Functional disconnection between the visual cortex and the sensorimotor cortex suggests a potential mechanism for self-disorder in schizophrenia.
Schizophr Res. 2015 Jul 1;
Authors: Chen X, Duan M, Xie Q, Lai Y, Dong L, Cao W, Yao D, Luo C
Self-disorder is a hallmark characteristic of schizophrenia. This deficit may stem from an inability to efficiently integrate multisensory bodily signals. Twenty-nine schizophrenia patients and thirty-one healthy controls underwent resting-state fMRI in this study. A data-driven method, functional connectivity density mapping (FCD), was used to investigate cortical functional connectivity changes in the patients. Areas with significantly different FCD were chosen to calculate functional connectivity maps. The schizophrenia patients exhibited increased local FCD in frontal areas while demonstrating decreased local FCD in the primary sensorimotor area and in the occipital lobe. The functional connectivity analysis illustrated decreased functional connectivity between visual areas and the primary sensorimotor area. These findings suggest disturbed integration in perception-motor processing, which may contribute to mapping the neural physiopathology associated with self-disorder in schizophrenia patients.
CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry. Registration number. ChiCTR-RCS-14004878.
PMID: 26143483 [PubMed - as supplied by publisher]
Preserved consciousness in vegetative and minimal conscious states: systematic review and meta-analysis.
J Neurol Neurosurg Psychiatry. 2015 Jul 2;
Authors: Kondziella D, Friberg CK, Frokjaer VG, Fabricius M, Møller K
Active, passive and resting state paradigms using functional MRI (fMRI) or EEG may reveal consciousness in the vegetative (VS) and the minimal conscious state (MCS). A meta-analysis was performed to assess the prevalence of preserved consciousness in VS and MCS as revealed by fMRI and EEG, including command following (active paradigms), cortical functional connectivity elicited by external stimuli (passive paradigms) and default mode networks (resting state). Studies were selected from multiple indexing databases until February 2015 and evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2. 37 studies were identified, including 1041 patients (mean age 43 years, range 16-89; male/female 2.1:1; 39.5% traumatic brain injuries). MCS patients were more likely than VS patients to follow commands during active paradigms (32% vs 14%; OR 2.85 (95% CI 1.90 to 4.27; p<0.0001)) and to show preserved functional cortical connectivity during passive paradigms (55% vs 26%; OR 3.53 (95% CI 2.49 to 4.99; p<0.0001)). Passive paradigms suggested preserved consciousness more often than active paradigms (38% vs 24%; OR 1.98 (95% CI 1.54 to 2.54; p<0.0001)). Data on resting state paradigms were insufficient for statistical evaluation. In conclusion, active paradigms may underestimate the degree of consciousness as compared to passive paradigms. While MCS patients show signs of preserved consciousness more frequently in both paradigms, roughly 15% of patients with a clinical diagnosis of VS are able to follow commands by modifying their brain activity. However, there remain important limitations at the single-subject level; for example, patients from both categories may show command following despite negative passive paradigms.
PMID: 26139551 [PubMed - as supplied by publisher]
The influence of mild carbon dioxide on brain functional homotopy using resting-state fMRI.
Hum Brain Mapp. 2015 Jul 2;
Authors: Marshall O, Uh J, Lurie D, Lu H, Milham MP, Ge Y
Homotopy reflects the intrinsic functional architecture of the brain through synchronized spontaneous activity between corresponding bilateral regions, measured as voxel mirrored homotopic connectivity (VMHC). Hypercapnia is known to have clear impact on brain hemodynamics through vasodilation, but have unclear effect on neuronal activity. This study investigates the effect of hypercapnia on brain homotopy, achieved by breathing 5% carbon dioxide (CO2 ) gas mixture. A total of 14 healthy volunteers completed three resting state functional MRI (RS-fMRI) scans, the first and third under normocapnia and the second under hypercapnia. VMHC measures were calculated as the correlation between the BOLD signal of each voxel and its counterpart in the opposite hemisphere. Group analysis was performed between the hypercapnic and normocapnic VMHC maps. VMHC showed a diffused decrease in response to hypercapnia. Significant regional decreases in VMHC were observed in all anatomical lobes, except for the occipital lobe, in the following functional hierarchical subdivisions: the primary sensory-motor, unimodal, heteromodal, paralimbic, as well as in the following functional networks: ventral attention, somatomotor, default frontoparietal, and dorsal attention. Our observation that brain homotopy in RS-fMRI is affected by arterial CO2 levels suggests that caution should be used when comparing RS-fMRI data between healthy controls and patients with pulmonary diseases and unusual respiratory patterns such as sleep apnea or chronic obstructive pulmonary disease. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
PMID: 26138728 [PubMed - as supplied by publisher]
Network analysis of EEG related functional MRI changes due to medication withdrawal in focal epilepsy.
