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Cortical connectivity

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https://www.readbyqxmd.com/read/28441420/mapping-of-the-brain-hemodynamic-responses-to-sensorimotor-stimulation-in-a-rodent-model-a-bold-fmri-study
#1
Salem Boussida, Amidou S Traoré, Franck Durif
Blood Oxygenation Level Dependent functional MRI (BOLD fMRI) during electrical paw stimulation has been widely used in studies aimed at the understanding of the somatosensory network in rats. However, despite the well-established anatomical connections between cortical and subcortical structures of the sensorimotor system, most of these functional studies have been concentrated on the cortical effects of sensory electrical stimulation. BOLD fMRI study of the integration of a sensorimotor input across the sensorimotor network requires an appropriate methodology to elicit functional activation in cortical and subcortical areas owing to the regional differences in both neuronal and vascular architectures between these brain regions...
2017: PloS One
https://www.readbyqxmd.com/read/28439519/structured-illumination-diffuse-optical-tomography-for-noninvasive-functional-neuroimaging-in-mice
#2
Matthew D Reisman, Zachary E Markow, Adam Q Bauer, Joseph P Culver
Optical intrinsic signal (OIS) imaging has been a powerful tool for capturing functional brain hemodynamics in rodents. Recent wide field-of-view implementations of OIS have provided efficient maps of functional connectivity from spontaneous brain activity in mice. However, OIS requires scalp retraction and is limited to superficial cortical tissues. Diffuse optical tomography (DOT) techniques provide noninvasive imaging, but previous DOT systems for rodent neuroimaging have been limited either by sparse spatial sampling or by slow speed...
April 2017: Neurophotonics
https://www.readbyqxmd.com/read/28439224/richness-in-functional-connectivity-depends-on-the-neuronal-integrity-within-the-posterior-cingulate-cortex
#3
Anton R Lord, Meng Li, Liliana R Demenescu, Johan van den Meer, Viola Borchardt, Anna Linda Krause, Hans-Jochen Heinze, Michael Breakspear, Martin Walter
The brain's connectivity skeleton-a rich club of strongly interconnected members-was initially shown to exist in human structural networks, but recent evidence suggests a functional counterpart. This rich club typically includes key regions (or hubs) from multiple canonical networks, reducing the cost of inter-network communication. The posterior cingulate cortex (PCC), a hub node embedded within the default mode network, is known to facilitate communication between brain networks and is a key member of the "rich club...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28438969/intracellular-in-vivo-dynamics-of-thalamocortical-synapses-in-visual-cortex
#4
Madineh Sedigh-Sarvestani, Leif Vigeland, Ivan Fernandez-Lamo, Morgan Taylor, Larry A Palmer, Diego Contreras
Seminal studies of the thalamocortical (TC) circuit in the visual system of the cat have been central to our understanding of sensory encoding. However, TC synaptic properties remain poorly understood. We used paired recordings, in the lateral geniculate nucleus (LGN) and primary visual cortex (V1), to provide the first in vivo characterization of sensory-driven TC potentials in V1. The amplitudes of EPSPs we characterized were smaller than those previously reported in vitro. Consistent with prior findings, connected LGN-V1 pairs were only found when their receptive fields (RFs) overlapped, and the probability of connection increased steeply with degree of RF overlap and response similarity...
April 24, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28438665/effective-connectivity-gateways-to-the-theory-of-mind-network-in-processing-communicative-intention
#5
Marco Tettamanti, Matilde M Vaghi, Bruno G Bara, Stefano F Cappa, Ivan Enrici, Mauro Adenzato
An Intention Processing Network (IPN), involving the medial prefrontal cortex, precuneus, bilateral posterior superior temporal sulcus, and temporoparietal junctions, plays a fundamental role in comprehending intentions underlying action goals. In a previous fMRI study, we showed that, depending on the linguistic or extralinguistic (gestural) modality used to convey the intention, the IPN is complemented by activation of additional brain areas, reflecting distinct modality-specific input gateways to the IPN...
