Abstract: A visual prosthesis apparatus including a video capture device for capturing a video image, a video processing unit associated with the video capture device, the video processing unit configured to convert the video image to stimulation patterns, and a stimulation system configured to stimulate subject's neural tissue based on the stimulation patterns, wherein the stimulation system provides a span of visual angle matched to the subject's neural tissue being stimulated.

Abstract: An electrical energy applicator in one embodiment extends from a proximal end to a distal end. The energy conducting applicator includes, at the proximal end, a connection to one or more electrical energy sources. The energy conducting applicator directs electrical energy from the one or more electrical energy sources to the distal end. The energy conducting applicator includes an outer conductor and an inner conductor extending to the distal end. The outer conductor and the inner conductor are separated by a gap. The outer conductor includes a plurality of moveable outer segments and the inner conductor includes a plurality of moveable inner segments. The plurality of outer segments and the plurality of inner segments form a total contact surface at the distal end. The total contact surface is positionable at a surface of an eye. The electrical energy is applied to the eye according to the total contact surface.

Abstract: Apparatus for use with an external non-visible light source is provided. The apparatus comprises an intraocular device configured for implantation in a human eye, and comprising an energy receiver. The energy receiver is configured to receive light emitted from the external non-visible light source, and extract energy from the emitted light for powering the intraocular device. The intraocular device is configured to regulate a parameter of operation of the intraocular device based on a modulation of the light emitted by the external non-visible light source and received by the energy receiver. Other embodiments are also described.

Abstract: A visual prostheses codes visual signals into electrical stimulation patterns for the creation of artificial vision. In some examples, coding of the information uses image compression techniques, temporal coding strategies, continuous interleaved sampling (CIS), and/or radar or sonar data. Examples of the approach are not limited to processing visual signals but can also be used to processing signals at other frequency ranges (e.g., infrared, radio frequency, and ultrasound), for instance, creating an augmented visual sensation.

Abstract: A method of editing a video configuration file downloadable to or from a video processing unit of a fitting system for a visual prosthesis is shown. The visual prosthesis has a plurality of electrodes and the video configuration file defines mapping of a video signal captured from a camera of the visual prosthesis to an electrical signal for the electrodes. The editing controls a brightness map for an individual electrode or electrode groups, together with a temporal stimulation pattern to which an individual electrode or electrode groups are assigned. A related computer-operated system is also disclosed.

Abstract: A system and method for applying stimulation to a target stimulation site within a patient, while avoiding undesirable eye movement side effects of the stimulation, are provided. The method includes determining whether eye movement, sensed by internal or external electrodes, is a side effect of a conveyed electrical stimulus. If the eye movement is a side effect, the electrical current distribution of the stimulus is modified in order to steer a locus of the electrical stimulus from one tissue region of the patient to another different tissue region of the patient, thereby mitigating the eye movement side effects. For example, the locus of the electrical stimulus may be steered away from the oculomotor nerve. Eye movement side effects of DBS treatment may include apraxia of lid opening, downward movement and adduction of only one eyeball, and/or continuous deviation of both eyeballs.

Abstract: The present invention is an electrode array for neural stimulation. In particular it is an electrode array for use with a visual prosthesis with the electrode array suitable to be positioned on the retina. The array includes multiple attachment points to provide for even pressure across the electrode array surface. The attachment points are arranged so as to not damage retinal tissue stimulated by the electrode array.

Abstract: Disclosed is an apparatus for stimulating living body including a light source unit which irradiates an optical signal for generating an electrical signal; a photovoltaic cell unit which generates an electrical signal using a received optical signal; and an electrode unit which stimulates living body using the electrical signal, wherein the photovoltaic cell unit and the electrode unit are implanted in the living body. The apparatus for stimulating living body may be manufactured in a flexible form, so that it may extend the range of choice for site to be implanted for the apparatus. Further, the adoption of the photovoltaic cell unit avoids the need of surgical operation for the change of battery.

Abstract: A medical device includes an array of electrodes, configured for implantation in contact with tissue in an eye of a living subject. Driver circuitry is configured to drive the electrodes in an alternating pattern, such that different groups of the electrodes are driven to stimulate the tissue during different, predetermined respective time periods. A power sensor, may be coupled to deactivate a first group of the electrodes when the available electrical power drops below a predetermined threshold, while a second group of the electrodes remains active. Other embodiments are also described.

