Bidirectional Neural Interface Circuits with On-Chip Stimulation Artifact Reduction Schemes

Bidirectional neural interfaces are tools designed to “communicate” with the brain via recording and modulation of neuronal activity. The bidirectional interface systems have been adopted for many applications. Neuroscientists employ them to map neuronal circuits through precise stimulation and recording. Medical doctors deploy them as adaptable medical devices which control therapeutic stimulation parameters based on monitoring real-time neural activity. Brain-machine-interface (BMI) researchers use neural interfaces to bypass the nervous system and directly control neuroprosthetics or brain-computer-interface (BCI) spellers. In bidirectional interfaces, the implantable transducers as well as the corresponding electronic circuits and systems face several challenges. A high channel count, low power consumption, and reduced system size are desirable for potential chronic deployment and wider applicability. Moreover, a neural interface designed for robust closed-loop operation requires the mitigation of stimulation artifacts which corrupt the recorded signals. This dissertation introduces several techniques targeting low power consumption, small size, and reduction of stimulation artifacts. These techniques are implemented for extracellular electrophysiological recording and two stimulation modalities: direct current stimulation for closed-loop control of seizure detection/quench and optical stimulation for optogenetic studies. While the two modalities differ in their mechanisms, hardware implementation, and applications, they share many crucial system-level challenges. The first method aims at solving the critical issue of stimulation artifacts saturating the preamplifier in the recording front-end. To prevent saturation, a novel mixed-signal stimulation artifact cancellation circuit is devised to subtract the artifact before amplification and maintain the standard input range of a power-hungry preamplifier. Additional novel techniques have been also implemented to lower the noise and power consumption. A common average referencing (CAR) front-end circuit eliminates the cross-channel common mode noise by averaging and subtracting it in analog domain. A range-adapting SAR ADC saves additional power by eliminating unnecessary conversion cycles when the input signal is small. Measurements of an integrated circuit (IC) prototype demonstrate the attenuation of stimulation artifacts by up to 42 dB and cross-channel noise suppression by up to 39.8 dB. The power consumption per channel is maintained at 330 nW, while the area per channel is only 0.17 mm2. The second system implements a compact headstage for closed-loop optogenetic stimulation and electrophysiological recording. This design targets a miniaturized form factor, high channel count, and high-precision stimulation control suitable for rodent in-vivo optogenetic studies. Monolithically integrated optoelectrodes (which include 12 µLEDs for optical stimulation and 12 electrical recording sites) are combined with an off-the-shelf recording IC and a custom-designed high-precision LED driver. 32 recording and 12 stimulation channels can be individually accessed and controlled on a small headstage with dimensions of 2.16 x 2.38 x 0.35 cm and mass of 1.9 g. A third system prototype improves the optogenetic headstage prototype by furthering system integration and improving power efficiency facilitating wireless operation. The custom application-specific integrated circuit (ASIC) combines recording and stimulation channels with a power management unit, allowing the system to be powered by an ultra-light Li-ion battery. Additionally, the µLED drivers include a high-resolution arbitrary waveform generation mode for shaping of µLED current pulses to preemptively reduce artifacts. A prototype IC occupies 7.66 mm2, consumes 3.04 mW under typical operating conditions, and the optical pulse shaping scheme can attenuate stimulation artifacts by up to 3x with a Gaussian-rise pulse rise time under 1 ms.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147674/1/mendrela_1.pd

Zmiany społeczno-polityczne w ZSRR i Federacji Rosyjskiej a społeczna rola i obraz kobiety

Dysertacja ukazuje jak bardzo złożonym problemem jest sytuacja kobiet we współczesnej Rosji. W pięciu rozdziałach przeanalizowano, w jaki sposób rola i obraz kobiety zmieniał się w państwie rosyjskim, jakie czynniki wpływały na jego ówczesny kształt i jakie siły go kreowały. Podejmując problem sytuacji kobiety w społeczeństwie rosyjskim uznano, że szczególnie ważnym okresem dla kształtowania się sytuacji kobiet była rewolucja październikowa, która diametralnie zmieniła podejście do kwestii kobiecej. Jednak by zrozumieć genezę tych zmian należy sięgnąć do wcześniejszego etapu, czyli okresu rządów carskich a nawet początków państwowości, charakteryzujących się patriarchalnym porządkiem społecznym. W rozdziale trzecim podjęto temat wpływu rewolucji 1917 r. a w późniejszym etapie, państwa radzieckiego, na sytuację i kreowanie roli kobiety. Wyzwolenie kobiety miało być ważnym aspektem kolektywnego życia. W dysertacji zawarto także najważniejsze problemy dotyczące roli i sytuacji Rosjanek po upadku ZSSR i w trakcie formowania nowego państwa rosyjskiego po 1991 r. Zwrócono uwagę na wielość regulacji prawnych FR, które pod względem formalnym gwarantowały Rosjankom równość wobec prawa i brak dyskrymiancji we wszystkich sferach życia. Niestety ze względu na brak narzędzi wdrażania i egzekwowania tych zapisów, także problemy ekonomiczne państwa związane z transformacją ustrojową, a finalnie zmianą polityki państwa po 2000 r. sprawiły, że większość zapisów nie została wdrożona. Zwrócono szczególną uwagę na sytuację kobiet rosyjskich w okresie transformacji ustrojowej. Wyróżniono ważniejsze problemy jakimi są: dyskryminacja na rynku pracy związana zarówno z nierównością w wynagrodzeniu za pracę jak i z traktowaniem kobiet na rynku pracy; przemoc wobec kobiet, która jest wciąż bardzo palącym problemem, szczególnie w sferze prywatnej. Analiza opracowań tekstów źródłowych, dostępnych danych statystycznych, uregulowań prawnych czy ówczesnej prasy pozwolił śledzić procesy formowania tendencji społecznych w podejściu do roli i wizerunku kobiety. W związku z różnorodnością źródeł i potrzebą sięgnięcia do różnych dyscyplin naukowych, można stwierdzić, iż niniejsza dysertacja ma charakter interdyscyplinarny

