Neuroimage. Reports最新文献

Objective

Introduction of brain hypoxia by frequent mask-wearing is a concern voiced by some who resist masking mandates. Studies have examined acute effects of one-shot mask-wearing on peripheral and cerebral oxygenation in the laboratory, but not effects of everyday mask-wearing frequencies on task-related functional activation. The objective of the current study was to examine whether frequency of mask-wearing in daily life is associated with lower task-related brain oxygenation levels, and whether the magnitude of any such effects vary by age and sex.

Methods

Participants were 78 community-dwelling adults between the ages of 18 and 84 years, all of whom were vaccinated at the time of participation; 65.4% (n = 51) were female. Frequency of mask-wearing was assessed using survey questions on mask-wearing practice during an active COVID-19 mask mandate. Recordings of task-related cerebral oxygenation were taken during the completion of a simple reaction time task using 16-channel functional near-infrared spectroscopy (fNIRS).

Results

The psychomotor vigilance task elicited reliable increases in cerebral oxygenation within the right mid-frontal gyrus (F(1,61.345) = 15.975, p < .001). However, there was no significant association between everyday masking frequency and performance on the psychomotor vigilance task (b = 0.059, SE = 0.092 (95% CI [-0.122, 0.241]), t = .646, p = .520), nor any association between everyday masking frequency and task-related brain oxygenation on any measurement channel (all ps < .05).

Conclusions

Higher mask-wearing frequency in daily life is not associated with significantly lower levels of task-related brain oxygenation, or worse performance on a sustained attention task.

Essential tremor (ET) is characterized by bilateral upper limb postural and/or kinetic tremor, but also cognitive deficits. Tremor in ET, as well as aspects of cognitive deficits associated with ET, have been suggested to be linked to dysfunction in the cerebello-thalamo-cerebral circuit. In ET patients with disabling and medically intractable motor symptoms, Deep Brain Stimulation (DBS) is effective in reducing tremor. DBS in the caudal Zona incerta (cZi) has been shown to modulate the activity of the sensorimotor cerebello-cerebral circuit during motor tasks. Whether the activity in the cerebello-cerebral circuit is modulated by DBS during tasks involving working memory is unknown. The present study therefore aimed to investigate the possible effects of cZi DBS on working-memory processing in ET patients by means of task-based blood oxygen level-dependent (BOLD) fMRI.

Thirteen ET patients completed a working-memory task during DBS OFF and ON conditions. The task involved three conditions: maintenance, manipulation, and control. Behaviorally, there was no significant effect from DBS on accuracy, but a marginally significant Task x DBS interaction was detected for response times (RTs). However, post hoc comparisons for each condition failed to reach statistical significance. FMRI analyses revealed that DBS did not alter BOLD signal in regions of interest (lateral prefrontal cortex, parietal cortex, and the cerebellum), or in a complementary whole-brain analysis.

The present study indicates that DBS in the cZi in patients with ET has at most marginal effects on working memory, which is consistent with the results of pre- and post-DBS neuropsychological assessment showing minimal cognitive effects of surgery.

In memory, familiar but no longer relevant information may disrupt encoding and retrieval of to-be-learned information. While it has been demonstrated that the ability to resolve proactive interference (PI) in working memory (WM) is reduced in aging, the neuroanatomical components of this decline have yet to be determined. Hippocampal (HC) involvement in age-related decline in control of PI is currently not known. In particular, the association between HC subfield volumes and control of PI in WM has not been examined previously. Here we investigate the associations between mean level and 5-year trajectories of gray matter subfield volumes and PI in WM across the adult life span (N = 157). Longitudinal analyses over 5-years across all participants revealed that reduced volume in the subiculum was related to impaired control of PI. Age-stratified analyses showed that this association was most pronounced in older adults. Furthermore, we found that in older adults the effect of age on PI was mediated by GM volume in the HC. The current results show that HC volume is associated with the ability to control PI in WM, and that these associations are modulated by age.

Background

Research indicates that Acceptance and Commitment Therapy in Daily Life (ACT-DL) is effective in reducing symptoms of depression, anxiety and psychosis. During adolescence, vulnerability to psychopathology peaks, creating a window for early interventions, while white matter development is ongoing. This study aims to examine microstructural white matter after ACT-DL intervention in youngsters with mild psychopathology.