Neuroimage Clin. 2015;8:560-571
Authors: Hermans K, Ossenblok P, van Houdt P, Geerts L, Verdaasdonk R, Boon P, Colon A, de Munck JC
Anti-epileptic drugs (AEDs) have a global effect on the neurophysiology of the brain which is most likely reflected in functional brain activity recorded with EEG and fMRI. These effects may cause substantial inter-subject variability in studies where EEG correlated functional MRI (EEG-fMRI) is used to determine the epileptogenic zone in patients who are candidate for epilepsy surgery. In the present study the effects on resting state fMRI are quantified in conditions with AED administration and after withdrawal of AEDs. EEG-fMRI data were obtained from 10 patients in the condition that the patient was on the steady-state maintenance doses of AEDs as prescribed (condition A) and after withdrawal of AEDs (condition B), at the end of a clinically standard pre-surgical long term video-EEG monitoring session. Resting state networks (RSN) were extracted from fMRI. The epileptic component (ICE) was identified by selecting the RSN component with the largest overlap with the EEG-fMRI correlation pattern. Changes in RSN functional connectivity between conditions A and B were quantified. EEG-fMRI correlation analysis was successful in 30% and 100% of the cases in conditions A and B, respectively. Spatial patterns of ICEs are comparable in conditions A and B, except for one patient for whom it was not possible to identify the ICE in condition A. However, the resting state functional connectivity is significantly increased in the condition after withdrawal of AEDs (condition B), which makes resting state fMRI potentially a new tool to study AED effects. The difference in sensitivity of EEG-fMRI in conditions A and B, which is not related to the number of epileptic EEG events occurring during scanning, could be related to the increased functional connectivity in condition B.
PMID: 26137444 [PubMed - as supplied by publisher]
Putamen-midbrain functional connectivity is related to striatal dopamine transporter availability in patients with Lewy body diseases.
Neuroimage Clin. 2015;8:554-559
Authors: Rieckmann A, Gomperts SN, Johnson KA, Growdon JH, Van Dijk KR
Prior work has shown that functional connectivity between the midbrain and putamen is altered in patients with impairments in the dopamine system. This study examines whether individual differences in midbrain-striatal connectivity are proportional to the integrity of the dopamine system in patients with nigrostriatal dopamine loss (Parkinson's disease and dementia with Lewy bodies). We assessed functional connectivity of the putamen during resting state fMRI and dopamine transporter (DAT) availability in the striatum using 11C-Altropane PET in twenty patients. In line with the hypothesis that functional connectivity between the midbrain and the putamen reflects the integrity of the dopaminergic neurotransmitter system, putamen-midbrain functional connectivity was significantly correlated with striatal DAT availability even after stringent control for effects of head motion. DAT availability did not relate to functional connectivity between the caudate and thalamus/prefrontal areas. As such, resting state functional connectivity in the midbrain-striatal pathway may provide a useful indicator of underlying pathology in patients with nigrostriatal dopamine loss.
PMID: 26137443 [PubMed - as supplied by publisher]
Aberrant corticostriatal functional circuits in adolescents with Internet addiction disorder.
