The past,present,and future of in vivo-implant-able recording microelectrodes:the neural interfaces / 中国药理学与毒理学杂志

Neural recording electrodes enable the acquisition and collection of electrical signals from neu-rons,and these recorded neural electrical signals are an important means of understanding neuronal activity.As a major component of the brain-machine interface,neu-ral recording electrodes serve as a bridge between the nervous system and external devices.The extracted information can be used to understand the state of the brain and acts as a feedback signal to regulate external devices,thus providing important information for the clini-cal treatment of neurological diseases.Moreover,the electrodes can be used as a vehicle for drug injection to directly treat diseases.Since the time that Strumwas-ser used microwires to achieve long-term recordings of neural activity in hibernating squirrels,implantable elec-trode technology has gradually improved over three gen-erations of development,and progress has been made in improving the biocompatibility,mechanical performance(size,shape,density,etc.),and signal-to-noise ratio.Implantable neural recording electrodes can acquire sig-nals from cortical and deep neural clusters,with the advantages of high signal-to-noise ratio,information con-tent,and spatial/temporal resolution.However,there is still a need to improve the structure and performance of these electrodes;for example,their high invasiveness and lack of biocompatibility pose technical difficulties in the process of translation to the clinic.This paper reviews the basic requirements for electrodes,main recording methods and signal types,common types of implant-able neural recording electrodes,and their challenges and future development directions.With the continuous development of electrode materials,equipment,systems,and neurotechnology,it should be possible to apply neu-ral recording electrodes in clinical practice,to promote safe and efficient treatment of human diseases.

Argus Ⅱ retinal prosthesis system:an update / 中华实验眼科杂志

Argus Ⅱ retinal prosthesis system (Argus Ⅱ;Second Sight Medical products,Sylmar,CA) is the first prosthetic retinal device approved for humanitarian use by both FDA in America and CE in Europe.It is a potential treatment for patients with end-stage outer retinal diseases.The system contains several parts,the camera first captures image and transfers it into electrical stimulating parameters conveying spatial-temporal information.The microelectrode epiretinal array then stimulate underlying bipolar cells and retinal ganglion cells.Patients present significant increases on levels of discrimination,target localization,motion detection and navigation.Possible adverse events include conjunctival erosion,hypotony and culture-negative presumed endophthalmitis.Future developments of the Argus Ⅱ system will not only comprise upgrading of image processing software and hardware,but also further disclosing retinal and visual signal processing mechanism.

Study on the method of microelectrodes implantation of artificial facial nerve prosthesis in closed mouth of orbicularis oris muscle in monkeys with facial nerve paralysis / 中华口腔医学杂志

Objective@#To explore the optimal method of microelectrode implantation that can produce efficient mouth closure with microelectrode for orbicularis oris muscle (OOM) in rhesus monkeys with unilateral peripheral facial paralysis (UPFP) in order to provide basis for the research and development of artificial facial nerve prosthesis (AFNP).@*Methods@#Right lateral peripheral facial paralysis model on four healthy rhesus monkeys (two males and two femles, aged 5-6 years, weighed 2.0-3.0 kg) were prepared. AFNP electric stimulation was used to induce closed-mouth reaction of the affected OOM with a one-way rectangular pulse, 50 Hz frequency and 0.2 ms pulse width in vitro. Around the affected lateral OOM, four stimulus electrodes implantation positions were selected at the upper lip (position A), the lower lip (position B), the connection with the corner of the mouth to the ipsilateral tragus (position C), and the horizontal line of the mouth angle (position D). According to the different implantation positions of three stimulation electrodes on the stimulation side of AFNP and the results of our previous study, six groups of microelectrode implantation methods were designed. In Group A, two microelectrodes were implanted at position A and one microelectrode was implanted at position B; in Group B, one microelectrode was implanted at position A, B and C respectively; in Group C, one microelectrode was implanted at position A and two microelectrodes were implanted at position B; in Group D, one microelectrode was implanted at position A, B and D respectively; in Group E, one microelectrode was implanted at position A, C and D respectively; in Group F, one microelectrode was implanted at position B, C and D respectively. The minimum stimulating current (threshold current) required for effective mouth closure were recorded. The threshold and peak current values were compared using one-way ANOVA and LSD-t multiple comparisons.@*Results@#The microelectrodes of the AFNP stimulating side in Group E and F failed to induce a smooth mouth closure. The microelectrodes in A, B, C and D group induced smooth mouth closure. The threshold current value of OOM contraction on affected side in the Group A, B, C, and D were (1.35±0.05), (1.02±0.04), (1.40±0.04) and (1.10±0.02) mA, respectively (F=295.302, P<0.001), with the lowest value in Group B and there was significant difference between the current value in Group B and those in the other groups (all P<0.05). The peak current value of OOM contraction on affected side in the four groups were (3.95±0.02), (2.95±0.03), (3.99±0.05) and (3.51±0.01) mA, respectively (F=1 014.985, P<0.001). Group B showed the best lip-closure morphology observed with naked eyes.@*Conclusions@#When three output microelectrode of the AFNP stimulated side are separately imbedded into the upper lip, the lower lip and the connection with the corner of the mouth to the ipsilateral tragus, AFNP can sufficiently induce closed-mouth reaction. These positions are suitable as priority options microelectrodes implantation positions for the microelectrodes of the AFNP stimulated side.

