A head mountable deep brain stimulation device for laboratory animals

Deep brain stimulation has emerged as an effective method to treat certain medical conditions. Electrical charges are injected into the target tissue through a conducting electrode exciting the tissue. A variety of DBS devices have been developed based on different operation principles. Majority of these devices, however, employ complex circuitry and are bulky. In clinical trials, laboratory animals need to freely move around and perform activities whilst receiving brain stimulation for days. This paper presents a simple lightweight head mountable deep brain stimulation device that can be carried by the animal during the course of a clinical trial. The device produces continuous current pulses of specific characteristics. It employs passive charge balancing to minimize undesirable effects on the target tissue. The device is constructed and its performance tested.

Presenting evidence-based health information for people with multiple sclerosis : the IN-DEEP project protocol

Background - Increasingly, evidence-based health information, in particular evidence from systematic reviews, is being made available to lay audiences, in addition to health professionals. Research efforts have focused on different formats for the lay presentation of health information. However, there is a paucity of data on how patients integrate evidence-based health information with other factors such as their preferences for information and experiences with information-seeking. The aim of this project is to explore how people with multiple sclerosis (MS) integrate health information with their needs, experiences, preferences and values and how these factors can be incorporated into an online resource of evidence-based health information provision for people with MS and their families.

Methods - This project is an Australian-Italian collaboration between researchers, MS societies and people with MS. Using a four-stage mixed methods design, a model will be developed for presenting evidence-based health information on the Internet for people with MS and their families. This evidence-based health information will draw upon systematic reviews of MS interventions from The Cochrane Library. Each stage of the project will build on the last. After conducting focus groups with people with MS and their family members (Stage 1), we will develop a model for summarising and presenting Cochrane MS reviews that is integrated with supporting information to aid understanding and decision making. This will be reviewed and finalised with people with MS, family members, health professionals and MS Society staff (Stage 2), before being uploaded to the Internet and evaluated (Stages 3 and 4).

Discussion - This project aims to produce accessible and meaningful evidence-based health information about MS for use in the varied decision making and management situations people encounter in everyday life. It is expected that the findings will be relevant to broader efforts to provide evidence-based health information for patients and the general public. The international collaboration also permits exploration of cultural differences that could inform international practice.

Record of the deep marine Clinocythereis australis Ayress and Swanson, 1991 (Ostracoda) from the upper Miocene Tambo River Formation, Gippsland Basin, Australia : Palaeo-oceanographic and biostratigraphic implications

Fossils of the deep marine ostracod, Clinocythereis australis Ayress & Swanson, 1991 occur within the Tambo River Formation, Gippsland Basin, southeastern Australia and record an approximately 6 Ma phase of late Miocene coastal ocean upwelling within this region. The presence of deep marine faunal elements within late Miocene Mitchellian strata is in contrast to the absence of such faunal elements in latest Miocene Cheltenhamian and younger marine strata of the Bass Strait hinterland. The absence of deep marine faunal elements in post-Mitchellian onshore strata is due to the Kosciusko Uplift, which transformed Bass Strait into a wholly shallow seaway placing adjacent coastal regions beyond the reach of ocean upwelling influences.

Underlying neurobiology and clinical correlates of mania status after subthalamic nucleus deep brain stimulation in Parkinson's Disease : a review of the literature

Deep brain stimulation (DBS) is a novel and effective surgical intervention for refractory Parkinson's disease (PD). The authors review the current literature to identify the clinical correlates associated with subthalamic nucleus (STN) DBS-induced hypomania/mania in PD patients. Ventromedial electrode placement has been most consistently implicated in the induction of STN DBS-induced mania. There is some evidence of symptom amelioration when electrode placement is switched to a more dorsolateral contact. Additional clinical correlates may include unipolar stimulation, higher voltage (>3 V), male sex, and/or early-onset PD. STN DBS-induced psychiatric adverse events emphasize the need for comprehensive psychiatric presurgical evaluation and follow-up in PD patients. Animal studies and prospective clinical research, combined with advanced neuroimaging techniques, are needed to identify clinical correlates and underlying neurobiological mechanisms of STN DBS-induced mania. Such working models would serve to further our understanding of the neurobiological underpinnings of mania and contribute valuable new insight toward development of future DBS mood-stabilization therapies.

Effect of deep brain stimulation on nucleus accumbens dopamine in a preclinicla model of antidepressant treatment-resistance

Background / Purpose: To determine if clinically effective deep brain stimulation (DBS) of neurosurgical targets for treatment-resistant depression regulates transient mesoaccumbens dopamine release in control and antidepressant-resistant animals (rats).

