Most recent paper

Res Sq [Preprint]. 2024 Dec 4:rs.3.rs-5356022. doi: 10.21203/rs.3.rs-5356022/v1.

ABSTRACT

Recent advancements in connectome analyses have enabled more precise measurements of brain network integrity. Identifying neural measures that can operate as mechanisms of cognitive reserve (CR) is integral for the study of individual variability in age-related cognitive changes. In the present study, we tested the hypothesis that network resilience, or the network's ability to maintain functionality when facing internal or external perturbations that cause damage or error, can function as a CR candidate, modifying the relationship between cognitive and brain changes in a lifespan cohort of cognitively healthy adults. One hundred cognitively healthy older adults from the Reference Ability Neural Network (RANN) longitudinal lifespan cohort (50-80 years) underwent resting-state fMRI and neuropsychological testing at baseline and five-year follow-up. Using undirected weighted adjacency matrices created from the Schaefer et al. (2018) 400-parcellation atlas and 19 additional subcortical regions (419 nodes in total), whole-brain network resilience was assessed through a targeted attack approach, where nodes were sequentially removed by nodal strength and resilience defined as the iteration of the steepest slope in the largest connected component (LCC) decay. We observed that brain resilience (BR) moderated the effect of cortical thickness (CT) changes on longitudinal changes in Fluid Reasoning performance, even after adjusting for baseline differences, demographic factors, and the initial LCC of the unlesioned matrix, indicating that individuals with greater resilience were less sensitive to the effect of cortical thickness changes on changes in cognition. These findings support the use of targeted attack as a measure of cognitive reserve, suggesting that higher brain network resilience may allow individuals with reduced brain integrity to better cope with structural loss and maintain cognitive function.

PMID:39678345 | PMC:PMC11643323 | DOI:10.21203/rs.3.rs-5356022/v1

Biol Psychiatry Cogn Neurosci Neuroimaging. 2024 Dec 13:S2451-9022(24)00377-X. doi: 10.1016/j.bpsc.2024.12.001. Online ahead of print.

ABSTRACT

BACKGROUND: Obsessive-compulsive disorder (OCD) is a common and debilitating mental disorder. Neuroimaging studies have highlighted that the dysfunctional default mode network (DMN) plays a key role in the pathophysiology mechanisms of OCD. However, the findings of impaired DMN regions have been inconsistent. We employed meta-analysis to identify the fMRI-specific abnormalities of the DMN in OCD.

METHODS: PubMed, Web of science and Embase were searched to screen resting-state functional magnetic resonance imaging (rs-fMRI) studies on the amplitude of low-frequency fluctuation/fractional amplitude of low-frequency fluctuation (ALFF/fALFF) and regional homogeneity (ReHo) of the DMN in OCD patients. Based on the activation likelihood estimation (ALE) algorithm, we compared all patients with OCD and control group in a primary meta-analysis, and analyzed the unmedicated OCD without comorbidities in secondary meta-analyses.

RESULTS: A total of 26 eligible studies with 1219 OCD patients (707men) and 1238 healthy controls (684 men) were included in the primary meta-analysis. We concluded specific changes in brain regions of DMN, mainly in the left medial frontal gurus (MFG), bilateral superior temporal gyrus (STG), bilateral inferior parietal lobule (IPL), bilateral precuneus (PCUN), bilateral posterior cingulate cortex (PCC), and right parahippocampal gyrus (PHG).

CONCLUSION: OCD patients showed dysfunction in the DMN, including impaired local important nodal brain regions. The PCC/PCUN appear to be the most affected regions within the DMN, providing valuable insights into understanding the potential pathophysiology of OCD and targets for clinical interventions.

PMID:39675630 | DOI:10.1016/j.bpsc.2024.12.001

Neuroimage. 2024 Dec 13:120961. doi: 10.1016/j.neuroimage.2024.120961. Online ahead of print.

