Functional Connectivity Analysis Research Articles

Aberrant amplitude of low-frequency fluctuation and functional connectivity in children with different subtypes of ADHD: a resting-state fNIRS study

BackgroundAttention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with different subtypes of pathogenesis. Insufficient research on the subtypes of ADHD has limited the effectiveness of therapeutic methods.MethodsThis study used resting-state functional near-infrared spectroscopy (fNIRS) to record hemodynamic signals in 34 children with ADHD-combined subtype (ADHD-C), 52 children with ADHD-inattentive subtype (ADHD-I), and 24 healthy controls (HCs). The amplitude of low-frequency fluctuation (ALFF) and the functional connectivity (FC) analysis were conducted for all subjects.ResultsCompared with HCs, the ADHD group exhibited significantly increased ALFF and decreased FC. The ADHD-C group showed significantly higher ALFF in partial brain regions and significantly lower FC between multiple brain regions than participants with ADHD-I. The male group displayed a significant increase in ALFF in some brain regions, while no significant difference was found in FC when compared to the female group.ConclusionsThis study provides evidence to support the subtype classification of ADHD-I and ADHD-C, and the combined analysis of ALFF and FC has the potential to be a promising biomarker for the diagnosis of ADHD.

Effects of childhood trauma on sustained attention in major depressive disorder: the mediating role of brain activity and functional connectivity

BackgroundSustained attention deficits were reported more significant in patients with major depressive disorder (MDD) than in healthy controls (HCs), and are pivotal in both the development and aggravation of depression. Childhood trauma is also common in MDD and the exposure to childhood trauma may impede sustained attention and increase the treatment resistance in MDD. However, the underlying neuro-mechanisms link the childhood trauma to sustained attention deficits in MDD remain unclear.MethodsWe collected resting-state functional magnetic resonance imaging data, and measured childhood trauma severity using the Childhood Trauma Questionnaire and sustained attention using the Continuous Performance Test, Identical Pairs version. After excluding subjects with significant head movement, 45 MDDs and 54 HCs were included in the analysis. We compared fractional amplitude of low-frequency fluctuation (fALFF) between the groups, conducted whole-brain correlation analysis between the fALFF and sustained attention in the MDD group, and defined significant regions as the regions of interest for the seed-to-whole brain functional connectivity (FC) analysis. We further performed mediation analyses to investigate the relationships among the childhood trauma, fALFF and FC values, and the level of sustained attention in the MDD group.ResultsCompared with HCs, MDDs exhibited higher fALFF in the right middle frontal gyrus and left inferior frontal gyrus, and lower fALFF in the bilateral insular cortex, left medial orbital superior frontal gyrus and left angular gyrus (ANG.L). Whole-brain correlation analysis showed that impaired sustained attention was associated with increased fALFF in the left postcentral gyrus (PoCG.L), and FC of PoCG.L-left precentral gyrus (PreCG.L) and ANG.L-right superior temporal gyrus (STG.R) in the MDD group. Furthermore, mediation analyses showed that the fALFF in PoCG.L, and FC of PoCG.L-PreCG.L and ANG.L-STG.R mediated the relationship between the childhood trauma and sustained attention in the MDD group.ConclusionThe fALFF in PoCG.L, and FC of PoCG.L-PreCG.L and ANG.L-STG.R might be potential neural substrate in the association between the childhood trauma and poor sustained attention in the MDDs, and might serve as potential intervention targets for the treatment of sustained attention deficits in MDDs with childhood trauma history.

Temporal Effects of Hypoxia Exposure at High Altitudes on Compensatory Brain Function: Evidence from Functional Connectivity of Resting-State EEG Brain Networks.

