A Framework for ODF Inference by Using Fiber Tract Adaptive MPG Selection

2013 ◽  
pp. 67-79
Author(s):  
Hidekata Hontani ◽  
Kazunari Iwamoto ◽  
Yoshitaka Masutani
Keyword(s):  
Fiber Tract

Microsurgical and Fiber Tract Anatomy of the Nucleus Accumbens

2016 ◽  
Vol 12 (3) ◽  
pp. 269-288 ◽  
Author(s):  
Serhat Baydin ◽  
Kaan Yagmurlu ◽  
Necmettin Tanriover ◽  
Abuzer Gungor ◽  
Albert L. Rhoton
Keyword(s):  
Nucleus Accumbens ◽  
Fiber Tract

High-Resolution Fiber and Fiber Tract Imaging Using Polarized Light Microscopy in the Human, Monkey, Rat, and Mouse Brain

2016 ◽  
pp. 369-389 ◽  
Author(s):  
Karl Zilles ◽  
Nicola Palomero-Gallagher ◽  
David Gräßel ◽  
Philipp Schlömer ◽  
Markus Cremer ◽  
...  
Keyword(s):  
High Resolution ◽  
Light Microscopy ◽  
Mouse Brain ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Fiber Tract

The microanatomy of the optic ganglia of Munida irrasa (Decapoda: Galatheidae)

1976 ◽  
Vol 54 (8) ◽  
pp. 1242-1255 ◽  
Author(s):  
Charles R. Bursey
Keyword(s):  
Serial Sections ◽  
Fiber Tract ◽  
Lamina Ganglionaris ◽  
Peripheral Structure ◽  
Receptor Organ ◽  
Medulla Terminalis ◽  
To Receive ◽  
The Brain ◽  
Proximal Zone ◽  
Invertebrate Ganglia

The microanatomy of the optic ganglia of Munida irrasa was examined by reconstruction from stained serial sections. There are four optic ganglia arranged in a consecutive manner: a distal lamina ganglionaris followed by a medulla externis, medulla internis, and medulla terminalis. Two optic chiasmata are present. Typically, the major constituents of invertebrate ganglia are present: rind, neuropil, blood sinuses, hemocytes, and glia.Neurosecretory cells are found within each of the four ganglia. They are arranged at regular intervals throughout the proximal zone of the lamina ganglionaris. They are collected into ganglionic X organs in the other three ganglia. The medulla externis X organ sends its fiber tract into the lamina ganglionaris. The medulla internis X organ and the medulla terminalis X organ send their combined fiber tract into the sinus gland.The sinus gland is the only peripheral structure to receive axons from cells of the optic ganglia. The organ of Bellonci is wholly contained within the medulla terminalis. A cavity receptor organ is present in the periphery of the eyestalk; however, its nerve parallels the optic ganglia and enters the brain directly.

Speech changes induced by deep brain stimulation of the subthalamic nucleus in Parkinson disease: involvement of the dentatorubrothalamic tract

2016 ◽  
Vol 126 (6) ◽  
pp. 2017-2027 ◽  
Author(s):  
Albert J. Fenoy ◽  
Monica A. McHenry ◽  
Mya C. Schiess
Keyword(s):  
Deep Brain Stimulation ◽  
Parkinson Disease ◽  
Brain Stimulation ◽  
Spontaneous Speech ◽  
Active Electrode ◽  
Fiber Tract ◽  
Speech Performance ◽  
Stn Dbs ◽  
Left Electrode ◽  
Deep Brain

OBJECTIVEPatients with Parkinson disease (PD) who undergo subthalamic nucleus (STN) deep brain stimulation (DBS) often develop a deterioration in speech performance, but there is no clear consensus on the specific effects seen or the mechanism involved and little description of the impact of DBS on conversational speech. Furthermore, there has been no fiber tract connectivity analysis to identify the structures potentially modulated by DBS to cause such deficits. The main objective of this study was to quantify spontaneous speech performance and identify potential involvement of the dentatorubrothalamic tract (DRTt) in patients who underwent STN DBS, because this tract has been implicated in speech deterioration.METHODSSpontaneous speech samples were obtained with STN DBS in both on and off modes in 35 patients with PD and assessed across multiple domains. Diffusion tensor imaging tractography seeded from the therapeutic DBS contacts was performed to identify the fiber tracts involved and, specifically, the DRTt. The position of active electrode contacts was assessed relative to that of the STN.RESULTSFifteen patients with akinetic-rigid (AR) PD and 20 with tremor-dominant (TD) PD subtypes were identified. In the AR-PD subgroup of patients, in whom there was DRTt involvement, 71% demonstrated much better overall speech and largely improved or unchanged fluency in the DBS-off condition. In patients with TD PD with DRTt involvement, 50% demonstrated better overall speech in the off condition, and equivocal results regarding improved or worsened fluency were found. When there was minimal DRTt involvement, 75% of patients with AR PD had better overall speech in the DBS-on condition and better or minimal fluency changes. Similarly, 83% of patients with TD PD with minimal DRTt involvement had better or minimal overall speech and fluency changes in the on condition. More medially placed left electrode contacts were associated with more DRTt involvement in 77% of patients (10 of 13).CONCLUSIONSTo the authors' knowledge, this is the first study to have investigated a specific fiber tract involved in STN DBS in different subtypes of PD relative to its impact on spontaneous speech. At optimal therapeutic programming of STN DBS, overall spontaneous speech and fluency were affected more negatively in patients with AR PD than in those with TD PD when there was DRTt involvement. After fiber tract analysis and modeling, it was found that medially positioned left electrode contacts more often involved fibers of the DRTt. If possible, avoidance of the DRTt by using active electrode contacts that are positioned less medially, specifically in patients with AR PD, might result in less speech deterioration.

