Vous êtes ici :   Accueil » Sommaires des Revues - Stereotactic and Functional Neurosurgery
 
Prévisualiser...  Imprimer...  Imprimer la page...
Menu Principal
Recherche
Recherche
Journal de Neurochirurgie

couv01.jpg

Publications
Sommaires des Revues - Stereotactic and Functional Neurosurgery

SFN : Last 10 articles


Last 10 articles published in Stereotactic and Functional Neurosurgery


A Novel Animal Model of Parkinson’s Disease Using Optogenetics: Representation of Various Disease Stages by Modulating the Illumination Parameter  Voir?

Background: The classic animal model of Parkinson’s disease (PD) using neurotoxin can only simulate fixed stages of the disease by causing irreversible damage to the nigrostriatal system. Objectives: To develop an optogenetic PD model that can modulate the severity of disease by optical stimulation by introducing the halorhodopsin (NpHR) gene into the substantia nigra compacta. Methods: Fifteen rats received injections of engineered AAV with NpHR-YFP gene into the substantia nigra. They were then subjected to illumination of 590-nm light wavelengths with 3 optical stimulation conditions, i.e., frequency-width: 5 Hz-10 ms (n = 5), 5 Hz-100 ms (n = 5), and 50 Hz-10 ms (n = 5). Eleven rats received 6-hydroxydopamine injections to establish the conventional PD model. Results: The optogenetic models showed characteristic PD manifestations, similar to those of the conventional models; the severity of forelimb akinesia correlated with the total illumination value (frequency × width). The group with a low illumination value (5 Hz-10 ms) was comparable to the conventional partial model whereas the groups with high illumination values (5 Hz-100 ms and 50 Hz-10 ms) were similar to the conventional complete model. Conclusions: An optogenetic PD model has the advantage of more appropriately representing various PD stages by controlling illumination parameters.
Stereotact Funct Neurosurg

... / ... Lire la suite

(???)

WSSFN Society News  Voir?


Stereotact Funct Neurosurg 2017;95:429
(???)

ASSFN Society News  Voir?


Stereotact Funct Neurosurg 2017;95:430
(???)

ESSFN The Mission  Voir?


Stereotact Funct Neurosurg 2017;95:431
(???)

Thalamic Deep Brain Stimulation Salvages Failed Focused Ultrasound Thalamotomy for Essential Tremor: A Case Report  Voir?

Background: A recent randomized controlled trial investigating unilateral MRI-guided focused ultrasound (FUS) for essential tremor demonstrated efficacy. The long-term durability of this thalamotomy, however, is unknown. Furthermore, the feasibility of stimulating a previously lesioned target such as the thalamic nucleus ventralis intermedius (Vim) is poorly understood. We report a case of tremor recurrence, following an initially successful FUS thalamotomy, in which Vim-DBS was subsequently utilized to regain tremor control. Methods: An 81-year-old right-handed female with medically refractory essential tremor (a Clinical Rating Scale for Tremor [CRST] value of 73) underwent left-sided FUS thalamotomy with initial abolition of right-upper extremity tremor. By the 6-month follow-up, there was complete recurrence of tremor (a CRST value of 76). The patient subsequently underwent left-sided Vim-DBS. Results: Vim-DBS provided clinical improvement with a CRST value of 42 at the 3-month follow-up; the patient continues to do clinically well at the 6-month follow-up. This result mirrors previous reported cases of stimulation following radiofrequency and gamma-knife lesioning. Our literature review highlights several reasons for the waning of clinical benefit seen with lesional procedures. Conclusion: This case demonstrates that thalamic DBS can salvage a failed FUS thalamotomy and also the feasibility of stimulating a previously lesioned target.
Stereotact Funct Neurosurg

... / ... Lire la suite

(???)

Contents Vol. 95, 2017  Voir?


Stereotact Funct Neurosurg 2017;95:I–IV
(???)

Battery Life Matters in Deep Brain Stimulation  Voir?


Stereotact Funct Neurosurg
(???)

DBStar: An Open-Source Tool Kit for Imaging Analysis with Patient-Customized Deep Brain Stimulation Platforms  Voir?