ABSTRACT

The etiology of cognitive decline linked to migraine remains unclear, with a growing recurrence rate and potential increased dementia risk among sufferers. Cognitive dysfunction has recently gained attention as a significant problem among migraine sufferers that can be related to alterations in hippocampal function and structure. This study explores hippocampal subfield connectivity and volume changes in migraine patients. We recruited 90 individuals from Alanya University's Neurology Department, including 49 migraine patients and 41 controls, for functional and anatomical imaging. Using the CONN toolbox and FreeSurfer, we assessed functional connectivity and subfield volumes, respectively. Montreal Cognitive Assessment (MOCA) was used to assess cognition in the entire sample. As a result, migraine patients exhibited significantly lower MOCA scores compared to controls (p<.001). Also, we found significant differences in hippocampal subfields between migraine patients and control groups in terms of functional connectivity after adjusting for years of education; here we showed that the left CA3 showed higher connectivity with right MFG and right occipitolateral cortex. Furthermore, the connectivity of left fimbria with the left temporal lobe and hippocampus and the connectivity of the right hippocampal-tail with right insula, heschl's gyrus, and frontorbital cortex were lower in the migraineurs. Additionally, volumes of specific hippocampal subfields significantly lower in the migraineurs (whole hippocampus p=0.004, whole hippocampus head p=0.003, right CA1 head p=0.006, and right HATA p=0.005) compared to controls. In conclusion, these findings indicate that migraine-associated cognitive impairment involves significant functional and structural brain changes, particularly in the hippocampus, which may heighten dementia risk. This pioneering study unveils critical hippocampal alterations linked to cognitive function in migraine sufferers, underscoring the potential for these changes to impact dementia development.

PMID:39675538 | DOI:10.1016/j.neuroimage.2024.120961

Brain Res. 2024 Dec 12:149401. doi: 10.1016/j.brainres.2024.149401. Online ahead of print.

ABSTRACT

AIMS: To explore the functional brain imaging characteristics of patients with disorders of consciousness (DoC).

METHODS: This prospective cohort study consecutively enrolled 27 patients in minimally conscious state (MCS), 23 in vegetative state (VS), and 25 age-matched healthy controls (HC). Resting-state functional magnetic resonance imaging (rs-fMRI) was employed to evaluate the amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), degree centrality (DC), and functional connectivity (FC). Sliding windows approach was conducted to construct dynamic FC (dFC) matrices. Moreover, receiver operating characteristic analysis and Pearson correlation were used to distinguish these altered characteristics in DoC.

RESULTS: Both MCS and VS exhibited lower ALFF, ReHo, and DC values, along with reduced FC in multiple brain regions compared with HC. Furthermore, the values in certain regions of VS were lower than those in MCS. The primary differences in brain function between patients with varying levels of consciousness were evident in the cortico-striatopallidal-thalamo-cortical mesocircuit. Significant differences in the temporal properties of dFC (including frequency, mean dwell time, number of transitions, and transition probability) were also noted among the three groups. Moreover, these multimodal alterations demonstrated high classificatory accuracy (AUC > 0.8) and were correlated with the Coma Recovery Scale-Revised (CRS-R).

CONCLUSION: Patients with DoC displayed abnormal patterns in local and global dynamic and static brain functions. These alterations in rs-fMRI were closely related to the level of consciousness.

PMID:39674532 | DOI:10.1016/j.brainres.2024.149401

Eur Arch Psychiatry Clin Neurosci. 2024 Dec 14. doi: 10.1007/s00406-024-01949-y. Online ahead of print.

ABSTRACT

The literature suggests that alterations in functional connectivity (FC) of the Salience Network (SN) may contribute to the manifestation of some clinical features of Autism Spectrum Disorder (ASD). The SN plays a key role in integrating external sensory information with internal emotional and bodily information. An atypical FC of this network could explain some symptomatic features of ASD such as difficulties in self-awareness and emotion processing and provide new insights into the neurobiological basis of autism. Using the Autism Brain Imaging Data Exchange II we investigated the resting-state FC of core regions of SN and its association with autism symptomatology in 29 individuals with ASD compared with 29 typically developing (TD) individuals. In ASD compared to TD individuals, seed-based connectivity analysis showed a reduced FC between the rostral prefrontal cortex and left cerebellum and an increased FC between the right supramarginal gyrus and the regions of the middle temporal gyrus and angular gyrus. Finally, we found that the clinical features of ASD are mainly associated with an atypical FC of the anterior insula and the involvement of dysfunctional mechanisms for emotional and social information processing. These findings expand the knowledge about the differences in the FC of SN between ASD and TD, highlighting atypical FC between structures that play key roles in social cognition and complex cognitive processes. Such anomalies could explain difficulties in processing salient stimuli, especially those of a socio-affective nature, with an impact on emotional and behavioral regulation.

