Gergely Márton

Gergely Márton
Research Centre for Natural Sciences

Ph.D.

About

48
Publications
6,921
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365
Citations

Publications

Publications (48)
Article
Full-text available
The meaning behind neural single unit activity has constantly been a challenge, so it will persist in the foreseeable future. As one of the most sourced strategies, detecting neural activity in high-resolution neural sensor recordings and then attributing them to their corresponding source neurons correctly, namely the process of spike sorting, has...
Article
Full-text available
Given the rising popularity of robotics, student-driven robot development projects are playing a key role in attracting more people towards engineering and science studies. This article presents the early development process of an open-source mobile robot platform—named PlatypOUs—which can be remotely controlled via an electromyography (EMG) applia...
Article
Objective: The growing number of recording sites of silicon-based probes means that an increasing amount of neural cell activities can be recorded simultaneously, facilitating the investigation of underlying complex neural dynamics. In order to overcome the challenges generated by the increasing number of channels, highly automated signal processi...
Article
Full-text available
In neuroscience the use of a microelectrode array allows the detection of neuroelectric signals with high temporal resolution in a confined space within the tissue, while two-photon laser scanning microscopy provides high spatial resolution in a wide region of interest. The combination of these two techniques promises better understanding of the op...
Article
This paper describes the development of PlatypOUs - an open-source electromyography (EMG)-controlled mobile robot platform that uses the MindRove Brain Computer Interface (BCI) headset as signal acquisition unit, implementing remote control. Simultaneously with the physical mobile robot, simulation environment is also prepared using Gazebo, within...
Conference Paper
Full-text available
Eyetracking opens new possibilities for people with physical disabilities, enabling them to explore new ways of communication and interaction with their environment. However, this field of assistive technology is not available to everyone in need and still faces substantial obstacles: high-cost devices for use in real-world environments, difficulty...
Chapter
Full-text available
Classification of electroencephalography (EEG) signals is a fundamental issue of Brain Computer Interface (BCI) systems, and deep learning techniques are still under investigation although they are dominant in other fields like computer vision and natural language processing. In this paper, we introduce the chessboard image transformation method in...
Article
Full-text available
The use of SU-8 material in the production of neural sensors has grown recently. Despite its widespread application, a detailed systematic quantitative analysis concerning its biocompatibility in the central nervous system is lacking. In this immunohistochemical study, we quantified the neuronal preservation and the severity of astrogliosis around...
Article
Objective: The extraction and identification of single-unit activities in intracortically recorded electric signals have a key role in basic neuroscience, but also in applied fields, like in the development of high-accuracy brain-computer interfaces. The purpose of this paper is to present our current results on the detection, classification and p...
Article
Full-text available
The simultaneous utilization of electrophysiological recordings and two-photon imaging allows the observation of neural activity in a high temporal and spatial resolution at the same time. The three dimensional monitoring of morphological features near the microelectrode array makes the observation more precise and complex. In vitro experiments wer...
Article
Aims In this study, we introduce an edge-type laminar silicon probe suitable for improved cell accessibility during in vitro brain slice recordings. With protruding contact sites, the spiky probe provides high signal yield and quality while approaching cells located deeper in the tissue. Methods. The spiky probe comprises an angled shank carrying 3...
Article
Full-text available
Softening neural implants that change their elastic modulus under physiological conditions are promising candidates to mitigate neuroinflammatory response due to the reduced mechanical mismatch between the artificial interface and the brain tissue. Intracortical neural probes have been used to demonstrate the viability of this material engineering...
Article
Full-text available
Neural probes designed for extracellular recording of brain electrical activity are traditionally implanted with an insertion speed between 1 µm/s and 1 mm/s into the brain tissue. Although the physical effects of insertion speed on the tissue are well studied, there is a lack of research investigating how the quality of the acquired electrophysiol...
Preprint
Full-text available
It is an uninformative truism to state that the brain operates at multiple spatial and temporal scales, each with each own set of emergent phenomena. More worthy of attention is the point that our current understanding of it cannot clearly indicate which of these phenomenological scales are the significant contributors to the brain’s function and p...
Article
Full-text available
Neural interface technologies including recording and stimulation electrodes are currently in the early phase of clinical trials aiming to help patients with spinal cord injuries, degenerative disorders, strokes interrupting descending motor pathways, or limb amputations. Their lifetime is of key importance; however, it is limited by the foreign bo...
Article
Full-text available
Objective: Exploring neural activity behind synchronization and time locking in brain circuits is one of the most important tasks in neuroscience. Our goal was to design and characterize a microelectrode array (MEA) system specifically for obtaining in vivo extracellular recordings from three deep-brain areas of freely moving rats, simultaneously....