Ren, Hong, Xi-Yue Yang, Rui Su, HaiLin Ma, and Hao Li. Temporal Effects of Hypoxia Exposure at High Altitudes on Compensatory Brain Function: Evidence from Functional Connectivity of Resting-State EEG Brain Networks. High Alt Med Biol. 00:00-00, 2024. Background: The aim of this study was to investigate the effects of prolonged exposure to hypobaric hypoxia at high altitude on changes in brain function measured by electroencephalography (EEG), focusing specifically on the resting-state brain network functional connectivity and compensatory adaptations in brain function among individuals with varying durations of high altitude residency. Methods: In study I, 64 participants were divided into high-altitude group (HG) and low-altitude group (LG). Ninety-six long-term migrants residing at an altitude of 3,650 m were recruited for studyII and categorized into three groups based on their duration of stay at high altitude: group A (1-2 years), group B (8-10 years), and group C (18-20 years). Resting-state EEG data were collected from each participant, and functional connectivity analysis was conducted using Phase Locking Value. Results: Study I showed that participants with HG had stronger functional connectivity in the occipital lobe than those with LG (p < 0.05). The study II findings indicate that there were significant differences in functional connectivity strength among the frontal and occipital lobes in groups A, B, and C across the α, β, δ, and θ frequency bands. Specifically, the functional connectivity strength of the frontal lobe was significantly higher in group A compared with group B, and in group B compared with group C (p < 0.05). Additionally, the functional connectivity of the occipital lobe was significantly higher in group C compared with group B, and in group B compared with group A (p < 0.05). Conclusions: The consistent results of the whole frequency band suggest that the individual's occipital lobe function is enhanced to compensate for the damage of frontal lobe function, so as to better adapt to the extreme environment at high altitude.

The efficacy and cerebral mechanism of intradermal acupuncture for major depressive disorder: a multicenter randomized controlled trial

AbstractNew combinations or alternative therapies for major depressive disorder (MDD) are necessary. Intradermal acupuncture (IA) shows promise but requires further investigation regarding its efficacy, safety, and mechanisms. Conducted across 3 centers from November 2022 to January 2024, our randomized controlled trial included 120 participants with moderate to severe MDD, divided into the selective serotonin reuptake inhibitors (SSRIs), SSRIs plus sham IA (SSRIs + SIA), and SSRIs plus active IA (SSRIs + AIA) groups. Acupuncture groups received 10 sessions over 6 weeks at Shenmen (HT7), Neiguan (PC6), Sanyinjiao (SP6) and Taichong (LR3) bilaterally, followed by a 4-week follow-up. The primary outcome was changes in Hamilton Depression Rating Scale-17 (HAMD-17) scores at week 6. Furthermore, healthy controls (HCs) and MDD patients underwent magnetic resonance imaging (MRI) scans for functional connectivity (FC) analysis. After 6 weeks of treatment, the SSRIs + AIA group showed a greater reduction in HAMD-17 score than the SSRIs + SIA group (MD, −4.9 [CI, −7.6 to −2.2], P &lt; 0.001) and SSRIs group (MD, −5.1 [CI, −7.8 to −2.3], P &lt; 0.001). No serious adverse events occurred. SSRIs + AIA resulted in lower incidences of palpitations (vs.SSRIs + SIA: OR, 0.1% [CI, 0.0–1.0%]; vs. SSRIs: OR, 0.1% [CI, 0.0–0.7%]; P &lt; 0.05), somnolence (vs.SSRIs + SIA: OR, 0.1% [CI, 0.0–0.9%]; vs.SSRIs: OR, 0.1% [CI, 0.0–0.7%]; P &lt; 0.05), and nausea (vs.SSRIs + SIA: OR, 0.1% [CI, 0.0–1.0%]; vs. SSRIs: OR, 0.1% [CI, 0.0–0.9%]; P &lt; 0.05). MDD patients showed abnormal FCs, and IA enhanced FCs between striatum and frontal_inf_tri, and striatum and cerebellum in the MRI study. Overall, IA as adjunctive therapy provides clinical efficacy and safety for MDD, and it may exert antidepressant effects by modulating striatal FCs.