PMID:39673625 | DOI:10.1007/s00406-024-01949-y

Transl Neurosci. 2024 Dec 11;15(1):20220356. doi: 10.1515/tnsci-2022-0356. eCollection 2024 Jan 1.

ABSTRACT

Functional magnetic resonance imaging (fMRI) stands as a pivotal tool in advancing our comprehension of Schizophrenia, offering insights into functional segregations and integrations. Previous investigations employing either task-based or resting-state fMRI primarily focused on large main regions of interest (ROI), revealing the thalamus and superior temporal gyrus (STG) as prominently affected areas. Recent studies, however, unveiled the cytoarchitectural intricacies within these regions, prompting a more nuanced exploration. In this study, resting-state fMRI was conducted on 72 schizophrenic patients and 74 healthy controls to discern whether distinct thalamic nuclei and STG sub-regions exhibit varied functional integrational connectivity to main networks and to identify the most affected sub-regions in Schizophrenia. Employing seed-based analysis, six sub-ROIs - four in the thalamus and two in the STG - were selected. Our findings unveiled heightened positive functional connectivity in Schizophrenic patients, particularly toward the anterior STG (aSTG) and posterior STG (pSTG). Notably, positive connectivity emerged between the medial division of mediodorsal thalamic nuclei (MDm) and the visual network, while increased functional connectivity linked the ventral lateral nucleus of the thalamus with aSTG. This accentuated functional connectivity potentially influences these sub-regions, contributing to dysfunctions and manifesting symptoms such as language and learning difficulties alongside hallucinations. This study underscores the importance of delineating sub-regional dynamics to enhance our understanding of the nuanced neural alterations in Schizophrenia, paving the way for more targeted interventions and therapeutic approaches.

PMID:39669226 | PMC:PMC11635424 | DOI:10.1515/tnsci-2022-0356

Neuroimage. 2024 Dec 10:120969. doi: 10.1016/j.neuroimage.2024.120969. Online ahead of print.

ABSTRACT

The preclinical stage of Alzheimer's Disease (AD) holds great potential for intervention, therefore, it is crucial to elucidate the neural mechanisms underlying the progression of subjective cognitive decline (SCD). Previous studies have predominantly focused on the neural changes in the cerebrum associated with SCD, but have relatively neglected the cerebellum, and the functional relationship between the cerebellum and the cerebrum. In the current study, we employed dynamic functional connectivity and large-scale brain network approaches to investigate the pathological characteristics of dynamic brain states and cerebro-cerebellar collaboration across different states between SCD (n = 32) and healthy elderly (n = 29) using resting-state fMRI. Two-way repeated measures ANOVA and permutation t-tests revealed significant group difference, with individuals with SCD exhibiting shorter state duration and more frequent transitions between states compared to healthy elderly individuals across three brain states. Additionally, individuals with SCD showed lower levels of intracerebellar functional connectivity, but higher levels of cerebellar-cerebral functional integration in the state representing cognitive processing. Furthermore, the hub nodes of the functional networks in SCD shifted between the cerebellum and cerebrum across different states. These findings indicate that SCD exhibits greater state instability but can compensate for the negative effects of early disease by integrating cerebellar and cerebral networks, thereby maintaining cognitive performance. This study enhances our theoretical understanding of cerebellar-cerebral relationship changes in the early stages of AD and provides evidence for early interventions targeting the cerebellum.

PMID:39667538 | DOI:10.1016/j.neuroimage.2024.120969

Biol Psychiatry Cogn Neurosci Neuroimaging. 2024 Dec 10:S2451-9022(24)00376-8. doi: 10.1016/j.bpsc.2024.11.022. Online ahead of print.

ABSTRACT

BACKGROUND: Cue-induced craving precipitates relapse in drug and alcohol use disorders. Theta burst stimulation (TBS) to the left frontal pole of the medial prefrontal cortex (MPFC) has previously been shown to reduce drinking and brain reactivity to alcohol cues. This randomized, double-blind, sham-controlled target-engagement study aimed to assess whether TBS has similar effects in individuals with cocaine use disorder (CUD).

METHODS: Thirty-three participants in intensive outpatient treatment received either real or sham TBS over 10 sessions across 3 weeks (36,000 pulses total; continuous TBS, 110% resting motor threshold, 3600 pulses/session). TBS was administered on days of behavioral counseling. Twenty-five individuals completed all 10 TBS sessions. Brain reactivity to cocaine cues was measured using fMRI at baseline, 1-month, 2-months, and 3-months.