Methods

Forty-five individuals with mild psychopathology were randomly allocated to ACT-DL (n=20) or topic discussion control (TD, n=25). Symptomatology was assessed with the Community Assessment of Psychic Experiences (CAPE), Montgomery–Åsberg Depression Rating Scale (MADRS) and the Experience Sampling Method (ESM). Diffusion Weighted Imaging (DWI) and network-connectivity parameters were obtained and compared before and after the intervention/control condition. Interactions between microstructural white matter change and condition were examined in models of CAPE positive symptoms and ESM subclinical psychotic experiences (PE) and negative affect (NA) levels.

Results

ACT-DL, compared to TD, was associated with changes on subclinical depressive and psychotic symptom levels. There was no significant change in DWI or network connectivity in either condition and no significant difference between both conditions. In the model of NA, several regional interactions between condition and network measures were significant, but stratification per condition provided no significant associations. There were no significant interactions between DWI or network connectivity parameters and condition in the models of the CAPE positive symptoms, MADRS and PE.

Conclusions

The findings suggest that behavioral (symptom) changes are more sensitive to a five-week psychological training than microstructural white matter changes which did not show significant changes over time.

Many studies have analyzed resting state functional magnetic resonance imaging (rs-fMRI) dynamic functional network connectivity (dFNC) data to elucidate the effects of neurological and neuropsychiatric disorders upon the interactions of brain regions over time. Existing studies often use either machine learning classification or clustering algorithms. Additionally, several studies have used clustering algorithms to extract features related to brain states trajectories that can be used to train interpretable classifiers. However, the combination of explainable dFNC classifiers followed by clustering algorithms is highly underutilized. In this study, we show how such an approach can be used to study the effects of schizophrenia (SZ) upon brain activity. Specifically, we train an explainable deep learning model to classify between individuals with SZ and healthy controls. We then cluster the resulting explanations, identifying discriminatory states of dFNC. We lastly apply several novel measures to quantify aspects of the classifier explanations and obtain additional insights into the effects of SZ upon brain network dynamics. Specifically, we uncover effects of schizophrenia upon subcortical, sensory, and cerebellar network interactions. We also find that individuals with SZ likely have reduced variability in overall brain activity and that the effects of SZ may be temporally localized. In addition to uncovering effects of SZ upon brain network dynamics, our approach could provide novel insights into a variety of neurological and neuropsychiatric disorders in future dFNC studies.

Mild cognitive impairment (MCI) and hearing loss (HL) have been separately associated with increased dementia risk. These highly co-occurring dementia risk factors are associated with aberrant functional brain connectivity. In individuals with HL aberrant functional connectivity has been associated with cognitive impairment. In individuals with MCI, aberrant brain connectivity has been associated with severity of cognitive impairment and conversion to dementia. Despite the high prevalence of HL in individuals with MCI, the relationship between the two is understudied, especially in the context of functional connectivity.

Participants

include 94 older adults with MCI. Hearing measures include pure-tone hearing thresholds and speech-reception thresholds. In analyses with pure-tone hearing loss, participants were classified as having normal hearing (n = 60) or hearing loss (n = 34) based on a pure-tone screening protocol. We used independent component analyses on resting-state functional magnetic resonance imaging data to identify the default-mode network (DMN). Analysis of variance with covariate control was used to investigate DMN connectivity differences between the normally hearing individuals with MCI and individuals with MCI and pure-tone HL. A linear regression was used to investigate the relationship between speech-reception threshold and DMN connectivity in the whole sample.

Compared to those with MCI and normal hearing, those with MCI and pure-tone HL had decreased connectivity between the DMN and the caudate and thalamus. There was no difference in DMN connectivity as a function of speech-reception threshold.

Our findings indicate that in individuals with MCI, HL is associated with decreased connectivity between the DMN and regions important for sensory and cognitive processing. This suggests that the increased risk for cognitive decline and dementia in individuals with HL may be due to decreased DMN connectivity in individuals with HL.

3D-Edge Enhancing Gradient Echo MRI (EDGE) is a promising method for identifying focal cortical dysplasia (FCD) because of its superior contrast-to-noise ratio. Gains in signal-to-noise ratio (SNR) and spatial resolution using 7T MRI should further enhance the utility of EDGE; however, the exquisite sensitivity to the optimal inversion time makes translation to 7T challenging given the extreme nonuniformities in the transmit field (B1+). By utilizing a combined MP2RAGE-EDGE sequence, the efficiency of the acquisition can be optimized to improve B1+ transmit uniformity and SNR. Using this approach, we report the first experience of using 7T EDGE MRI for the diagnosis of FCD in epilepsy, showing the feasibility of achieving high spatial resolution, SNR, and image contrast uniformity. EDGE-MP2RAGE sequence improves the detection of gray-white matter junction abnormalities associated with FCD and is a valuable, time-efficient addition to a 7T MR protocol in patients with focal epilepsy.