Front Hum Neurosci. 2015;9:356
Authors: Lin F, Zhou Y, Du Y, Zhao Z, Qin L, Xu J, Lei H
Abnormal structure and function in the striatum and prefrontal cortex (PFC) have been revealed in Internet addiction disorder (IAD). However, little is known about alterations of corticostriatal functional circuits in IAD. The aim of this study was to investigate the integrity of corticostriatal functional circuits and their relations to neuropsychological measures in IAD by resting-state functional connectivity (FC). Fourteen IAD adolescents and 15 healthy controls underwent resting-state fMRI scans. Using six predefined bilateral striatal regions-of-interest, voxel-wise correlation maps were computed and compared between groups. Relationships between alterations of corticostriatal connectivity and clinical measurements were examined in the IAD group. Compared to controls, IAD subjects exhibited reduced connectivity between the inferior ventral striatum and bilateral caudate head, subgenual anterior cingulate cortex (ACC), and posterior cingulate cortex, and between the superior ventral striatum and bilateral dorsal/rostral ACC, ventral anterior thalamus, and putamen/pallidum/insula/inferior frontal gyrus (IFG), and between the dorsal caudate and dorsal/rostral ACC, thalamus, and IFG, and between the left ventral rostral putamen and right IFG. IAD subjects also showed increased connectivity between the left dorsal caudal putamen and bilateral caudal cigulate motor area. Moreover, altered cotricostriatal functional circuits were significantly correlated with neuropsychological measures. This study directly provides evidence that IAD is associated with alterations of corticostriatal functional circuits involved in the affective and motivation processing, and cognitive control. These findings emphasize that functional connections in the corticostriatal circuits are modulated by affective/motivational/cognitive states and further suggest that IAD may have abnormalities of such modulation in this network.
PMID: 26136677 [PubMed - as supplied by publisher]
Multidimensional frequency domain analysis of full-volume fMRI reveals significant effects of age, gender, and mental illness on the spatiotemporal organization of resting-state brain activity.
Front Neurosci. 2015;9:203
Authors: Miller RL, Erhardt EB, Agcaoglu O, Allen EA, Michael AM, Turner JA, Bustillo J, Ford JM, Mathalon DH, Van Erp TG, Potkin S, Preda A, Pearlson G, Calhoun VD
Clinical research employing functional magnetic resonance imaging (fMRI) is often conducted within the connectionist paradigm, focusing on patterns of connectivity between voxels, regions of interest (ROIs) or spatially distributed functional networks. Connectivity-based analyses are concerned with pairwise correlations of the temporal activation associated with restrictions of the whole-brain hemodynamic signal to locations of a priori interest. There is a more abstract question however that such spatially granular correlation-based approaches do not elucidate: Are the broad spatiotemporal organizing principles of brains in certain populations distinguishable from those of others? Global patterns (in space and time) of hemodynamic activation are rarely scrutinized for features that might characterize complex psychiatric conditions, aging effects or gender-among other variables of potential interest to researchers. We introduce a canonical, transparent technique for characterizing the role in overall brain activation of spatially scaled periodic patterns with given temporal recurrence rates. A core feature of our technique is the spatiotemporal spectral profile (STSP), a readily interpretable 2D reduction of the native four-dimensional brain × time frequency domain that is still "big enough" to capture important group differences in globally patterned brain activation. Its power to distinguish populations of interest is demonstrated on a large balanced multi-site resting fMRI dataset with nearly equal numbers of schizophrenia patients and healthy controls. Our analysis reveals striking differences in the spatiotemporal organization of brain activity that correlate with the presence of diagnosed schizophrenia, as well as with gender and age. To the best of our knowledge, this is the first demonstration that a 4D frequency domain analysis of full volume fMRI data exposes clinically or demographically relevant differences in resting-state brain function.
PMID: 26136646 [PubMed - as supplied by publisher]
Exploitation of temporal redundancy in compressed sensing reconstruction of fMRI studies with a prior-based algorithm (PICCS).
Med Phys. 2015 Jul;42(7):3814
Authors: Chavarrías C, Abascal JF, Montesinos P, Desco M
PURPOSE: Compressed sensing is a technique used to accelerate magnetic resonance imaging (MRI) acquisition without compromising image quality. While it has proven particularly useful in dynamic imaging procedures such as cardiac cine, very few authors have applied it to functional magnetic resonance imaging (fMRI). The purpose of the present study was to check whether the prior image constrained compressed sensing (PICCS) algorithm, which is based on an available prior image, can improve the statistical maps in fMRI better than other strategies that also exploit temporal redundancy.
