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https://www.readbyqxmd.com/read/28634624/population-averaged-macaque-brain-atlas-with-high-resolution-ex-vivo-dti-integrated-into-in-vivo-space
#1
Lei Feng, Tina Jeon, Qiaowen Yu, Minhui Ouyang, Qinmu Peng, Virendra Mishra, Mihovil Pletikos, Nenad Sestan, Michael I Miller, Susumu Mori, Steven Hsiao, Shuwei Liu, Hao Huang
Animal models of the rhesus macaque (Macaca mulatta), the most widely used nonhuman primate, have been irreplaceable in neurobiological studies. However, a population-averaged macaque brain diffusion tensor imaging (DTI) atlas, including comprehensive gray and white matter labeling as well as bony and facial landmarks guiding invasive experimental procedures, is not available. The macaque white matter tract pathways and microstructures have been rarely recorded. Here, we established a population-averaged macaque brain atlas with high-resolution ex vivo DTI integrated into in vivo space incorporating bony and facial landmarks, and delineated microstructures and three-dimensional pathways of major white matter tracts in vivo MRI/DTI and ex vivo (postmortem) DTI of ten rhesus macaque brains were acquired...
June 20, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28631404/structural-connectivity-differences-in-motor-network-between-tremor-dominant-and-nontremor-parkinson-s-disease
#2
Gaetano Barbagallo, Maria Eugenia Caligiuri, Gennarina Arabia, Andrea Cherubini, Angela Lupo, Rita Nisticò, Maria Salsone, Fabiana Novellino, Maurizio Morelli, Giuseppe Lucio Cascini, Domenico Galea, Aldo Quattrone
Motor phenotypes of Parkinson's disease (PD) are recognized to have different prognosis and therapeutic response, but the neural basis for this clinical heterogeneity remains largely unknown. The main aim of this study was to compare differences in structural connectivity metrics of the main motor network between tremor-dominant and nontremor PD phenotypes (TD-PD and NT-PD, respectively) using probabilistic tractography-based network analysis. A total of 63 PD patients (35 TD-PD patients and 28 NT-PD patients) and 30 healthy controls underwent a 3 T MRI...
June 20, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28630661/intrainsular-connectivity-and-somatosensory-responsiveness-in-young-children-with-asd
#3
Michelle D Failla, Brittany R Peters, Haleh Karbasforoushan, Jennifer H Foss-Feig, Kimberly B Schauder, Brynna H Heflin, Carissa J Cascio
BACKGROUND: The human somatosensory system comprises dissociable paths for discriminative and affective touch, reflected in separate peripheral afferent populations and distinct cortical targets. Differences in behavioral and neural responses to affective touch may have an important developmental role in early social experiences, which are relevant for autism spectrum disorder (ASD). METHODS: Using probabilistic tractography, we compared the structural integrity of white matter pathways for discriminative and affective touch in young children with ASD and their typically developing (TD) peers...
2017: Molecular Autism
https://www.readbyqxmd.com/read/28628946/structural-plasticity-of-the-ventral-stream-and-aphasia-recovery
#4
Emilie T McKinnon, Julius Fridriksson, G Russell Glenn, Jens H Jensen, Joseph A Helpern, Alexandra Basilakos, Christopher Rorden, Andy Y Shih, M Vittoria Spampinato, Leonardo Bonilha
Re-strengthening of the residual language network is likely crucial for speech recovery in post-stroke aphasia. Eight participants with chronic aphasia received intensive speech therapy for three weeks, with standardized naming tests and brain MRIs before and after therapy. Kurtosis-based diffusion tensor tractography was used to measure mean kurtosis (MK) along a segment of the inferior longitudinal fasciculus (ILF). Therapy related reduction in the number of semantic but not phonemic errors was associated with strengthening (renormalization) of ILF MK (r=-0...
June 19, 2017: Annals of Neurology
https://www.readbyqxmd.com/read/28628541/apathy-due-to-injury-of-the-prefrontocaudate-tract-following-mild-traumatic-brain-injury
#5
Sung Ho Jang, Hyeok Gyu Kwon
In this study, we report on a patient who developed apathy resulting from injury to the prefrontocaudate tract following mild traumatic brain injury (TBI), which was observed on diffusion tensor tractography (DTT). A 46-year-old female patient was involved in a bus accident. Her history included intracerebral hemorrhage (ICH) in the left putamen 4 years ago before the head trauma, and her family reported that she had fully recovered. She developed apathy after the TBI, worsening over time. Decreased neural connectivity of the left caudate nucleus (CN) to the left upper medial prefrontal cortex (PFC) resulting from the ICH was observed on the pre-TBI-DTT, whereas on the post-TBI-DTT (28 months after TBI), the neural connectivity of the left CN to the left upper medial PFC was increased, whereas that to the left lower medial PFC and orbitofrontal cortex was decreased...