Background/Objectives: To create an open-source method for reconstructing microelectrode recording (MER) and deep brain stimulation (DBS) electrode coordinates along multiple parallel trajectories with patient-specific DBS implantation platforms to facilitate DBS research. Methods: We combined the surgical geometry (extracted from WayPoint Planner), pre-/intra-/postoperative computed tomography (CT) and/or magnetic resonance (MR) images, and integrated them into the Analysis of Functional NeuroImages (AFNI) neuroimaging analysis environment using functions written in Python. Electrode coordinates were calculated from image-based electrode surfaces and recording trajectory depth values. Coordinates were translated into appropriate trajectories, and were tested for proximity to patient-specific or atlas-based anatomical structures. Final DBS electrode coordinates for 3 patient populations (ventral intermediate nucleus [VIM], subthalamic nucleus [STN], and globus pallidus pars interna [GPi]) were calculated. For STN cases, MER site coordinates were then analyzed to see whether they were inside or outside the STN. Results: Final DBS electrode coordinates were described for VIM, STN, and GPi patient populations. 115/169 (68%) STN MER sites were within 1 mm of the STN in AFNI’s Talairach and Tournoux (TT) atlas. Conclusions: DBStar is a robust tool kit for understanding the anatomical location and context of electrode locations, and can easily be used for imaging, behavioral, or electrophysiological analyses.
Stereotact Funct Neurosurg

... / ... Lire la suite

(???)

Prelemniscal Lesion for Selective Improvement of Parkinson Disease Tremor  Voir?

Background: Selective improvement of symptoms may be required when treating Parkinson disease (PD) patients with a predominantly monosymptomatic clinical picture. Objective: To define a target in prelemniscal radiation fibers (Raprl) related to the physiopathology of tremor evidenced by tractography. Case Report: We report a patient with predominant unilateral rest and postural tremor, diagnosed as PD based on 80% improvement induced by the administration of L-DOPA/carbidopa, subsequently complicated by motor fluctuations, L-DOPA dyskinesia, and a reduced ON period. A stereotactic radiofrequency lesion was made for tremor control, and postoperative diffusion-weighted imaging (DWI) demonstrated the precise location and extension of the lesioned tract. Results: Perfect control of the tremor was achieved with the patient OFF medication; this has lasted for 5 years, without hypotonia in the treated extremities. DWI revealed a 3.0-mm lesion at the base of the nucleus ventralis intermedius (Vim) interrupting cerebellar-Vim fibers sparing the cerebellar ventralis oralis posterior nucleus component. Conclusion: Selective improvement of symptoms is feasible in patients with a predominantly monosymptomatic PD clinical presentation.
Stereotact Funct Neurosurg

... / ... Lire la suite

(???)

Theoretical Effect of DBS on Axonal Fibers of Passage: Firing Rates, Entropy, and Information Content  Voir?

Background: Deep brain stimulation (DBS) has effects on axons that originate and terminate outside the DBS target area. Objective: We hypothesized that DBS generates action potentials (APs) in both directions in “axons of passage,” altering their information content and that of all downstream cells and circuits, and sought to quantify the change in fiber information content. Methods: We incorporated DBS parameters (fiber firing frequency and refractory time, and AP initiation location along the fiber and propagation velocity) in a filtering function determining the AP frequency reaching the postsynaptic cell. Using neural circuitry simulation software, we investigated the ability of the filtering function to predict the firing frequency of APs reaching neurons targeted by axons of passage. We calculated their entropy with and without DBS, and with the electrode applied at various distances from the cell body. Results: The predictability of the filtering function exceeded 98%. Entropy calculations showed that the entropy ratio “without DBS” to “with DBS” was always >1.0, thus DBS reduces fiber entropy. Conclusions: (1) The results imply that DBS effects are due to entropy reduction within fibers, i.e., a reduction in their information. (2) Where fibers of passage do not terminate in target regions, DBS may have side effects on nontargeted circuitry.
Stereotact Funct Neurosurg

... / ... Lire la suite

(???)

Dernière mise à jour : 21/02/2018 : 00:56


Préférences

Se reconnecter :
Votre nom (ou pseudo) :
Votre mot de passe
Captcha reload
Recopier le code :


  Nombre de membres 413 membres
Connectés :
( personne )
Snif !!!
Lettre d'information
Pour avoir des nouvelles de ce site, inscrivez-vous à notre Newsletter.
Captcha reload
Recopier le code :