Abstract: A device for electrostimulation of the eye is provided with a spectacles-like supporting frame (11) which has a nose part (12) and an arrangement (17, 18), connected to the nose part (12), for holding the supporting frame (11) on the head of the patient, wherein at least one stimulation electrode (26, 27) is arranged on the nose part (12). Furthermore, provision is made for at least two electrode holders (22, 23, 24, 25) on the nose part (12), between which electrode holders an interchangeable, wire-shaped stimulation electrode (26, 27) is clamped (FIG. 1).

Abstract: Polymer materials are useful as electrode array bodies for neural stimulation. They are particularly useful for retinal stimulation to create artificial vision, cochlear stimulation to create artificial hearing, or cortical stimulation many purposes. The pressure applied against the retina, or other neural tissue, by an electrode array is critical. Too little pressure causes increased electrical resistance, along with electric field dispersion. Too much pressure may block blood flow. Common flexible circuit fabrication techniques generally require that a flexible circuit electrode array be made flat. Since neural tissue is almost never flat, a flat array will necessarily apply uneven pressure. Further, the edges of a flexible circuit polymer array may be sharp and cut the delicate neural tissue. By applying the right amount of heat to a completed array, a curve can be induced.

Abstract: An apparatus includes: an input configured to receive information indicative of sensed light locations; memory coupled to the input and storing indicia of receptive fields forming a mosaic, each of the receptive fields corresponding to an electrode, the mosaic including first and receptive fields having first and second shapes that are different, the memory further storing instructions; a processor coupled to the input and the memory and configured to read and execute the instructions to: analyze the information indicative of sensed light locations; determine, for each of respective ones of the sensed light locations, one or more receptive fields that include the corresponding sensed light location; and produce excitation indicia; the apparatus further including an output coupled to the processor and configured to be coupled to a retinal implant and to convey the excitation indicia toward the retinal implant.

Abstract: An implantable biocompatible electrical device is uniformly covered with a coating approximately one-micron thick of ultra-nanocrystalline diamond, hermetically sealing the electrical device. Selected electrodes are either left uncovered during coating or uncovered by conventional patterning techniques, allowing the electrodes to be exposed to living tissue and fluids. The ultra-nanocrystalline diamond coating may be doped to create electrically conductive electrodes. These approaches eliminate the need for a hermetically sealed lid or cover to protect electrical circuitry, and thus allow the device to be thinner than otherwise possible. The conformal ultra-nanocrystalline diamond coating uniformly covers the device, providing relief from sharp edges and producing a strong, uniformly thick hermetic coating around sharp edges and on high aspect-ratio parts.

Abstract: In order to generate the smallest phosphenes possible, it is advantageous to selectively stimulate smaller cells. By hyperpolarizing the somas of the large cells selectively with sub-threshold anodic ‘pre-pulse’ stimuli (making them more difficult to stimulate) and then selectively depolarize the smaller cells one can selectively stimulate smaller cells. Alternatively, one can hyperpolarize the dendrites of the cells with larger dendritic fields by applying sub-threshold anodic currents on surrounding electrodes and then depolarizing the smaller cells in the center. Further, one can manipulate the phases of an individual biphasic wave to affect selective stimulation resulting in more focal responses. It is possible to increase resolution with the ‘pre-pulse’ described above. One can also effect resolution by modifying the pulse order of the cathodic and anodic phases.

Abstract: Stimulation inputs are provided to a visual prosthesis implant. The images captured by a video decoder are received and digitized to provide a plurality of video frames; integrity of the video frames is checked, the checked video frames are filtered, and the filtered video frames are converted to stimulation inputs. A similar system is also disclosed.

Abstract: The present invention is a method of stimulating visual neurons to create the perception of light. A visual prosthesis electrically stimulating the retina with implanted electrodes exhibits interaction between electrodes stimulated closely together in both space and time. The method of the present invention includes determining a minimum distance at which spatiotemporal interactions occur, determining a minimum time at which spatiotemporal interactions occur, and avoiding stimulation of electrodes within the minimum distance during the minimum time. The minimum are ideally established for each individual patient. Alternatively, approximate minimums have been established by the applicants at 2 mm and 1.8 ?sec.

