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https://www.readbyqxmd.com/read/28429068/nicotine-deprivation-elevates-neural-representation-of-smoking-related-cues-in-object-sensitive-visual-cortex-a-proof-of-concept-study
#1
Anne Havermans, Onno C P van Schayck, Eric F P M Vuurman, Wim J Riedel, Job van den Hurk
OBJECTIVE: In the current study, we use functional magnetic resonance imaging (fMRI) and multi-voxel pattern analysis (MVPA) to investigate whether tobacco addiction biases basic visual processing in favour of smoking-related images. We hypothesize that the neural representation of smoking-related stimuli in the lateral occipital complex (LOC) is elevated after a period of nicotine deprivation compared to a satiated state, but that this is not the case for object categories unrelated to smoking...
April 21, 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28426553/greater-fear-of-visceral-pain-contributes-to-differences-between-visceral-and-somatic-pain-in-healthy-women
#2
Laura Ricarda Koenen, Adriane Icenhour, Katarina Forkmann, Annika Pasler, Nina Theysohn, Michael Forsting, Ulrike Bingel, Sigrid Elsenbruch
This functional magnetic resonance imaging (fMRI) study addressed similarities and differences in behavioral and neural responses to experimental visceral compared to somatic pain stimuli and explored the contribution of fear of pain to differences between pain modalities. In N=22 healthy women, blood oxygen level-dependent (BOLD) responses to rectal distensions and cutaneous heat stimuli matched for perceived pain intensity. Fear of pain and pain unpleasantness were assessed before and after scanning. Visceral pain was more fear-evoking, more unpleasant, and trial-by-trial intensity ratings failed to habituate across trials (all interactions modality X time/trial: p<...
April 18, 2017: Pain
https://www.readbyqxmd.com/read/28424572/functional-sensitivity-of-2d-simultaneous-multi-slice-echo-planar-imaging-effects-of-acceleration-on-g-factor-and-physiological-noise
#3
Nick Todd, Oliver Josephs, Peter Zeidman, Guillaume Flandin, Steen Moeller, Nikolaus Weiskopf
Accelerated data acquisition with simultaneous multi-slice (SMS) imaging for functional MRI studies leads to interacting and opposing effects that influence the sensitivity to blood oxygen level-dependent (BOLD) signal changes. Image signal to noise ratio (SNR) is decreased with higher SMS acceleration factors and shorter repetition times (TR) due to g-factor noise penalties and saturation of longitudinal magnetization. However, the lower image SNR is counteracted by greater statistical power from more samples per unit time and a higher temporal Nyquist frequency that allows for better removal of spurious non-BOLD high frequency signal content...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28421854/reduction-of-bold-interference-in-pseudo-continuous-arterial-spin-labeling-towards-quantitative-fmri
#4
Geoffrey Warnock, Pinar S Özbay, Felix P Kuhn, Daniel Nanz, Alfred Buck, Andreas Boss, Cristina Rossi
Fluctuations in blood-oxygenation level dependent (BOLD) signal and perfusion affect the quantification of changes in cerebral blood flow (CBF), coupled to neuronal activity, in arterial spin labeling (ASL). Subtraction methods for control and labeled MR images (i.e. pair-wise, surround subtraction, and subtraction of sinc-interpolated images), postulated to mitigate this interference in pseudo-continuous ASL (pCASL), were evaluated by comparison with quantitative (15)O-water PET. At rest, a good agreement in the CBF values was found between PET and MRI for each of the subtraction methods...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28409565/can-pornography-be-addictive-an-fmri-study-of-men-seeking-treatment-for-problematic-pornography-use
#5
Mateusz Gola, Małgorzata Wordecha, Guillaume Sescousse, Michał Lew-Starowicz, Bartosz Kossowski, Marek Wypych, Scott Makeig, Marc N Potenza, Artur Marchewka
Pornography consumption is highly prevalent, particularly among young adult males. For some individuals, problematic pornography use (PPU) is a reason for seeking treatment. Despite the pervasiveness of pornography, PPU appears under-investigated, including with respect to the underlying neural mechanisms. Using functional magnetic resonance imaging (fMRI), we examined ventral striatal responses to erotic and monetary stimuli, disentangling cue-related 'wanting' from reward-related 'liking' among 28 heterosexual males seeking treatment for PPU and 24 heterosexual males without PPU...