Article
This paper presents the results of in vivo local release of a neuronal tracer, biotinylated dextran amine (BDA) in the rat somatosensory cortex using monolithically integrated microfluidic channel of a silicon neural microelectrode. The tracer injection is controlled by iontophoresis using Pt electrodes in the vicinity of the outlet of the microflu...
Article
Full-text available
This paper presents in vivo local iontophoretic release of a neuronal tracer, biotinylated dextran amine (BDA) in the rat brain using monolithically integrated microfluidic channel buried in a neural multielectrode. The tracer injection is controlled by iontophoresis using Pt electrodes in the vicinity of the outlet of the microfluidic channel. The...
Article
Full-text available
Utilization of polymers as insulator and bulk materials of microelectrode arrays (MEAs) makes the realization of flexible, biocompatible sensors possible, which are suitable for various neurophysiological experiments such as in vivo detection of local field potential changes on the surface of the neocortex or unit activities within the brain tissue...
Data
The file is a zipped folder, containing data of the spikes presented in Fig 8B. Matlab can be used in order to open the.fig files and to extract the data. E.g. the file Rat1_ClusterAvg02.fig represents the average single unit waveforms of the 2nd cluster of Rat-1. Piled single unit waveforms of Rat-2 measured on channel 7 are stored in Rat2_ch07.fi...
Data
The file is a Microsoft Excel document. Its first page contains the data obtained by depth electrodes (Fig 8B). Its second page contains data obtained by surface electrodes (Fig 8A). (XLSX)
Data
A Matalab .m file, containing an avg matrix (which is the average of 10 periods of slow waves). The CSD can be calculated from the avg matrix and can be visualized using the CSDplotter toolbox with the following electrode positions: 0.0:0.2:3.0. (MAT)
Data
The results of electrochemical impedance spectroscopy measurements on a probe. (XLSX)
Data
Polyimide microelectrode arrays on a 4-inch silicon wafer (JPG)
Article
Full-text available
In vivo insertion experiments are essential to optimize novel neural implants. Our work focuses on the interaction between intact dura mater of rats and as-fabricated single-shaft silicon microprobes realized by deep reactive ion etching. Implantation parameters like penetration force and dimpling through intact dura mater were studied as a functio...
Article
Full-text available
Precise and reproducible construction of microelectrode arrays (MEAs) is possible due to the advanced technology of microelectromechanical systems (MEMS). Polymer-based MEMS devices are gaining increasing attention in the field of experimental electrophysiology, since their mechanical flexibility allows smooth coupling with the soft neural tissue....
Article
The advanced technology of microelectromechanical systems (MEMS) makes possible precise and reproducible construction of various microelectrode arrays (MEAs) with patterns of high spatial density. Polymer-based MEMS devices are gaining increasing attention in the field of electrophysiology, since they can be used to form flexible, yet reliable elec...
Article
Full-text available
The durability of high surface area platinum electrodes during acute intracerebral measurements was investigated. Electrode sites with extremely rough surfaces were realized using electrochemical deposition of platinum onto silicon-based microelectrode arrays from a lead-free platinizing solution. The close to 1000-fold increase in effective surfac...
Article
Full-text available
In this paper, manufacturing and in vivo testing of extreme-long Si-based neural microelectrode arrays are presented. Probes with different shaft lengths (15-70 mm) are formed by deep reactive ion etching and have been equipped with platinum electrodes of various configurations. In vivo measurements on rats indicate good mechanical stability, robus...
Article
Recent progress in microtechnology has made room for novel applications in neural stimulation as well as for extending our knowledge on several malfunction of the nerval system such as tremor, epilepsy or Parkinson’s disease, which belong to the most serious medical issues in the population of developed countries. Integrated drug delivery function...
Article
Due to the rapid development in micro- and nanofabrication technologies, several types of medical implants have been proposed and applied successfully in neurosurgery. In order to determine the safety margins and design rules of newly emerged realization techniques, in vivo mechanical characterisation is essential to be performed. In this work, exp...
Article
Full-text available
Silicon micromachined deep brain multielectrodes (up to 70 mm) with monolithically integrated microfluidic channels have been realized to perform simultaneous electrical recording and drug delivery in deep brain regions. Fabrication process of the drug delivery channels and the Pt recording sites is demonstrated. Electrical characterization, impeda...
Article
This paper aims the characterization of buried microchannels in silicon realized by deep reactive ion etching. The effects of dry etching parameters on the integrability into hollow microprobes are thoroughly investigated from both technological and functional aspects. Results are supposed to give physiology related probe designers a deeper insight...
Conference Paper
Full-text available
Extreme-long (up to 70 mm) Si neural multielectrodes are presented for the first time. Probes with different shaft lengths (15-70 mm) were formed by deep reactive ion etching and have been equipped with Pt recording sites of various configurations. In vivo measurements on rodents indicated good mechanical stability, robust implantation and targetin...
Article
Full-text available
A novel wet chemical etching process has been developed for the construction of multisite silicon-based neural interfaces. The fabricated probe shaft is 280μm wide, 80μm thick and 7mm long. The current probe is equipped with 24 square-shaped platinum recording sites of 30μm×30μm. The applied combination of wet chemical etching steps for the formati...