Objective

Patients with left perisylvian gliomas might undergo language mapping with nTMS in preparation for awake brain surgery. Action naming is an important addition to the presurgical language mapping protocol. However, it has not yet been determined whether specific action stimuli can influence mapping outcomes in terms of number and/or localisation of induced errors.

Methods

We investigated this question by employing tractography-based nTMS language mapping of the left arcuate fasciculus (AF) with two types of verbs: transitive and intransitive. Data were collected from 22 patients with a left perisylvian glioma.

Results

Our results demonstrated that nTMS induced a higher error rate with transitive rather than intransitive verbs, specifically during stimulation of the posterior temporal terminations of the left AF (transitive error rate: 8.3%; intransitive error rate: 4.8%). The effect was absent when gliomas displaced the temporal terminations of the AF. Also, nTMS triggered a higher number of semantic errors with transitive (vs intransitive) actions during stimulation of the posterior temporal terminations of the AF (semantic error rate – transitives: 3.3%; semantic error rate – intransitives: 0%).

Conclusion

Our work highlights that clinical outcomes of language mapping with nTMS are affected by the choice of linguistic stimuli. Transitive verbs may be suited to achieve optimal nTMS mapping outcomes in posterior temporal areas of the left AF in this population. Displacement of white matter terminations due to the tumor can affect these results, and semantic errors may indicate core language processes that can be mapped when administering transitive verbs.

Performance monitoring is essential for successful action execution and previous studies have suggested that frontomedial theta (FMT) activity in scalp-recorded EEG reflects need for control signaling in response to negative outcomes. However, these studies have overlooked the fact that anticipating the most probable outcome is often possible. To optimize action execution, it is necessary for the time-critical performance monitoring system to utilize continuously updated information to adjust actions in time. This study used a combination of mobile EEG and virtual reality to investigate how the performance monitoring system adapts to continuously updated information during brief phases of outcome evaluation that follow action execution. In two virtual shooting tasks, participants were either able to observe the projectile and hence anticipate the outcome or not. We found that FMT power increased in response to missing shots in both tasks, but this effect was suppressed when participants were able to anticipate the outcome. Specifically, the suppression was linearly related to the duration of the anticipatory phase. Our results suggest that the performance monitoring system dynamically integrates incoming information to evaluate the most likely outcome of an action as quickly as possible. This dynamic mode of performance monitoring provides significant advantages over idly waiting for an action outcome before getting engaged. Early and adaptive performance monitoring not only helps prevent negative outcomes but also improves overall performance. Our findings highlight the crucial role of dynamic integration of incoming information in the performance monitoring system, providing insights for real-time decision-making and action control.

Introduction

Though empathy, compassion, and Theory of Mind (ToM) are related, they have been distinguished conceptually and empirically across behavioural and neuroimaging experiments. The EmpaToM task was the first realistic paradigm developed for use in functional Magnetic Resonance Imaging (fMRI), which can reliably detect and distinguish three different types of neural pathways crucial for understanding others with a single well-controlled task. Though the paradigm holds the potential for use in research settings as well as clinical practice, it has thus far only been validated in German speaking populations, using stimuli in German language, restricting its usability across countries. We present an English-language translation of the original paradigm here.

Method

Thirty-two English speaking adults underwent fMRI scanning, during which we collected neural and behavioural data as in the original validation of the EmpaToM task.

Results

Apart from minor differences, these results replicated the main behavioural and neural findings observed during the validation of the German paradigm. Participants reported increased negative affect and activity in brain regions previously associated with empathy when observing video clips with negative vs neutral valence. They further reported increased compassion. The pattern of neural activity differentiating empathy from compassion was largely consistent with previous research. Increased activity in regions previously associated with ToM were observed in response to stimuli with ToM vs factual reasoning content.

Conclusion

We therefore conclude that the English version of the EmpaToM task can be used to reliably assess empathy, compassion, and ToM on a behavioural as well as neuronal level across English speaking countries and institutions.