April 14, 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/28408411/active-avoidance-neural-mechanisms-and-attenuation-of-pavlovian-conditioned-responding
#6
Emily A Boeke, Justin Moscarello, Joseph E LeDoux, Elizabeth A Phelps, Catherine A Hartley
Patients with anxiety disorders often experience a relapse in symptoms after exposure therapy. Similarly, threat responses acquired during Pavlovian threat conditioning often return after extinction learning. Accordingly, there is a need for alternative methods to persistently reduce threat responding. Studies in rodents have suggested that exercising behavioral control over an aversive stimulus can persistently diminish threat responses, and that these effects are mediated by the amygdala, ventromedial prefrontal cortex (vmPFC), and striatum...
April 13, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28407555/thalamocortical-connectivity-in-major-depressive-disorder
#7
Elliot C Brown, Darren L Clark, Stefanie Hassel, Glenda MacQueen, Rajamannar Ramasubbu
BACKGROUND: Major Depressive Disorder (MDD) is highly prevalent and potentially devastating, with widespread aberrations in brain activity. Thalamocortical networks are a potential candidate marker for psychopathology in MDD, but have not yet been thoroughly investigated. Here we examined functional connectivity between major cortical areas and thalamus. METHOD: Resting-state fMRI from 54 MDD patients and 40 healthy controls were collected. The cortex was segmented into six regions of interest (ROIs) consisting of frontal, temporal, parietal, and occipital lobes and pre-central and post-central gyri...
April 5, 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/28406906/water-diffusion-closely-reveals-neural-activity-status-in-rat-brain-loci-affected-by-anesthesia
#8
Yoshifumi Abe, Tomokazu Tsurugizawa, Denis Le Bihan
Diffusion functional MRI (DfMRI) reveals neuronal activation even when neurovascular coupling is abolished, contrary to blood oxygenation level-dependent (BOLD) functional MRI (fMRI). Here, we show that the water apparent diffusion coefficient (ADC) derived from DfMRI increased in specific rat brain regions under anesthetic conditions, reflecting the decreased neuronal activity observed with local field potentials (LFPs), especially in regions involved in wakefulness. In contrast, BOLD signals showed nonspecific changes, reflecting systemic effects of the anesthesia on overall brain hemodynamics status...
April 2017: PLoS Biology
https://www.readbyqxmd.com/read/28402478/the-neural-basis-of-emotions-varies-over-time-different-regions-go-with-onset-and-offset-bound-processes-underlying-emotion-intensity
#9
Maxime Résibois, Philippe Verduyn, Pauline Delaveau, Jean-Yves Rotgé, Peter Kuppens, Iven Van Mechelen, Philippe Fossati
According to theories of emotion dynamics, emotions unfold across two phases in which different types of processes come to the fore: emotion onset and emotion offset. Differences in onset-bound processes are reflected by the degree of explosiveness or steepness of the response at onset, and differences in offset-bound processes by the degree of accumulation or intensification of the subsequent response. Whether onset- and offset-bound processes have distinctive neural correlates and, hence, whether the neural basis of emotions varies over time, still remains unknown...
April 11, 2017: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/28397386/brain-atrophy-can-introduce-age-related-differences-in-bold-response
#10
Xueqing Liu, Raphael T Gerraty, Jack Grinband, David Parker, Qolamreza R Razligh
Use of functional magnetic resonance imaging (fMRI) in studies of aging is often hampered by uncertainty about age-related differences in the amplitude and timing of the blood oxygenation level dependent (BOLD) response (i.e., hemodynamic impulse response function (HRF)). Such uncertainty introduces a significant challenge in the interpretation of the fMRI results. Even though this issue has been extensively investigated in the field of neuroimaging, there is currently no consensus about the existence and potential sources of age-related hemodynamic alterations...