Main conclusion: In control rats, DBS stimulation of either the nucleus accumbens or infralimbic cortex significantly attenuated transient mesoaccumbens dopamine efflux, with nucleus accumbens DBS inducing a greater attenuation than infralimbic DBS. High frequency DBS of both targets induced long-term depression of transient accumbens dopamine release, lasting > 2hr post DBS.

Conversely, in antidepressant-resistant rats, infralimbic DBS significantly potentiated transient mesoaccumbens dopamine efflux during stimulation, but failed to induce long-lasting changes in neurotransmission. This suggests that a key mechanism of DBS for treatment-resistant depression is the regulation of dysfunctional mesoaccumbens dopamine neurotransmission.

Incorporation of fused tetrathiafulvalenes (TTFs) into polythiophene architectures : varying the electroactive dominance of the TTF species in hybrid systems

A novel polythienylenevinylene (PTV) and two new polythiophenes (PTs), featuring fused tetrathiafulvalene (TTF) units, have been prepared and characterized by ultraviolet−visible (UV−vis) and electron paramagnetic resonance (EPR) spectroelectrochemistry. All polymers undergo two sequential, reversible oxidation processes in solution. Structures in which the TTF species is directly linked to the polymer backbone (2 and 4) display redox behavior which is dictated by the fulvalene system. Once the TTF is spatially removed from the polymer chain by a nonconjugated link (polymer 3), the electroactivity of both TTF and polythiophene moieties can be detected. Computational studies confirm the delocalization of charge over both electroactive centers (TTF and PT) and the existence of a triplet dication intermediate. PTV 4 has a low band gap (1.44 eV), is soluble in common organic solvents, and is stable under ambient conditions. Organic solar cells of polymer 4:[6,6]-phenyl-C₆₁ butyric acid methyl ester (PCBM) have been fabricated. Under illumination, a photovoltaic effect is observed with a power conversion efficiency of 0.13% under AM1.5 solar simulated light. The onset of photocurrent at 850 nm is consistent with the onset of the π−π absorption band of the polymer. Remarkably, UV−vis spectroelectrochemistry of polymer 4 reveals that the conjugated polymer chain remains unchanged during the oxidation of the polymer.

AlN nanostructures : tunable architectures and optical properties

Novel AlN nanostructures with tunable building units of the architectures have been successfully synthesized without any catalyst or template; the subsequent photoluminescence (PL) indicates that the optical properties of the AlN nanostructures can be adjusted by tuning the architectures.

Compact stacked planar inverted-F antenna for passive deep brain stimulation implants

A compact meandered three-layer stacked circular planar inverted-F antenna is designed and simulated at the UHF band (902.75 – 927.25 MHz) for passive deep brain stimulation implants. The UHF band is used because it offers small antenna size, and high data rate. The top and middle radiating layers are meandered, and low cost substrate and superstrate materials are used to limit the radius and height of the antenna to 5 mm and 1.64 mm, respectively. A dielectric substrate of FR-4 of εr= 4.7 and δ= 0.018, and a biocompatible superstrate of silicone of er= 3.7 and d= 0.003 with thickness of 0.2 mm are used in the design. The resonance frequency of the proposed antenna is 918 MHz with a bandwidth of 24 MHz at return loss of −10 dB in free space. The antenna parameter such as 3D gain pattern of the designed antenna within a skin-tissue model is evaluated by using the finite element method. The compactness, wide bandwidth, round shape, and stable characteristics in skin make this antenna suitable for DBS. The feasibility of the wireless power transmission to the implant in the human head is also examined.

Multi-layer implantable antenna for closed loop deep brain stimulation system

A multi-layer circular planar inverted-F antenna is designed and simulated at the industrial, scientific, and medical (ISM) band of 915 MHz for closed loop deep brain stimulation implant. The ISM band is considered due to the capabilities of small antenna size, high data rate, and long transmission range. In the proposed four-layer antenna, the top three radiating layers are meandered, and a high permittivity substrate and superstrate materials are used to limit the radius and the height of the antenna to 3.5 mm and 2.2 mm, respectively. The bottom layer works as a ground plate. The Roger RO3210 of εr = 10.2 and δ = 0.003 is used as a dielectric substrate and superstrate. The resonance frequency of the proposed antenna is 915 MHz with a bandwidth of 12 MHz at the return loss of -10 dB in free space. The stacked layered structure reduces the antenna size, and the circular shape makes it easily implantable into the human head. The antenna parameters (e.g. 3D gain pattern), SAR value, and electric field distribution within a six layers spherical head model are evaluated by using the finite element method (FEM). The feasibility of the wireless transmission of power, control and command signal to the implant in the human head is also examined. © 2012 IEEE.