Olfactory training affects the correlation between brain structure and functional connectivity.

and background: Neuroimaging studies have increasingly found functional connectivity (FC) changes and structural cortical abnormalities in patients with post-traumatic anosmia (PTA). Training and repeated exposure to odorants lead to enhanced olfactory capability. This study is conducted to investigate the correlations between FC and cortical thickness on the olfaction-related regions of the brain in PTA after olfactory training (OT). Twenty-five PTA patients were randomly divided in three groups: (1) 9 control patients who did not receive any training, (2) 9 patients underwent classical OT by 4 fixed odors, and (3) 7 patients underwent modified OT coming across 4 sets of 4 different odors sequentially. Before and after the training period, all patients performed olfactory function tests, and magnetic resonance imaging (MRI). Sniffin' Sticks test was used to assess olfactory function. MRI data were analyzed using functional connectivity analysis and brain morphometry. Modified OT resulted in heightened activation in the medial orbitofrontal cortex and anterior cingulate cortex and increased FC between the piriform cortex (PIRC) and the caudate cortex. Conversely, classical OT induced increased activation in the insula cortex and greater FC between the PIRC and the pre-central gyrus. Furthermore, after OT, both training groups achieved significantly improved scores in the changes in brain connectivity associated with OT, which were attributable to anatomical measures. This study demonstrates that intensive olfactory training can enhance functional connectivity, and this improvement correlates with structural changes in the brain's olfactory processing areas.

Dynamic brain states underlying advanced concentrative absorption meditation: A 7T fMRI intensive case study

Abstract Advanced meditation consists of states and stages of practice that unfold with mastery and time. Dynamic functional connectivity (dFC) analysis of fMRI could identify brain states underlying advanced meditation. We conducted an intensive dFC case study of a meditator who completed 27 runs of jhāna advanced absorptive concentration meditation (ACAM-J), concurrently with 7-Tesla fMRI and phenomenological reporting. We identified three brain states that marked differences between ACAM-J and non-meditative control conditions. These states were characterized as a DMN-anticorrelated brain state, a hyperconnected brain state, and a sparsely connected brain state. Our analyses indicate higher prevalence of the DMN-anticorrelated brain state during ACAM-J than control states, and the prevalence increased significantly with deeper ACAM-J states. The hyperconnected brain state was also more common during ACAM-J, and was characterized by elevated thalamo-cortical connectivity and somatomotor network connectivity. The hyperconnected brain state significantly decreased over the course of ACAM-J, associating with self-reports of wider attention and diminished physical sensations. This brain state may be related to sensory awareness. Advanced meditators have developed well-honed abilities to move in and out of different altered states of consciousness, and this study provides initial evidence that functional neuroimaging can objectively track their dynamics.

Impaired contour object perception in psychosis.

Contour integration, the process of joining spatially separated elements into a single unified line, has consistently been found to be impaired in schizophrenia. Recent work suggests that this deficit could be associated with psychotic symptomatology, rather than a specific diagnosis such as schizophrenia. Examining a transdiagnostic sample of participants with psychotic psychopathology, we obtained quantitative indices of contour perception in a psychophysical behavioral task. We also measured responses during an analogous task using ultra-high field (7T) functional MRI. We found impaired contour discrimination performance among people with psychotic psychopathology (PwPP, n = 63) compared to healthy controls (n = 34) and biological relatives of PwPP (n = 44). Participants with schizophrenia (n = 31) showed impaired task performance compared to participants with bipolar disorder (n = 18). FMRI showed higher responses in the lateral occipital cortex of PwPP compared to controls. Using task-based functional connectivity analyses, we observed abnormal connectivity between visual brain areas during contour perception among PwPP. These connectivity differences only emerged when participants had to distinguish the contour object from background distractors, suggesting that a failure to suppress noise elements relative to contour elements may underlie impaired contour processing in PwPP. Our results are consistent with impaired contour integration in psychotic psychopathology, and especially schizophrenia, that is related to cognitive dysfunction, and may be linked to impaired functional connectivity across visual regions.

Distinct brain network structure of mesial temporal lobe epilepsy compared to that of neocortical epilepsy: functional MRI study with surgically treated patients.

Mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy (NE) have different anatomo-clinical characteristics. The authors hypothesized that this may be reflected in the different functional connectivity of the epileptogenic zone between mTLE and NE. The authors, therefore, examined preoperative resting-state functional connectivity MRI with regional global connectivity (rGC) analysis for surgically treated patients. The goal of this study was to detect the different functional networks associated with the epileptogenic zone between mTLE and NE. Twenty-four patients (12 with mTLE and 12 with NE) who underwent surgery were included in the study. All patients received resting-state functional MRI preoperatively. The mean rGC and number of high-rGC or low-rGC voxels were calculated using preoperative MRI in various regions of interest including the resected area. The ratio of mean rGC in the resected area to that of the whole brain was significantly lower in mTLE patients than in NE patients. Mean rGC was significantly lower than that of the contralateral counterpart of the resected area in mTLE patients, although it was not significantly different in NE patients. Low rGC was more frequently observed in the resected area in mTLE patients than NE patients, and high rGC more frequently observed in NE than mTLE. Multivariate analysis showed that the etiology of hippocampal sclerosis, the ratio of mean rGC in the resected area to that in the whole brain, and the ratio of the number of low- and high-rGC voxels relative to the whole brain were significant factors to distinguish mTLE from NE. The authors revealed a distinct brain network structure between mTLE and NE based on rGC analysis with resting-state functional MRI. The authors' unique functional connectivity analysis may be helpful for providing landmarks for lateralization or epileptogenic zones in mTLE and NE.

Frontal Deactivation and the Efficacy of Statistical Learning: Neural Mechanisms Accompanying Exposure to Visual Statistical Sequences.

Statistical learning is the cognitive ability to rapidly identify structure and meaning in unfamiliar streams of sensory experience, even in the absence of feedback. Despite extensive studies, the neurocognitive mechanisms underlying this phenomenon still require further clarification under varying cognitive conditions. Here, we examined neural mechanisms during the first exposure to visually presented sequences in 47 healthy participants. We used two types of visual objects: abstract symbols and pictures of cartoon-like animals. This allowed us to compare informational processing mechanisms with defined distinguishing features. Participants achieved better performance for sequences with easy-to-name than difficult-to-name abstract stimuli. fMRI results revealed greater activation in widespread brain regions in response to random versus statistical sequences for all stimuli types. Behavioral accuracy was associated with increased deactivation of the ventromedial pFC for easy-to-name statistical versus random sequences. For difficult-to-name statistical versus random sequences, performance correlated with dmPFC deactivation. ROI analysis showed a generally positive involvement of the caudate head in sequence processing with significantly stronger activity during the first run of performing the task. Functional connectivity analysis of prefrontal deactivation regions revealed significant connectivity with nodes of the salience network for both object types and inverse connectivity with the caudate head only for easy-to-name objects. The results indicated that distinct subregions of pFC modulate task performance depending on the visual stimulus characteristic. They also showed that among striatal regions, only the head of the caudate was sensitive to initial exposure to visual statistical information.

Investigating sex-related differences in brain structure and function in bipolar I disorder using multimodal MRI

BackgroundPast research has highlighted that bipolar I disorder is associated with significant changes in brain structure and function. Notably, the manifestation and progression of bipolar I disorder have been known to differ between males and females. However, the relationship between sex-related differences and bipolar I disorder diagnosis affecting these changes was not fully understood. This study aimed to investigate the sex-by-diagnosis interactions concerning the structural and functional features of the brain in individuals with bipolar I disorder.MethodsBoth structural and functional MRI data were obtained from 105 individuals with bipolar I disorder (36 males and 69 females) and 210 healthy controls (72 males and 138 females). Voxel-wise analyses of gray matter volume and functional connectivity were conducted using a general linear regression model. This model included age, sex, diagnosis, and a sex-by-diagnosis interaction as predictors to explore potential sex-related differences in the brain features of participants with bipolar I disorder.ResultsThe gray matter volume analysis revealed significant sex-by-diagnosis interactions in six brain regions: the left caudate (p < 0.001), left thalamus (p < 0.001), right caudate (p = 0.003), right thalamus (p < 0.001), left anterior cingulate gyrus (p = 0.022), and left middle/posterior cingulate gyrus (p = 0.015). Using these regions as seeds, we detected a significant sex-by-diagnosis interaction in the functional connectivity alteration between the left thalamus and right angular gyrus (p = 0.019).ConclusionsOur findings revealed a noteworthy sex-by-diagnosis interaction, with male individuals with bipolar I disorder displaying larger gray matter volume and altered functional connectivity in the limbic system compared to female individuals with bipolar I disorder and healthy participants. These results hint at potential sex-related differences in the pathophysiology of the limbic system in bipolar I disorder, which may have significant implications for understanding the underlying mechanisms in bipolar I disorder. Our findings could contribute to developing more personalized treatment approaches for individuals with bipolar I disorder.