METHODS: PICCS was compared to spatiotemporal total variation (TTV) and k-t FASTER, since they have already demonstrated high performance and robustness in other MRI applications, such as cardiac cine MRI and resting state fMRI, respectively. The prior image for PICCS was the average of all undersampled data. Both PICCS and TTV were solved using the split Bregman formulation. K-t FASTER algorithm relies on matrix completion to reconstruct the undersampled k-spaces. The three algorithms were evaluated using two datasets with high and low signal-to-noise ratio (SNR)-BOLD contrast-acquired in a 7 T preclinical MRI scanner and retrospectively undersampled at various rates (i.e., acceleration factors). The authors evaluated their performance in terms of the sensitivity/specificity of BOLD detection through receiver operating characteristic curves and by visual inspection of the statistical maps.
RESULTS: With high SNR studies, PICCS performed similarly to the state-of-the-art algorithms TTV and k-t FASTER and provided consistent BOLD signal at the ROI. In scenarios with low SNR and high acceleration factors, PICCS still provided consistent maps and higher sensitivity/specificity than TTV, whereas k-t FASTER failed to provide significant maps.
CONCLUSIONS: The authors performed a comparison between three reconstructions (PICCS, TTV, and k-t FASTER) that exploit temporal redundancy in fMRI. The prior-based algorithm, PICCS, preserved BOLD activation and sensitivity/specificity better than TTV and k-t FASTER in noisy scenarios. The PICCS algorithm can potentially reach an acceleration factor of ×8 and still provide BOLD contrast in the ROI with an area under the curve over 0.99.
PMID: 26133583 [PubMed - as supplied by publisher]
Small-World Brain Network and Dynamic Functional Distribution in Patients with Subcortical Vascular Cognitive Impairment.
PLoS One. 2015;10(7):e0131893
Authors: Yu Y, Zhou X, Wang H, Hu X, Zhu X, Xu L, Zhang C, Sun Z
To investigate the topological properties of the functional connectivity and their relationships with cognition impairment in subcortical vascular cognitive impairment (SVCI) patients, resting-state fMRI and graph theory approaches were employed in 23 SVCI patients and 20 healthy controls. Functional connectivity between 90 brain regions was estimated using bivariate correlation analysis and thresholded to construct a set of undirected graphs. Moreover, all of them were subjected to a battery of cognitive assessment, and the correlations between graph metrics and cognitive performance were further analyzed. Our results are as follows: functional brain networks of both SVCI patients and controls showed small-world attributes over a range of thresholds(0.15≤sparsity≤0.40). However, global topological organization of the functional brain networks in SVCI was significantly disrupted, as indicated by reduced global and local efficiency, clustering coefficients and increased characteristic path lengths relative to normal subjects. The decreased activity areas in SVCI predominantly targeted in the frontal-temporal lobes, while subcortical regions showed increased topological properties, which are suspected to compensate for the inefficiency of the functional network. We also demonstrated that altered brain network properties in SVCI are closely correlated with general cognitive and praxis dysfunction. The disruption of whole-brain topological organization of the functional connectome provides insight into the functional changes in the human brain in SVCI.
PMID: 26132397 [PubMed - as supplied by publisher]
SU-E-I-66: Brief Occurrences of Brain Signals Leading to Dynamic Patterns in Resting State FMRI.
Med Phys. 2015 Jun;42(6):3257
Authors: Ball N, Chen N
PURPOSE: To identify functional connectivity patterns in the resting-state network of the brain using blood-oxygen level dependent (BOLD) signals from functional magnetic resonance imaging (fMRI).
METHODS: Extracted fMRI BOLD signals from the posterior cingulate cortex (PCC) were averaged and used to find time points at which the BOLD signal exceeded a threshold. These time points were then compared with signals at all points within the brain to locate the BOLD signals which breached a threshold within a given time period. Next, regions with similar temporal patterns were grouped and analyzed to create networks.
RESULTS: Investigation of the number of correlating time points between PCC region activity, and above threshold signals throughout the brain, demonstrates signal correlation with the seed region's activity. Time points in the top 5% demonstrated 87% more matches relative to those within the 5% of time points closest to zero activity. When comparing the bottom 12% of the time points in the PCC, this number dropped to 12%, however this is substantially higher than the median BOLD signals.