RESULTS: Cocaine abstinence during the 3-month follow-up period was greater in the real TBS group (1-month: 92.0%, 2-month: 100.0%, 3-month: 85.0%) compared to sham (1-month: 66.6%, 2-month: 66.6%, 3-month: 66.6%), though not statistically significant [1-month: 6.00, p=0.14; 2-month OR=:14.30, p=0.09, and 3-month OR=2.75, p=0.30]. However, there was a significant effect on cocaine cue reactivity (treatment effect: F1,365= 8.92, p=0.003; time*treatment interaction: F3,365=12.88, p<0.001). Real TBS reduced cocaine cue reactivity in the MPFC (F3,72=5.46, p=0.02) overall, and in the anterior cingulate (F3,72=3.03, p=0.04), and insula (F3,72=3.60, p=0.02).

CONCLUSIONS: This early-stage trial demonstrates TBS to the MPFC reduces brain reactivity to cocaine cues in key nodes of the Salience Network in treatment-seeking cocaine users. Future, well-powered trials are warranted to evaluate clinical efficacy outcomes.

PMID:39667495 | DOI:10.1016/j.bpsc.2024.11.022

Am J Otolaryngol. 2024 Dec 3;46(1):104531. doi: 10.1016/j.amjoto.2024.104531. Online ahead of print.

ABSTRACT

PURPOSE: To examine alterations in Blood Oxygen Level-Dependent (BOLD) resting-state functional magnetic resonance imaging (rs-fMRI) signals, utilizing regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuation (fALFF) metrics, within activated brain regions. Additionally, this study aims to explore the relationship between these neural changes and clinical characteristics, as well as emotional states, in patients diagnosed with unilateral Meniere's disease (MD).

METHOD: The study included 24 patients diagnosed with left Meniere's disease (L-MD), 25 patients diagnosed with right Meniere's disease (R-MD), and 23 healthy control subjects. Resting-state blood‑oxygen-level-dependent functional magnetic resonance imaging (rest-BOLD-fMRI) data were preprocessed. A two-sample t-test was employed to compare the regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuation (fALFF) between the patient groups and the control group. Brain regions exhibiting significant differences were further analyzed for correlations with disease duration, vertigo severity, vertigo duration, hearing loss grade, and levels of anxiety and depression.

RESULTS: In patients with L-MD, fALFF values were significantly decreased in the right cerebellar hemisphere, middle occipital gyrus, among other regions. In patients with right-sided Ménière's disease (R-MD), fractional amplitude of low-frequency fluctuation (fALFF) values were elevated in the right middle inferior temporal gyrus and fusiform gyrus. Regional homogeneity (ReHo) values exhibited both increases and decreases in the temporal gyrus, parahippocampal gyrus, occipital gyrus, superior marginal gyrus, anterior central gyrus, and fusiform gyrus. In studies examining relational aspects, the parahippocampal gyrus, inferior temporal gyrus, middle occipital gyrus, superior middle occipital gyrus, superior marginal gyrus, and occipital gyrus demonstrated positive or negative correlations with clinical characteristics and emotional states.

CONCLUSIONS: Patients with unilateral Meniere's disease (MD) exhibited both increased and decreased activation in various brain regions when compared to control subjects. A correlation was identified between these neural activation patterns and clinical characteristics, as well as emotional state, which holds significant implications for clinical treatment, prognosis, and rehabilitation strategies for MD patients.

PMID:39667311 | DOI:10.1016/j.amjoto.2024.104531

Hum Brain Mapp. 2024 Dec 1;45(17):e70086. doi: 10.1002/hbm.70086.

