyrification.

CONCLUSIONS

Our findings provide a neurobiological marker to distinguish the OCD population into more neurodevelopmentally homogeneous subtypes, which may contribute to the understanding of the neurodevelopmental underpinnings of an etiology in early-onset OCD consistent with the accumulated phenotypic evidence of greater neurodevelopmental deficits in early-onset OCD than in late-onset OCD.