April 11, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28396293/the-impact-of-ultra-high-field-mri-on-cognitive-and-computational-neuroimaging
#11
Federico De Martino, Essa Yacoub, Valentin Kemper, Michelle Moerel, Kamil Uludag, Peter De Weerd, Kamil Ugurbil, Rainer Goebel, Elia Formisano
The ability to measure functional brain responses non-invasively with ultra high field MRI (7 T and above) represents a unique opportunity in advancing our understanding of the human brain. Compared to lower fields (3 T and below), ultra high field MRI has an increased sensitivity, which can be used to acquire functional images with greater spatial resolution, and greater specificity of the blood oxygen level dependent (BOLD) signal to the underlying neuronal responses. Together, increased resolution and specificity enable investigating brain functions at a submillimeter scale, which so far could only be done with invasive techniques...
April 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28393106/a-million-variables-and-more-the-fast-greedy-equivalence-search-algorithm-for-learning-high-dimensional-graphical-causal-models-with-an-application-to-functional-magnetic-resonance-images
#12
Joseph Ramsey, Madelyn Glymour, Ruben Sanchez-Romero, Clark Glymour
We describe two modifications that parallelize and reorganize caching in the well-known Greedy Equivalence Search (GES) algorithm for discovering directed acyclic graphs on random variables from sample values. We apply one of these modifications, the Fast Greedy Search (FGS) assuming faithfulness, to an i.i.d. sample of 1,000 units to recover with high precision and good recall an average degree 2 directed acyclic graph (DAG) with one million Gaussian variables. We describe a modification of the algorithm to rapidly find the Markov Blanket of any variable in a high dimensional system...
March 2017: Int J Data Sci Anal
https://www.readbyqxmd.com/read/28389384/correspondence-between-fmri-and-electrophysiology-during-visual-motion-processing-in-human-mt
#13
Anna Gaglianese, Mariska J Vansteensel, Ben M Harvey, Serge O Dumoulin, Natalia Petridou, Nick F Ramsey
Changes in brain neuronal activity are reflected by hemodynamic responses mapped through Blood Oxygenation Level Dependent (BOLD) functional magnetic resonance imaging (fMRI), a primary tool to measure brain functioning non-invasively. However, the exact relationship between hemodynamics and neuronal function is still a matter of debate. Here, we combine 3T BOLD fMRI and High Frequency Band (HFB) electrocorticography (ECoG) signals to investigate the relationship between neuronal activity and hemodynamic responses in the human Middle Temporal complex (hMT+), a higher order brain area involved in visual motion processing...
April 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/28388627/a-neuronal-mct2-knockdown-in-the-rat-somatosensory-cortex-reduces-both-the-nmr-lactate-signal-and-the-bold-response-during-whisker-stimulation
#14
Leslie Mazuel, Jordy Blanc, Cendrine Repond, Véronique Bouchaud, Gérard Raffard, Nicole Déglon, Gilles Bonvento, Luc Pellerin, Anne-Karine Bouzier-Sore
Although several in vitro and ex vivo evidence support the existence of lactate exchange between astrocytes and neurons, a direct demonstration in vivo is still lacking. In the present study, a lentiviral vector carrying a short hairpin RNA (shRNA) was used to downregulate the expression of the monocarboxylate transporter type 2 (MCT2) in neurons of the rat somatosensory cortex (called S1BF) by ~ 25%. After one hour of whisker stimulation, HRMAS 1H-NMR spectroscopy analysis of S1BF perchloric acid extracts showed that while an increase in lactate content is observed in both uninjected and shRNA-control injected extracts, such an effect was abrogated in shMCT2 injected rats...
2017: PloS One
https://www.readbyqxmd.com/read/28387975/insular-and-cingulate-attenuation-during-decision-making-is-associated-with-future-transition-to-stimulant-use-disorder
#15
Jennifer L Stewart, Mamona Butt, April C May, Susan F Tapert, Martin P Paulus
AIMS: To understand processes placing individuals at risk for stimulant (amphetamine and cocaine) use disorder. DESIGN: Longitudinal study. SETTING: University of California, San Diego Department of Psychiatry, USA. PARTICIPANTS: Occasional stimulant users (OSU; n = 184) underwent a baseline clinical interview and a functional magnetic resonance imaging (fMRI) session. On the basis of a follow-up clinical interview completed three years later, OSU (n = 147) were then categorized as problem stimulant users (PSU: n = 36; those who developed stimulant use disorders in the interim) or desisted stimulant users (DSU: n = 74; those who stopped using)...
