Multicontrast connectometry: A new tool to assess cerebellum alterations in early relapsing-remitting multiple sclerosis.
Hum Brain Mapp. 2014 Nov 24;
Authors: Romascano D, Meskaldji DE, Bonnier G, Simioni S, Rotzinger D, Lin YC, Menegaz G, Roche A, Schluep M, Pasquier RD, Richiardi J, Van De Ville D, Daducci A, Sumpf T, Fraham J, Thiran JP, Krueger G, Granziera C
Background: Cerebellar pathology occurs in late multiple sclerosis (MS) but little is known about cerebellar changes during early disease stages. In this study, we propose a new multicontrast "connectometry" approach to assess the structural and functional integrity of cerebellar networks and connectivity in early MS. Methods: We used diffusion spectrum and resting-state functional MRI (rs-fMRI) to establish the structural and functional cerebellar connectomes in 28 early relapsing-remitting MS patients and 16 healthy controls (HC). We performed multicontrast "connectometry" by quantifying multiple MRI parameters along the structural tracts (generalized fractional anisotropy-GFA, T1/T2 relaxation times and magnetization transfer ratio) and functional connectivity measures. Subsequently, we assessed multivariate differences in local connections and network properties between MS and HC subjects; finally, we correlated detected alterations with lesion load, disease duration, and clinical scores. Results: In MS patients, a subset of structural connections showed quantitative MRI changes suggesting loss of axonal microstructure and integrity (increased T1 and decreased GFA, P < 0.05). These alterations highly correlated with motor, memory and attention in patients, but were independent of cerebellar lesion load and disease duration. Neither network organization nor rs-fMRI abnormalities were observed at this early stage. Conclusion: Multicontrast cerebellar connectometry revealed subtle cerebellar alterations in MS patients, which were independent of conventional disease markers and highly correlated with patient function. Future work should assess the prognostic value of the observed damage. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc.
PMID: 25421928 [PubMed - as supplied by publisher]
Holistic Atlases of Functional Networks and Interactions Reveal Reciprocal Organizational Architecture of Cortical Function.
IEEE Trans Biomed Eng. 2014 Nov 20;
Authors: Lv J, Jiang X, Li X, Zhu D, Zhang S, Zhao S, Chen H, Zhang T, Hu X, Han J, Ye J, Guo L, Liu T
For decades, it has been largely unknown to what extent multiple functional networks spatially overlap/interact with each other and jointly realize the total cortical function. Here, by developing novel sparse representation of whole-brain fMRI signals and by using the recently publicly released large-scale Human Connectome Project (HCP) high-quality fMRI data, we show that a number of reproducible and robust functional networks, including both task-evoked and resting state networks, are simultaneously distributed in distant neuroanatomic areas and substantially spatially overlapping with each other, thus forming an initial collection of holistic atlases of functional networks and interactions (HAFNI). More interestingly, the HAFNIs revealed two distinct patterns of highly overlapped regions and highly-specialized regions and exhibited that these two patterns of areas are reciprocally localized, revealing a novel organizational principle of cortical function.
PMID: 25420254 [PubMed - as supplied by publisher]
The impact of normalization and segmentation on resting state brain networks.
Brain Connect. 2014 Nov 24;
Authors: Magalhães R, Marques P, Soares J, Alves V, Sousa N
Graph theory has recently received a lot of attention from the neuroscience community as a method to represent and characterize brain networks. Still, there is a lack of a gold standard for the methods that should be employed for the preprocessing of the data and the construction of the networks, as well as a lack of knowledge on how different methodologies can affect the metrics reported. We used graph theory analysis applied to resting-state functional Magnetic Resonance Imaging (rs-fMRI) to investigate the influence of different node-defining strategies and the effect of normalizing the functional acquisition on several commonly reported metrics used to characterize brain networks. The nodes of the network were defined using either the individual FreeSurfer segmentation of each subject or the FreeSurfer segmented MNI (Montreal National Institute) 152 template, using the Destrieux and sub-cortical atlas. The functional acquisition was either kept on the functional native space or normalized into MNI standard space. The comparisons were done at three levels: on the connections, on the edge properties and on the network properties levels. Our results reveal that different registration and brain parcellation strategies have a strong impact on all the levels of analysis, possibly favoring the use of individual segmentation strategies and conservative registration approaches. In conclusion, several technical aspects must be considered so that graph theoretical analysis of connectivity MRI data can provide a framework to understand brain pathologies.