July 2017: American Journal of Physical Medicine & Rehabilitation
https://www.readbyqxmd.com/read/28624562/impact-of-gradient-number-and-voxel-size-on-dti-tractography-for-resective-brain-surgery
#6
Friso W A Hoefnagels, Philip C de Witt Hamer, Petra J W Pouwels, Frederik Barkhof, W Peter Vandertop
OBJECTIVE: To explore quantitatively and qualitatively how the number of gradient directions (NGD) and spatial resolution (SR) affect DTI-tractography in patients planned for brain tumor surgery, using routine clinical MR-imaging protocols. METHODS: Of 67 patients with intracerebral lesions who had two different DTI-scans, three DTI-series were reconstructed to compare the effects of NGD and SR. Tractographies for four clinically relevant tracts (corticospinal tract, superior longitudinal fasciculus, optic radiation and inferior fronto-occipital fasciculus) were constructed with a probabilistic tracking algorithm and automated ROI-placement and compared for three quantitative measurements: tract volume, median fiber density and mean FA, using linear mixed-effects models...
June 14, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28623671/feasibility-of-diffusion-tensor-imaging-for-assessing-functional-recovery-in-rats-with-olfactory-ensheathing-cell-transplantation-after-contusive-spinal-cord-injury-sci
#7
Mengchao Gu, Zhengchao Gao, Xiaohui Li, Feng Zhao, Lei Guo, Jiantao Liu, Xijing He
BACKGROUND Olfactory ensheathing cell transplantation is a promising treatment for spinal cord injury. Diffusion tensor imaging has been applied to assess various kinds of spinal cord injury. However, it has rarely been used to evaluate the beneficial effects of olfactory ensheathing cell transplantation. This study aimed to explore the feasibility of diffusion tensor imaging in the evaluation of functional recovery in rats with olfactory ensheathing cell transplantation after contusive spinal cord injury. MATERIAL AND METHODS Immunofluorescence staining was performed to determine the purity of olfactory ensheathing cells...
June 17, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28618361/diffusion-tensor-mri-tractography-reveals-increased-fractional-anisotropy-fa-in-arcuate-fasciculus-following-music-cued-motor-training
#8
Emma Moore, Rebecca S Schaefer, Mark E Bastin, Neil Roberts, Katie Overy
Auditory cues are frequently used to support movement learning and rehabilitation, but the neural basis of this behavioural effect is not yet clear. We investigated the microstructural neuroplasticity effects of adding musical cues to a motor learning task. We hypothesised that music-cued, left-handed motor training would increase fractional anisotropy (FA) in the contralateral arcuate fasciculus, a fibre tract connecting auditory, pre-motor and motor regions. Thirty right-handed participants were assigned to a motor learning condition either with (Music Group) or without (Control Group) musical cues...
August 2017: Brain and Cognition
https://www.readbyqxmd.com/read/28616638/piriformis-muscle-syndrome-with-assessment-of-sciatic-nerve-using-diffusion-tensor-imaging-and-tractography-a-case-report
#9
Keizo Wada, Tomohiro Goto, Tomoya Takasago, Daisuke Hamada, Koichi Sairyo
Piriformis muscle syndrome (PMS) is difficult to diagnose by objective evaluation of sciatic nerve injury. Here we report a case of PMS diagnosed by diffusion tensor imaging (DTI) and tractography of the sciatic nerve, which can assess and visualize the extent of nerve injury. The patient was a 53-year-old man with a 2-year history of continuous pain and numbness in the left leg. His symptoms worsened when sitting. Physical examination, including sensorimotor neurologic tests, the deep tendon reflex test, and the straight leg raise test, revealed no specific findings...
