scholarly journals Tracking the visual system—from the optic chiasm to primary visual cortex

2020 ◽  
Author(s):  
Robert J. Puzniak ◽  
Gokulraj T. Prabhakaran ◽  
Lars Buentjen ◽  
Friedhelm C. Schmitt ◽  
Michael B. Hoffmann
Keyword(s):  
Visual System ◽  
Brain Structures ◽  
Optic Chiasm ◽  
Visual Pathways ◽  
Visual Field Defects ◽  
Neural Pathways ◽  
Diffusion Modeling ◽  
Resonance Imaging ◽  
Established Method ◽  
Inherent Risk

AbstractEpilepsy surgery is a well-established method of treatment for pharmacoresistant focal epilepsies, but it carries an inherent risk of damaging eloquent brain structures. This holds true in particular for visual system pathways, where the damage to, for example, the optic radiation may result in postoperative visual field defects. Such risk can be minimized by the identification and localization of visual pathways using diffusion magnetic resonance imaging (dMRI). The aim of this article is to provide an overview of the step-by-step process of reconstructing the visual pathways applying dMRI analysis. This includes data acquisition, preprocessing, identification of key structures of the visual system necessary for reconstruction, as well as diffusion modeling and the ultimate reconstruction of neural pathways. As a result, the reader will become familiar both with the ideas and challenges of imaging the visual system using dMRI and their relevance for planning the intervention.

Impact of Prolactin Hipersecrey on Glucid and Lipid Metabolisms

2019 ◽  
Vol 70 (5) ◽  
pp. 1603-1607
Author(s):  
Elena Ionescu ◽  
Bogdan Virgil Cotoi ◽  
Anca Ganescu
Keyword(s):  
Cranial Nerves ◽  
Pituitary Tumors ◽  
Optic Chiasm ◽  
Anterior Lobe ◽  
Visual Field Defects ◽  
Large Tumor ◽  
Metabolic Complications ◽  
Clinical Onset ◽  
Vision Defects ◽  
Upper Level

Pituitary is a common terrain for the appearance of tumoral changes, representing the origin of about 15% of all intracranial tumors [13]. These tumors are, for the most part, histologically benign, as they arise from hormone secreting cells in the anterior lobe. Therefore, the aim of the paper is to specify the clinical and paraclinical clinical onset characteristics, the evolutionary peculiarities, as well as the metabolic complications secondary to the prolactin hypersecretion. The effects of prolactin-secreting pituitary tumors may occur as a result of mass effects of tumors or even hyperprolactinaemia. Because microadenomas are intrathecal, visual defects may not occur, but headaches occur more often (50%) than normal (27%) [1, 6]. A large tumor that extends beyond the limbs of the turkey can cause headaches and vision defects. The classical presentation is bitemporal hemianopsia due to the compression of the optic chiasm from a tumor that extends to the upper level. If chiasma is prefixed or if the tumor extends posteriorly, compression of a single optical system results in visual field defects similar. The lateral extension in the cavernous sinus can lead to the illness of the oculomotor function involving the cranial nerves III, IV and VI and the branches V1 and V2 of the cranial nerve V, alone or in combinations.

scholarly journals Identifying a Common Functional Framework for Apathy Large-Scale Brain Network

2021 ◽  
Vol 11 (7) ◽  
pp. 679
Author(s):  
Vincenzo Alfano ◽  
Mariachiara Longarzo ◽  
Giulia Mele ◽  
Marcello Esposito ◽  
Marco Aiello ◽  
...  
Keyword(s):  
Large Scale ◽  
Brain Magnetic Resonance Imaging ◽  
Brain Network ◽  
Neural Pathways ◽  
Resonance Imaging ◽  
Daily Life Activities ◽  
Functional Differences ◽  
Central Gyrus ◽  
Magnetic Resonance Imaging Mri ◽  
Disease Specific