ABSTRACT

Large-scale brain network function is critical for healthy cognition, yet links between such network function, neurochemistry, and smaller-scale neurocircuitry are unclear. Here, we evaluated 59 healthy individuals using resting-state fMRI to determine how network-level temporal dynamics were impacted by two well-characterized pharmacotherapies targeting catecholamines: methylphenidate (20 mg) and haloperidol (2 mg)-administered via randomized, double-blind, placebo-controlled design. Network temporal dynamic changes were tested for links with drug-induced alterations in complex corticostriatal connections as this circuit is a primary site of action for both drugs. Methylphenidate increased time in the default mode network state (DMN p < 0.001) and dorsal attention network state (DAN p < 0.001) and reduced time in the frontoparietal network state (p < 0.01). Haloperidol increased time in a sensory motor-DMN state (p < 0.01). The magnitude of change in network dynamics induced by methylphenidate vs. placebo correlated with the magnitude of methylphenidate-induced rearrangement of complex corticostriatal connectivity (R = 0.32, p = 0.014). Haloperidol did not alter complex corticostriatal connectivity. Methylphenidate enhanced time in network states involved in internal and external attention (DMN and DAN, respectively), aligning with methylphenidate's established role in attention. Methylphenidate also significantly changed complex corticostriatal connectivity by altering the relative strength between multiple corticostriatal connections, indicating that methylphenidate may shift which corticostriatal connections are prioritized relative to others. Findings show that these corticostriatal circuit changes are linked with large-scale network temporal dynamics. Collectively, these findings provide a deeper understanding of large-scale network function, set a stage for mechanistic understanding of network engagement, and provide useful information to guide medication use based on network-level effects. Trial Registration: Registry name: ClinicalTrials.gov; URL: Brain Networks and Addiction Susceptibility-Full Text View-ClinicalTrials.gov; URL Plain text: https://classic.clinicaltrials.gov/ct2/show/NCT01924468; Identifier: NCT01924468.

PMID:39665506 | DOI:10.1002/hbm.70086

Imaging Neurosci (Camb). 2024;2. doi: 10.1162/imag_a_00163. Epub 2024 May 8.

ABSTRACT

Aging is associated with impaired signaling between brain regions when measured using resting-state fMRI. This age-related destabilization and desynchronization of brain networks reverses itself when the brain switches from metabolizing glucose to ketones. Here, we probe the mechanistic basis for these effects. First, we confirmed their robustness across measurement modalities using two datasets acquired from resting-state EEG (Lifespan: standard diet, 20-80 years, N = 201; Metabolic: individually weight-dosed and calorically-matched glucose and ketone ester challenge, μ a g e = 26.9 ± 11.2 years , N = 36). Then, using a multiscale conductance-based neural mass model, we identified the unique set of mechanistic parameters consistent with our clinical data. Together, our results implicate potassium (K+) gradient dysregulation as a mechanism for age-related neural desynchronization and its reversal with ketosis, the latter finding of which is consistent with direct measurement of ion channels. As such, the approach facilitates the connection between macroscopic brain activity and cellular-level mechanisms.

PMID:39664914 | PMC:PMC11633768 | DOI:10.1162/imag_a_00163

Front Neurol. 2024 Nov 27;15:1487796. doi: 10.3389/fneur.2024.1487796. eCollection 2024.

ABSTRACT

Traumatic brain injury (TBI) is common and costly. Although neuroimaging modalities such as resting-state functional MRI (rsfMRI) promise to differentiate injured from healthy brains and prognosticate long-term outcomes, the field suffers from heterogeneous findings. To assess whether this heterogeneity stems from variability in the TBI populations studied or the imaging methods used, and to determine whether a consensus exists in this literature, we performed the first systematic review of studies comparing rsfMRI functional connectivity (FC) in patients with TBI to matched controls for seven canonical brain networks across injury severity, age, chronicity, population type, and various imaging methods. Searching PubMed, Web of Science, Google Scholar, and ScienceDirect, 1,105 manuscripts were identified, 50 fulfilling our criteria. Across these manuscripts, 179 comparisons were reported between a total of 1,397 patients with TBI and 1,179 matched controls. Collapsing across injury characteristics, imaging methods, and networks, there were roughly equal significant to null findings and increased to decreased connectivity differences reported. Whereas most factors did not explain these mixed findings, stratifying across severity and chronicity, separately, showed a trend of increased connectivity at higher severities and greater chronicities of TBI. Among methodological factors, studies were more likely to find connectivity differences when scans were longer than 360 s, custom image processing pipelines were used, and when patients kept their eyes open versus closed during scans. We offer guidelines to address this variability, focusing on aspects of study design and rsfMRI acquisition to move the field toward reproducible results with greater potential for clinical translation.

PMID:39664747 | PMC:PMC11631856 | DOI:10.3389/fneur.2024.1487796

Brain Behav. 2024 Dec;14(12):e70196. doi: 10.1002/brb3.70196.

