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Purpose: The study aimed to assess how isocitrate dehydrogenase 1 (IDH1) mutation status in patients with glioma may alter functional connectivity (FC) in the default mode network (DMN) and fronto-parietal network (FPN). Methods: Using resting-state functional magnetic resonance imaging, a seed-based FC analysis was employed to investigate connectivity within and between networks in seventeen patients with IDH1-mutant glioma (IDH1-M), eleven patients with IDH1-wildtype glioma (IDH1-WT), and nineteen healthy controls (HC). Results: For FC within the DMN, compared to HC, both IDH1-M and IDH1-WT exhibited significantly increased FC between the posterior cingulate cortex (PCC) and the right retrosplenial cortex, right precuneus/cuneus, and right middle cingulate cortex and between the right lateral parietal cortex (LP_R) and the right middle temporal gyrus. For FC within the FPN, compared with HC, IDH1-M showed significantly greater FC between the right posterior parietal cortex (PPC_R) and the right inferior, right medial, and right middle frontal gyrus, and IDH1-WT showed significantly increased FC between the PPC_R and the right middle frontal gyrus. For FC between the DMN and FPN, relative to IDH1-WT and HC, IDH1-M exhibited significantly increased FC between the LP_R and the right superior frontal gyrus and between the PPC_R and the right precuneus/cuneus. In contrast, compared to IDH1-M and HC, IDH1-WT showed significantly reduced FC between the PPC_R and the right angular gyrus. Conclusion: The preliminary findings revealed that there should be differences in the patterns of network reorganization between IDH1-M and IDH1-WT with different growth kinetics. [ABSTRACT FROM AUTHOR]

Purpose: Resting state functional magnetic resonance imaging (rsfMRI) is an emerging tool to explore the functional connectivity of different brain regions. We aimed to assess the disruption of functional connectivity of the Default Mode Network (DMN), Dorsal Attention Network(DAN) and Fronto-Parietal Network (FPN) in patients with glial tumors. Methods: rsfMRI data acquired on 3T-MR of treatment-naive glioma patients prospectively recruited (2015–2019) and matched controls from the 1000 functional-connectomes-project were analyzed using the CONN functional toolbox. Seed-Based Connectivity Analysis (SBCA) and Independent Component Analysis (ICA, with 10 to 100 components) were performed to study reliably the three networks of interest. Results: 35 patients with gliomas (17 WHO grade I-II, 18 grade III-IV) and 70 controls were included. Global increased DMN connectivity was consistently found with SBCA and ICA in patients compared to controls (Cluster1: Precuneus, height: p < 10−6; Cluster2: subcallosum; height: p < 10−5). However, an area of decreased connectivity was found in the posterior corpus callosum, particularly in high-grade gliomas (height: p < 10−5). The DAN demonstrated small areas of increased connectivity in frontal and occipital regions (height: p < 10−6). For the FPN, increased connectivity was noted in the precuneus, posterior cingulate gyrus, and frontal cortex. No difference in the connectivity of the networks of interest was demonstrated between low- and high-grade gliomas, as well as when stratified by their IDH1-R132H (isocitrate dehydrogenase) mutation status. Conclusion: Altered functional connectivity is reliably found with SBCA and ICA in the DMN, DAN, and FPN in glioma patients, possibly explained by decreased connectivity between the cerebral hemispheres across the corpus callosum due to disruption of the connections. [ABSTRACT FROM AUTHOR]

Working memory deficits are common in youth with epilepsy and consistently associated with long-term negative outcomes. Existing research on the neural basis of working memory disruptions in pediatric epilepsy is limited. The question of whether differences in the functional connectivity of neural networks underlie working memory disruptions in pediatric patients with epilepsy remains unanswered. A total of 49 adolescents between the ages of 13–17 years participated in this study. Twenty-nine adolescents had confirmed epilepsy (n = 17 generalized epilepsy, n = 6 localization-related, n = 6 unclassified). The control group included 20 healthy adolescents. A total of 10-min resting state functional magnetic resonance imaging was obtained for all participants. NeuroSynth-derived regions of interest were used as nodes that comprise working memory neural networks. Group differences in resting state functional connectivity were examined between adolescents with epilepsy and controls. Functional connectivity was computed as the temporal correlation of functional magnetic resonance imaging signal fluctuations between any two regions of interest. Compared to controls, adolescents in the epilepsy group demonstrated both hypoconnectivity and hyperconnectivity in cortical areas that map onto fronto-parietal and cingulo-opercular networks, as well as cerebellar regions. Functional connectivity between pairs of regions of interest was also significantly associated with behavioral measures of working memory across epilepsy and control groups. This study demonstrates that the presence of abnormal patterns in resting state neural network connectivity may underlie the working memory disruptions that frequently characterize the neurocognitive profile of youth with epilepsy. [ABSTRACT FROM AUTHOR]