PMID: 25420048 [PubMed - as supplied by publisher]
Improvement of white matter and functional connectivity abnormalities by repetitive transcranial magnetic stimulation in crossed aphasia in dextral.
Int J Clin Exp Med. 2014;7(10):3659-3668
Authors: Lu H, Wu H, Cheng H, Wei D, Wang X, Fan Y, Zhang H, Zhang T
As a special aphasia, the occurrence of crossed aphasia in dextral (CAD) is unusual. This study aims to improve the language ability by applying 1 Hz repetitive transcranial magnetic stimulation (rTMS). We studied multiple modality imaging of structural connectivity (diffusion tensor imaging), functional connectivity (resting fMRI), PET, and neurolinguistic analysis on a patient with CAD. Furthermore, we applied rTMS of 1 Hz for 40 times and observed the language function improvement. The results indicated that a significantly reduced structural and function connectivity was found in DTI and fMRI data compared with the control. The PET imaging showed hypo-metabolism in right hemisphere and left cerebellum. In conclusion, one of the mechanisms of CAD is that right hemisphere is the language dominance. Stimulating left Wernicke area could improve auditory comprehension, stimulating left Broca's area could enhance expression, and the results outlasted 6 months by 1 Hz rTMS balancing the excitability inter-hemisphere in CAD.
PMID: 25419415 [PubMed - as supplied by publisher]
Virtual water maze learning in human increases functional connectivity between posterior hippocampus and dorsal caudate.
Hum Brain Mapp. 2014 Nov 21;
Authors: Woolley DG, Mantini D, Coxon JP, D'Hooge R, Swinnen SP, Wenderoth N
Recent work has demonstrated that functional connectivity between remote brain regions can be modulated by task learning or the performance of an already well-learned task. Here, we investigated the extent to which initial learning and stable performance of a spatial navigation task modulates functional connectivity between subregions of hippocampus and striatum. Subjects actively navigated through a virtual water maze environment and used visual cues to learn the position of a fixed spatial location. Resting-state functional magnetic resonance imaging scans were collected before and after virtual water maze navigation in two scan sessions conducted 1 week apart, with a behavior-only training session in between. There was a large significant reduction in the time taken to intercept the target location during scan session 1 and a small significant reduction during the behavior-only training session. No further reduction was observed during scan session 2. This indicates that scan session 1 represented initial learning and scan session 2 represented stable performance. We observed an increase in functional connectivity between left posterior hippocampus and left dorsal caudate that was specific to scan session 1. Importantly, the magnitude of the increase in functional connectivity was correlated with offline gains in task performance. Our findings suggest cooperative interaction occurs between posterior hippocampus and dorsal caudate during awake rest following the initial phase of spatial navigation learning. Furthermore, we speculate that the increase in functional connectivity observed during awake rest after initial learning might reflect consolidation-related processing. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc.
PMID: 25418860 [PubMed - as supplied by publisher]
Impaired Functional Connectivity Unmasked by Simple Repetitive Motor Task in Early Relapsing-Remitting Multiple Sclerosis.