April 7, 2017: Addiction
https://www.readbyqxmd.com/read/28385875/correlates-of-perceptual-orientation-biases-in-human-primary-visual-cortex
#16
Matthew L Patten, Damien J Mannion, Colin W G Clifford
Vision can be considered as a process of probabilistic inference. In a Bayesian framework, perceptual estimates from sensory information are combined with prior knowledge, with a stronger influence of the prior when the sensory evidence is less certain. Here, we explored the behavioral and neural consequences of manipulating stimulus certainty in the context of orientation processing. First, we asked participants to judge whether a stimulus was oriented closer to vertical or the clockwise primary oblique (45°) for two stimulus types (spatially-filtered noise textures, sinusoidal gratings) and three manipulations of certainty (orientation bandwidth, contrast, duration)...
April 6, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28382543/the-role-of-beta-arrestin2-in-shaping-fmri-bold-responses-to-dopaminergic-stimulation
#17
Kristoffer Sahlholm, Giovanna D Ielacqua, Jinbin Xu, Lynne A Jones, Felix Schlegel, Robert H Mach, Markus Rudin, Aileen Schroeter
RATIONALE: The dopamine D2 receptor (D2R) couples to inhibitory Gi/o proteins and is targeted by antipsychotic and antiparkinsonian drugs. Beta-arrestin2 binds to the intracellular regions of the agonist-occupied D2R to terminate G protein activation and promote internalization, but also to initiate downstream signaling cascades which have been implicated in psychosis. Functional magnetic resonance imaging (fMRI) has proven valuable for measuring dopamine receptor-mediated changes in neuronal activity, and might enable beta-arrestin2 function to be studied in vivo...
April 5, 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28373890/restructuring-reward-mechanisms-in-nicotine-addiction-a-pilot-fmri-study-of-mindfulness-oriented-recovery-enhancement-for-cigarette-smokers
#18
B Froeliger, A R Mathew, P A McConnell, C Eichberg, M E Saladin, M J Carpenter, E L Garland
The primary goal of this pilot feasibility study was to examine the effects of Mindfulness-Oriented Recovery Enhancement (MORE), a behavioral treatment grounded in dual-process models derived from cognitive science, on frontostriatal reward processes among cigarette smokers. Healthy adult (N = 13; mean (SD) age 49 ± 12.2) smokers provided informed consent to participate in a 10-week study testing MORE versus a comparison group (CG). All participants underwent two fMRI scans: pre-tx and after 8-weeks of MORE...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
https://www.readbyqxmd.com/read/28373123/sensitivity-and-specificity-considerations-for-fmri-encoding-decoding-and-mapping-of-auditory-cortex-at-ultra-high-field
#19
Michelle Moerel, Federico De Martino, Valentin G Kemper, Sebastian Schmitter, An T Vu, Kâmil Uğurbil, Elia Formisano, Essa Yacoub
Following rapid technological advances, ultra-high field functional MRI (fMRI) enables exploring correlates of neuronal population activity at an increasing spatial resolution. However, as the fMRI blood-oxygenation-level-dependent (BOLD) contrast is a vascular signal, the spatial specificity of fMRI data is ultimately determined by the characteristics of the underlying vasculature. At 7T, fMRI measurement parameters determine the relative contribution of the macro- and microvasculature to the acquired signal...
March 31, 2017: NeuroImage
https://www.readbyqxmd.com/read/28371646/contextual-effects-on-cognitive-control-and-bold-activation-in-single-versus-mixed-saccade-tasks
#20
Jordan E Pierce, Jennifer E McDowell
The context or trial history of a task influences response efficiency in mixed paradigms based on cognitive control demands for task set selection. In the current study, the impact of context on prosaccade and antisaccade trials in single and mixed tasks was investigated with BOLD fMRI. Prosaccades require a look towards a newly appearing target, while antisaccades require cognitive control for prepotent response inhibition and generation of a saccade to the opposite location. Results indicated slower prosaccade reaction times and more antisaccade errors for switched than repeated or single trials, and slower antisaccade reaction times for single than mixed trials...
March 31, 2017: Brain and Cognition
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