Female Soviet samizdat in contemporary Russian culture — complicated ways of Second-wave feminists

The article aims to reconstruct the history of women who created female Soviet samizdat Woman and Russia and magazine Maria. They are examples of  a postsoviet woman who needs to find a place for herself in the new Russian reality after  the fall  of the Eastern Block. Despite her experience in dissident activity she cannot find her place in the new women`s movement in Russia. The Russian women’s movement in 90’s had two main sources: women organizations originating from the Soviet times and the Russian feminist research institutes, which were cooperating with Western feminist organizations. Despite big popularity of women`s organization in the beginning nowadays Russia has got a problem with poor social and political activity of Russian women.  The author of the article indicates several reasons for such a situation.The article aims to reconstruct the history of women who created female Soviet samizdat Woman and Russia and magazine Maria. They are examples of  a postsoviet woman who needs to find a place for herself in the new Russian reality after  the fall  of the Eastern Block. Despite her experience in dissident activity she cannot find her place in the new women`s movement in Russia. The Russian women’s movement in 90’s had two main sources: women organizations originating from the Soviet times and the Russian feminist research institutes, which were cooperating with Western feminist organizations. Despite big popularity of women`s organization in the beginning nowadays Russia has got a problem with poor social and political activity of Russian women.  The author of the article indicates several reasons for such a situation

Development and evaluation of an innovative model of inter-professional education focused on asthma medication use

BACKGROUND: Inter-professional learning has been promoted as the solution to many clinical management issues. One such issue is the correct use of asthma inhaler devices. Up to 80% of people with asthma use their inhaler device incorrectly. The implications of this are poor asthma control and quality of life. Correct inhaler technique can be taught, however these educational instructions need to be repeated if correct technique is to be maintained. It is important to maximise the opportunities to deliver this education in primary care. In light of this, it is important to explore how health care providers, in particular pharmacists and general medical practitioners, can work together in delivering inhaler technique education to patients, over time. Therefore, there is a need to develop and evaluate effective inter-professional education, which will address the need to educate patients in the correct use of their inhalers as well as equip health care professionals with skills to engage in collaborative relationships with each other. METHODS: This mixed methods study involves the development and evaluation of three modules of continuing education, Model 1, Model 2 and Model 3. A fourth group, Model 4, acting as a control. Model 1 consists of face-to-face continuing professional education on asthma inhaler technique, aimed at pharmacists, general medical practitioners and their practice nurses. Model 2 is an electronic online continuing education module based on Model 1 principles. Model 3 is also based on asthma inhaler technique education but employs a learning intervention targeting health care professional relationships and is based on sociocultural theory. This study took the form of a parallel group, repeated measure design. Following the completion of continuing professional education, health care professionals recruited people with asthma and followed them up for 6 months. During this period, inhaler device technique training was delivered and data on patient inhaler technique, clinical and humanistic outcomes were collected. Outcomes related to professional collaborative relationships were also measured. DISCUSSION: Challenges presented included the requirement of significant financial resources for development of study materials and limited availability of validated tools to measure health care professional collaboration over time

Implantable Neural Probes for Brain-Machine Interfaces - Current Developments and Future Prospects

A Brain-Machine interface (BMI) allows for direct communication between the brain and machines. Neural probes for recording neural signals are among the essential components of a BMI system. In this report, we review research regarding implantable neural probes and their applications to BMIs. We first discuss conventional neural probes such as the tetrode, Utah array, Michigan probe, and electroencephalography (ECoG), following which we cover advancements in next-generation neural probes. These next-generation probes are associated with improvements in electrical properties, mechanical durability, biocompatibility, and offer a high degree of freedom in practical settings. Specifically, we focus on three key topics: (1) novel implantable neural probes that decrease the level of invasiveness without sacrificing performance, (2) multi-modal neural probes that measure both electrical and optical signals, (3) and neural probes developed using advanced materials. Because safety and precision are critical for practical applications of BMI systems, future studies should aim to enhance these properties when developing next-generation neural probes