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Projects

Projects (2)
Project
Brain-computer interface systems are meant to translate our intentions and decisions into digital signals for our electronic devices with the exclusion of muscular activity. Immediate beneficiaries of such technology are patients with tetraplegia and locked-in syndrome. Currently, cortically implanted (“depth”) microelectrode arrays (MEAs) are the supreme choice from the different sensors in the aspect of signal information content, which is a crucial factor for creating reliable, robust, fast and high bandwidth BCIs. Electrocorticography (ECoG), the use of electrode arrays on the surface of the brain cortex offers lower spatial and temporal resolution while being less invasive. In recent years, deep learning has revolutionized systems where inputs from fast and high-definition sensor arrays are available, from which inputs relatively low dimension control signals are to be generated in real-time. The rapid increase in channel numbers of neural microelectrode arrays and some pioneering studies in this field suggest that deep learning will inevitably conquer the BCI domain as well. The goals of these projects include creating a deep neural network with the capability of processing depth MEA and ECoG signals in real-time. Such networks would form a paramount basis for the fastest, most robust and most reliable BCI systems, and by applying rule extraction methods, we could gain invaluable insight into which brain areas, structures and functions offer signals of high relevance for BCI control. These results could give rise to novel implanted brain sensor designs with decreased size and increased efficiency.
Project
We aim to utilize an optical method (two-photon micorscopy) in order to study the cells surrounding an in vivo implanted, functioning MEA in the central nervous system of mice. We would like to describe the contribution of action potentials to the signals measured on an extracellular MEA. We hope that we will better understand how the morphology and relative location of a neuron affects the measurements. By comparing the efficacy of two modalities (optical and electrophysiological) for the construction of BCIs, we might be able to determine key elements that are crucial to improve the accuracy and speed of BCI systems.