April 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/28438183/semaphorin-plexin-signaling-influences-early-ventral-telencephalic-development-and-thalamocortical-axon-guidance
#6
Manuela D Mitsogiannis, Graham E Little, Kevin J Mitchell
BACKGROUND: Sensory processing relies on projections from the thalamus to the neocortex being established during development. Information from different sensory modalities reaching the thalamus is segregated into specialized nuclei, whose neurons then send inputs to cognate cortical areas through topographically defined axonal connections. Developing thalamocortical axons (TCAs) normally approach the cortex by extending through the subpallium; here, axonal navigation is aided by distributed guidance cues and discrete cell populations, such as the corridor neurons and the internal capsule (IC) guidepost cells...
April 24, 2017: Neural Development
https://www.readbyqxmd.com/read/28437128/neural-dynamics-of-grouping-and-segmentation-explain-properties-of-visual-crowding
#7
Gregory Francis, Mauro Manassi, Michael H Herzog
Investigations of visual crowding, where a target is difficult to identify because of flanking elements, has largely used a theoretical perspective based on local interactions where flanking elements pool with or substitute for properties of the target. This successful theoretical approach has motivated a wide variety of empirical investigations to identify mechanisms that cause crowding, and it has suggested practical applications to mitigate crowding effects. However, this theoretical approach has been unable to account for a parallel set of findings that crowding is influenced by long-range perceptual grouping effects...
April 24, 2017: Psychological Review
https://www.readbyqxmd.com/read/28435046/a-multilevel-roi-features-based-machine-learning-method-for-detection-of-morphometric-biomarkers-in-parkinson-s-disease
#8
Bo Peng, Suhong Wang, Zhiyong Zhou, Yan Liu, Baotong Tong, Tao Zhang, Yakang Dai
Machine learning methods have been widely used in recent years for detection of neuroimaging biomarkers in regions of interest (ROIs) and assisted diagnosis of neurodegenerative diseases. The innovation of this study is to use multilevel-ROI-features-based machine learning method to detect sensitive morphometric biomarkers in Parkinson's disease (PD). Specifically, the low-level ROI features (gray matter volume, cortical thickness, etc.) and high-level correlative features (connectivity between ROIs) are integrated to make the multilevel ROI features...
April 20, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28434861/representation-of-multiple-body-parts-in-the-missing-hand-territory-of-congenital-one-handers
#9
Avital Hahamy, Scott N Macdonald, Fiona van den Heiligenberg, Paullina Kieliba, Uzay Emir, Rafael Malach, Heidi Johansen-Berg, Peter Brugger, Jody C Culham, Tamar R Makin
Individuals born without one hand (congenital one-handers) provide a unique model for understanding the relationship between focal reorganization in the sensorimotor cortex and everyday behavior. We previously reported that the missing hand's territory of one-handers becomes utilized by its cortical neighbor (residual arm representation), depending on residual arm usage in daily life to substitute for the missing hand's function [1, 2]. However, the repertoire of compensatory behaviors may involve utilization of other body parts that do not cortically neighbor the hand territory...
April 19, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28433628/ca-2-dependent-hyperpolarization-hypothesis-for-mammalian-sleep
#10
REVIEW
Fumiya Tatsuki, Koji L Ode, Hiroki R Ueda
The detailed molecular mechanisms underlying the regulation of sleep/wake cycles in mammals are elusive. In this regulation, at least two mechanisms with fast and slow time scales are involved. In the faster time scale, a state of non-rapid-eye-movement (NREM) sleep can be microscopically characterized by the millisecond-to-second-order electrical behavior of neurons, namely slow-wave oscillations described by electrophysiology. In the slower time scale, the total duration of NREM sleep is homeostatically regulated by sleep pressure (the need for sleep), which is usually sustained for hours or even days and can be macroscopically described by electroencephalogram (EEG)...
April 19, 2017: Neuroscience Research
https://www.readbyqxmd.com/read/28432143/focal-local-field-potential-lfp-signature-of-the-single-axon-monosynaptic-thalamocortical-connection
#11
Espen Hagen, Janne C Fossum, Klas H Pettersen, Jose-Manuel Alonso, Harvey A Swadlow, Gaute T Einevolla
Recent years have seen a resurgence in use of the extracellularly recorded local field potential (LFP) to investigate neural network activity. To probe monosynaptic thalamic activation of cortical postsynaptic target cells, so called spike-trigger-averaged LFP (stLFP) signatures have been measured. In these experiments the cortical LFP is measured by means of multielectrodes covering several cortical lamina and averaged on spontaneous spikes of thalamocortical (TC) cells. Using a well-established forward-modeling scheme, we investigate the biophysical origin of this stLFP signature with simultaneous synaptic activation of cortical layer 4 neurons, mimicking the effect of a single afferent spike from a single TC neuron...