Abstract: An implantable device (10) is used to emit electrical stimulation signals to surrounding tissue by means of at least one stimulation electrode (17). The device (10) has a sensor unit (26), which generates a useful signal (D) in the form of analogue voltage pulses (73) from externally fed signals, and an output stage (28) which generates the stimulation signals (E) from the useful signal (D). The output stage (28) emits the stimulation signals (E) in, averaged over time, a substantially DC voltage free fashion to an external ground (29), which can be connected to the tissue (64).

Abstract: Nanoscale photovoltaic devices fabricated from nanoscale waveguides that receive, propagate, and convert incident light into electrical neural signals, and methods of using these photovoltaic devices for visual perception are disclosed herein. A visual neuroprosthetic device includes an array of nanoscale waveguides each nanoscale waveguide in the array having a photovoltaic material located between an internal conductor and an external conductor, wherein each nanoscale waveguide receives, propagates, and converts incident light into electrical neural signals.

Abstract: One aspect of the present disclosure relates to a method for modulating, suppressing or preventing an ocular disorder in a subject. One step of the method can include positioning at least one electrode on or proximate to at least one of a sphenopalatine ganglion (SPG), a sphenopalatine nerve (SN), a vidian nerve (VN), a greater petrosal nerve (GPN), a deep petrosal nerve (DPN), or a branch thereof, of the subject. Next, the at least one electrode can be activated to apply an electrical signal to at least one of the SPG, the SN, the VN, the GPN, the DPN, or the branch thereof.

Abstract: A visual prosthesis apparatus including a video capture device for capturing a video image, a video processing unit associated with the video capture device, the video processing unit configured to convert the video image to stimulation patterns, and a stimulation system configured to stimulate subject's neural tissue based on the stimulation patterns, wherein the stimulation system provides a span of visual angle matched to the subject's neural tissue being stimulated.

Abstract: The present invention is a method of neural stimulation and more specifically an improved method of providing flexible video/image possessing in a visual prosthesis by providing downloadable video filters. In a visual prosthesis, the input video image will, for the foreseeable future, be higher resolution than the output stimulation of the retina, optic nerve or visual cortex. This is due to limits of electrode array technology and the rapid advancement of video camera technology. It is therefore, advantageous to apply video processing algorithms (filters) to help provide the most useful information to the lower resolution electrode array. Different filters are more effective in different environments and for different subjects. Furthermore, filters will continue to improve over time. Examples of situation dependent filters include reverse image, contrast increasing, edge detection, segmentation using chromatic information and motion detection.

Abstract: A medical device includes an array of electrodes, configured for implantation in contact with tissue in an eye of a living subject. Driver circuitry is configured to drive the electrodes in an alternating pattern, such that different groups of the electrodes are driven to stimulate the tissue during different, predetermined respective time periods. A power sensor, may be coupled to deactivate a first group of the electrodes when the available electrical power drops below a predetermined threshold, while a second group of the electrodes remains active. Other embodiments are also described.

Abstract: The present disclosure discloses an apparatus to be implanted in eyes, including: a configuration memory used for storing signal parameter configuration; a signal generator connected to the configuration memory and used for generating stimulating signals according to the signal parameter configuration in the configuration memory; electrodes connected to the signal generator and contact with outer surface of eye ball after implanted; a communication assembly connected to the configuration memory and used for receiving the signal parameter configuration, storing the received signal parameter configuration in the configuration memory; and a power supply connected to the configuration memory, signal generator and communication assembly, used for providing power. An update system for the apparatus is also disclosed.

Abstract: A retinal prosthesis with an inductive coil mounted to the side of the eye by using a strap around the eye. This allows for close coupling to an external coil and movement of the entire implanted portion with movement of the eye ball.

Abstract: Methods of electrically stimulating percepts in a patient with a visual prosthesis are discussed. Changes in amplitude of stimulation increase both the perceived brightness and the perceived size of the precept. Changes in frequency of stimulation change the perceived brightness without altering the perceived size of the percept. Hence, a source image may be mapped to a combination of amplitude and frequency that best induces the desired image.

Abstract: The present invention is a method of treating glaucoma by applying an electric field in the vicinity of the juxtacanalicular region of the trabecular meshwork sufficient to cause migration or reorientation of glycosaminoglycans located in the extracellular matrix. A device for applying the electric field includes a controller coupled to a pressure sensor, and a pair of electrodes coupled to a voltage source. The electrodes apply the electric field, and the controller controls the application of the electric field based on IOP measurements from the pressure sensor.