Neurorehabil Neural Repair. 2014 Nov 21;
Authors: Petsas N, Tomassini V, Filippini N, Sbardella E, Tona F, Piattella MC, Pozzilli C, Wise RG, Pantano P
Background. Resting brain activity can be modulated by motor tasks to adapt to function. In multiple sclerosis (MS) patients, altered resting-state functional connectivity (RS-FC) has been reported and associated with impaired function and disability; little is known on how RS-FC is modulated by a simple repetitive motor task. Objective. To assess changes in RS-FC in early relapsing-remitting MS (RRMS) patients associated with repetitive thumb flexions (RTFs). Methods. A total of 20 right-handed patients with early RRMS and 14 healthy controls underwent a resting functional magnetic resonance imaging (fMRI) scan, before and after 25 minutes of alternate 30-s blocks of right RTF and rest. Dual-regression analysis of resting fMRI data followed the independent component analysis. Individual spatial maps of coherence between brain areas for 2 networks of interest, sensorimotor and cerebellar, were compared at the group level and correlated with measures of both clinical impairment and brain damage. Results. Significant RTF-induced differences in RS-FC were observed between groups in the cerebellar network because of increased RS-FC in patients but not in controls. In the sensorimotor network, the RS-FC after RTF increased in both groups, with no significant between-group differences. The sensorimotor and the cerebellar RS-FC were intercorrelated only in patients and only after the RTF. The sensorimotor RS-FC increase in patients correlated with structural MRI alterations. Conclusions. Our study unmasked RS-FC changes of motor-related networks occurring after a simple repetitive motor task in early RRMS patients only. Evaluation of altered RSN dynamics might prove useful for anticipating neuroplasticity and for MRI-informed neurorehabilitation.
PMID: 25416740 [PubMed - as supplied by publisher]
Mapping the relationship between subgenual cingulate cortex functional connectivity and depressive symptoms across adolescence.
Soc Cogn Affect Neurosci. 2014 Nov 21;
Authors: Strikwerda-Brown C, Davey CG, Whittle S, Allen NB, Byrne ML, Schwartz OS, Simmons JG, Dwyer D, Harrison BJ
Changes in the functional connectivity of the subgenual anterior cingulate cortex (SGC) have been linked with depressive symptoms. The aim of this study was to map this relationship across mid- to late adolescence. Employing a longitudinal functional magnetic resonance imaging (fMRI) design, associations between patterns of resting-state SGC functional connectivity and symptoms of depression were examined at two time points in an initial sample of seventy-two adolescents. Using a region-of-interest approach, these associations were evaluated cross-sectionally and longitudinally. Cross-sectionally, weaker SGC functional connectivity with the posterior cingulate (PCC), angular gyrus and dorsal prefrontal cortex at baseline, and weaker SGC connectivity with the dorsomedial prefrontal (DMPFC) and ventromedial prefrontal cortices at follow-up, were associated with higher depressive symptoms. Longitudinally, a decrease in SGC functional connectivity with DMPFC, PCC, angular gyrus and middle temporal gyrus was associated with higher depressive symptoms at follow-up. The observation of weaker SGC connectivity predicting increased symptoms contrasts with the majority of resting-state fMRI studies in clinically depressed populations. Taken together with these past studies, our findings suggest depression-related changes in SGC functional connectivity may differ across developmental and illness stages.
PMID: 25416726 [PubMed - as supplied by publisher]
Pediatric Tourette syndrome: insights from recent neuroimaging studies.
J Obsessive Compuls Relat Disord. 2014 Oct 1;3(4):386-393
Authors: Church JA, Schlaggar BL
Tourette syndrome has been examined using many different neuroimaging techniques. There has been a recent surge of neuroimaging research papers related to Tourette syndrome that are exploring many different aspects of the disorder and its comorbidities. This brief review focuses on recent MRI-based imaging studies of pediatric Tourette syndrome, including anatomical, functional, resting state, and diffusion tensor MRI techniques. Consistencies across studies are explored, and particularly important issues involved in acquiring data from this special population are discussed.
PMID: 25414812 [PubMed - as supplied by publisher]
Mapping Epileptic Activity: Sources or Networks for the Clinicians?
