Here we describe and illustrate our methods for multi-channel in vivo recording in mice, including the fabrication of the microdrive array and the surgical procedure for implanting electrodes. The multi-channel microdrive is fabricated from printed circuit board base, screws, nuts and clamping screws. Rotation of the screw drives both the nut and the attached electrodes to move forward simultaneously. Each full turn of the screw corresponds to 280 µm in depth penetration. The recording electrodes are self-made tetrodes consisting 4 wires (13 µm in diameter). The major steps of headstage fabrication include: tetrode making, microdrive construction, headstage assembling and tetrode plating. The finished headstage is suitable for multi-channel recording in freely moving rodents with the modest weight and the adjustable number of recording electrodes. Additionally, the recording site is allowed to be manipulated after implantation at any time. In the latter part of this paper, we introduce the procedure of the implant surgery to record in bilateral hippocampus in mice. Using these headstages, we simultaneously recorded population activity in bilateral CA1 in freely behaving mice.
Animals ; Electrodes, Implanted ; Electrophysiology ; instrumentation ; Hippocampus ; Mice

Vision is one of the most important human sensations about the surrounding world. Visual deprivation not only markedly affects the life of blind people, but also gives a heavy burden to their family and the society. A visual prosthesis is an electronic device that helps the blinds to regain visual perception by directly stimulating the visual pathway using the microelectrodes implanted into the body. In recent years, visual prostheses have been developed rapidly and some devices have already become clinically available. In this paper, we reviewed the history of visual prosthesis, introduced different visual prostheses classified according to the location of the implanted stimulating electrodes. Clinical study results as well as the functional status of the currently available visual prosthesis devices were also summarized.
Blindness ; Electrodes, Implanted ; Humans ; Microelectrodes ; Visual Perception ; Visual Prosthesis

Objective: To investigate the effect of insertion technique and electrode array type on the insertion force of electrode array, and to provide a basis for further optimizing electrode design and facilitating mini-invasive electrode insertion. Methods: Three types of electrode array from Nurotron (Standard Electrode, Slim-medium Electrode, Slim-long Electrode) were studied. from July 2019 to December 2019. These electrode arrays were inserted into the phantom models of the cochlea, manually or robot-assisted(medium speed and low speed). The real-time force during electrode array insertion was recorded by ATI Nano 17 Ti sensors and was analyzed by accessory software. Origin 2020b software was used for statistical processing. Results: The insertion force of all electrode arrays progressively increased with the insertion depth. With the manual technique, the peak force of slim-medium electrode insertion was significantly smaller than that of the standard electrode insertion((71.0±16.6) mN vs (140.9±52.7) mN, Z=3.683, P<0.01), and the peak force of the slim-long electrode insertion was between the peak force of standard electrode and slim-medium electrode(P>0.05). No difference was found in the force variation of insertion among the three electrodes(P>0.05). With medium-speed and low-speed robotic assistance, the peak force characteristics of three electrodes were similar to those with the manual technique, but the force variation of standard electrode insertion ((83.9±9.7) mN/s) at medium speed was significantly larger than that of the slim-long electrode insertion ((69.2±4.0)mN/s), and the force variation of the standard electrode insertion at low speed was significantly greater than the other two electrodes. For the same electrode, robot-assisted insertion presented significantly lower peak force and force variation than manual insertion for each type of electrode array. But there was no difference in the peak force and force variation between two-speed levels of robot assistance (P>0.05). Conclusions: The insertion force of the electrode array will be lower when a slim electrode array or robot technique is applied. Long electrode array might make manual insertion difficult or less precise. Robot assistance has advantage on force control during electrode array insertion.
Cochlea/surgery* ; Cochlear Implantation ; Cochlear Implants ; Electrodes, Implanted ; Humans ; Robotics