CONCLUSION: This work demonstrates that interactions between different regions of the brain can be revealed through spontaneous increases in BOLD activity within the PCC. Future investigation is needed to find out how low fluctuations in the signal from a seed region interact and form patterns with other regions of the brain. Further analysis of temporal patterns and subtle changes in the pathology can be used to potentially investigate possible differences between healthy brains, and those afflicted with abnormalities such as Parkinson's disease. This research is supported by NIH R01-NS074045.
PMID: 26127371 [PubMed - in process]
Memory consolidation of fear conditioning: bi-stable amygdala connectivity with dorsal anterior cingulate and medial prefrontal cortex.
Soc Cogn Affect Neurosci. 2014 Nov;9(11):1730-7
Authors: Feng P, Feng T, Chen Z, Lei X
Investigations of fear conditioning in rodents and humans have illuminated the neural mechanisms of fear acquisition and extinction. However, the neural mechanism of memory consolidation of fear conditioning is not well understood. To address this question, we measured brain activity and the changes in functional connectivity following fear acquisition using resting-state functional magnetic resonance imaging. The amygdala-dorsal anterior cingulate cortex (dACC) and hippocampus-insula functional connectivity were enhanced, whereas the amygdala-medial prefrontal cortex (mPFC) functional coupling was decreased during fear memory consolidation. Furthermore, the amygdala-mPFC functional connectivity was negatively correlated with the subjective fear ratings. These findings suggest the amygdala functional connectivity with dACC and mPFC may play an important role in memory consolidation of fear conditioning. The change of amygdala-mPFC functional connectivity could predict the subjective fear. Accordingly, this study provides a new perspective for understanding fear memory consolidation.
PMID: 24194579 [PubMed - indexed for MEDLINE]
Sparse temporally dynamic resting-state functional connectivity networks for early MCI identification.
Brain Imaging Behav. 2015 Jun 28;
Authors: Wee CY, Yang S, Yap PT, Shen D, Alzheimer’s Disease Neuroimaging Initiative
In conventional resting-state functional MRI (R-fMRI) analysis, functional connectivity is assumed to be temporally stationary, overlooking neural activities or interactions that may happen within the scan duration. Dynamic changes of neural interactions can be reflected by variations of topology and correlation strength in temporally correlated functional connectivity networks. These connectivity networks may potentially capture subtle yet short neural connectivity disruptions induced by disease pathologies. Accordingly, we are motivated to utilize disrupted temporal network properties for improving control-patient classification performance. Specifically, a sliding window approach is firstly employed to generate a sequence of overlapping R-fMRI sub-series. Based on these sub-series, sliding window correlations, which characterize the neural interactions between brain regions, are then computed to construct a series of temporal networks. Individual estimation of these temporal networks using conventional network construction approaches fails to take into consideration intrinsic temporal smoothness among successive overlapping R-fMRI sub-series. To preserve temporal smoothness of R-fMRI sub-series, we suggest to jointly estimate the temporal networks by maximizing a penalized log likelihood using a fused sparse learning algorithm. This sparse learning algorithm encourages temporally correlated networks to have similar network topology and correlation strengths. We design a disease identification framework based on the estimated temporal networks, and group level network property differences and classification results demonstrate the importance of including temporally dynamic R-fMRI scan information to improve diagnosis accuracy of mild cognitive impairment patients.
PMID: 26123390 [PubMed - as supplied by publisher]
Degree centrality and fractional amplitude of low-frequency oscillations associated with Stroop interference.
Neuroimage. 2015 Jun 26;
Authors: Takeuchi H, Taki Y, Nouchi R, Sekiguchi A, Hashizume H, Sassa Y, Kotozaki Y, Miyauchi CM, Yokoyama R, Iizuka K, Nakagawa S, Nagase T, Kunitoki K, Kawashima R
Stroop paradigms are commonly used as an index of attention deficits and a tool for investigating functions of the frontal lobes and other associated structures. Here we investigated the correlation between resting-state functional magnetic imaging (fMRI) measures [degree centrality (DC)/fractional amplitude of low frequency fluctuations (fALFF)] and Stroop interference. We examined this relationship in the brains of 958 healthy young adults. DC reflects the number of instantaneous functional connections between a region and the rest of the brain within the entire connectivity matrix of the brain (connectome), and thus how much of the node influences the entire brain areas, while fALFF, is an indicator of the intensity of regional brain spontaneous activity. Reduced Stroop interference was associated with larger DC in the left lateral prefrontal cortex, left IFJ, and left inferior parietal lobule as well as larger fALFF in the areas of the dorsal attention network and the precuneus. These findings suggest that Stroop performance is reflected in resting state functional properties of these areas and the network. In addition, default brain activity of the dorsal attention network and precuneus as well as higher cognitive processes represented there, and default stronger global influence of the areas critical in executive functioning underlies better Stroop performance.