Characterization of Tetrodes Coated with Au Nanoparticles (AuNPs) and PEDOT and Their Application to Thalamic Neural Signal Detection in vivo

Tetrodes, consisting of four twisted micro-wires can simultaneously record the number of neurons in the brain. To improve the quality of neuronal activity detection, the tetrode tips should be modified to increase the surface area and lower the impedance properties. In this study, tetrode tips were modified by the electrodeposition of Au nanoparticles (AuNPs) and dextran (Dex) doped poly (3,4-ethylenedioxythiophene) (PEDOT). The electrochemical properties were measured using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A decrease in the impedance value from 4.3 MΩ to 13 kΩ at 1 kHz was achieved by the modified tetrodes. The cathodic charge storage capacity (CSC(C)) of AuNPs-PEDOT deposited tetrodes was 4.5 mC/cm², as determined by CV measurements. The tetrodes that were electroplated with AuNPs and PEDOT exhibited an increased surface area, which reduced the tetrode impedance. In vivo recording in the ventral posterior medial (VPM) nucleus of the thalamus was performed to investigate the single-unit activity in normal rats. To evaluate the recording performance of modified tetrodes, spontaneous spike signals were recorded. The values of the L-ratio, isolation distance and signal-to-noise (SNR) confirmed that electroplating the tetrode surface with AuNPs and PEDOT improved the recording performance, and these parameters could be used to effectively quantify the spikes of each cluster.

Abordaje cerrado en patología de vía aérea superior con el uso de microelectrodos: nuestra experiencia / Approach closed upper airway pathology using microelectrodes: our experience

El láser como alternativa a la cirugía abierta de la vía aérea superior ha venido a modificar la forma de abordaje de las patologías en esta área, pero no deja de ser un procedimiento costoso que no está al alcance de todos los servicios. Por este motivo se han reinventado nuevas formas de abordaje que cumplan los mismos requisitos tanto de la cirugía abierta como con láser pero con un menor coste. Presentamos una serie de 30 casos realizados en un período de 6 años por motivos tanto tumorales como no, en los que se realizaron abordajes cerrados a través de microcirugía con disección mediante microelectrodos. Obteniendo pocas complicaciones y una disminución de la estancia hospitalaria significativa. Con lo cual nos parece una técnica eficiente para abordajes de este tipo.

The laser as an alternative to open surgery of the upper airway has come to change the form of approaching the disease in this area, but it is still an expensive procedure that is not available to all services. For this reason a new ways of approach to meet the same requirements both open as laser but at a lower cost surgery. We present a series of 30 cases performed over a period of 6 years for reasons as much tumor, which closed approaches through microsurgical dissection were performed using microelectrodes. Obtaining few complications and significant decreased hospital stay. Our considerations is it seems an efficient technique for such approaches.

Positions of the implanted stimulating electrodes for artificial facial nerve for inducing contraction of the orbicularis oris muscle in rabbit with peripheral facial paralysis / 中华耳鼻咽喉头颈外科杂志

Objective@#To explore the optimal positions of the implanted stimulating eletrodes for artificial facial nerve (AFN) for inducing contraction of the orbicularis oris muscle (OOM) in rabbit with peripheral facial paralysis.@*Methods@#According to the four microelectrodes of the AFN stimulating side, four modes of the implanted positions were divided. In line with different modes, the electrodes were implanted into the affected OOM of the rabbits with unilateral peripheral facial paralysis. AFN output electric stimulation to induce contraction of the affected OOM with uniform stimulating frequency and pulse length in vitro. Then compared the stimulus threshold amplitude and the peak amplitude separately among different modes by SAS 9.3 version statistical software.@*Results@#The differences of the stimulus threshold amplitude and the peak amplitude had no statistically significant separately between the first mode and the second mode (P>0.05), but there were statistically significant differences between the third mode and the fourth mode (P<0.05). Both kinds of the amplitudes were approximated between the first mode and the second mode respectively, and higher than those in the third mode or the fourth mode. Furthermore, both kinds of the amplitudes in the fourth mode were higher than those in the third mode.@*Conclusions@#The microelectrodes of the AFN stimulating lateral are implanted into the upper lip with a public microelectrode and an output microelectrode, into the lower lip with an output microelectrode, and into the way, which is located to the angle 40° to 45° about the line joining between the midpoint of the ipsilateral auricle root and the corner of the mouth with an output microelectrode. This is the third positional mode which requires lowest effective stimulus current intensity. Thus the mode is suitable as the optimal placement programme.

