Virtual Electrodes for High-Density Electrode Arrays

• US 20130041449A1
• Filed: 04/05/2012
• Published: 02/14/2013
• Est. Priority Date: 04/08/2011
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Lazzi, Gianluca, Cela, Carlos J.
• Granted Patent: US 9,155,879 B2
• Time in Patent Office: Days
• US Class Current: 607/148
• CPC Class Codes: A61N 1/0531 Brain cortex electrodes
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

The present embodiments are directed to implantable electrode arrays having virtual electrodes. The virtual electrodes may improve the resolution of the implantable electrode array without the burden of corresponding complexity of electronic circuitry and wiring. In a particular embodiment, a virtual electrode may include one or more passive elements to help steer current to a specific location between the active electrodes. For example, a passive element may be a metalized layer on a substrate that is adjacent to, but not directly connected to an active electrode. In certain embodiments, an active electrode may be directly coupled to a power source via a conductive connection. Beneficially, the passive elements may help to increase the overall resolution of the implantable array by providing additional stimulation points without requiring additional wiring or driver circuitry for the passive elements.

Claims

1. An apparatus for stimulating biological tissue, the apparatus comprising:

a first active electrode configured to receive a current injection from a current source;

a second active electrode configured to sink current emitted by the first active electrode; and

a region defining a virtual electrode disposed proximate to the first active electrode and the second active electrode and positioned such that the virtual electrode receives at least a portion of the current transferred between the first active electrode and the second active electrode.

2. The apparatus of claim 1, wherein a portion of the current emitted by the first active electrode is collected in the region defining the virtual electrode.

3. The apparatus of claim 2, wherein the current density collected in the region defining the virtual electrode is sufficient to stimulate biological tissue in proximate to the region defining the virtual electrode.

4. The apparatus of claim 1, wherein the region defining the virtual electrode comprises one or more passive elements.

5. The apparatus of claim 4, wherein the passive elements comprise a conductive layer disposed on a substrate in the region defining the virtual electrode.

6. The apparatus of claim 4, wherein an electrical insulation barrier is disposed between the first and second active elements and the one or more passive elements.

7. The apparatus of claim 4, wherein the one or more passive elements are shaped in a pattern of a cross, a center point of the cross being disposed at a center point of the region defining the virtual electrode.

8. The apparatus of claim 4, wherein a majority portion of the region defining the virtual electrode comprises the one or more passive elements.

9. The apparatus of claim 4, wherein the one or more passive elements each comprise a portion adjacent to one of the plurality of active electrodes that is configured to match a contour of the active electrode.

10. The apparatus of claim 4, comprising a plurality of active electrodes arranged in an array.

11. The apparatus of claim 10, comprising a plurality of regions defining virtual electrodes, the virtual electrodes positioned between the plurality of active electrodes in the array.

12. A system for stimulating biological tissue comprising:

an implantable bio-stimulator device comprising;

a first active electrode configured to receive a current injection from a current source;

a second active electrode configured to return current emitted by the first active electrode to ground; and

a region defining a virtual electrode disposed proximate to the first active electrode and the second active electrode and positioned such that the virtual electrode receives at least a portion of the current transferred between the first active electrode and the second active electrode; and

a current source coupled to the implantable bio-stimulator device and configured to supply current to the first and second active electrodes in the implantable bio-stimulator array.

13. The system of claim 12, further comprising an electrode controller coupled to the implantable bio-stimulator device, and configured to control operation of the implantable bio-stimulator device.

14. The system of claim 13, further comprising one or more conductors coupling the first and second active electrodes to the electrode controller.

15. The system of claim 13, wherein the electrode controller comprises one or more driver circuits coupled to the first and second active electrodes, the driver circuit configured to supply current from the current source to the first and second active electrodes according to a timing sequence.

16. A method of stimulating biological tissue, the method comprising:

providing a stimulating current to a first active electrode in an implantable bio-stimulator device; and

collecting return current from a second active electrode in the implantable bio-stimulator device.

17. The method of claim 16, wherein the first active electrode and the second active electrode are arranged in an array configuration with one or more regions defining a virtual electrode disposed adjacent to the first active electrode and the second active electrode, and wherein the virtual electrode positioned such that the virtual electrode receives at least a portion of the current transferred between the first active electrode and the second active electrode.

18. The method of claim 16, further comprising providing the stimulating current in a pulse current pulse having finite pulse duration, the pulse duration sufficient to allow a portion of the current emitted by the first electrode to accumulate in a region defining a virtual electrode.

19. The method of claim 18, wherein the region defining a pulse duration comprises one or more passive elements configured to direct the current to a predetermined position within the region defining the virtual electrode.

20. The method of claim 19, comprising providing a plurality current pulses to a plurality of active electrodes in an implantable array of bio-stimulator electrodes comprising both active electrodes and virtual electrodes, wherein a duration of the pulses is sufficient to generate a stimulation current in the virtual electrodes.

21. The method of claim 20, wherein a sequence of the pulses are applied to preselected active electrodes in the array of electrodes according to a predetermined pattern.