PMID: 26123381 [PubMed - as supplied by publisher]
Brain networks underlying bistable perception.
Neuroimage. 2015 Jun 26;
Authors: Baker DH, Karapanagiotidis T, Coggan DD, Wailes-Newson K, Smallwood J
Bistable stimuli, such as the Necker Cube, demonstrate that experience can change in the absence of changes in the environment. Such phenomena can be used to assess stimulus-independent aspects of conscious experience. The current study used resting state functional magnetic resonance imaging (rs-fMRI) to index stimulus-independent changes in neural activity to understand the neural architecture that determines dominance durations during bistable perception (using binocular rivalry and Necker cube stimuli). Anterior regions of the Superior Parietal Lobule (SPL) exhibited robust connectivity with regions of primary sensorimotor cortex. The strength of this region's connectivity with the striatum predicted shorter dominance durations during binocular rivalry, whereas its connectivity to pre-motor cortex predicted longer dominance durations for the Necker Cube. Posterior regions of the SPL, on the other hand, were coupled to associative cortex in the temporal and frontal lobes. The posterior SPL's connectivity to the temporal lobe predicted longer dominance during binocular rivalry. In conjunction with prior work, these data suggest that the anterior SPL contributes to perceptual rivalry through the inhibition of incongruent bottom up information, whereas the posterior SPL influences rivalry by supporting the current interpretation of a bistable stimulus. Our data suggests that the functional connectivity of the SPL with regions of sensory, motor and associative cortex allows it to regulate the interpretation of the environment that forms the focus of conscious attention at a specific moment in time.
PMID: 26123379 [PubMed - as supplied by publisher]
Cognitive behavioural therapy for depression: systematic review of imaging studies.
Acta Neuropsychiatr. 2015 Jun 30;:1-14
Authors: Franklin G, Carson AJ, Welch KA
OBJECTIVE: Although cognitive behavioural therapy (CBT) has been shown to be an effective treatment for depression, the biological mechanisms underpinning it are less clear. This review examines if it is associated with changes identifiable with current brain imaging technologies.
METHODS: To better understand the mechanisms by which CBT exerts its effects, we undertook a systematic review of studies examining brain imaging changes associated with CBT treatment of depression.
RESULTS: Ten studies were identified, five applying functional magnetic resonance imaging, three positron emission tomography, one single photon emission computer tomography, and one magnetic resonance spectroscopy. No studies used structural MRI. Eight studies included a comparator group; in only one of these studies was there randomised allocation to another treatment. CBT-associated changes were most commonly observed in the anterior cingulate cortex (ACC), posterior cingulate, ventromedial prefrontal cortex/orbitofrontal cortex (VMPFC/OFC) and amygdala/hippocampus. Discussion The evidence, such as it is, suggests resting state activity in the dorsal ACC is decreased by CBT. It has previously been suggested that treatment with CBT may result in increased efficiency of a putative 'dorsal cognitive circuit', important in cognitive control and effortful regulation of emotion. It is speculated this results in an increased capacity for 'top-down' emotion regulation, which is employed when skills taught in CBT are engaged. Though changes in activity of the dorsal ACC could be seen as in-keeping with this model, the data are currently insufficient to make definitive statements about how CBT exerts its effects. Data do support the contention that CBT is associated with biological brain changes detectable with current imaging technologies.
PMID: 26122039 [PubMed - as supplied by publisher]
Alteration of brain regional homogeneity of monkeys with spinal cord injury: A longitudinal resting-state functional magnetic resonance imaging study.