In healthy participants, the strength of task-evoked network reconfigurations is associated with cognitive performance across several cognitive domains. It is, however, unclear whether the capacity for network reconfiguration also plays a role in cognitive deficits in brain tumor patients. In the current study, we examined whether the level of reconfiguration of the fronto-parietal ('FPN') and default mode network ('DMN') during task execution is correlated with cognitive performance in patients with different types of brain tumors. For this purpose, we combined data from a resting state and task-fMRI paradigm in patients with a glioma or meningioma. Cognitive performance was measured using the in-scanner working memory task, as well as an out-of-scanner cognitive flexibility task. Task-evoked changes in functional connectivity strength (defined as the mean of the absolute values of all connections) and in functional connectivity patterns within and between the FPN and DMN did not differ significantly across meningioma and fast (HGG) and slowly growing glioma (LGG) patients. Across these brain tumor patients, a significant and positive correlation was found between the level of task-evoked reconfiguration of the FPN and cognitive performance. This suggests that the capacity for FPN reconfiguration also plays a role in cognitive deficits in brain tumor patients, as was previously found for normal cognitive performance in healthy controls. [ABSTRACT FROM AUTHOR]

Anxiety is a common neuropsychiatric symptom in Parkinson's disease (PD). Until now, anxiety has been consistently related to cognitive deficits and severity of motor symptoms, whereas the association between anxiety and motor subtypes (TD-PD, tremor dominant and PIGD-PD, postural instability/gait disturbances dominant) revealed contrasting results. The present study aims to investigate the relationship between PD motor subtypes and anxiety and to explore whether the relationship between anxiety and cognitive deficits occurs in a specific PD motor subtype. Consecutive PD outpatients were recruited and divided into TD-PD and PIGD-PD groups according to Jankovic et al.'s criteria. All participants underwent a neuropsychological battery to evaluate anxiety, apathy, the global cognitive functioning, memory abilities, executive and visuo-constructional functions. Thirty-six patients with TD-PD and 35 patients with PIGD-PD were enrolled. The two groups did not differ on demographical and clinical variables. As for the severity of anxiety, no significant difference between the two groups was found. Regression analysis revealed that higher anxiety score was associated with poorer performance on constructional visuospatial test in both TD-PD and PIGD-PD. Clinical variables were not associated with anxiety in the two groups. Our findings indicated that the severity of anxiety was not associated with any PD motor subtypes. Moreover, regression analysis revealed that impaired visuo-constructional abilities are related to anxiety independently of PD motor subtypes. Since altered fronto-parietal network might be one of the pathogenetic mechanisms underpinning anxiety and constructional visuospatial deficits, the treatment of cognitive dysfunctions might reduce anxious symptoms. [ABSTRACT FROM AUTHOR]

Early numeracy provides the foundation of acquiring mathematical skills that is essential for future academic success. This study examined numerical functional networks in relation to counting and number relational skills in preschoolers at 4 and 6 years of age. The counting and number relational skills were assessed using school readiness test (SRT). Resting-state fMRI (rs-fMRI) was acquired in 123 4-year-olds and 146 6-year-olds. Among them, 61 were scanned twice over the course of 2 years. Meta-analysis on existing task-based numeracy fMRI studies identified the left parietal-dominant network for both counting and number relational skills and the right parietal-dominant network only for number relational skills in adults. We showed that the fronto-parietal numerical networks, observed in adults, already exist in 4-year and 6-year-olds. The counting skills were associated with the bilateral fronto-parietal network in 4-year-olds and with the right parietal-dominant network in 6-year-olds. Moreover, the number relational skills were related to the bilateral fronto-parietal and right parietal-dominant networks in 4-year-olds and had a trend of the significant relationship with the right parietal-dominant network in 6-year-olds. Our findings suggested that neural fine-tuning of the fronto-parietal numerical networks may subserve the maturation of numeracy in early childhood. [ABSTRACT FROM AUTHOR]

Previous neuroimaging studies have revealed cognitive dysfunction in patients with systemic lupus erythematosus (SLE) and suggested that it may be related to disrupted brain white matter (WM) connectivity. However, no study has examined the topological properties of brain WM structural networks in SLE patients, especially in patients with non-neuropsychiatric SLE (non-NPSLE). In this study, we acquired DTI datasets from 28 non-NPSLE patients and 24 healthy controls, constructed their brain WM structural networks by using a deterministic fiber tracking approach, estimated the topological parameters of their structural networks, and compared their group differences. We reached the following results: 1) At the global level, the non-NPSLE patients showed significantly increased characteristic path length, normalized clustering coefficient and small-worldness, but significantly decreased global efficiency and local efficiency compared to the controls; 2) At the nodal level, the non-NPSLE patients had significantly decreased nodal efficiency in regions related to movement control, executive control, and working memory (bilateral precentral gyri, bilateral middle frontal gyri, bilateral inferior parietal lobes, left median cingulate gyrus and paracingulate gyrus, and right middle temporal gyrus). In addition, to pinpointing the injured WM fiber tracts in the non-NPSLE patients, we reconstructed the major brain WM pathways connecting the abnormal regions at the nodal level with the corticospinal tract (CST), superior longitudinal fasciculus-parietal terminations (SLFP), and superior longitudinal fasciculus-temporal terminations (SLFT). By analyzing the diffusion parameters along these WM fiber pathways, we detected abnormal diffusion parameters in the bilateral CST and right SLFT in the non-NPSLE patients. These results seem to indicate that injured brain WM connectivity exists in SLE patients even in the absence of neuropsychiatric symptoms. [ABSTRACT FROM AUTHOR]

