Journals News

Anticipation and violated expectation of pain are influenced by trait rumination: An fMRI study.

NITRC ADMIN — Wed, 26 Sep 2018 3:31:09 GMT

Anticipation and violated expectation of pain are influenced by trait rumination: An fMRI study.

Cogn Affect Behav Neurosci. 2018 Sep 24;:

Authors: Kokonyei G, Galambos A, Edes AE, Kocsel N, Szabo E, Pap D, Kozak LR, Bagdy G, Juhasz G

Abstract

Rumination - as a stable tendency to focus repetitively on feelings related to distress - represents a transdiagnostic risk factor. Theories suggest altered emotional information processing as the key mechanism of rumination. However, studies on the anticipation processes in relation to rumination are scarce, even though expectation in this process is demonstrated to influence the processing of emotional stimuli. In addition, no published study has investigated violated expectation in relation to rumination yet. In the present study we examined the neural correlates of pain anticipation and perception using a fear conditioning paradigm with pain as the unconditioned stimulus in healthy subjects (N = 30). Rumination was assessed with the 10-item Ruminative Response Scale (RRS). Widespread brain activation - extending to temporal, parietal, and occipital lobes along with activation in the cingulate cortex, insula, and putamen - showed a positive correlation with rumination, supporting our hypothesis that trait rumination influences anticipatory processes. Interestingly, with violated expectation (when an unexpected, non-painful stimulus follows a pain cue compared to when an expected, painful stimulus follows the same pain cue) a negative association between rumination and activation was found in the posterior cingulate cortex, which is responsible for change detection in the environment and subsequent behavioral modification. Our results suggest that rumination is associated with increased neural response to pain perception and pain anticipation, and may deteriorate the identification of an unexpected omission of aversive stimuli. Therefore, targeting rumination in cognitive behavioral therapy of chronic pain could have a beneficial effect.

PMID: 30251186 [PubMed - as supplied by publisher]

Functional connectivity with cortical depth assessed by resting state fMRI of subregions of S1 in squirrel monkeys.

NITRC ADMIN — Wed, 26 Sep 2018 3:31:09 GMT

Functional connectivity with cortical depth assessed by resting state fMRI of subregions of S1 in squirrel monkeys.

Hum Brain Mapp. 2018 Sep 25;:

Authors: Mishra A, Majumdar S, Wang F, Wilson GH, Gore JC, Chen LM

Abstract

Whereas resting state blood oxygenation-level dependent (BOLD) functional MRI has been widely used to assess functional connectivity between cortical regions, the laminar specificity of such measures is poorly understood. This study aims to determine: (a) whether the resting state functional connectivity (rsFC) between two functionally related cortical regions varies with cortical depth, (b) the relationship between layer-resolved tactile stimulus-evoked activation pattern and interlayer rsFC pattern between two functionally distinct but related somatosensory areas 3b and 1, and (c) the effects of spatial resolution on rsFC measures. We examined the interlayer rsFC between areas 3b and 1 of squirrel monkeys under anesthesia using tactile stimulus-driven and resting state BOLD acquisitions at submillimeter resolution. Consistent with previous observations in the areas 3b and 1, we detected robust stimulus-evoked BOLD activations with foci were confined mainly to the upper layers (centered at 21% of the cortical depth). By carefully placing seeds in upper, middle, and lower layers of areas 3b and 1, we observed strong rsFC between upper and middle layers of these two areas. The layer-resolved activation patterns in areas 3b and 1 agree with their interlayer rsFC patterns, and are consistent with the known anatomical connections between layers. In summary, using BOLD rsFC pattern, we identified an interlayer interareal microcircuit that shows strong intrinsic functional connections between upper and middle layer areas 3b and 1. RsFC can be used as a robust invasive tool to probe interlayer corticocortical microcircuits.

PMID: 30251760 [PubMed - as supplied by publisher]

Cortical and subcortical areas involved in the regulation of reach movement speed in the human brain: An fMRI study.

NITRC ADMIN — Wed, 26 Sep 2018 3:31:09 GMT

Cortical and subcortical areas involved in the regulation of reach movement speed in the human brain: An fMRI study.