Altered Blood Oxygen Level-Dependent Signal Stability in the Brain of Patients with Major Depressive Disorder Undergoing Resting-State Functional Magnetic Resonance Imaging

Introduction: Major depressive disorder (MDD) is a common, relapse-prone psychiatric disorder with unknown pathogenesis. Previous studies on resting-state functional magnetic resonance imaging of MDD have mostly focused on the spontaneous activity of blood oxygen level-dependent (BOLD) signals; however, a few studies have investigated BOLD signal stability. Methods: We conducted a resting-state functional study in 42 patients with MDD and 42 healthy controls (HC) matched for age and sex. This included the BOLD signal stability, resting-state functional connectivity (RSFC) analysis, correlation analysis, and support vector machine (SVM) analysis. Results: The BOLD signal stability of the left fusiform gyrus, right inferior temporal gyrus, right temporal pole superior temporal gyrus, and left thalamus was significantly lower in the MDD group compared to the HC group. Further RSFC analysis revealed that the connectivity between right inferior temporal gyrus and both left inferior temporal gyrus and left supramarginal gyrus was significantly reduced in the MDD group. Additionally, the RSFC levels of left thalamus and right thalamus were decreased. Combining BOLD signal stability and RSFC, the SVM-based classification model achieved an accuracy of 80.95% (sensitivity: 78.57%; specificity: 83.33%; receiver-operating characteristic area under the curve: 0.8793). Conclusion: The integration of the BOLD signal stability index and RSFC index demonstrates a robust capability to differentiate between individuals with MDD and HC subjects. We tentatively believe that a combination of the BOLD signal stability index and RSFC can be used to diagnose MDD.

Characterising the anxiogenic network from functional connectivity analysis of the CO2 challenge model

The CO2 challenge model (CCM) is a gas inhalation paradigm that provides precisely controlled anxiety induction in experimental settings. Despite its potential as an experimental model of anxiety, our understanding of the neural effects of the CCM is incomplete. This study employs resting-state functional magnetic resonance imaging (rs-fMRI) to explore functional connectivity (FC) changes underlying the CCM. Following a preliminary CO2 tolerance assessment, participants completed an MRI session that included three rs-fMRI scans: during inhalation of control air (pre and post), and during a 6% CCM exposure. Here, we confirm that 6% CCM is a tolerable anxiogenic model in the MRI setting. We demonstrate that a transient CCM-induced increase in subjective anxiety is associated with an increase in FC within limbic and anxiety-related regions, with the insula emerging as a central node in this altered connectivity pattern. Further analysis revealed a significant correlation between the levels of subjective anxiety and enhanced FC between the brainstem and medial frontal cortex, highlighting the dynamic role of the brainstem in response to CO2-induced anxiety. These findings underscore the value of combining CCM and rs-fMRI to characterise the neural mechanisms of anxiety, with important implications for evaluating potential therapeutic interventions.

Negative BOLD Responses Surpass Positive Responses in Task Specificity, Reflecting Neural Reconfigurations Better Than Functional Connectivity.