Magn Reson Imaging. 2015 Jun 24;
Authors: Rao JS, Ma M, Zhao C, Liu Z, Yang ZY, Li XG
PURPOSE: To investigates the longitudinal brain regional homogeneity (ReHo) changes in nonhuman primate after spinal cord injury (SCI) by resting-state functional magnetic resonance imaging (fMRI).
METHODS: Three adult female rhesus monkeys underwent unilateral thoracic cord injury. A resting-state fMRI examination was performed in the healthy stage and 4, 8, and 12weeks after the injury. The ReHo value of each voxel in the monkey brain was calculated and compared between pre- and post-SCI monkeys with paired t test. The regions of interest (ROI) in the significantly changed ReHo regions were set. The correlations between the ReHo change and the time after injury were also determined.
RESULTS: Compared with those in healthy period, the ReHo values of the left premotor cortex and the anterior cingulate cortex (ACC) in post-SCI rhesus monkeys significantly increased in 4-week follow-up examinations. The ReHo values of posterior cingulate cortex, left precuneus, left temporal parietooccipital area, and bilateral superior parietal lobules decreased at 8-week follow-up examinations. In 12-week follow-up examinations, the ReHo values of the left postcentral gyrus, right caudate nucleus, and superior temporal gyrus increased. Correlation analysis showed positive correlations between left ACC and the postoperative time.
CONCLUSION: SCI can change the regional synchronism of brain activity in sensorimotor system and the default mode network. These findings may help us to understand the potential pathophysiological changes in the central nervous system after SCI.
PMID: 26117702 [PubMed - as supplied by publisher]
The mediating role of LPFC-vmPFC functional connectivity in the relation between regulatory mode and delay discounting.
Behav Brain Res. 2015 Jun 24;
Authors: Guo Y, Feng T
Previous studies have shown that regulatory mode orientation can affect many human behaviors, such as risk-taking, counterfactual thinking and economic decision making. However, little is known about how regulatory mode affects delay discounting. To address this question, we used resting-state functional magnetic resonance imaging (rs-fMRI) to investigate whether regulatory mode orientations can be represented by functional connectivity and the influence of two regulatory modes (Assessment and Locomotion) on delay discounting. The behavioral results showed that delay discounting was negatively correlated with Assessment scores but positively correlated with Locomotion scores. Neuroimaging results indicated that the functional connectivity between lateral prefrontal cortex (LPFC) and ventromedial prefrontal cortex (vmPFC) was negatively correlated with Assessment scores but positively correlated with Locomotion scores. Furthermore, mediation analysis showed that the effect of regulatory mode on delay discounting is mediated by LPFC-vmPFC functional connectivity. These results suggested that people's regulatory mode orientation could predict delay discounting, which is mediated by LPFC-vmPFC functional connectivity. Therefore, the present study extends our perspective on regulatory mode and provides neural mechanism for understanding the link between regulatory mode and delay discounting.
PMID: 26116812 [PubMed - as supplied by publisher]
Abnormal intrinsic brain activity patterns in leukoaraiosis with and without cognitive impairment.
Behav Brain Res. 2015 Jun 24;
Authors: Li C, Yang J, Yin X, Liu C, Zhang L, Zhang X, Gui L, Wang J
The amplitude of low frequency fluctuations (ALFF) from resting-state functional MRI (rs-fMRI) signals can be used to detect intrinsic spontaneous brain activity and provide valuable insights into the pathomechanism of neural disease. In this study, we recruited 56 patients who had been diagnosed as having mild to severe leukoaraiosis. According to the neuropsychological tests, they were subdivided into a leukoaraiosis with cognitive impairment group (n=28) and a leukoaraiosis without cognitive impairment group (n=28). 28 volunteers were included as normal controls. We found that the three groups showed significant differences in ALFF in the brain regions of the right inferior occipital gyrus (IOG_R), left middle temporal gyrus (MTG_L), left precuneus (Pcu_L), right superior frontal gyrus (SFG_R) and right superior occipital gyrus (SOG_R). Compared with normal controls, the leukoaraiosis without cognitive impairment group exhibited significantly increased ALFF in the IOG_R, Pcu_L, SFG_R and SOG_R. While compared with leukoaraiosis without cognitive impairment group, the leukoaraiosis with cognitive impairment group showed significantly decreased ALFF in IOG_R, MTG_L, Pcu_L and SOG_R. A close negative correlation was found between the ALFF values of the MTG_L and the Montreal Cognitive Assessment (MoCA) scores. Our data demonstrate that white matter integrity and cognitive impairment are associated with different amplitude fluctuations of rs-fMRI signals. Leukoaraiosis is related to ALFF increases in IOG_R, Pcu_L, SFG_Orb_R and SOG_R. Decreased ALFF in MTG_L is characteristic of cognitive impairment and may aid in its early detection.