Hum Brain Mapp. 2018 Sep 25;:

Authors: Shirinbayan SI, Dreyer AM, Rieger JW

Abstract

Reach movements are characterized by multiple kinematic variables that can change with age or due to medical conditions such as movement disorders. While the neural control of reach direction is well investigated, the elements of the neural network regulating speed (the nondirectional component of velocity) remain uncertain. Here, we used a custom made magnetic resonance (MR)-compatible arm movement tracking system to capture the real kinematics of the arm movements while measuring brain activation with functional magnetic resonance imaging to reveal areas in the human brain in which BOLD-activation covaries with the speed of arm movements. We found significant activation in multiple cortical and subcortical brain regions positively correlated with endpoint (wrist) speed (speed-related activation), including contralateral premotor cortex (PMC), supplementary motor area (SMA), thalamus (putative VL/VA nuclei), and bilateral putamen. The hand and arm regions of primary sensorimotor cortex (SMC) and a posterior region of thalamus were significantly activated by reach movements but showed a more binary response characteristics (movement present or absent) than with continuously varying speed. Moreover, a subregion of contralateral SMA also showed binary movement activation but no speed-related BOLD-activation. Effect size analysis revealed bilateral putamen as the most speed-specific region among the speed-related clusters whereas primary SMC showed the strongest specificity for movement versus non-movement discrimination, independent of speed variations. The results reveal a network of multiple cortical and subcortical brain regions that are involved in speed regulation among which putamen, anterior thalamus, and PMC show highest specificity to speed, suggesting a basal-ganglia-thalamo-cortical loop for speed regulation.

PMID: 30251771 [PubMed - as supplied by publisher]

Predicting conversion from MCI to AD by integrating rs-fMRI and structural MRI.

NITRC ADMIN — Tue, 25 Sep 2018 10:31:09 GMT

Predicting conversion from MCI to AD by integrating rs-fMRI and structural MRI.

Comput Biol Med. 2018 Sep 15;102:30-39

Authors: Hojjati SH, Ebrahimzadeh A, Khazaee A, Babajani-Feremi A, Alzheimer's Disease Neuroimaging Initiative

Abstract

Structural MRI (sMRI) and resting-state functional MRI (rs-fMRI) have provided promising results in the diagnosis of Alzheimer's disease (AD), though the utility of integrating sMRI with rs-fMRI has not been explored thoroughly. We investigated the performances of rs-fMRI and sMRI in single modality and multi-modality approaches for classifying patients with mild cognitive impairment (MCI) who progress to probable AD-MCI converter (MCI-C) from those with MCI who do not progress to probable AD-MCI non-converter (MCI-NC). The cortical and subcortical measurements, e.g. cortical thickness, extracted from sMRI and graph measures extracted from rs-fMRI functional connectivity were used as features in our algorithm. We trained and tested a support vector machine to classify MCI-C from MCI-NC using rs-fMRI and sMRI features. Our algorithm for classifying MCI-C and MCI-NC utilized a small number of optimal features and achieved accuracies of 89% for sMRI, 93% for rs-fMRI, and 97% for the combination of sMRI with rs-fMRI. To our knowledge, this is the first study that investigated integration of rs-fMRI and sMRI for identification of the early stage of AD. Our findings shed light on integration of sMRI with rs-fMRI for identification of the early stages of AD.

PMID: 30245275 [PubMed - as supplied by publisher]

Analysis of Alzheimer's Disease Based on the Random Neural Network Cluster in fMRI.

NITRC ADMIN — Tue, 25 Sep 2018 10:31:09 GMT

Analysis of Alzheimer's Disease Based on the Random Neural Network Cluster in fMRI.

Front Neuroinform. 2018;12:60

Authors: Bi XA, Jiang Q, Sun Q, Shu Q, Liu Y

Abstract

As Alzheimer's disease (AD) is featured with degeneration and irreversibility, the diagnosis of AD at early stage is important. In recent years, some researchers have tried to apply neural network (NN) to classify AD patients from healthy controls (HC) based on functional MRI (fMRI) data. But most study focus on a single NN and the classification accuracy was not high. Therefore, this paper used the random neural network cluster which was composed of multiple NNs to improve classification performance. Sixty one subjects (25 AD and 36 HC) were acquired from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. This method not only could be used in the classification, but also could be used for feature selection. Firstly, we chose Elman NN from five types of NNs as the optimal base classifier of random neural network cluster based on the results of feature selection, and the accuracies of the random Elman neural network cluster could reach to 92.31% which was the highest and stable. Then we used the random Elman neural network cluster to select significant features and these features could be used to find out the abnormal regions. Finally, we found out 23 abnormal regions such as the precentral gyrus, the frontal gyrus and supplementary motor area. These results fully show that the random neural network cluster is worthwhile and meaningful for the diagnosis of AD.