ABSTRACT

INTRODUCTION: Spinal cord injury (SCI) can result in sensory and locomotor function loss below the injured segment. Hyperbaric oxygen therapy (HBOT) has been proven to alleviate SCI. This study aims to establish a reproducible rat model of SCI and investigate the impact of HBOT on alterations in brain neuronal activity and neuromotor function in this experimental rat SCI model using resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS: This is a prospective randomized controlled animal trial. A total number of 27 female SD rats were randomly divided into three groups: sham (n = 9), SCI (n = 9), and HBO (n = 9). rs-fMRI was utilized to assess regional homogeneity (ReHo) values and functional connectivity (FC) strength over the whole brain with the motor cortex as seeds. Correlation between neuroimaging characteristics and behavioral assessment was calculated. We examined Nissl body, NeuN, and caspase-3 expression in relevant brain regions.

RESULTS: Following SCI, reduced ReHo values were observed in the left primary somatosensory cortex, left striatum, right agranular insular cortex, and partial cortex in the limbic system, which was reversed after HBOT. HBOT could increase FC strength between the motor cortex and other brain regions, including the left secondary motor cortex, right basal forebrain region, bilateral primary somatosensory cortex, bilateral thalamus, and another partial cortex in the limbic system. BBB scale scores showed that HBOT promoted motor function recovery in SCI rats. The ReHo and FC values in all positive clusters were positively correlated with BBB scores. By histopathological analysis, our study found that HBOT could reduce apoptotic proteins, increase the number of neurons, and protect neuronal function in brain regions with significant ReHo and FC alteration in SCI rats.

CONCLUSION: This study reveals that HBOT facilitates functional and structural plasticity in the brain, contributing to the recovery of motor function in rats with SCI.

PMID:39663753 | DOI:10.1002/brb3.70196

Pain. 2024 Nov 19. doi: 10.1097/j.pain.0000000000003478. Online ahead of print.

ABSTRACT

The perception of pain and ability to cope with it varies widely amongst people, which in part could be due to the presence of inhibitory (antinociceptive) or facilitatory (pronociceptive) effects in conditioned pain modulation (CPM). This study examined whether individual differences in CPM reflect functional connectivity (FC) strengths within nodes of the descending antinociceptive pathway (DAP). A heat-based CPM paradigm and resting-state functional magnetic resonance imaging (rs-fMRI) were used to test the hypothesis that an individual's capacity to exhibit inhibitory CPM (changes in test stimuli [TS] pain due to a conditioning stimulus [CS]) reflects FC of the subgenual anterior cingulate cortex (sgACC), periaqueductal gray (PAG), and rostral ventromedial medulla (RVM). A total of 151 healthy participants (72 men, 79 women) underwent CPM testing and rs-fMRI. Three types of CPM were identified based on the effect of the CS on TS pain: (1) Antinociception: CS reduced TS pain in 45% of participants, (2) No-CPM: CS did not change TS pain in 15% of participants, and (3) Pronociception: CS increased TS pain in 40% of participants. Only the Antinociceptive subgroup exhibited FC between the left sgACC and PAG, right sgACC and PAG, and RVM and PAG. Furthermore, only the Antinociceptive subgroup exhibited a correlation of both left and right sgACC-RVM FC (medium effect sizes) with CPM effect magnitude. Women, compared with men were more likely to be categorized as pronociceptive. These data support the proposition that FC of the DAP reflects or contributes to inhibitory CPM.

PMID:39661368 | DOI:10.1097/j.pain.0000000000003478

AJR Am J Roentgenol. 2024 Dec 11. doi: 10.2214/AJR.24.32163. Online ahead of print.

ABSTRACT

Resting-state functional MRI (rs-fMRI), a promising method for interrogating different brain functional networks from a single MRI acquisition, is increasingly utilized in clinical presurgical and other pretherapeutic brain mapping. However, challenges in standardization of acquisition, preprocessing, and analysis methods across centers, and variability in results interpretation, complicate its clinical use. Additionally, inherent problems regarding reliability of language lateralization, interpatient variability of cognitive network representation, dynamic aspects of intranetwork and internetwork connectivity, and effects of neurovascular uncoupling on network detection still must be overcome. Although deep-learning solutions and further methodologic standardization will help address these issues, rs-fMRI remains generally considered an adjunct to task-based fMRI (tb-fMRI) for clinical presurgical mapping. Nonetheless, in many clinical instances, rs-fMRI may offer valuable additional information that supplements tb-fMRI, especially if tb-fMRI is inadequate due to patient performance or other limitations. Future growth in clinical applications of rs-fMRI is anticipated as challenges are increasingly addressed. In this AJR Expert Panel Narrative Review, we summarize the current state and emerging clinical utility of rs-fMRI, focusing on its role in presurgical mapping. We present ongoing controversies and limitations in clinical applicability and discuss future directions including the developing role of rs-fMRI in neuromodulation treatment for various neurologic disorders.