To investigate whether the Negative BOLD Response (NBR) is more task-specific than the Positive BOLD Response (PBR) during cognitive tasks and to determine whether task-evoked activity reflects brain reconfigurations during different tasks better than functional connectivity. Functional Magnetic Resonance Imaging (fMRI) data were collected from 214 participants under 50 years old (152 in Dataset 1 and 62 in Dataset 2) performing twelve cognitive tasks spanning vocabulary, speed of processing, fluid reasoning, and memory domains. Data analysis included subject-level and group-level analyses, focusing on comparing the spatial patterns and task specificity of NBR and PBR through similarity measures using Dice coefficients. Additionally, functional connectivity was assessed using the Multi-session Hierarchical Bayesian Model (MS-HBM) to evaluate its sensitivity to task-induced brain reconfigurations compared to task-evoked activity. NBR demonstrated significantly greater task specificity compared to PBR across all cognitive tasks, with lower mean Dice coefficients for NBR maps (mean: 0.44, SD: 0.13) than for PBR maps (mean: 0.67, SD: 0.09; t(65) = 18.38, p < 0.001). Functional connectivity analyses indicated that the default mode network (DMN) remained stable across tasks, suggesting that task-evoked activity reflects task-specific brain reconfigurations better than functional connectivity. The findings confirm that NBR is inherently more task-specific than PBR and that task-evoked activity provides a more sensitive measure of task-specific neural reconfigurations than functional connectivity. This enhances our understanding of the neural mechanisms underlying cognitive processes and highlights the importance of considering NBR in cognitive neuroscience research.

Maintenance of Bodily Expressions Modulates Functional Connectivity Between Prefrontal Cortex and Extrastriate Body Area During Working Memory Processing

Background/Objectives: As a form of visual input, bodily expressions can be maintained and manipulated in visual working memory (VWM) over a short period of time. While the prefrontal cortex (PFC) plays an indispensable role in top-down control, it remains largely unclear whether this region also modulates the VWM storage of bodily expressions during a delay period. Therefore, the two primary goals of this study were to examine whether the emotional bodies would elicit heightened brain activity among areas such as the PFC and extrastriate body area (EBA) and whether the emotional effects subsequently modulate the functional connectivity patterns for active maintenance during delay periods. Methods: During functional magnetic resonance imaging (fMRI) scanning, participants performed a delayed-response task in which they were instructed to view and maintain a body stimulus in working memory before emotion categorization (happiness, anger, and neutral). If processing happy and angry bodies consume increased cognitive demands, stronger PFC activation and its functional connectivity with perceptual areas would be observed. Results: Results based on univariate and multivariate analyses conducted on the data collected during stimulus presentation revealed an enhanced processing of the left PFC and left EBA. Importantly, subsequent functional connectivity analyses performed on delayed-period data using a psychophysiological interaction model indicated that functional connectivity between the PFC and EBA increases for happy and angry bodies compared to neutral bodies. Conclusions: The emotion-modulated coupling between the PFC and EBA during maintenance deepens our understanding of the functional organization underlying the VWM processing of bodily information.

Periodontitis associated with brain function impairment in middle-aged and elderly individuals with normal cognition.

The present study aimed to investigate changes in intranetwork functional connectivity (FC) and internetwork FC in middle-aged and elderly individuals with normal cognition (NC) and varying degrees of periodontitis to determine the effects of periodontitis on brain function. Periodontal findings and resting-state functional magnetic resonance imaging data were acquired from 51 subjects with NC. Independent component analysis and correlation analysis were used for the statistical analysis of the data. Differences in intranetwork FC were observed among groups in the anterior default-mode network (aDMN), dorsal attention network and dorsal sensorimotor network (dSMN). Compared with the nonperiodontitis (NP) group or the mild-periodontitis group, the analysis of internetwork FC showed increased FC between the auditory network and the ventral attention network (VAN), between the aDMN and the salience network (SN), and between the SN and the VAN and decreased FC between the posterior default-mode network and the right frontoparietal network in the moderate-to-severe periodontitis group. Additionally, internetwork FC between the dSMN and the VAN was also increased in the moderate-to-severe periodontitis group compared to the NP group. The altered intra- and internetwork FC were significantly correlated with the periodontal clinical index. Our results confirmed that periodontitis was associated with both intra- and internetwork FC changes even in NC. The present study indicates that periodontitis might be a potential risk factor for brain damage and provides a theoretical clue and a new treatment target for the early prevention of Alzheimer disease. Recent research has proposed that periodontitis is a potential risk factor for Alzheimer disease (AD). However, the relationship between periodontitis and the brain function of middle-aged and elderly individuals with normal cognition (NC) remains unclear. Analyzing the effect of periodontitis on brain function in the NC stage can provide clues to AD development and help achieve early prevention of dementia. The present study aimed to investigate changes in brain functional connectivity (FC) in NC with different severity of periodontitis to determine the effects of periodontitis on brain function. Both changed intranetwork FC and internetwork FC were found in the moderate-to-severe periodontitis group, and periodontitis was associated with brain network function impairment in NC. The present study indicates that periodontitis might be a potential risk factor for brain damage even in NC stage, and provides a theoretical clue and a new treatment target for the early prevention of AD.