PMID: 30245623 [PubMed]

SCTICA: Sub-packet constrained temporal ICA method for fMRI data analysis.

NITRC ADMIN — Tue, 25 Sep 2018 10:31:09 GMT

SCTICA: Sub-packet constrained temporal ICA method for fMRI data analysis.

Comput Biol Med. 2018 Sep 17;102:75-85

Authors: Shi Y, Zeng W

Abstract

Independent component analysis (ICA) has become a widely used method for functional magnetic resonance imaging (fMRI) data analysis. However, spatial ICA usually performs better than temporal ICA with regard to the stability and accuracy of functional connectivity detection, and temporal ICA is often not feasible when it is applied to the analysis of real fMRI data of the whole brain because of the excessive spatial dimensions. In this paper, to overcome these problems, we propose a sub-packet constrained temporal ICA (SCTICA) method to take advantage of the a priori information using a multi-objective optimization framework with the Newton iterative algorithm. Moreover, a splitting strategy is presented to improve the feasibility of the temporal ICA for whole brain fMRI data analysis. The experimental results of real data show that the splitting strategy improved the ability of the temporal ICA to analyze whole brain fMRI data. Furthermore, the experimental results also demonstrated that the proposed SCTICA method can not only improve the stability of the temporal ICA, but can also improve the functional connectivity detection ability compared with the classical ICA and ICA with a priori information methods. In brief, the proposed SCTICA method overcomes the problem that prevents temporal ICA from being applied to fMRI data of the whole brain, and the functional connectivity detection performance is greatly improved compared with that of traditional methods.

PMID: 30248514 [PubMed - as supplied by publisher]

An fMRI study of decision-making under sunk costs in gambling disorder.

NITRC ADMIN — Mon, 24 Sep 2018 10:31:10 GMT

An fMRI study of decision-making under sunk costs in gambling disorder.

Eur Neuropsychopharmacol. 2018 Sep 19;:

Authors: Fujino J, Kawada R, Tsurumi K, Takeuchi H, Murao T, Takemura A, Tei S, Murai T, Takahashi H

Abstract

The sunk cost effect is the tendency to continue an investment, or take an action, even though it has higher future costs than benefits, if costs of time, money, or effort were previously incurred. This type of decision bias is pervasive in real life and has been studied in various disciplines. Previous studies and clinical observations suggest that decision-making under sunk costs is altered in gambling disorder (GD). However, the neural mechanisms of decision-making under sunk costs in GD remain largely unknown, and so is their association with the clinical characteristics of this patient group. Here, by combining functional magnetic resonance imaging and the task that demonstrated a clear example of the sunk cost effect, we investigated the neural correlates during decision-making under sunk costs in GD. We found no significant differences in the strength of the sunk cost effect between the GD and healthy control (HC) groups. However, the strength of the sunk cost effect in patients with GD showed a significant negative correlation with abstinence period and a marginally significant positive correlation with the duration of illness. We also found a reduction in the neural activation in the dorsal medial prefrontal cortex during decision-making under sunk costs for the GD group compared with the HC group. Furthermore, in patients with GD, the levels of activation in this area negatively correlated with the duration of illness. These findings have important clinical implications. This study will contribute to a better understanding of the mechanisms underlying altered decision-making abilities in GD.

PMID: 30243683 [PubMed - as supplied by publisher]

Eccentricity-dependent temporal contrast tuning in human visual cortex measured with fMRI.

NITRC ADMIN — Mon, 24 Sep 2018 10:31:10 GMT

Eccentricity-dependent temporal contrast tuning in human visual cortex measured with fMRI.