Implanted brain-computer interface (iBCI) is a system that establishes a direct communication channel between human brain and computer or an external devices by implanted neural electrode. Because of the good functional extensibility, iBCI devices as a platform technology have the potential to bring benefit to people with nervous system disease and progress rapidly from fundamental neuroscience discoveries to translational applications and market access. In this report, the industrialization process of implanted neural regulation medical devices is reviewed, and the translational pathway of iBCI in clinical application is proposed. However, the Food and Drug Administration (FDA) regulations and guidances for iBCI were expounded as a breakthrough medical device. Furthermore, several iBCI products in the process of applying for medical device registration certificate were briefly introduced and compared recently. Due to the complexity of iBCI in clinical application, the translational applications and industrialization of iBCI as a medical device need the closely cooperation between regulatory departments, companies, universities, institutes and hospitals in the future.
Humans ; Brain-Computer Interfaces ; Brain/physiology* ; Electrodes, Implanted

Treatments of choice for cardiac implantable electronic device (CIED) infections are the removal of the entire CIED system, control of infection, and new device implantation. Occasionally, a complete CIED removal can not be performed for several reasons, such as very old age, severe comobidity, limited life expectancy, or refusal by a patient. We encountered a male patient who developed traumatic CIED infection five years after cardioverter-defibrillator implantation. An intravenous electrode could not be removed by a simple transvenous extraction procedure, and he refused surgical removal of the remnant electrode. After control of local infection, the tips of the electrode were separated and buried between muscles, and the wound was closed with a local flap. CIED infection did not recur for 12 months even without relying on long-term antimicrobial treatment.
Defibrillators, Implantable ; Disulfiram ; Electrodes ; Electrodes, Implanted ; Electronics ; Electrons ; Humans ; Life Expectancy ; Male ; Muscles

In order to accurately implant the brain electrodes of carp robot for positioning and navigation, the three-dimensional model of brain structure and brain electrodes is to be proposed in the study. In this study, the tungsten electrodes were implanted into the cerebellum of a carp with the aid of brain stereotaxic instrument. The brain motor areas were found and their three-dimensional coordinate values were obtained by the aquatic electricity stimulation experiments and the underwater control experiments. The carp brain and the brain electrodes were imaged by 3.0 T magnetic resonance imaging instrument, and the three-dimensional reconstruction of carp brain and brain electrodes was carried out by the 3D-DOCTOR software and the Mimics software. The results showed that the brain motor areas and their coordinate values were accurate. The relative spatial position relationships between brain electrodes and brain tissue, brain tissue and skull surface could be observed by the three-dimensional reconstruction map of brain tissue and brain electrodes which reconstructed the three-dimensional structure of brain. The anatomical position of the three-dimensional reconstructed brain tissue in magnetic resonance image and the relationship between brain tissue and skull surface could be observed through the three-dimensional reconstruction comprehensive display map of brain tissue. The three-dimensional reconstruction model in this study can provide a navigation tool for brain electrodes implantation.
Animals ; Brain/diagnostic imaging* ; Carps ; Electrodes ; Electrodes, Implanted ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging

BACKGROUND: Spinal cord stimulation is a well-established method for the management of several types of chronic and intractable pain. This form of stimulation elicits a tingling sensation (paresthesia) in the corresponding dermatomes. The goal of this study was to establish a correlation between the spinal levels of the implanted epidural electrodes and the paresthesia elicited due to stimulation of the neural structures. METHODS: Thirty five patients, who received trial spinal cord stimulation, were evaluated. After the insertion of the lead to the selected position, the areas of paresthesia evoked by stimulation were evaluated. RESULTS: Seventy-one percent of cases showed paresthesia in the shoulder area when the tip of the electrode was located between the C2 C4 levels. At the upper extremities, paresthesia was evoked in 86 93% of cases, regardless of the location of the electrode tip within the cervical spinal segments. The most common tip placement of the leads eliciting hand stimulation was at the C5 level. The most common level of electrode tip placement eliciting paresthesia of the anterior and posterior thigh and the foot were at the T7 T12, T10 L1 and T11 L1 vertebral segments, respectively. CONCLUSIONS: Detailed knowledge of the patterns of stimulation induced paresthesia in relation to the spine level of the implanted electrodes has allowed the more consistent and successful placement of epidural electrodes at the desired spine level.
Electrodes* ; Electrodes, Implanted ; Foot ; Hand ; Humans ; Pain, Intractable ; Paresthesia* ; Sensation ; Shoulder ; Spinal Cord Stimulation* ; Spinal Cord* ; Spine ; Thigh ; Upper Extremity