PMID: 26116811 [PubMed - as supplied by publisher]
Thalamic resting-state functional connectivity: disruption in patients with type 2 diabetes.
Metab Brain Dis. 2015 Jun 27;
Authors: Chen YC, Xia W, Qian C, Ding J, Ju S, Teng GJ
To explore the disrupted thalamic functional connectivity and its relationships with cognitive dysfunction in type 2 diabetes mellitus (T2DM) by using resting-state functional magnetic resonance imaging (fMRI). A total of 38 T2DM patients and 39 well-matched healthy controls participated in the resting-state fMRI and T1-weighted imaging scans. The thalamic functional connectivity was characterized by using a seed-based whole-brain correlation method and compared T2DM patients with healthy controls. Pearson correlation analysis was performed between thalamic functional connectivity and clinical data. When compared with healthy controls, T2DM showed significantly decreased functional connectivity of the thalamus mainly in the right middle temporal gyrus (MTG), right precentral gyrus and bilateral occipital cortex; Increased functional connectivity of the thalamus was detected in the left cerebellum, bilateral middle frontal gyrus and middle cingulate gyrus (p < 0.05, corrected for AlphaSim). In T2DM patients, the decreased thalamic functional connectivity of the right MTG was positively associated with the Verbal Fluency Test score (r = 0.438, p = 0.006). Meanwhile, the decreased thalamic functional connectivity of the right cuneus was positively correlated with the Complex Figure Test-delayed score and negatively correlated with the Trail Making Test-B score, respectively (r = 0.492, p = 0.002; r = -0.504, p = 0.001). Moreover, there was no structural damage in the thalamus of T2DM patients. T2DM patients develop disrupted thalamocortical functional connectivity, which is associated with cognitive impairment in selected brain regions. Resting-state thalamocortical connectivity disturbance may play a central role in the underlying neuropathological process of T2DM-related cognitive dysfunction.
PMID: 26116166 [PubMed - as supplied by publisher]
Default mode network maturation and psychopathology in children and adolescents.
J Child Psychol Psychiatry. 2015 Jun 26;
Authors: Sato JR, Salum GA, Gadelha A, Crossley N, Vieira G, Manfro GG, Zugman A, Picon FA, Pan PM, Hoexter MQ, Anés M, Moura LM, Del'Aquilla MA, Jr EA, McGuire P, Lacerda AL, Rohde LA, Miguel EC, Jackowski AP, Bressan RA
BACKGROUND: The human default mode (DMN) is involved in a wide array of mental disorders. Current knowledge suggests that mental health disorders may reflect deviant trajectories of brain maturation.
METHOD: We studied 654 children using functional magnetic resonance imaging (fMRI) scans under a resting-state protocol. A machine-learning method was used to obtain age predictions of children based on the average coefficient of fractional amplitude of low frequency fluctuations (fALFFs) of the DMN, a measure of spontaneous local activity. The chronological ages of the children and fALFF measures from regions of this network, the response and predictor variables were considered respectively in a Gaussian Process Regression. Subsequently, we computed a network maturation status index for each subject (actual age minus predicted). We then evaluated the association between this maturation index and psychopathology scores on the Child Behavior Checklist (CBCL).
RESULTS: Our hypothesis was that the maturation status of the DMN would be negatively associated with psychopathology. Consistent with previous studies, fALFF significantly predicted the age of participants (p < .001). Furthermore, as expected, we found an association between the DMN maturation status (precocious vs. delayed) and general psychopathology scores (p = .011).
CONCLUSIONS: Our findings suggest that child psychopathology seems to be associated with delayed maturation of the DMN. This delay in the neurodevelopmental trajectory may offer interesting insights into the pathophysiology of mental health disorders.
PMID: 26111611 [PubMed - as supplied by publisher]