Abstract: The present invention is an electrode array for neural stimulation. In particular it is an electrode array for use with a visual prosthesis with the electrode array suitable to be positioned on the retina. The array includes multiple attachment points to provide for even pressure across the electrode array surface. The attachment points are arranged so as to not damage retinal tissue stimulated by the electrode array.

Abstract: The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual patient. By recording neural response to a predetermined input stimulus, one can alter that input stimulus to the needs of an individual patient. A minimum input stimulus is applied to a patient, followed by recording neural response in the vicinity of the input stimulus. By alternating stimulation and recording at gradually increasing levels, one can determine the minimum input that creates a neural response, thereby identifying the threshold stimulation level. One can further determine a maximum level by increasing stimulus until a predetermined maximum neural response is obtained.

Abstract: The present invention is a visor for retinal stimulation of visually impaired subjects. The visor comprises a frame, an external coil, a camera and a mounting system. A connector allows the external coil to be positioned along a first direction. A sliding device allows the external coil to be positioned along a second direction. Positioning of the visor on a subject's nose allows the external coil to be positioned along a third direction. Positioning of the external coil along the first, second or third direction is useful to maximize coupling RF coupling between the external coil and an internal coil implanted on a subject wearing the visor.

Abstract: A device for electrostimulation of the eye is provided with a spectacles-like supporting frame (11) which has a nose part (12) and an arrangement (17, 18), connected to the nose part (12), for holding the supporting frame (11) on the head of the patient, wherein at least one stimulation electrode (26, 27) is arranged on the nose part (12). Furthermore, provision is made for at least two electrode holders (22, 23, 24, 25) on the nose part (12), between which electrode holders an interchangeable, wire-shaped stimulation electrode (26, 27) is clamped (FIG. 1).

Abstract: A flexible circuit electrode array, which comprises: a polymer base layer; metal traces deposited on said polymer base layer, including electrodes suitable to stimulate neural tissue; a polymer top layer deposited on said polymer base layer and said metal traces; and a partial or entire coating of the base and top layer by a soft polymer.

Abstract: A method and an apparatus are provided for interacting with targeted tissue of a patient. The apparatus comprises a central control module, a satellite module, and a lead. The satellite module comprises a processor, a communication module, a switching module, a memory, a sense amp, and a A/D converter. The apparatus is adapted for subcutaneous implantation. The central control module is coupled to the satellite module. The lead is coupled to the satellite module. A programming word comprising information to be sent to the satellite module is provided. The programming word is converted into identifiable groups of pulses corresponding to bits of the programming word. The identifiable groups of pulses are sent to the satellite module. The identifiable groups of pulses are converted to information for providing a therapy to the patient. The energy from the identifiable groups of pulses is stored to power the satellite module.

Abstract: A device for neuronal therapies comprising a high frequency and/or very high frequency generator (1) functioning by means of coils (11), and associated with two main electrodes (2), which are respectively configured by a core (21) of insulating material with the front end (22) in point form and surrounded by a flexible insulating tubular body (23) extended on the point end (22) of the electrode for separate and safe positioning thereof with respect to the eyes of the patient on which said electrodes (2) are placed in a use operation, in order to cause stimulation of the nervous system and improvement of neuronal transmission by means of the circulation of high frequency currents. Both electrodes (2) are associated with at least one element for support (3) and positioning over the eyes of the patient, based on an element for fastening (4) to the head or a cabin (6).

Abstract: The present invention is a visual prosthesis including a visor with an embedded camera and changeable optical filters to limit light entering the lens of the camera. This invention will allow use of custom filters to limit light intensity or certain light frequencies sent to the camera of the visual prosthesis in a variety of brightness conditions which will remove glare. It will allow modification of the color of the light sent to camera of the visual prosthesis to respond to different environments. Users may choose the best filter to suit their needs in real time.