OBJECTIVE: To observe the effect of the depolarizing stimulation in amyotrophic lateral sclerosis (ALS) mouse model on the survival and behavioral performance. METHOD: Transgenic male mouse model of ALS at the age of 9~11 weeks were divided into sham control group (n=10) and stimulation group (n=9). Electrode was implanted in the motor cortex in left hemisphere. Movement thresholds (MT) were regularly checked. Half threshold of MT, unipolar, and continuous electrical stimulation (frequency, 50 Hz; pulse duration, 220micron s) was delivered through implanted electrode. Behavioral tests including Rota-rod and Paw-grip endurance were checked every day. RESULTS: Induction of symptom was delayed in 8 days in stimulation than sham control group. However, there was no significant difference in survival in both groups. Behavioral tests showed that stimulation group is significantly better than sham group in Rota-rod (11~15 weeks) and in grip endurance (11~14, 16 weeks). MT was always between 1.0 volt and 3.2 volt in sham group, however, MT was between 0.8 volt and 2.8 volt in stimulation group. MT was jumped up around the time of death in both groups. CONCLUSION: Electrical stimulation is considered to be one of possible trial methods in ALS model. However, parameters of the stimulation in the experiment should be modified for better results.
Amyotrophic Lateral Sclerosis ; Animals ; Electric Stimulation ; Electrodes ; Electrodes, Implanted ; Hand Strength ; Humans ; Male ; Mice ; Motor Cortex ; Salicylamides

The main shortcomings of using electrocortical stimulation (ECS) in identifying the motor functional area around the focus in neurosurgery are certainly time-consuming, possibly cerebral cortex injuring and perhaps triggering epilepsy. To solve these problems, we in our research presented an intraoperative motor cortex functional mapping based on electrocorticography (ECoG). At first, using power spectrum estimation, we analyzed the characteristic of ECoG which was related to move task, and selected Mu rhythm as the move-related feature. Then we extracted the feature from original ECoG by multi-resolution wavelet analysis. By calculating the sum value of feature in every channel and observing the distribution of these sum values, we obtained the correlation between the cortex area under the electrode and motor cortex functional area. The results showed that the distribution of the relationship between the cortex under the electrode and motor cortex functional area was almost consistent with those identified by ECS which was called as the gold-standard. It indicated that this method was basically feasible, and it just needed five minutes totally. In conclusion, ECoG-based and passive identification of motor cortical function may serve as a useful adjunct to ECS in the intraoperative mapping.
Brain Mapping ; Electric Stimulation ; Electrocorticography ; Electrodes, Implanted ; Electroencephalography ; Epilepsy ; Humans ; Motor Cortex ; physiology ; Wavelet Analysis

OBJECTIVETo develop a new method for REZ-1 cochlear implant electrode array insertion.

METHODSREZ-1 cochlear implant electrode array was implanted in 22 human temporal bone specimens. Cochlear diameters were measured from spiral CT scan before implantation. Cochlear views were taken before and after pullback technique. Modiolus-electrode distances were measured and compared. The diameters of sixty normal cochleae were measured.

RESULTSIn 3 cases, 27 electrode rings were inserted into the cochlea, while in others, all 28 electrode rings were inserted into the cochlea. After pullback of the electrode array, No. 12 to No. 19 electrode rings were closer to the modiolus in 17 cases (paired t test, P<0.01). The cochlear diameters in the 17 cases were smaller than 9.50 mm, while in the other 5 cases, the cochlear diameters were at least 9.60 mm. The cochlear diameters in the 17 cases were 9.11 (0.57) mm, while the cochlear diameters in the 5 cases were 9.78 (0.28) mm (Mann-Whitney test, P<0.001). The diameters of normal cochleae were (9.04 +/- 0.45) mm, with 90% larger than 9.50 mm.

CONCLUSIONSIn cases whose cochlear diameter is smaller than 9.50 mm, pullback technique can help some electrode rings be closer to the modiolus. Measurement of the cochlear diameter can help the surgeon to have a better choice in the selection of REZ-1 cochlear implantation methods.