June 14, 2017: Skeletal Radiology
https://www.readbyqxmd.com/read/28616385/neurophysiological-evidence-of-preserved-connectivity-in-tuber-tissue
#10
H L Kaye, J M Peters, R Gersner, M Chamberland, A Sansevere, A Rotenberg
We present a case of preserved corticospinal connectivity in a cortical tuber, in a 10 year-old boy with intractable epilepsy and tuberous sclerosis complex (TSC). The patient had multiple subcortical tubers, one of which was located in the right central sulcus. In preparation for epilepsy surgery, motor mapping, by neuronavigated transcranial magnetic stimulation (nTMS) coupled with surface electromyography (EMG) was performed to locate the primary motor cortical areas. The resulting functional motor map revealed expected corticospinal connectivity in the left precentral gyrus...
2017: Epilepsy & Behavior Case Reports
https://www.readbyqxmd.com/read/28616384/comparison-of-large-scale-human-brain-functional-and-anatomical-networks-in-schizophrenia
#11
Brent G Nelson, Danielle S Bassett, Jazmin Camchong, Edward T Bullmore, Kelvin O Lim
Schizophrenia is a disease with disruptions in thought, emotion, and behavior. The dysconnectivity hypothesis suggests these disruptions are due to aberrant brain connectivity. Many studies have identified connectivity differences but few have been able to unify gray and white matter findings into one model. Here we develop an extension of the Network-Based Statistic (NBS) called NBSm (Multimodal Network-based statistic) to compare functional and anatomical networks in schizophrenia. Structural, resting functional, and diffusion magnetic resonance imaging data were collected from 29 chronic patients with schizophrenia and 29 healthy controls...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28615334/diffusion-weighted-tractography-in-the-common-marmoset-monkey-at-9-4-t
#12
David J Schaeffer, Ramina Adam, Kyle M Gilbert, Joseph S Gati, Alex X Li, Ravi S Menon, Stefan Everling
The common marmoset (Callithrix jacchus) is a small New World primate that is becoming increasingly popular in the neurosciences as an animal model of preclinical human disease. With several major disorders characterized by alterations in neural white matter (e.g., multiple sclerosis, Alzheimer's, schizophrenia) proposed to be transgenically modelled using marmosets, the ability to reliably isolate and characterize major white matter fiber tracts with MRI will be of utility for evaluating structural brain changes related to disease processes and symptomatology...
June 14, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28611820/white-matter-disruption-and-connected-speech-in-non-fluent-and-semantic-variants-of-primary-progressive-aphasia
#13
Karine Marcotte, Naida L Graham, Kathleen C Fraser, Jed A Meltzer, David F Tang-Wai, Tiffany W Chow, Morris Freedman, Carol Leonard, Sandra E Black, Elizabeth Rochon
Differential patterns of white matter disruption have recently been reported in the non-fluent (nfvPPA) and semantic (svPPA) variants of primary progressive aphasia (PPA). No single measure is sufficient to distinguish between the PPA variants, but connected speech allows for the quantification of multiple measures. The aim of the present study was to further investigate the white matter correlates associated with connected speech features in PPA. We examined the relationship between white matter metrics and connected speech deficits using an automated analysis of transcriptions of connected speech and diffusion tensor imaging in language-related tracts...
January 2017: Dementia and Geriatric Cognitive Disorders Extra
https://www.readbyqxmd.com/read/28611620/atpp-a-pipeline-for-automatic-tractography-based-brain-parcellation
#14
Hai Li, Lingzhong Fan, Junjie Zhuo, Jiaojian Wang, Yu Zhang, Zhengyi Yang, Tianzi Jiang
There is a longstanding effort to parcellate brain into areas based on micro-structural, macro-structural, or connectional features, forming various brain atlases. Among them, connectivity-based parcellation gains much emphasis, especially with the considerable progress of multimodal magnetic resonance imaging in the past two decades. The Brainnetome Atlas published recently is such an atlas that follows the framework of connectivity-based parcellation. However, in the construction of the atlas, the deluge of high resolution multimodal MRI data and time-consuming computation poses challenges and there is still short of publically available tools dedicated to parcellation...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28608616/whole-brain-structural-connectivity-in-dyskinetic-cerebral-palsy-and-its-association-with-motor-and-cognitive-function
#15
Júlia Ballester-Plané, Ruben Schmidt, Olga Laporta-Hoyos, Carme Junqué, Élida Vázquez, Ignacio Delgado, Leire Zubiaurre-Elorza, Alfons Macaya, Pilar Póo, Esther Toro, Marcel A de Reus, Martijn P van den Heuvel, Roser Pueyo
Dyskinetic cerebral palsy (CP) has long been associated with basal ganglia and thalamus lesions. Recent evidence further points at white matter (WM) damage. This study aims to identify altered WM pathways in dyskinetic CP from a standardized, connectome-based approach, and to assess structure-function relationship in WM pathways for clinical outcomes. Individual connectome maps of 25 subjects with dyskinetic CP and 24 healthy controls were obtained combining a structural parcellation scheme with whole-brain deterministic tractography...
