Edge detections of MER Signals of STN with DBS micro electrode local field potential acquisitions in Parkinson`s

Deep brain stimulation of the subthalamic nucleus (STN) is a highly effective treatment for motor symptoms of Parkinson’s disease. Sub thalamic nucleus deep brain stimulation (STN-DBS) is a therapeutic surgical procedure for reducing the symptoms Parkinson’s and restoring and increasing the motor functioning. However, precise intraoperative edge or perimeter detection of STN remains a procedural challenge. In this study, we present the micro electrode signals recordings (MER) of STNs and local field potentials (LFPs) were acquired from deep brain stimulation macro electrodes during trajectory towards STN, in Parkinson patients. The frequency versus intensity atlas of field potential activity was obtained and further than investigated in distinct sub band’s, to explore whether field potentials activity can be employed for STN edge detection. STN perimeter detections by means of L F Ps were evaluated to edge predictions by way of the functional stereotactic DBS neurosurgeon, based on micro electrode derived, single unit recordings (M E R – S N A of S T Ns). The findings show variation amongst M E R – S N A and macro electrode L F P-signals gathering through MER-system pertaining to the d o r s a l S T N b o r d e r of -1.00±0.85mm plus -0.42±1.08 mm in the and frequencies, correspondingly. For these sub band`s, root mean square of the voids was found to be 1.27milli meters and 1.07milli meters. The Assessment of other sub band`s didn`t set a limit for differentiating the posterior (c a u d a l) point of sub-thalamic nuclei. We may infer that In conclusion, macro electrode signal acquisitions of STNs derived L F P gatherings might offer an unconventional methodology in the direction of m e r – s n a, for detecting the aimed target subthalamic nucleus borders during DBS-surgery.

Changes in pallidal neural activity following long-term symptom improvement from botulinum toxin treatment in DYT6 dystonia: a case report

Background The globus pallidus internus is the main target for the treatment of dystonia by deep brain stimulation. Unfortunately, for some genetic etiologies, the therapeutic outcome of dystonia is less predictable. In particular, therapeutic outcomes for deep brain stimulation in craniocervical and orolaryngeal dystonia in DYT6-positive patients are poor. Little is known about the neurophysiology of the globus pallidus internus in DYT6-positive dystonia, and how symptomatic treatment affects the neural activity of this region. Case presentation We present here the case of a 55-year-old Caucasian female DYT6-dystonic patient with blepharospasm, spasmodic dysphonia, and oromandibular dystonia where single-unit and local field potential activity was recorded from the globus pallidus internus during two deep brain stimulation revision surgeries 4 years apart with no symptomatic improvement. Botulinum toxin injections consistently improved dysphonia, while some of the other symptoms were only inconsistently or marginally improved. Neural activity in the globus pallidus internus during both revision surgeries were compared with previously published results from an idiopathic dystonic cohort. Single-cell firing characteristics and local field potential from the first revision surgery showed no differences with our control group. However, during the second revision surgery, the mean firing rate of single units and local field potential power in the gamma range were lower than those present during the first revision surgery or the control group. Conclusions Symptoms related to facial movements were greatly improved by botulinum toxin treatment between revision surgeries, which coincided with lower discharge rate and changes in gamma local field oscillations.

Unveiling radial breathing mode in a particle-on-mirror plasmonic nanocavity

Plasmonic radial breathing mode (RBM), featured with radially oscillating charge density, arises from the surface plasmon waves confined in the flat nanoparticles. The zero net dipole moment endows the RBM with an extremely low radiation yet a remarkable intense local field. On the other hand, owing to the dark mode nature, the RBMs routinely escape from the optical measurements, severely preventing their applications in optoelectronics and nanophotonics. Here, we experimentally demonstrate the existence of RBM in a hexagonal Au nanoplate-on-mirror nanocavity using a far-field linear-polarized light source. The polarization-resolved scattering measurements cooperated with the full-wave simulations elucidate that the RBM originates from the standing plasmon waves residing in the Au nanoplate. Further numerical analysis shows the RBM possesses the remarkable capability of local field enhancement over the other dark modes in the same nanocavity. Moreover, the RBM is sensitive to the gap and nanoplate size of the nanocavity, providing a straightforward way to tailor the wavelength of RBM from the visible to near-infrared region. Our approach provides a facile optical path to access to the plasmonic RBMs and may open up a new route to explore the intriguing applications of RBM, including surface-enhanced Raman scattering, enhanced nonlinear effects, nanolasers, biological and chemical sensing.

Спектры поглощения пробного сигнала и резонансной флуоресценции для излучателей при их взаимодействии с локальным окружением в прозрачных средах

The current paper demonstrates theoretical analysis of two types of spectral curves for several configurations of system of two-level light emitters, considering the influence of local field and close environment inside a transparent medium. Probe field absorption spectra and resonant fluorescence spectra are calculated under excitation of a strong monochromatic cw laser. The sensitivity of absorption and emission optical spectroscopy method is compared for revealing the effects of the medium on individual emitters and their ensembles. Spectral curves were calculated for model emitters considering local field influence of a transparent dielectric medium and local electron-phonon interactions, which determined the response of the emitters to an external laser field and effective relaxation mechanisms. The calculation formalism is based on a semiclassical approach, while the relaxation processes associated with the phonon contribution are introduced phenomenologically with references to other studies.

Посвящается памяти А.И. Морозова Фаза Имри-Ма в системах с дефектами типа "случайное локальное поле" и "случайная локальная анизотропия" (О б з о р)

The conditions for the appearance in systems with defects of the "random local field" and "random local anisotropy" type of the Imry-Ma phases, in which the direction of the order parameter follows large-scale fluctuations of a random field or random anisotropy, are considered. It is shown that the anisotropy of the distribution of random fields of defects in the space of the order parameter can lead to the appearance of the long-range order. An attention is paid to phase diagrams arising as a result of competition between random fields of defects and anisotropy induced by defects. By the example of a system with random anisotropy (nanocrystalline ferromagnet), the dependences of the coercive field on the crystallite size are considered.

Photoelastic plasmonic metasurfaces with ultra-large near infrared spectral tuning

Metasurfaces, consisting of artificially fabricated sub-wavelength meta-atoms with pre-designable electromagnetic properties, provide novel opportunities to a variety of applications such as light detectors/sensors, local field imaging and optical displays. Currently,...

Changes in the spatiotemporal pattern of spontaneous activity across a cortical column after noise trauma

In the auditory modality, noise trauma has often been used to investigate cortical plasticity as it causes cochlear hearing loss. One limitation of these past studies, however, is that the effects of noise trauma have been mostly documented at the granular layer, which is the main cortical recipient of thalamic inputs. Importantly, the cortex is composed of six different layers each having its own pattern of connectivity and specific role in sensory processing. The present study aims at investigating the effects of acute and chronic noise trauma on the laminar pattern of spontaneous activity in primary auditory cortex of the anesthetized guinea pig. We show that spontaneous activity is dramatically altered across cortical layers after acute and chronic noise-induced hearing loss. First, spontaneous activity was globally enhanced across cortical layers, both in terms of firing rate and amplitude of spike-triggered average of local field potentials. Second, current source density on (spontaneous) spike-triggered average of local field potentials indicates that current sinks develop in the supra- and infragranular layers. These latter results suggest that supragranular layers become a major input recipient and that the propagation of spontaneous activity over a cortical column is greatly enhanced after acute and chronic noise-induced hearing loss. We discuss the possible mechanisms and functional implications of these changes.