Front Neurol. 2014;5:218
Authors: Pittau F, Mégevand P, Sheybani L, Abela E, Grouiller F, Spinelli L, Michel CM, Seeck M, Vulliemoz S
Epileptic seizures of focal origin are classically considered to arise from a focal epileptogenic zone and then spread to other brain regions. This is a key concept for semiological electro-clinical correlations, localization of relevant structural lesions, and selection of patients for epilepsy surgery. Recent development in neuro-imaging and electro-physiology and combinations, thereof, have been validated as contributory tools for focus localization. In parallel, these techniques have revealed that widespread networks of brain regions, rather than a single epileptogenic region, are implicated in focal epileptic activity. Sophisticated multimodal imaging and analysis strategies of brain connectivity patterns have been developed to characterize the spatio-temporal relationships within these networks by combining the strength of both techniques to optimize spatial and temporal resolution with whole-brain coverage and directional connectivity. In this paper, we review the potential clinical contribution of these functional mapping techniques as well as invasive electrophysiology in human beings and animal models for characterizing network connectivity.
PMID: 25414692 [PubMed - as supplied by publisher]
Stereoscopic three-dimensional visualization applied to multimodal brain images: clinical applications and a functional connectivity atlas.
Front Neurosci. 2014;8:328
Authors: Rojas GM, Gálvez M, Vega Potler N, Craddock RC, Margulies DS, Castellanos FX, Milham MP
Effective visualization is central to the exploration and comprehension of brain imaging data. While MRI data are acquired in three-dimensional space, the methods for visualizing such data have rarely taken advantage of three-dimensional stereoscopic technologies. We present here results of stereoscopic visualization of clinical data, as well as an atlas of whole-brain functional connectivity. In comparison with traditional 3D rendering techniques, we demonstrate the utility of stereoscopic visualizations to provide an intuitive description of the exact location and the relative sizes of various brain landmarks, structures and lesions. In the case of resting state fMRI, stereoscopic 3D visualization facilitated comprehension of the anatomical position of complex large-scale functional connectivity patterns. Overall, stereoscopic visualization improves the intuitive visual comprehension of image contents, and brings increased dimensionality to visualization of traditional MRI data, as well as patterns of functional connectivity.
PMID: 25414626 [PubMed - as supplied by publisher]
Different neural pathways linking personality traits and eudaimonic well-being: a resting-state functional magnetic resonance imaging study.
Cogn Affect Behav Neurosci. 2014 Nov 21;
Authors: Kong F, Liu L, Wang X, Hu S, Song Y, Liu J
Eudaimonic well-being (EWB) is the fulfillment of human potential and a meaningful life. Previous studies have shown that personality traits, especially extraversion, neuroticism, and conscientiousness, significantly contribute to EWB. However, the neurobiological pathways linking personality and EWB are not understood. Here, we used resting-state functional magnetic resonance imaging (rs-fMRI) to investigate this issue. Specifically, we correlated individuals' EWB scores with the regional fractional amplitude of low-frequency fluctuations (fALFF) of the brain, and then examined how personality traits predicted EWB-related spontaneous brain activity. We found that EWB was positively correlated with the fALFF in the right posterior superior temporal gyrus (pSTG) and thalamus, and negatively correlated with the strength of the thalamic-insular connectivity. More importantly, we found that personality traits influenced EWB in different ways. At the regional level, the fALFF in the pSTG and thalamus mediated the effects of neuroticism and extraversion on EWB, whereas the thalamus mediated the effect of conscientiousness on EWB. At the functional connectivity level, the thalamic-insular connectivity only mediated the effect of neuroticism on EWB. Taken together, our study provides the first evidence that EWB is associated with personality traits through different neural substrates.
PMID: 25413497 [PubMed - as supplied by publisher]
Negative BOLD Signals During Speech Comprehension.