Long-Term Improvement of Parkinson Disease Motor Symptoms Derived From Lesions of Prelemniscal Fiber Tract Components

2020 ◽  
Vol 19 (5) ◽  
pp. 539-550
Author(s):  
Maria Guadalupe García-Gomar ◽  
Luis Concha ◽  
Julian Soto-Abraham ◽  
Jacques D Tournier ◽  
Gustavo Aguado-Carrillo ◽  
...  
Keyword(s):  
Parkinson Disease ◽  
Rating Scale ◽  
Pedunculopontine Nucleus ◽  
Cerebellar Nuclei ◽  
Symptom Improvement ◽  
Fiber Tract ◽  
Fiber Tracts ◽  
Score Improvement ◽  
Updrs Score ◽  
Specific Symptoms

Abstract BACKGROUND Prelemniscal radiations (Raprl) are composed of different fiber tracts, connecting the brain stem and cerebellum with basal ganglia and cerebral cortex. In Parkinson disease (PD), lesions in Raprl induce improvement of tremor, rigidity, and bradykinesia in some patients, while others show improvement of only 1 or 2 symptoms, suggesting different fiber tracts mediate different symptoms. OBJECTIVE To search for correlations between improvements of specific symptoms with surgical lesions of specific fiber tract components of Raprl in patients with PD. METHODS A total of 10 patients were treated with unilateral radiofrequency lesions directed to Raprl. The improvement for tremor, rigidity, bradykinesia, posture, and gait was evaluated at 24 to 33 mo after operation through the Unified Parkinson's Disease Rating Scale (UPDRS) score, and the precise location and extension of lesions through structural magnetic resonance imaging and probabilistic tractography at 6 to 8 mo postsurgery. Correlation between percentage of fiber tract involvement and percentage of UPDRS-III score improvement was evaluated through Spearman's correlation coefficient. RESULTS Group average improvement was 86% for tremor, 62% for rigidity, 56% for bradykinesia, and 45% for gait and posture. Improvement in global UPDRS score correlated with extent of lesions in fibers connecting with contralateral cerebellar cortex and improvement of posture and gait with fibers connecting with contralateral deep cerebellar nuclei. Lesion of fibers connecting the globus pallidum with pedunculopontine nucleus induced improvement of gait and posture over other symptoms. CONCLUSION Partial lesion of Raprl fibers resulted in symptom improvement at 2-yr follow-up. Lesions of selective fiber components may result in selective improvement of specific symptoms.

scholarly journals Identification of a distinct association fiber tract “IPS-FG” to connect the intraparietal sulcus areas and fusiform gyrus by white matter dissection and tractography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatsuya Jitsuishi ◽  
Atsushi Yamaguchi
Keyword(s):  
White Matter ◽  
Posterior Parietal Cortex ◽  
Structural Connectivity ◽  
Temporal Cortex ◽  
Fusiform Gyrus ◽  
Intraparietal Sulcus ◽  
Visuomotor Integration ◽  
Fiber Tract ◽  
Fiber Tracts ◽  
Human Connectome Project

Abstract The intraparietal sulcus (IPS) in the posterior parietal cortex (PPC) is well-known as an interface for sensorimotor integration in visually guided actions. However, our understanding of the human neural network between the IPS and the cortical visual areas has been devoid of anatomical specificity. We here identified a distinctive association fiber tract “IPS-FG” to connect the IPS areas and the fusiform gyrus (FG), a high-level visual region, by white matter dissection and tractography. The major fiber bundles of this tract appeared to arise from the medial bank of IPS, in the superior parietal lobule (SPL), and project to the FG on the ventral temporal cortex (VTC) in post-mortem brains. This tract courses vertically at the temporo-parieto-occipital (TPO) junction where several fiber tracts intersect to connect the dorsal-to-ventral cortical regions, including the vertical occipital fasciculus (VOF). We then analyzed the structural connectivity of this tract with diffusion-MRI (magnetic resonance imaging) tractography. The quantitative tractography analysis revealed the major streamlines of IPS-FG interconnect the posterior IPS areas (e.g., IP1, IPS1) with FG (e.g., TF, FFC, VVC, PHA2, PIT) on the Human Connectome Project multimodal parcellation atlas (HCP MMP 1.0). Since the fronto-parietal network, including the posterior IPS areas, is recruited by multiple cognitive demands, the IPS-FG could play a role in the visuomotor integration as well as the top-down modulation of various cognitive functions reciprocally.

Antigenic Abnormalities in Fiber Tract Astrocytes of Myelin-Deficient Rats: An Immunocytochemical Study in the Olfactory Cortex

1989 ◽  
Vol 11 (2) ◽  
pp. 99-111 ◽  
Author(s):  
B. Friedman ◽  
J.A. Black ◽  
S. Hockfield ◽  
S.G. Waxman ◽  
B.R. Ransom
Keyword(s):  
Olfactory Cortex ◽  
Immunocytochemical Study ◽  
Fiber Tract ◽  
Myelin Deficient
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