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Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue.

Seymour EÇ, Freedman DS, Gökkavas M, Ozbay E, Sahin M, Unlü MS - Front Neuroeng (2014)

Bottom Line: Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications.We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study.We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Boston University, Boston MA, USA.

ABSTRACT
Electrical neural stimulation with micro electrodes is a promising technique for restoring lost functions in the central nervous system as a result of injury or disease. One of the problems related to current neural stimulators is the tissue response due to the connecting wires and the presence of a rigid electrode inside soft neural tissue. We have developed a novel, optically activated, microscale photovoltaic neurostimulator based on a custom layered compound semiconductor heterostructure that is both wireless and has a comparatively small volume (<0.01 mm(3)). Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications. This neurostimulator was shown to evoke action potentials and a functional motor response in the rat spinal cord. In this work, we extend our design to include wavelength selectivity and thus allowing independent activation of devices. As a proof of concept, we fabricated two different microscale devices with different spectral responsivities in the near-infrared region. We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study. We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

No MeSH data available.


Related in: MedlinePlus

The current generated in a second device (moving in the horizontal direction) as a percentage of the current in a FLAMES B device placed in the center when both devices are at depths of (A) 500 μm (B) 1000 μm (C) 2000 μm. When no wavelength selectivity is assumed (solid line), the current generated in the moving device is much greater compared to devices with wavelength selectivity included (dashed line), for all depths.
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Figure 10: The current generated in a second device (moving in the horizontal direction) as a percentage of the current in a FLAMES B device placed in the center when both devices are at depths of (A) 500 μm (B) 1000 μm (C) 2000 μm. When no wavelength selectivity is assumed (solid line), the current generated in the moving device is much greater compared to devices with wavelength selectivity included (dashed line), for all depths.

Mentions: Figure 10 shows the crosstalk currents from the second device as a function of the horizontal distance from the first device at different depths. The currents generated by the second device are calculated as a percentage of the current generated by the FLAMES B device. Figure 10 shows the percent crosstalk from the second device as a function of its distance from the first device at the depths of 500, 1000, and 2000 μm.


Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue.

Seymour EÇ, Freedman DS, Gökkavas M, Ozbay E, Sahin M, Unlü MS - Front Neuroeng (2014)

The current generated in a second device (moving in the horizontal direction) as a percentage of the current in a FLAMES B device placed in the center when both devices are at depths of (A) 500 μm (B) 1000 μm (C) 2000 μm. When no wavelength selectivity is assumed (solid line), the current generated in the moving device is much greater compared to devices with wavelength selectivity included (dashed line), for all depths.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927122&req=5

Figure 10: The current generated in a second device (moving in the horizontal direction) as a percentage of the current in a FLAMES B device placed in the center when both devices are at depths of (A) 500 μm (B) 1000 μm (C) 2000 μm. When no wavelength selectivity is assumed (solid line), the current generated in the moving device is much greater compared to devices with wavelength selectivity included (dashed line), for all depths.
Mentions: Figure 10 shows the crosstalk currents from the second device as a function of the horizontal distance from the first device at different depths. The currents generated by the second device are calculated as a percentage of the current generated by the FLAMES B device. Figure 10 shows the percent crosstalk from the second device as a function of its distance from the first device at the depths of 500, 1000, and 2000 μm.

Bottom Line: Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications.We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study.We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Boston University, Boston MA, USA.

ABSTRACT
Electrical neural stimulation with micro electrodes is a promising technique for restoring lost functions in the central nervous system as a result of injury or disease. One of the problems related to current neural stimulators is the tissue response due to the connecting wires and the presence of a rigid electrode inside soft neural tissue. We have developed a novel, optically activated, microscale photovoltaic neurostimulator based on a custom layered compound semiconductor heterostructure that is both wireless and has a comparatively small volume (<0.01 mm(3)). Optical activation provides a wireless means of energy transfer to the neurostimulator, eliminating wires and the associated complications. This neurostimulator was shown to evoke action potentials and a functional motor response in the rat spinal cord. In this work, we extend our design to include wavelength selectivity and thus allowing independent activation of devices. As a proof of concept, we fabricated two different microscale devices with different spectral responsivities in the near-infrared region. We assessed the improved addressability of individual devices via wavelength selectivity as compared to spatial selectivity alone through on-bench optical measurements of the devices in combination with an in vivo light intensity profile in the rat cortex obtained in a previous study. We show that wavelength selectivity improves the individual addressability of the floating stimulators, thus increasing the number of devices that can be implanted in close proximity to each other.

No MeSH data available.


Related in: MedlinePlus