Brain Connect. 2014 Nov 20;
Authors: Rodriguez Moreno D, Schiff N, Hirsch J
Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level-dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, we test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time-reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in fronto-parietal regions and were specific to the natural speech condition. However, BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity.
PMID: 25412406 [PubMed - as supplied by publisher]
Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: A meta-analysis of 75 fMRI studies.
Hum Brain Mapp. 2014 Nov 19;
Authors: Li HJ, Hou XH, Liu HH, Yue CL, He Y, Zuo XN
Most of the previous task functional magnetic resonance imaging (fMRI) studies found abnormalities in distributed brain regions in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and few studies investigated the brain network dysfunction from the system level. In this meta-analysis, we aimed to examine brain network dysfunction in MCI and AD. We systematically searched task-based fMRI studies in MCI and AD published between January 1990 and January 2014. Activation likelihood estimation meta-analyses were conducted to compare the significant group differences in brain activation, the significant voxels were overlaid onto seven referenced neuronal cortical networks derived from the resting-state fMRI data of 1,000 healthy participants. Thirty-nine task-based fMRI studies (697 MCI patients and 628 healthy controls) were included in MCI-related meta-analysis while 36 task-based fMRI studies (421 AD patients and 512 healthy controls) were included in AD-related meta-analysis. The meta-analytic results revealed that MCI and AD showed abnormal regional brain activation as well as large-scale brain networks. MCI patients showed hypoactivation in default, frontoparietal, and visual networks relative to healthy controls, whereas AD-related hypoactivation mainly located in visual, default, and ventral attention networks relative to healthy controls. Both MCI-related and AD-related hyperactivation fell in frontoparietal, ventral attention, default, and somatomotor networks relative to healthy controls. MCI and AD presented different pathological while shared similar compensatory large-scale networks in fulfilling the cognitive tasks. These system-level findings are helpful to link the fundamental declines of cognitive tasks to brain networks in MCI and AD. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc.
PMID: 25411150 [PubMed - as supplied by publisher]
Effects of Beta-Amyloid on Resting State Functional Connectivity Within and Between Networks Reflect Known Patterns of Regional Vulnerability.
Cereb Cortex. 2014 Nov 7;
Authors: Elman JA, Madison CM, Baker SL, Vogel JW, Marks SM, Crowley S, O'Neil JP, Jagust WJ
Beta-amyloid (Aβ) deposition is one of the hallmarks of Alzheimer's disease (AD). However, it is also present in some cognitively normal elderly adults and may represent a preclinical disease state. While AD patients exhibit disrupted functional connectivity (FC) both within and between resting-state networks, studies of preclinical cases have focused primarily on the default mode network (DMN). The extent to which Aβ-related effects occur outside of the DMN and between networks remains unclear. In the present study, we examine how within- and between-network FC are related to both global and regional Aβ deposition as measured by [(11)C]PIB-PET in 92 cognitively normal older people. We found that within-network FC changes occurred in multiple networks, including the DMN. Changes of between-network FC were also apparent, suggesting that regions maintaining connections to multiple networks may be particularly susceptible to Aβ-induced alterations. Cortical regions showing altered FC clustered in parietal and temporal cortex, areas known to be susceptible to AD pathology. These results likely represent a mix of local network disruption, compensatory reorganization, and impaired control network function. They indicate the presence of Aβ-related dysfunction of neural systems in cognitively normal people well before these areas become hypometabolic with the onset of cognitive decline.
PMID: 25405944 [PubMed - as supplied by publisher]
CONNECTOMICS SIGNATURE FOR CHARACTERIZATON OF MILD COGNITIVE IMPAIRMENT AND SCHIZOPHRENIA.