Sleep deprivation impairs spatial cognitive processing and Alters brain connectivity in table tennis athletes

Spatial cognitive ability is critical for table tennis athletes to achieve excellent competitive performance, and sleep may be an important factor influencing this ability. This study investigated the impact of 36h sleep deprivation on the spatial cognitive processing of 20 s-level table tennis athletes, using event-related potentials and functional connectivity analysis to assess changes in cognitive resource allocation and inter-regional brain coordination before and after sleep deprivation. The results showed that sleep deprivation significantly prolonged reaction time and led to a decrease in P3 amplitude, reflecting a reduction in participants’ attentional resource allocation and cognitive processing capacity. Functional connectivity analysis further revealed that β frequency band functional connectivity between the frontal and occipital regions significantly decreased after sleep deprivation, indicating reduced brain efficiency in processing spatial information. After 36 h of SD, the spatial cognitive ability of table tennis athletes was impaired. SD not only led to a reduction in the allocation of attentional resources and cognitive processing capabilities in these athletes, but also weakened functional connectivity between the frontal and occipital lobes of the brain.

EEG and brain network analysis in the early diagnosis of Alzheimer's disease

Abstract. The early diagnosis of Alzheimers Disease (AD) is critical for effective intervention and improved patient outcomes. This paper explores the role of electroencephalography (EEG) and brain network analysis in the early detection of AD, with a particular focus on neurofeedback training as a therapeutic intervention. We review the characteristic changes in EEG signals, such as decreased alpha power and increased theta power, and their implications for identifying early cognitive decline. Functional connectivity analysis using coherence and phase synchronization methods reveals disruptions in key brain networks, providing valuable biomarkers for early AD. We also discuss quantitative EEG (qEEG) techniques, including power spectral density and fractal dimension, which enhance diagnostic accuracy. Additionally, mathematical models like the Kuramoto model offer insights into network dynamics and predict disease progression. Integrating EEG with other diagnostic tools, such as MRI and PET, creates a comprehensive multimodal approach. This integrative framework enhances early diagnosis and informs personalized treatment strategies, representing a significant advancement in the field of AD research and clinical practice.

Altered parasympathetic outflow and central sensitization response to continuous pain in cyclic vomiting syndrome: a functional magnetic resonance imaging study.

Cyclic vomiting syndrome (CVS) is a disorder of brain-gut interaction characterized by recurrent episodes of nausea and vomiting interspersed with asymptomatic periods and associated with autonomic nervous system dysfunction. We examined the dysautonomic response to noxious stimuli seen in CVS patients using our previously validated approach to integrate peripheral autonomic outflow metrics, temporal summation of pain, and brain fMRI. BOLD fMRI and ECG were acquired from CVS patients and healthy adults during a rest condition and a sustained cuff pressure pain stimulus at the leg. After the latter scan, participants rated pain for the full 6-minute pain stimulus as well as first, middle, and last two-minutes to calculate temporal summation. During sustained pain, patients (n=13) exhibited greater reduction in heart rate variability within the high-frequency range (HF-HRV) and reduced anticorrelation between HF-HRV and fMRI signal in the anterior insula, pregenual anterior cingulate cortex, and ventrolateral and dorsolateral prefrontal cortex relative to healthy adults (n=13). Compared to healthy adults (n=14), patients (n=14) exhibited increasing pain intensity over the course of sustained cuff pressure. Seed-based functional connectivity analysis revealed for healthy adults (n=13), pain sensitization correlated with pain-induced increases in connectivity between primary somatosensory cortex and regions of interest in both left anterior insula/posterior orbitofrontal cortex and right pre-supplementary motor area, while this correlation was disrupted in CVS (n=10). Our results support altered central coding of nociceptive stimuli and autonomic responsivity of CVS patients in key brain regions implicated in autonomic control and interoception.