June 13, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28605052/effects-of-pedunculopontine-nucleus-stimulation-on-human-bladder-function
#16
Holly A Roy, Debbie Pond, Christopher Roy, Beth Forrow, Thomas Foltynie, Ludvic Zrinzo, Harith Akram, Tipu Z Aziz, James J FitzGerald, Alexander L Green
AIMS: The pedunculopontine nucleus (PPN) is a deep brain stimulation target for Parkinson's disease (PD). Unilateral PPN stimulation has been described in a previous case report to provoke urinary frequency, urgency and detrusor overactivity, due to probable activation of the pontine micturition center. Our aim was to evaluate the effect of bilateral PPN DBS on urodynamic parameters and to investigate the likely mechanisms using probabilistic tractography. METHODS: Six male PD subjects with bilateral PPN deep brain stimulators were recruited...
June 12, 2017: Neurourology and Urodynamics
https://www.readbyqxmd.com/read/28604153/modified-structural-network-backbone-in-the-contralesional-hemisphere-chronically-after-stroke-in-rat-brain
#17
Michel Rt Sinke, Willem M Otte, Maurits Pa van Meer, Annette van der Toorn, Rick M Dijkhuizen
Functional outcome after stroke depends on the local site of ischemic injury and on remote effects within connected networks, frequently extending into the contralesional hemisphere. However, the pattern of large-scale contralesional network remodeling remains largely unresolved. In this study, we applied diffusion-based tractography and graph-based network analysis to measure structural connectivity in the contralesional hemisphere chronically after experimental stroke in rats. We used the minimum spanning tree method, which accounts for variations in network density, for unbiased characterization of network backbones that form the strongest connections in a network...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28597208/subject-specific-regional-measures-of-water-diffusion-are-associated-with-impairment-in-chronic-spinal-cord-injury
#18
Ann S Choe, Cristina L Sadowsky, Seth A Smith, Peter C M van Zijl, James J Pekar, Visar Belegu
PURPOSE: We aimed to identify non-invasive imaging parameters that can serve as biomarkers for the integrity of the spinal cord, which is paramount to neurological function. Diffusion tensor imaging (DTI) indices are sensitive to axonal and myelin damage, and have strong potential to serve as such biomarkers. However, averaging DTI indices over large regions of interest (ROIs), a common approach to analyzing the images of injured spinal cord, leads to loss of subject-specific information...
June 8, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28594428/compromised-integrity-of-central-visual-pathways-in-patients-with-macular-degeneration
#19
Maka Malania, Julia Konrad, Herbert Jägle, John S Werner, Mark W Greenlee
Purpose: Macular degeneration (MD) affects the central retina and leads to gradual loss of foveal vision. Although, photoreceptors are primarily affected in MD, the retinal nerve fiber layer (RNFL) and central visual pathways may also be altered subsequent to photoreceptor degeneration. Here we investigate whether retinal damage caused by MD alters microstructural properties of visual pathways using diffusion-weighted magnetic resonance imaging. Methods: Six MD patients and six healthy control subjects participated in the study...
June 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28590508/pyramidal-tract-activation-due-to-subthalamic-deep-brain-stimulation-in-parkinson-s-disease
#20
Philipp Mahlknecht, Harith Akram, Dejan Georgiev, Elina Tripoliti, Joseph Candelario, Andre Zacharia, Ludvic Zrinzo, Jonathan Hyam, Marwan Hariz, Thomas Foltynie, John C Rothwell, Patricia Limousin
BACKGROUND: Subthalamic deep brain stimulation (STN-DBS) is an effective treatment for Parkinson's disease (PD), but can have side effects caused by stimulus spread to structures outside the target volume such as the pyramidal tract. OBJECTIVES: To assess the relevance of pyramidal tract activation with STN-DBS in PD. METHODS: In a multimodal, blinded study in 20 STN-DBS patients, we measured stimulation thresholds for evoking electromyographic activity in orbicularis oris and first dorsal interosseous muscles at each of 150 electrode sites...
June 7, 2017: Movement Disorders: Official Journal of the Movement Disorder Society
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