Proc IEEE Int Symp Biomed Imaging. 2014 May;2014:325-328
Authors: Zhu D, Shen D, Jiang X, Liu T
Human connectomes constructed via neuroimaging data offer a comprehensive description of the macro-scale structural connectivity within the brain. Thus quantitative assessment of connectome-scale structural and functional connectivities will not only fundamentally advance our understanding of normal brain organization and function, but also have significant importance to systematically and comprehensively characterize many devastating brain conditions. In recognition of the importance of connectome and connectomics, in this paper, we develop and evaluate a novel computational framework to construct structural connectomes from diffusion tensor imaging (DTI) data and assess connectome-scale functional connectivity alterations in mild cognitive impairment (MCI) and schizophrenia (SZ) from concurrent resting state fMRI (R-fMRI) data, in comparison with their healthy controls. By applying effective feature selection approaches, we discovered informative and robust functional connectomics signatures that can distinctively characterize and successfully differentiate the two brain conditions of MCI and SZ from their healthy controls (classification accuracies are 96% and 100%, respectively). Our results suggest that connectomics signatures could be a general, powerful methodology for characterization and classification of many brain conditions in the future.
PMID: 25404998 [PubMed - as supplied by publisher]
Functional organization of intrinsic connectivity networks in Chinese-chess experts.
Brain Res. 2014 Apr 16;1558:33-43
Authors: Duan X, Long Z, Chen H, Liang D, Qiu L, Huang X, Liu TC, Gong Q
The functional architecture of the human brain has been extensively described in terms of functional connectivity networks, detected from the low-frequency coherent neuronal fluctuations during a resting state condition. Accumulating evidence suggests that the overall organization of functional connectivity networks is associated with individual differences in cognitive performance and prior experience. Such an association raises the question of how cognitive expertise exerts an influence on the topological properties of large-scale functional networks. To address this question, we examined the overall organization of brain functional networks in 20 grandmaster and master level Chinese-chess players (GM/M) and twenty novice players, by means of resting-state functional connectivity and graph theoretical analyses. We found that, relative to novices, functional connectivity was increased in GM/Ms between basal ganglia, thalamus, hippocampus, and several parietal and temporal areas, suggesting the influence of cognitive expertise on intrinsic connectivity networks associated with learning and memory. Furthermore, we observed economical small-world topology in the whole-brain functional connectivity networks in both groups, but GM/Ms exhibited significantly increased values of normalized clustering coefficient which resulted in increased small-world topology. These findings suggest an association between the functional organization of brain networks and individual differences in cognitive expertise, which might provide further evidence of the mechanisms underlying expert behavior.
PMID: 24565926 [PubMed - indexed for MEDLINE]
Subclinical delusional thinking predicts lateral temporal cortex responses during social reflection.
Soc Cogn Affect Neurosci. 2014 Mar;9(3):273-82
Authors: Brent BK, Coombs G, Keshavan MS, Seidman LJ, Moran JM, Holt DJ
Neuroimaging studies have demonstrated associations between delusions in psychotic disorders and abnormalities of brain areas involved in social cognition, including medial prefrontal cortex (MPFC), posterior cingulate cortex, and lateral temporal cortex (LTC). General population studies have linked subclinical delusional thinking to impaired social cognition, raising the question of whether a specific pattern of brain activity during social perception is associated with delusional beliefs. Here, we tested the hypothesis that subclinical delusional thinking is associated with changes in neural function, while subjects made judgments about themselves or others ['social reflection' (SR)]. Neural responses during SR and non-social tasks, as well as resting-state activity, were measured using functional magnetic resonance imaging in 22 healthy subjects. Delusional thinking was measured using the Peters et al. Delusions Inventory. Delusional thinking was negatively correlated with responses of the left LTC during SR (r = -0.61, P = 0.02, Bonferroni corrected), and connectivity between the left LTC and left ventral MPFC, and was positively correlated with connectivity between the left LTC and the right middle frontal and inferior temporal cortices. Thus, delusional thinking in the general population may be associated with reduced activity and aberrant functional connectivity of cortical areas involved in SR.
PMID: 23160817 [PubMed - indexed for MEDLINE]
Resting-state functional connectivity in anterior cingulate cortex in normal aging.