Abstract: A method for controlling heat dissipated from a prosthetic retinal device is described. A heat transfer device employs the Peltier heat transfer effect to cool the surface of the retinal device that faces the retina by dissipating/transferring collected heat away from the retina and towards the iris or front of the eye. According to one embodiment, a heat pump is formed in a second substrate on the retinal device. The heat pump is controlled by a temperature sense device that activates the heat pump, when a first predetermined temperature limit is exceeded. The temperature sense device deactivates the heat pump, when a temperature of the retinal device drops below a second predetermined temperature. According to another embodiment, a supply current of the retinal device may pass through the heat pump and a direction of heat transfer by the heat pump can be reversed, when the first predetermined temperature is exceeded.

Abstract: The present invention is a method of improving the contrast of electrical neural stimulation and expanding the dynamic range for brightness, and specifically a method of improving the contrast of an image supplied to the retina, or visual cortex, through a visual prosthesis. The background brightness for a blind subject is often not perfectly black, but a dark gray or brown. When stimulating visual neurons in the retina, low current stimulation tends to create a dark percept, the perception of a phosphene darker than the background brightness level perceived in the un-stimulated state. The human retina contains neurons that signal light increments (“on” cells) and neurons that signal light decrements (“off” cells). In a healthy retina, the on cells tend to fire in response to an increase in light above the background level, while the off cells tend to fire in response to a decrease in light below the background level.

Abstract: An apparatus and method for retinal stimulation are shown. The method comprises varied parameters, including frequency, pulse width, and pattern of pulse trains to determine a stimulation pattern and neural perception threshold, and creating a model based on the neural perception thresholds to optimize patterns of neural stimulation.

Abstract: The present invention is a method of improving the contrast of electrical neural stimulation and expanding the dynamic range for brightness, and specifically a method of improving the contrast of an image supplied to the retina, or visual cortex, through a visual prosthesis. The background brightness for a blind subject is often not perfectly black, but a dark gray or brown. When stimulating visual neurons in the retina, low current stimulation tends to create a dark percept, the perception of a phosphene darker than the background brightness level perceived in the un-stimulated state. The human retina contains neurons that signal light increments (“on” cells) and neurons that signal light decrements (“off” cells). In a healthy retina, the on cells tend to fire in response to an increase in light above the background level, while the off cells tend to fire in response to a decrease in light below the background level.

Abstract: Methods and systems for controlling a prosthesis using a brain imager that images a localized portion of the brain are provided according to one embodiment of the invention. The brain imager provides motor cortex activation data by illuminating the motor cortex with near infrared light (NIR) and detecting the spectral changes of the NIR light as passes through the brain. These spectral changes can be correlated with brain activity related to limbic control and may be provided to a neural network, for example, a fuzzy neural network that maps brain activity data to limbic control data. The limbic control data may then be used to control a prosthetic limb. Other embodiments of the invention include fiber optics that provide light to and receive light from the surface of the scalp through hair.

Abstract: Apparatus for use with an external non-visible light source is provided. The apparatus comprises an intraocular device configured for implantation in a human eye, and comprising an energy receiver. The energy receiver is configured to receive light emitted from the external non-visible light source, and extract energy from the emitted light for powering the intraocular device. The intraocular device is configured to regulate a parameter of operation of the intraocular device based on a modulation of the light emitted by the external non-visible light source and received by the energy receiver. Other embodiments are also described.

Abstract: A visual prosthesis system comprises a retina implant at least partly located in the interior of a patient's eye. The retina implant comprises an array of micro-contacts adapted for contacting ganglia of the patient's retinal tissue. The visual prosthesis system further comprises a data processing unit with an additional interface for receiving an external signal from an external signal source, the data processing unit being adapted for converting the external signal into corresponding stimulation data for the retina implant, and a wireless transmission unit adapted for transmitting the stimulation data to the retina implant via wireless transmission. The retina implant is adapted for receiving the stimulation data and for stimulating the micro-contacts according to the stimulation data.

Abstract: A retinal implant can include an array of photoreceptors adapted for positioning in the eye. Each photoreceptor can include a core, for example a carbon nanostructure, and a shell. The shell can include a light-responsive layer, and in many cases, the light-responsive layer can be formed of two semiconductor layers forming a heterojunction. The photoreceptors can be adapted to generate an electric field in response to incident light so as to stimulate a retinal neuron in its vicinity. The photoreceptors can be micron-sized or nano-sized, and can be arranged in densities similar to the density of rods and cones in the human eye. In one embodiment, an exemplary sensor for an imaging device can include a plurality of photosensors disposed on a substrate. Each photosensor can include a carbon nanostructure, a light-responsive layer coating at least a portion of the carbon nanostructure.