PMID:39660823 | DOI:10.2214/AJR.24.32163

Heliyon. 2024 Nov 2;10(23):e37890. doi: 10.1016/j.heliyon.2024.e37890. eCollection 2024 Dec 15.

ABSTRACT

BACKGROUND: and purpose: The investigation of functional plasticity and remodeling of the brain in patients with retinal detachment (RD) has gained increasing attention and validation. However, the precise alterations in the topological configuration of dynamic functional networks are still not fully understood. This study aimed to investigate the topological structure of dynamic brain functional networks in RD patients.

METHODS: We recruited 32 patients with RD and 33 healthy controls (HCs) to participate in resting-state fMRI. Employing the sliding time window analysis and K-means clustering method, we sought to identify dynamic functional connectivity (dFC) variability patterns in both groups. The investigation into the topological structure of whole-brain functional networks utilized a graph theoretical approach. Furthermore, we employed machine learning analysis, selecting altered topological properties as classification features to distinguish RD patients from HCs.

RESULTS: All participants exhibited four distinct states of dynamic functional connectivity. Compared to the healthy control (HC) group, patients with RD experienced a significant reduction in the number of transitions among these four states. Additionally, the dynamic topological properties of RD patients demonstrated notable changes in both global and node-specific characteristics, with these changes correlating with clinical parameters. The support vector machine (SVM) model used for classification achieved an accuracy of 0.938, an area under the curve (AUC) of 0.988, and both sensitivity and specificity of 0.937.

CONCLUSION: The alterations in the topological properties of the brain in RD patients may indicate the integration function and information exchange efficiency of the whole brain network were reduced. In addition, the topological properties hold considerable promise for distinguishing between RD and HCs.

PMID:39660184 | PMC:PMC11629196 | DOI:10.1016/j.heliyon.2024.e37890

Int J Clin Health Psychol. 2024 Oct-Dec;24(4):100528. doi: 10.1016/j.ijchp.2024.100528. Epub 2024 Nov 28.

ABSTRACT

OBJECTIVE: To investigate the spatial distribution characteristics of alterations in spontaneous brain activity in severe traumatic brain injury (sTBI) patients with disorders of consciousness (DOC), based on the mesocircuit theoretical framework, and to establish models for predicting recovery of consciousness.

METHODS: Resting-state functional magnetic resonance imaging was employed to measure the mean fractional amplitude of low-frequency fluctuations (mfALFF) in sTBI patients with DOC and healthy controls, identifying differential brain regions for conducting gene and functional decoding analyses. Patients were classified into wake and DOC groups according to Extended Glasgow Outcome Score at 6 months. Furthermore, predictive models for consciousness recovery were developed using Nomogram and Linear Support Vector Machine (LSVM) based on mfALFF.

RESULTS: In total, 28 sTBI patients with DOC and 30 healthy controls were included, with no significant baseline differences between groups (P > 0.05). The results revealed increased mfALFF of subcortical Ascending Reticular Activating System and decreased cortical mfALFF (default mode network) in DOC patients within the framework of the mesocircuit model (FDR_P < 0.001, Clusters > 100). The study identified 2080 differentially expressed genes associated with reduced brain activity regions, indicating mechanisms involving synaptic function, the oxytocin signaling pathway, and GABAergic processes in DOC formation. In addition, significantly higher mfALFF values were observed in the left angular gyrus, supramarginal gyrus, and inferior parietal lobule of DOC group compared to the wake group (AlphaSim_P < 0.01, Cluster > 19). The Nomogram prediction model highlighted the pivotal role of these regions' activity levels in prognosis (AUC = 0.90). Validation using LSVM demonstrated robust predictive performance with an AUC of 0.90 and positive predictive values of 80% for wake and 83% for DOC.

CONCLUSIONS: This study offered crucial insights underlying DOC in sTBI patients, demonstrating the dissociation between cortical and subcortical brain activities. The findings supported the use of mfALFF as a robust and non-invasive biomarker for evaluating brain function and predicting recovery outcomes.

PMID:39659957 | PMC:PMC11629552 | DOI:10.1016/j.ijchp.2024.100528