Motor learning is modulated by dopamine availability in the sensorimotor putamen.

Successful motor skill acquisition requires the dynamic interaction of multiple brain regions, with the striatum playing a critical role in this network. Animal studies suggest that dopaminergic mechanisms are involved in the regulation of motor learning-associated striatal plasticity. In humans, however, the contribution of nigrostriatal dopaminergic transmission to motor learning remains elusive beyond its well-characterized role in initiation and fluent execution of movements. In this prospective observational study, we investigated motor sequence learning in individuals who had undergone 123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane single-photon emission computed tomography for the differential diagnosis of Parkinson's disease (n = 41) and age-matched healthy controls (n = 20). We found that striatal dopamine transporter depletion exhibited distinct spatial patterns that were associated with impairments in motor sequence learning and the manifestation of Parkinsonian motor symptoms, respectively. Specifically, significant associations between striatal dopamine transporter depletion and impairments in motor sequence learning were confined to posterior putaminal regions, whereas significant associations of striatal dopamine transporter depletion with Parkinsonian motor symptom severity showed a widespread spatial pattern across the entire striatal volume with an anterior maximum. Normative functional connectivity analysis revealed that both behavioural domains shared largely overlapping connectivity patterns with the basal ganglia and supplementary motor area. However, apart from connectivity with more posterior parts of the supplementary motor area, significant functional connectivity with primary motor cortical areas was only present for striatal dopamine transporter availability-related modulation of online motor learning. Our findings indicate that striatal dopaminergic signalling plays a specific role in motor sequence learning beyond its influence on mere motor execution, implicating learning-related sensorimotor striatum recruitment and cortico-striatal plasticity as dopamine-dependent mechanisms.

Cerebello-Cerebral Resting-State Functional Connectivity in Poststroke Aphasia.

Introduction: The influence of the cerebellum in poststroke aphasia recovery is poorly understood. Despite the right cerebellum being identified as a critical region involved in both language and cognitive functions, little is known about functional connections between the cerebellum and bilateral cortical hemispheres following stroke. This study investigated the relationship between chronic poststroke naming deficits and cerebello-cerebral resting-state functional connectivity (FC). Methods: Twenty-five cognitively normal participants and 42 participants with chronic poststroke aphasia underwent resting-state functional magnetic resonance imaging. Participants with aphasia also underwent language assessment. We conducted regions of interest (ROI)-to-ROI analyses to investigate the FC between the right cerebellar Crus I/II (seed ROI; Cereb1r/Cereb2r) and bilateral cortical language regions and compared these results to cognitively normal controls. Single-subject connectivity parameters were extracted and used as independent variables in a stepwise multiple linear regression model associating Boston Naming Test (BNT) score with FC measures. Results: FC analyses demonstrated correlations between the right cerebellar Crus I/II and both left and right cortical regions for both cognitively normal controls and stroke participants. Additionally, aphasia severity and lesion load had an effect on the cerebello-cerebral network connectivity in participants with aphasia. In a stepwise multiple linear regression, controlling for aphasia severity, time poststroke and lesion load, FC between the right Cereb2-left Cereb1 (standardized beta [std B]= -0.255, p < 0.004), right Cereb2-right anterior MTG (std B = 0.259, p < 0.004), and the right Cereb2-left anterior STG (std B = -0.208, p < 0.018) were significant predictors of BNT score. The overall model fit was R2 = 0.786 (p = 0.001). Conclusion: Functional connections between the right cerebellum and residual bilateral cerebral hemisphere regions may play a role in predicting naming ability in poststroke aphasia.