Apathy is a neuropsychiatric condition characterized by reduced motivation, initiative, and interest in daily life activities, and it is commonly reported in several neurodegenerative disorders. The study aims to investigate large-scale brain networks involved in apathy syndrome in patients with frontotemporal dementia (FTD) and Parkinson’s disease (PD) compared to a group of healthy controls (HC). The study sample includes a total of 60 subjects: 20 apathetic FTD and PD patients, 20 non apathetic FTD and PD patients, and 20 HC matched for age. Two disease-specific apathy-evaluation scales were used to measure the presence of apathy in FTD and PD patients; in the same day, a 3T brain magnetic resonance imaging (MRI) with structural and resting-state functional (fMRI) sequences was acquired. Differences in functional connectivity (FC) were assessed between apathetic and non-apathetic patients with and without primary clinical diagnosis revealed, using a whole-brain, seed-to-seed approach. A significant hypoconnectivity between apathetic patients (both FTD and PD) and HC was detected between left planum polare and both right pre- or post-central gyrus. Finally, to investigate whether such neural alterations were due to the underlying neurodegenerative pathology, we replicated the analysis by considering two independent patients’ samples (i.e., non-apathetic PD and FTD). In these groups, functional differences were no longer detected. These alterations may subtend the involvement of neural pathways implicated in a specific reduction of information/elaboration processing and motor outcome in apathetic patients.

scholarly journals Preservation Effect: Cigarette Smoking Acts on the Dynamic of Influences Among Unifying Neuropsychiatric Triple Networks in Schizophrenia

2018 ◽  
Vol 45 (6) ◽  
pp. 1242-1250 ◽  
Author(s):  
Wei Liao ◽  
Yun-Shuang Fan ◽  
Siqi Yang ◽  
Jiao Li ◽  
Xujun Duan ◽  
...  
Keyword(s):  
Cigarette Smoking ◽  
Analysis Of Covariance ◽  
Neural Pathways ◽  
Healthy Controls ◽  
Causality Analysis ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Self Medication ◽  
Granger Causality Analysis ◽  
High Prevalence

Abstract Objective The high prevalence of cigarette smoking in schizophrenia (SZ) is generally explained by the self-medication theory. However, its neurobiological mechanism remains unclear. The impaired dynamic of influences among unifying neuropsychiatric triple networks in SZ, including the central executive network (CEN), the default mode network (DMN), and the salience network (SN), might explain the nature of their syndromes, whereas smoking could regulate the dynamics within networks. Therefore, this study examined whether cigarette smoking could elicit a distinct improvement in the dynamics of triple networks in SZ and associated with the alleviation of symptoms. Methods Four groups were recruited, namely, SZ smoking (n = 22)/nonsmoking (n = 25), and healthy controls smoking (n = 22)/nonsmoking (n = 21). All participants underwent a resting-state functional magnetic resonance imaging (fMRI). The dynamics among unifying neuropsychiatric triple networks were measured using Granger causality analysis on the resting-sate fMRI signal. Interaction effects between SZ and smoking on dynamics were detected using 2-way analysis of covariance, correcting for sex, age, and education level. Results Whereas smoking reduced SN→DMN dynamic in healthy controls, it preserved the dynamic in SZ, thus suggesting a preservation effect. Moreover, smoking additionally increased DMN→CEN dynamic in SZ. Conclusions This finding from neural pathways shed new insights into the prevailing self-medication hypothesis in SZ. More broadly, this study elaborates on the neurobiological dynamics that may assist in the treatment of the symptomatology of SZ.

scholarly journals A Frontal Lobe Meningioma in a Child Leading to Visual Loss

2015 ◽  
Vol 2015 ◽  
pp. 1-3 ◽  
Author(s):  
Nedime Sahinoglu-Keşkek ◽  
Gokhan Soker ◽  
Şakir Özgür Keşkek ◽  
Sehire Sahinoglu ◽  
Figen Unal ◽  
...  
Keyword(s):  
Visual Loss ◽  
Clinical Presentation ◽  
Low Vision ◽  
Optic Chiasm ◽  
Intracranial Tumor ◽  
Intracranial Meningioma ◽  
Resonance Imaging ◽  
Blurred Vision ◽  
History Of ◽  
Meningeal Tumors

Objective. Meningiomas are benign primary meningeal tumors and are seen rare in children and adolescents.Clinical Presentation and Intervention. A 15-year-old Turkish boy reported a 1-month history of headache and blurred vision in both eyes. His visual acuity was 0.3 in both eyes with papilledema. Magnetic resonance imaging showed a77×97×77 mm intracranial-extra-axial frontal lesion which compresses the chiasm. He was diagnosed with intracranial meningioma and referred to neurosurgery clinic.Conclusion. Ophthalmologists should be aware of the fact that papilledema and low vision can be caused by an intracranial tumor which compresses optic chiasm.

Magnetic resonance imaging of the optic chiasm

1991 ◽  
Vol 36 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Saunders L. Hupp ◽  
Lanning B. Kline
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Optic Chiasm ◽  
Resonance Imaging
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