April 21, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28431323/transcranial-magnetic-stimulation-in-developmental-stuttering-relations-with-previous-neurophysiological-research-and-future-perspectives
#12
REVIEW
P Busan, P P Battaglini, M Sommer
Developmental stuttering (DS) is a disruption of the rhythm of speech, and affected people may be unable to execute fluent voluntary speech. There are still questions about the exact causes of DS. Evidence suggests there are differences in the structure and functioning of motor systems used for preparing, executing, and controlling motor acts, especially when they are speech related. Much research has been obtained using neuroimaging methods, ranging from functional magnetic resonance to diffusion tensor imaging and electroencephalography/magnetoencephalography...
April 3, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28430289/evidence-from-spatial-pattern-analysis-for-the-anatomical-spread-of-%C3%AE-synuclein-pathology-in-parkinson-s-disease-dementia
#13
Richard A Armstrong
<i>The objective of this study was to determine whether there is evidence from quantitative morphometry and spatial pattern analysis to support the hypothesis of anatomical spread of -synuclein in Parkinson's disease dementia (PDD). Hence, clustering of -synuclein-immunoreactive Lewy bodies (LB), Lewy neurites (LN), and Lewy grains (LG) was studied in -synuclein-immunolabeled sections of cortical and limbic regions in 12 cases of PDD. The data suggested that: (1) LB, LN, and LG occurred in clusters which in 63% of regions were regularly distributed parallel to the tissue boundary, (2) in approximately 30% of cortical regions, the estimated cluster size of LB, LN, and LG was within the size range of cellular columns associated with the cortico-cortical pathways, (3) regularly distributed clusters were present in anatomically connected regions, and (4) the clustering pattern was similar to that of prion protein (PrPsc) deposits in Creutzfeldt-Jacob disease (CJD)...
2017: Folia Neuropathologica
https://www.readbyqxmd.com/read/28430287/dysembryoplastic-neuroepithelial-tumour-insight-into-the-pathology-and-pathogenesis
#14
Iwona Sontowska, Ewa Matyja, Jacek Malejczyk, Wieslawa Grajkowska
<i>Dysembryoplastic neuroepithelial tumour (DNT) is categorized as a benign glioneuronal neoplasm affecting children and young adults with chronic epileptic seizures. It is characterized by predominant intracortical localization and nodular architecture. Dysembryoplastic neuroepithelial tumour usually demonstrates a distinctive morphological pattern with a specific glioneuronal element but occasionally, its morphological picture is heterogeneous and unspecific. Thus, considering the morphology of DNT, three different histopathological subtypes are distinguished: simple, complex, and non-specific and diffuse...
2017: Folia Neuropathologica
https://www.readbyqxmd.com/read/28429774/synchronization-and-variability-imbalance-underlie-cognitive-impairment-in-primary-progressive-multiple-sclerosis
#15
Maria Petracca, Catarina Saiote, Heidi A Bender, Franchesca Arias, Colleen Farrell, Paola Magioncalda, Matteo Martino, Aaron Miller, Georg Northoff, Fred Lublin, Matilde Inglese
We aimed to investigate functional connectivity and variability across multiple frequency bands in brain networks underlying cognitive deficits in primary-progressive multiple sclerosis (PP-MS) and to explore how they are affected by the presence of cortical lesions (CLs). We analyzed functional connectivity and variability (measured as the standard deviation of BOLD signal amplitude) in resting state networks (RSNs) associated with cognitive deficits in different frequency bands in 25 PP-MS patients (12 M, mean age 50...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28429383/altered-eigenvector-centrality-is-related-to-local-resting-state-network-functional-connectivity-in-patients-with-longstanding-type-1-diabetes-mellitus
#16
Eelco van Duinkerken, Menno M Schoonheim, Richard G IJzerman, Annette C Moll, Jesus Landeira-Fernandez, Martin Klein, Michaela Diamant, Frank J Snoek, Frederik Barkhof, Alle-Meije Wink
INTRODUCTION: Longstanding type 1 diabetes (T1DM) is associated with microangiopathy and poorer cognition. In the brain, T1DM is related to increased functional resting-state network (RSN) connectivity in patients without, which was decreased in patients with clinically evident microangiopathy. Subcortical structure seems affected in both patient groups. How these localized alterations affect the hierarchy of the functional network in T1DM is unknown. Eigenvector centrality mapping (ECM) and degree centrality are graph theoretical methods that allow determining the relative importance (ECM) and connectedness (degree centrality) of regions within the whole-brain network hierarchy...