Long-term motor skill learning can induce plastic structural and functional reorganization of the brain. Our previous studies detected brain structural plasticity related to long-term intensive gymnastic training in world class gymnasts (WCGs). The goal of this study was to investigate brain functional plasticity in WCGs by using network measures of brain functional networks. Specifically, we acquired resting-state fMRI data from 13 WCGs and 14 controls, constructed their brain functional networks, and compared the differences in their network parameters. At the whole brain level, we detected significantly decreased overall functional connectivity (FC) and decreased local and global efficiency in the WCGs compared to the controls. At the modular level, we found intra- and inter-modular reorganization in three modules, the cerebellum, the cingulo-opercular and fronto-parietal networks, in the WCGs. On the nodal level, we revealed significantly decreased nodal strength and efficiency in several non-rich club regions of these three modules in the WCGs. These results suggested that functional plasticity can be detected in the brain functional networks of WCGs, especially in the cerebellum, fronto-parietal network, and cingulo-opercular network. In addition, we found that the FC between the fronto-parietal network and the sensorimotor network was significantly negatively correlated with the number of years of training in the WCGs. These findings may help us to understand the outstanding gymnastic performance of the gymnasts and to reveal the neural mechanisms that distinguish WCGs from controls. [ABSTRACT FROM AUTHOR]

We investigated differences of EEG coherence within (short-range), and between (long-range) specified brain areas as diagnostic markers for different states in disorders of consciousness (DOC), and their predictive value for recovery from unresponsive wakefulness syndrome (UWS). EEGs of 73 patients and 24 controls were recorded and coma recovery scale- revised (CRS-R) scores were assessed. CRS-R of UWS patients was collected after 12 months and divided into two groups (improved/unimproved). Frontal, parietal, fronto-parietal, fronto-temporal, and fronto-occipital coherence was computed, as well as EEG power over frontal, parietal, occipital, and temporal areas. Minimally conscious patients (MCS) and UWS patients could not be differentiated based on their coherence patterns or on EEG power. Fronto-parietal and parietal coherence could positively predict improvement of UWS patients, i.e. recovery from UWS to MCS. Parietal coherence was significantly higher in delta and theta frequencies in the improved group, as well as the coherence between frontal and parietal regions in delta, theta, alpha, and beta frequencies. High parietal delta and theta, and high fronto-parietal theta and alpha coherence appear to provide strong early evidence for recovery from UWS with high predictive sensitivity and specificity. Short and long-range coherence can have a diagnostic value in the prognosis of recovery from UWS. [ABSTRACT FROM AUTHOR]

Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N = 26) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient. [ABSTRACT FROM AUTHOR]

In a new working memory paradigm, CapMan, we independently investigated brain activity associated with capacity and manipulation of information. The investigation of Capacity, resulted in activation of the fronto-parietal network of regions that overlapped with areas usually found to be active in working memory tasks. The investigation of Manipulation revealed a more dorsal network of areas that also overlapped with areas usually found to be active in working memory tasks, but that did not overlap with the areas associated with Capacity. The CapMan paradigm thus appears to be able to separate the processes associated with capacity and manipulation increases and promises to be a valuable addition to the tools available for the study of working memory. [ABSTRACT FROM AUTHOR]

Coding of reaching in the cerebral cortex is based on the operation of distributed populations of parietal and frontal neurons, whose main functional characteristics reside in their combinatorial power, i.e., in the capacity for combining different information related to the spatial aspects of reaching. The tangential distribution of reach-related neurons endowed with different functional properties changes gradually in the cortex and defines, in the parieto-frontal network, trends of functional properties. These visual-to-somatic gradients imply the existence of cortical regions of functional overlaps, i.e., of combinatorial domains, where the integration of different reach-related signals occurs. Studies of early coding of reaching in the mesial parietal areas show how somatomotor information, such as that related to arm posture and movement, influences neuronal activity in the very early stages of the visuomotor transformation underlying the composition of the motor command and is not added “downstream” in the frontal cortex. This influence is probably due to re-entrant signals traveling through fronto-parietal-association connections. Together with the gradient architecture of the network and the reciprocity of cortico-cortical connections, this implies that coding of reaching cannot be regarded as a top-down, serial sequence of coordinate transformation, each performed by a given cortical area, but as a recursive process, where different signals are progressively matched and further elaborated locally, due to intrinsic cortical connections. This model of reaching is also supported by psychophysical studies stressing the parallel processing of the different relevant parameters and the “hybrid” nature of the reference frame where they are combined. The theoretical frame presented here can also offer a background for a new interpretation of a well-known visuomotor disorder, due to superior parietal lesions, i.e., optic ataxia. More than a disconnection syndrome, this can now be interpreted as the consequence of the breakdown of the operations occurring in the combinatorial domains of the superior parietal segment of the parieto-frontal network. [ABSTRACT FROM AUTHOR]