Neuroimage. 2018 Sep 20;:

Authors: Himmelberg MM, Wade AR

Abstract

Cells in the peripheral retina tend to have higher contrast sensitivity and respond at higher flicker frequencies than those closer to the fovea. Although this predicts increased behavioural temporal contrast sensitivity in the peripheral visual field, this effect is rarely observed in psychophysical experiments. It is unknown how temporal contrast sensitivity is represented across eccentricity within cortical visual field maps and whether such sensitivities reflect the response properties of retinal cells or psychophysical sensitivities. Here, we used functional magnetic resonance imaging (fMRI) to measure contrast sensitivity profiles at four temporal frequencies in five retinotopically-defined visual areas. We also measured population receptive field (pRF) parameters (polar angle, eccentricity, and size) in the same areas. Overall contrast sensitivity, independent of pRF parameters, peaked at 10 Hz in all visual areas. In V1, V2, V3, and V3a, peripherally-tuned voxels had higher contrast sensitivity at a high temporal frequency (20 Hz), while hV4 more closely reflected behavioural sensitivity profiles. We conclude that our data reflect a cortical representation of the increased peripheral temporal contrast sensitivity that is already present in the retina and that this bias must be compensated later in the cortical visual pathway.

PMID: 30243956 [PubMed - as supplied by publisher]

Brain responses to different types of salience in antipsychotic naïve first episode psychosis: An fMRI study.

NITRC ADMIN — Sun, 23 Sep 2018 10:30:25 GMT

Brain responses to different types of salience in antipsychotic naïve first episode psychosis: An fMRI study.

Transl Psychiatry. 2018 Sep 21;8(1):196

Authors: Knolle F, Ermakova AO, Justicia A, Fletcher PC, Bunzeck N, Düzel E, Murray GK

Abstract

Abnormal salience processing has been suggested to contribute to the formation of positive psychotic symptoms in schizophrenia and related conditions. Previous research utilising reward learning or anticipation paradigms has demonstrated cortical and subcortical abnormalities in people with psychosis, specifically in the prefrontal cortex, the dopaminergic midbrain and the striatum. In these paradigms, reward prediction errors attribute motivational salience to stimuli. However, little is known about possible abnormalities across different forms of salience processing in psychosis patients, and whether any such abnormalities involve the dopaminergic midbrain. The aim of our study was, therefore, to investigate possible alterations in psychosis in neural activity in response to various forms of salience: novelty, negative emotion, targetness (task-driven salience) and rareness/deviance. We studied 14 antipsychotic naïve participants with first episode psychosis, and 37 healthy volunteers. During fMRI scanning, participants performed a visual oddball task containing these four forms of salience. Psychosis patients showed abnormally reduced signalling in the substantia nigra/ventral tegmental area (SN/VTA) for novelty, negative emotional salience and targetness; reduced striatal and occipital (lingual gyrus) signalling to novelty and negative emotional salience, reduced signalling in the amygdala, anterior cingulate cortex and parahippocamal gyrus to negative emotional salience, and reduced cerebellar signalling to novelty and negative emotional salience. Our results indicate alterations of several forms of salience processing in patients with psychosis in the midbrain SN/VTA, with additional subcortical and cortical regions also showing alterations in salience signalling, the exact pattern of alterations depending on the form of salience in question.

PMID: 30242202 [PubMed - in process]

Multi-modal functional MRI to explore placental function over gestation.

NITRC ADMIN — Sun, 23 Sep 2018 10:30:25 GMT

Multi-modal functional MRI to explore placental function over gestation.

Magn Reson Med. 2018 Sep 21;:

Authors: Hutter J, Slator PJ, Jackson L, Gomes ADS, Ho A, Story L, O'Muircheartaigh J, Teixeira RPAG, Chappell LC, Alexander DC, Rutherford MA, Hajnal JV

Abstract

PURPOSE: To investigate, visualize and quantify the physiology of the human placenta in several dimensions - functional, temporal over gestation, and spatial over the whole organ.

METHODS: Bespoke MRI techniques, combining a rich diffusion protocol, anatomical data and T2* mapping together with a multi-modal pipeline including motion correction and extracted quantitative features were developed and employed on pregnant women between 22 and 38 weeks gestational age including two pregnancies diagnosed with pre-eclampsia.

RESULTS: A multi-faceted assessment was demonstrated showing trends of increasing lacunarity, and decreasing T2* and diffusivity over gestation.

CONCLUSIONS: The obtained multi-modal acquisition and quantification shows promising opportunities for studying evolution, adaptation and compensation processes.

PMID: 30242899 [PubMed - as supplied by publisher]