April 21, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28427989/egocentric-and-allocentric-visuospatial-working-memory-in-premotor-huntington-s-disease-a-double-dissociation-with-caudate-and-hippocampal-volumes
#17
Katherine L Possin, Hosung Kim, Michael D Geschwind, Tacie Moskowitz, Erica T Johnson, Sharon J Sha, Alexandra Apple, Duan Xu, Bruce L Miller, Steven Finkbeiner, Christopher P Hess, Joel H Kramer
Our brains represent spatial information in egocentric (self-based) or allocentric (landmark-based) coordinates. Rodent studies have demonstrated a critical role for the caudate in egocentric navigation and the hippocampus in allocentric navigation. We administered tests of egocentric and allocentric working memory to individuals with premotor Huntington's disease (pmHD), which is associated with early caudate nucleus atrophy, and controls. Each test had 80 trials during which subjects were asked to remember 2 locations over 1-sec delays...
April 17, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28427871/arthroscopic-assisted-coracoclavicular-ligament-reconstruction-for-acute-acromioclavicular-dislocation-using-2-clavicular-and-1-coracoid-cortical-fixation-buttons-with-suture-tapes
#18
Sang-Jin Shin, Yoon Sang Jeon, Rag Gyu Kim
PURPOSE: To introduce an arthroscopically assisted coracoclavicular (CC) fixation technique using a cortical fixation button device and to evaluate the clinical and radiologic outcomes in patients with acute acromioclavicular (AC) dislocation who were treated with the technique. METHODS: Twenty-one consecutive patients with grade III and V acute AC dislocation who underwent arthroscopically assisted CC ligament reconstruction using a cortical fixation button device were prospectively enrolled...
April 17, 2017: Arthroscopy: the Journal of Arthroscopic & related Surgery
https://www.readbyqxmd.com/read/28424894/the-integrity-of-the-nucleus-of-the-lateral-olfactory-tract-is-essential-for-the-normal-functioning-of-the-olfactory-system
#19
Ricardo P Vaz, Armando Cardoso, Susana I Sá, Pedro A Pereira, M Dulce Madeira
The nucleus of the lateral olfactory tract (nLOT) is a relatively small component of the cortical pallial amygdala, with peculiar neurogenic, neurochemical and connectivity patterns. Although it has been suggested that it might be involved in non-pheromonal olfactory-guided behaviors, particularly feeding, the functional implications of the nLOT have never been investigated. In view of this fact, we have tackled this subject by performing a series of behavioral tests and by quantifying biological and biochemical parameters in sexually naïve adult male rats that were submitted to bilateral excitotoxic lesions of the nLOT...
April 19, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28424597/working-memory-after-traumatic-brain-injury-the-neural-basis-of-improved-performance-with-methylphenidate
#20
Anne E Manktelow, David K Menon, Barbara J Sahakian, Emmanuel A Stamatakis
Traumatic brain injury (TBI) often results in cognitive impairments for patients. The aim of this proof of concept study was to establish the nature of abnormalities, in terms of activity and connectivity, in the working memory network of TBI patients and how these relate to compromised behavioral outcomes. Further, this study examined the neural correlates of working memory improvement following the administration of methylphenidate. We report behavioral, functional and structural MRI data from a group of 15 Healthy Controls (HC) and a group of 15 TBI patients, acquired during the execution of the N-back task...
2017: Frontiers in Behavioral Neuroscience
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