Abstract: This system gives the experimenter great flexibility to present spatio-temporal stimulation patterns to a subject. A video configuration file (VCF) editor allows the experimenter to determine the electrical stimulation parameters for each electrode. A Pattern Stimulation software program allows direct stimulation of chosen patterns of electrodes, scaled by the subject's VCF, through a Graphical User Interface. The subject then responds by drawing the outline of the phosphene he or she perceives on a touchscreen. The Pattern Stimulation program saves all of the trial parameters and the parameters of an ellipse fit to their drawing, as well as a raw data file containing the input to the touchscreen is saved. After the experiment, offline image analysis can be performed to obtain a detailed quantitative description of the subject's percepts. Image descriptors can assigned to the touchscreen data; these image descriptors can be used to make formalized comparisons between various experimental conditions.

Abstract: Apparatus is provided including an external device including, a mount, which is placed in front of an eye of a subject. A power source is coupled to the mount and emits energy toward the eye. An intraocular device is implanted entirely in the subject's eye, and includes a control unit, a plurality of stimulating electrodes, and an energy receiver, which receives the energy from the power source and generates a voltage drop in response. A plurality of photosensors detect photons and generate a signal in response. Driving circuitry is coupled to the energy receiver and to the photosensors, and drives the electrodes to apply electrical charges to a retina in response to the signals from the photosensors. The external device modulates the emitted energy, and the control unit demodulates the modulated energy to regulate an operation parameter of the intraocular device. Other embodiments are also described.

Abstract: A method and apparatus is described for electrically stimulating a patient's retina with an electrode array (32) implanted in the patient's eye, wherein one or more images are captured; at least one line and/or edge in the images is determined (21), a line of electrodes in the electrode array corresponding to a detected line and/or edge is identified (24); and electrical current is applied simultaneously to electrodes of the identified line of electrodes.

Abstract: In a method for treating at least one eye of a patient in need of such treatment with a pulsed electrical stimulation signal, first an individual parameter of the patient is determined, thereafter at least one stimulation parameter of the pulsed electrical stimulation signal is set depending on the at least one individual parameter, and then the pulsed electrical stimulation signal is applied to the at least one eye.

Abstract: A visual prosthesis apparatus and a method for limiting power consumption in a visual prosthesis apparatus. The visual prosthesis apparatus comprises a camera for capturing a video image, a video processing unit associated with the camera, the video processing unit configured to convert the video image to stimulation patterns, and a retinal stimulation system configured to stop stimulating neural tissue in a subject's eye based on the stimulation patterns when an error is detected in a forward telemetry received from the video processing unit.

Abstract: Described here are stimulation systems and methods for stimulating one or more anatomical targets in a patient for treatment conditions such as dry eye. The stimulation system may include a controller and a microstimulator. The components of the controller and microstimulator may be implemented in a single unit or in separate devices. When implemented separately, the controller and microstimulator may communicate wirelessly or via a wired connection. The microstimulator may generate pulses from a signal received from the controller and apply the signal via one or more electrodes to an anatomical target. In some variations, the microstimulator may include a passive generation circuit configured to generate a pulse based on a signal received from the controller.

Abstract: A system and method of treating target tissue in a patient's eye, which includes generating a light beam, deflecting the light beam using a scanner to form first and second treatment patterns, delivering the first treatment pattern to the target tissue to form an incision that provides access to an eye chamber of the patient's eye, and delivering the second treatment pattern to the target tissue to form a relaxation incision along or near limbus tissue or along corneal tissue anterior to the limbus tissue of the patient's eye to reduce astigmatism thereof.

Abstract: The present invention is a system for mapping a high resolution image to a lower resolution electrode array and, by applying varying stimulus to neighboring electrodes, creating a perceived image greater in resolution than the electrode array. The invention is applicable to a wide range of neural stimulation devices including artificial vision and artificial hearing. By applying a sub-threshold stimulus to two neighboring electrodes where the sum of the stimuli is above the threshold of perception, a perception is created in neural tissue between the two electrodes. By adjusting the stimulus on neighboring electrodes, the location of stimulation can be altered. Further, noise can be applied to the stimulating electrode or its neighboring electrodes to reduce the threshold of stimulation.