The role of foreign languages in modern world

Knowledge of foreign languages - is the key to success in today's world, where communication in foreign languages and processing large amounts of information is becoming increasingly important. Nowadays knowledge of foreign languages plays an important role in the person‘s career, political and economic spheres of life

The role of foreign languages in modern world

Knowledge of foreign languages - is the key to success in today's world, where communication in foreign languages and processing large amounts of information is becoming increasingly important. Nowadays knowledge of foreign languages plays an important role in the person‘s career, political and economic spheres of life

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

Entwicklung Hochflexibler Multikanal-Mikroelektroden für die Neuroprothetik : zuverlässige Aufbau-&Verbindungstechnik und langfristige Stabilität in Kochsalzlösung

An Electrocorticography Micro-Electrode Array (ECoG MEA) is a promising signal-acquisition solution for weakly-invasive brain-computer interfaces. This PhD Thesis proposes a microfabrication scheme for a high-density ECoG MEA and investigates its long-term performance in saline. The ECoG device contains 124 circular electrodes of 100, 300 and 500 um diameters, situated on concentric hexagons (150 mm2 total recording area). The reference electrode, situated beside them, is to be bent to the array backside to become a skull-facing electrode (2.5 mm2 surface area). Metallization paths connect the electrodes to the assembly pads of 4 x 32 SMD Omnetics connectors. The ECoG device was realized as a polyimide-metal-polyimide stack on a silicon wafer. A DRIE process shaped a silicon interposer out of the carrier wafer, serving as mechanical platform for the assembly of fine-pitch electrical connectors. Electrical characterization was performed by means of electrochemical impedance spectroscopy. The electrode impedance scaled with electrode area. The strength of the solder joints was tested by means of pull tests. Electrical and mechanical tests revealed that removing the bottom polyimide from the solder-joint area enables a more reliable electrical contact. The array was implanted on the primary visual cortex (V1) of a macaque and recorded natural electrophysiological signals: the larger the electrode, the larger the signal. The skull-facing reference electrode provided signals of greater average Power Spectral Density (PSD) than common average referencing. However, the onset of parasitic short-circuits formation was encountered ca. 3-4 months after implantation. Accelerated soak tests were performed on planar-capacitor IDE structures to simulate the formation of parasitic short-circuits. The influence of curing, adhesion and sterilization on the water-barrier properties of polyimide and parylene coatings was monitored. Based on the results, a new ECoG MEA was fabricated and stored under accelerated soak conditions. The proposed ECoG MEA can be beneficial for the design, microfabrication and long-term stability of future flexible microdevices

A Flex-Rigid, Multi-Channel ECoG Microelectrode Array : Reliable Electrical Contact & Long-Term Stability in Saline

An Electrocorticography Micro-Electrode Array (ECoG MEA) is a promising signal-acquisition solution for weakly-invasive brain-computer interfaces. This PhD Thesis proposes a microfabrication scheme for a high-density ECoG MEA and investigates its long-term performance in saline. The ECoG device contains 124 circular electrodes of 100, 300 and 500 um diameters, situated on concentric hexagons (150 mm2 total recording area). The reference electrode, situated beside them, is to be bent to the array backside to become a skull-facing electrode (2.5 mm2 surface area). Metallization paths connect the electrodes to the assembly pads of 4 x 32 SMD Omnetics connectors. The ECoG device was realized as a polyimide-metal-polyimide stack on a silicon wafer. A DRIE process shaped a silicon interposer out of the carrier wafer, serving as mechanical platform for the assembly of fine-pitch electrical connectors. Electrical characterization was performed by means of electrochemical impedance spectroscopy. The electrode impedance scaled with electrode area. The strength of the solder joints was tested by means of pull tests. Electrical and mechanical tests revealed that removing the bottom polyimide from the solder-joint area enables a more reliable electrical contact. The array was implanted on the primary visual cortex (V1) of a macaque and recorded natural electrophysiological signals: the larger the electrode, the larger the signal. The skull-facing reference electrode provided signals of greater average Power Spectral Density (PSD) than common average referencing. However, the onset of parasitic short-circuits formation was encountered ca. 3-4 months after implantation. Accelerated soak tests were performed on planar-capacitor IDE structures to simulate the formation of parasitic short-circuits. The influence of curing, adhesion and sterilization on the water-barrier properties of polyimide and parylene coatings was monitored. Based on the results, a new ECoG MEA was fabricated and stored under accelerated soak conditions. The proposed ECoG MEA can be beneficial for the design, microfabrication and long-term stability of future flexible microdevices

A Multi-Channel, Flex-Rigid ECoG Microelectrode Array for Visual Cortical Interfacing

High-density electrocortical (ECoG) microelectrode arrays are promising signal-acquisition platforms for brain-computer interfaces envisioned, e.g., as high-performance communication solutions for paralyzed persons. We propose a multi-channel microelectrode array capable of recording ECoG field potentials with high spatial resolution. The proposed array is of a 150 mm2 total recording area; it has 124 circular electrodes (100, 300 and 500 µm in diameter) situated on the edges of concentric hexagons (min. 0.8 mm interdistance) and a skull-facing reference electrode (2.5 mm2 surface area). The array is processed as a free-standing device to enable monolithic integration of a rigid interposer, designed for soldering of fine-pitch SMD-connectors on a minimal assembly area. Electrochemical characterization revealed distinct impedance spectral bands for the 100, 300 and 500 µm-type electrodes, and for the array’s own reference. Epidural recordings from the primary visual cortex (V1) of an awake Rhesus macaque showed natural electrophysiological signals and clear responses to standard visual stimulation. The ECoG electrodes of larger surface area recorded signals with greater spectral power in the gamma band, while the skull-facing reference electrode provided higher average gamma power spectral density (γPSD) than the common average referencing technique

Implications for a Wireless, External Device System to Study Electrocorticography

Implantable neuronal interfaces to the brain are an important keystone for future medical applications. However, entering this field of research is difficult since such an implant requires components from many different areas of technology. Since the complete avoidance of wires is important due to the risk of infections and other long-term problems, means for wirelessly transmitting data and energy are a necessity which adds to the requirements. In recent literature, many high-tech components for such implants are presented with remarkable properties. However, these components are typically not freely available for such a system. Every group needs to re-develop their own solution. This raises the question if it is possible to create a reusable design for an implant and its external base-station, such that it allows other groups to use it as a starting point. In this article, we try to answer this question by presenting a design based exclusively on commercial off-the-shelf components and studying the properties of the resulting system. Following this idea, we present a fully wireless neuronal implant for simultaneously measuring electrocorticography signals at 128 locations from the surface of the brain. All design files are available as open source

Portable wireless electrocorticography system with a fexible microelectrodes array for epilepsy treatment

In this paper, we present a portable wireless electrocorticography (ECoG) system. It uses a high resolution 32-channel fexible ECoG electrodes array to collect electrical signals of brain activities and to stimulate the lesions. Electronic circuits are designed for signal acquisition, processing and transmission using Bluetooth Low Energy 4 (LTE4) for wireless communication with cell phone. In-vivo experiments on a rat show that the fexible ECoG system can accurately record electrical signals of brain activities and transmit them to cell phone with a maximal sampling rate of 30 ksampling/s per channel. It demonstrates that the epilepsy lesions can be detected, located and treated through the ECoG system. The wireless ECoG system has low energy consumption and high brain spatial resolution, thus has great prospects for future application