Front Aging Neurosci. 2014;6:280
Authors: Cao W, Luo C, Zhu B, Zhang D, Dong L, Gong J, Gong D, He H, Tu S, Yin W, Li J, Chen H, Yao D
Growing evidence suggests that normal aging is associated with cognitive decline and well-maintained emotional well-being. The anterior cingulate cortex (ACC) is an important brain region involved in emotional and cognitive processing. We investigated resting-state functional connectivity (FC) of two ACC subregions in 30 healthy older adults vs. 33 healthy younger adults, by parcellating into rostral (rACC) and dorsal (dACC) ACC based on clustering of FC profiles. Compared with younger adults, older adults demonstrated greater connection between rACC and anterior insula, suggesting that older adults recruit more proximal dACC brain regions connected with insula to maintain a salient response. Older adults also demonstrated increased FC between rACC and superior temporal gyrus and inferior frontal gyrus, decreased integration between rACC and default mode, and decreased dACC-hippocampal and dACC-thalamic connectivity. These altered FCs reflected rACC and dACC reorganization, and might be related to well emotion regulation and cognitive decline in older adults. Our findings provide further insight into potential functional substrates of emotional and cognitive alterations in the aging brain.
PMID: 25400578 [PubMed]
Cortical connective field estimates from resting state fMRI activity.
Front Neurosci. 2014;8:339
Authors: Gravel N, Harvey B, Nordhjem B, Haak KV, Dumoulin SO, Renken R, Curčić-Blake B, Cornelissen FW
One way to study connectivity in visual cortical areas is by examining spontaneous neural activity. In the absence of visual input, such activity remains shaped by the underlying neural architecture and, presumably, may still reflect visuotopic organization. Here, we applied population connective field (CF) modeling to estimate the spatial profile of functional connectivity in the early visual cortex during resting state functional magnetic resonance imaging (RS-fMRI). This model-based analysis estimates the spatial integration between blood-oxygen level dependent (BOLD) signals in distinct cortical visual field maps using fMRI. Just as population receptive field (pRF) mapping predicts the collective neural activity in a voxel as a function of response selectivity to stimulus position in visual space, CF modeling predicts the activity of voxels in one visual area as a function of the aggregate activity in voxels in another visual area. In combination with pRF mapping, CF locations on the cortical surface can be interpreted in visual space, thus enabling reconstruction of visuotopic maps from resting state data. We demonstrate that V1 ➤ V2 and V1 ➤ V3 CF maps estimated from resting state fMRI data show visuotopic organization. Therefore, we conclude that-despite some variability in CF estimates between RS scans-neural properties such as CF maps and CF size can be derived from resting state data.
PMID: 25400541 [PubMed]
Separate neural representations for physical pain and social rejection.
Nat Commun. 2014;5:5380
Authors: Woo CW, Koban L, Kross E, Lindquist MA, Banich MT, Ruzic L, Andrews-Hanna JR, Wager TD
Current theories suggest that physical pain and social rejection share common neural mechanisms, largely by virtue of overlapping functional magnetic resonance imaging (fMRI) activity. Here we challenge this notion by identifying distinct multivariate fMRI patterns unique to pain and rejection. Sixty participants experience painful heat and warmth and view photos of ex-partners and friends on separate trials. FMRI pattern classifiers discriminate pain and rejection from their respective control conditions in out-of-sample individuals with 92% and 80% accuracy. The rejection classifier performs at chance on pain, and vice versa. Pain- and rejection-related representations are uncorrelated within regions thought to encode pain affect (for example, dorsal anterior cingulate) and show distinct functional connectivity with other regions in a separate resting-state data set (N=91). These findings demonstrate that separate representations underlie pain and rejection despite common fMRI activity at the gross anatomical level. Rather than co-opting pain circuitry, rejection involves distinct affective representations in humans.
PMID: 25400102 [PubMed - in process]