Study on intervention mechanism of acupuncture for neuron abnormal neural coding in visual cortex area 17 of monocular deprivation rats / 针灸推拿医学（英文版）

Objective: To investigate the electrophysiological mechanism of acupuncture for the visual cortex plasticity during the sensitive period. Methods: Fifty 2-week-old Wistar rats were randomly divided into a blank control group, a model group, an early-stage acupuncture group, a middle-stage acupuncture group and a late-stage acupuncture group, 10 rats in each group. Monocular deprivation amblyopia models were prepared in rats except those in the blank control group by unilateral eyelid suture. After successful modeling, no treatment was applied to the rats in the model group. Rats in each acupuncture group were treated with acupuncture at bilateral Jingming (BL 1), Cuanzhu (BL 2), Fengchi (GB 20) and Guangming (GB 37), started from the 3rd day, 12th day or 21st day after modeling separately, once a day, for a total of 9 d treatment. The neuronal discharge frequency and action potential inter-spike interval (ISI) in the rat visual cortex area 17 of each group were measured by multi-channel microelectrode array nerve signal technique. Results: The discharge number of neurons in the visual cortex of the model group was significantly lower than that in the blank control group (P0.05). The discharge number in the middle-stage acupuncture group was lower than that in the early-stage acupuncture group (P<0.05), and the discharge number of the late-stage acupuncture group was lower than that in the middle-stage acupuncture group (P<0.05). The ISI sequences of the visual cortex neurons were mainly distributed under 0.3 s in the blank control group, under 15 s in the model group, under 1 s in the early-stage acupuncture group, under 4 s in the middle-stage acupuncture group, and under 10 s in the late-stage acupuncture group, divergent in each group. Conclusion: The neuronal coding appears abnormality in the visual cortex area 17 of monocular deprivation rats, indicating that there is a plasticity change in the visual cortex neurons during the sensitive period. Acupuncture has a significant effect on the abnormal neural coding. The therapeutic efficacy is closely related to the stage to start the treatment. Early stage treatment in the sensitive period is the key to achieving the good efficacy.

Present situation and prospects about application of microelectrode array in study on acupuncture efficacy / 针灸推拿医学（英文版）

As a component of traditional Chinese medical therapies, the therapeutic effects of acupuncture for some nervous system diseases have been proven by a large number of clinical and experimental studies. But, the electrophysiological techniques of the commonly used EEG and evoked potentials are still not sufficient to reveal the functional mechanism of acupuncture therapy. The recording technique of microelectrode array (MEA), a kind of electrophysiological technique originated from the overseas biological electrical signal monitoring technique, can be used to record multiple electrical signals of the nervous cells in vivo or in vitro, and maintain the accuracy and stability of the recorded information at the same time, which greatly enriches the means of electrophysiological study. This technique has been already applied in the basic study and clinical treatment abroad, but it is very seldom used in the study of acupuncture field. In order to guide the application of MEA in the research field of acupuncture science, a general survey about the application of MEA technique in vivo was done, and the present situation and prospects of the application of the technique in acupuncture science was briefly analyzed.

Emerging Neural Stimulation Technologies for Bladder Dysfunctions / 대한배뇨장애요실금학회지

In the neural engineering field, physiological dysfunctions are approached by identifying the target nerves and providing artificial stimulation to restore the function. Neural stimulation and recording technologies play a central role in this approach, and various engineering devices and stimulation techniques have become available to the medical community. For bladder control problems, electrical stimulation has been used as one of the treatments, while only a few emerging neurotechnologies have been used to tackle these problems. In this review, we introduce some recent developments in neural stimulation technologies including microelectrode array, closed-loop neural stimulation, optical stimulation, and ultrasound stimulation.

Influence of Propofol and Fentanyl on Deep Brain Stimulation of the Subthalamic Nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7+/-16.8 spikes/sec, n=78) and the right side MERs (35.5+/-17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients.

Effects of genistein on neuronal discharges in paraventricular nucleus of rat hypothalamic slices / 中国药理学与毒理学杂志

AIM To study the central role of genistein (GST) in regulating cardiovascular function of nervous center by examining the effects of GST on the electrical activity of rat paraventricular nucleus neurons in slice preparation and to elucidate the mechanism involved. METHODS Using extracellular single-unit discharge recording technique to examine discharges of neurons in paraventricular nucleus of hypothalamic slices at the resting potential level. RESULTS ①In response to the application of GST 10, 50 and 100 μmol·L-1, respectively, in the perfusate for 2 min, the spontaneous discharge rates (SDR) of neurons in 25/26 hypothalamic slices were significantly decreased in a concentration-dependent manner. ②Pretreatment with L-glutamate 0.2 mmol·L-1 led to a marked increase in the SDR of slices in an epileptiform pattern. GST 50 μmol·L-1 significantly attenuated the increased SDR in all 7 slices. ③In 8/8 slices, the G protein-coupled inwardly rectifying K+ channels (GIRKs) antagonist, tetraethylammonium 1 mmol·L-1 completely blocked the inhibitory effect of GST 50 μmol·L-1. ④Pretreatment with nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester 50 μmol·L-1 increased SDR in all 7 slices, but did not affect the inhibitory effect of GST 50 μmol·L-1. CONCLUSION GST can inhibit the electrical activity of paraventricular neurons, and play a protective role on the central neurons. The inhibitory effect of GST may be related to the activation of GIRKs which induce K+ outward current and then engender the cell membrane hyperpolarization, but be not due to the NO release.

Electrophysiological effect of resveratrol on pacemaker cells in sinoatrial node of rabbits / 中国药理学与毒理学杂志

AIM In order to investigate whether resveratrol can be used as a kind of antiarrhythmic drug, the electrophysiological effect of resveratrol on pacemaker cells in sinoatrial node was studied. METHODS Using intracellular microelectrode technique to record the action potential of pacemaker cells in sinoatrial node of rabbits. RESULTS Resveratrol (30-120 μmol·L-1) significantly decreased amplitude of action potential, maximal rate of depolarization (Vmax), velocity of diastolic (phase 4) depolarization and rate of pacemaker firing, but did not affect maximal diastolic potential and duration of 90% repolarization of action potential. Pretreatment with L-type calcium channel agonist Bay-K-8644 (0.5 μmol·L-1) 10 min antagonized the effect of resveratrol (60 μmol·L-1). While applying cesium chloride (2 mmol·L-1), a hyperpolarization-activated current blocker, adding tetraethylammonium chloride (20 mmol·L-1), a potassium channel antagonist, or applying L-NAME (0.5 mmol·L-1), a NO synthase inhibitor, had no significantly influence on the electrophysiological effects of resveratrol. CONCLUSION Resveratrol exerts inhibitory electrophysiological effects on pacemaker cells in sinoatrial node of rabbits, which may be due to reduction in calcium influx via a NO-independent manner.

Treatment of Parkinson's Disease by Microelectrode-guided Thalamotomy and/or Pallidotomy: a Report of 225 Cases / 中国医师杂志

Objective To explore indications, ablated targets, efficacy and complications of microelectrode-guided thalamotomy and pallidotomy for treating Parkinson's disease(PD). Methods The clinical date of 225 PD patients underwent microelectrode guided thalamotomy and/or pallidotomg were retrospectively analyzed with UPDRS scores. Results The outcome of operation was excellent.The rate of improvement for tremor, rigidity, gait, balance and bradykinesia were 98 0%, 89 0%, 72 8%, 70 5% and 47 8% respectively. Postoperative motor UPDRS scores of both "on"/"off"states significantly decreased by 54 4% and 62 6% respectively. The frequency of post-operative complications was such as the following: bleeding caused by puncturing (0 48%),transient hiccup(6 7%), temporary dysarthria(5 5%), transient somnolence(10 0%) and mental disorder(4 5%). There were no severe and permanent complications. Conclusions The thalamotomy and/or pallidotomy guided by the microelectrode were the effective and safe method for treatment of PD, but the indications of this surgery should be well familiarize. The ablated target selection and its precise localization were of key importance for a better outcome.

The alteration of extracellular sodium and potassium ionic activities of hippocampal neurons in epileptiform rats kindled by coriaria lactone / 中国病理生理杂志

AIM and METHODS: The sodium ion(Na +) and potassium ion(K +) selective microelectrodes were used to measure changes of ionic activity of extracellular sodium and potassium([Na +] o, [K +] o) in hippocampus and hippocampal slice during epieptic seizure induced by intrahippocampal microinjection of coriaria lactone(CL) in rats and perfusing hippocampal slice with CL. RESULTS:30 s, 1min and 2min after injection of CL into hippocampus, the [Na +] o decreased 27.7 mmol/L, 50.3 mmol/L, 57.8 mmol/L respectively and the [K +] o increased 2.3 mmol/L, 2.4 mmol/L, 2.9 mmol/L respectively compared with control values( P