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An array of highly flexible electrodes with a tailored configuration locked by gelatin during implantation-initial evaluation in cortex cerebri of awake rats.

Agorelius J, Tsanakalis F, Friberg A, Thorbergsson PT, Pettersson LM, Schouenborg J - Front Neurosci (2015)

Bottom Line: The structure of the electrode array was well preserved 3 weeks after implantation.A new implantable multichannel neural interface, comprising electrodes individually flexible in 3D that retain its architecture and functionality after implantation has been developed.Since the new neural interface design is adaptable, it offers a versatile tool to explore the function of various brain structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medical Science, Neuronano Research Centre, Lund University Lund, Sweden ; The Nanometer Structure Consortium, Lund University Lund, Sweden.

ABSTRACT

Background: A major challenge in the field of neural interfaces is to overcome the problem of poor stability of neuronal recordings, which impedes long-term studies of individual neurons in the brain. Conceivably, unstable recordings reflect relative movements between electrode and tissue. To address this challenge, we have developed a new ultra-flexible electrode array and evaluated its performance in awake non-restrained animals.

Methods: An array of eight separated gold leads (4 × 10 μm), individually flexible in 3D, were cut from a gold sheet using laser milling and insulated with Parylene C. To provide structural support during implantation into rat cortex, the electrode array was embedded in a hard gelatin based material, which dissolves after implantation. Recordings were made during 3 weeks. At termination, the animals were perfused with fixative and frozen to prevent dislocation of the implanted electrodes. A thick slice of brain tissue, with the electrode array still in situ, was made transparent using methyl salicylate to evaluate the conformation of the implanted electrode array.

Results: Median noise levels and signal/noise remained relatively stable during the 3 week observation period; 4.3-5.9 μV and 2.8-4.2, respectively. The spike amplitudes were often quite stable within recording sessions and for 15% of recordings where single-units were identified, the highest-SNR unit had an amplitude higher than 150 μV. In addition, high correlations (>0.96) between unit waveforms recorded at different time points were obtained for 58% of the electrode sites. The structure of the electrode array was well preserved 3 weeks after implantation.

Conclusions: A new implantable multichannel neural interface, comprising electrodes individually flexible in 3D that retain its architecture and functionality after implantation has been developed. Since the new neural interface design is adaptable, it offers a versatile tool to explore the function of various brain structures.

No MeSH data available.


Related in: MedlinePlus

A schematic of the 3D flexible electrode array. Note the Z-shaped proximal part of the electrode array located between the cranium and the brain surface, and the tips (10 μm) of the distal protrusions which serve as recording sites.
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Figure 1: A schematic of the 3D flexible electrode array. Note the Z-shaped proximal part of the electrode array located between the cranium and the brain surface, and the tips (10 μm) of the distal protrusions which serve as recording sites.

Mentions: We designed an array of eight wavy electrodes, thus flexible/extendable in three dimensions, each equipped with a distal protruding branch from where neuronal recordings could be made (Figure 1). The electrode array conformation was designed to allow recordings from different cortical laminae. The design was created using AutoCAD 2011 software and digitally imported into a Laser Machining System (Laser mill 50, standard micro-milling system, Nd:YAG laser system, New Wave Research, Inc., Fremont, CA). A 4 μm-thick sheet of gold foil (Rosenobel-Doppelgold 23 ¾ karat, J.G. Eytzinger GmbH, Germany) was fastened onto a microscope glass slide using polyethylene glycol (Sigma-Aldrich). Gold leads, 10 μm in width were milled under a fixed 20X objective using pulsed green laser light (wavelength 532 nm, energy density 10 J/cm2).


An array of highly flexible electrodes with a tailored configuration locked by gelatin during implantation-initial evaluation in cortex cerebri of awake rats.

Agorelius J, Tsanakalis F, Friberg A, Thorbergsson PT, Pettersson LM, Schouenborg J - Front Neurosci (2015)

A schematic of the 3D flexible electrode array. Note the Z-shaped proximal part of the electrode array located between the cranium and the brain surface, and the tips (10 μm) of the distal protrusions which serve as recording sites.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585103&req=5

Figure 1: A schematic of the 3D flexible electrode array. Note the Z-shaped proximal part of the electrode array located between the cranium and the brain surface, and the tips (10 μm) of the distal protrusions which serve as recording sites.
Mentions: We designed an array of eight wavy electrodes, thus flexible/extendable in three dimensions, each equipped with a distal protruding branch from where neuronal recordings could be made (Figure 1). The electrode array conformation was designed to allow recordings from different cortical laminae. The design was created using AutoCAD 2011 software and digitally imported into a Laser Machining System (Laser mill 50, standard micro-milling system, Nd:YAG laser system, New Wave Research, Inc., Fremont, CA). A 4 μm-thick sheet of gold foil (Rosenobel-Doppelgold 23 ¾ karat, J.G. Eytzinger GmbH, Germany) was fastened onto a microscope glass slide using polyethylene glycol (Sigma-Aldrich). Gold leads, 10 μm in width were milled under a fixed 20X objective using pulsed green laser light (wavelength 532 nm, energy density 10 J/cm2).

Bottom Line: The structure of the electrode array was well preserved 3 weeks after implantation.A new implantable multichannel neural interface, comprising electrodes individually flexible in 3D that retain its architecture and functionality after implantation has been developed.Since the new neural interface design is adaptable, it offers a versatile tool to explore the function of various brain structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medical Science, Neuronano Research Centre, Lund University Lund, Sweden ; The Nanometer Structure Consortium, Lund University Lund, Sweden.

ABSTRACT

Background: A major challenge in the field of neural interfaces is to overcome the problem of poor stability of neuronal recordings, which impedes long-term studies of individual neurons in the brain. Conceivably, unstable recordings reflect relative movements between electrode and tissue. To address this challenge, we have developed a new ultra-flexible electrode array and evaluated its performance in awake non-restrained animals.

Methods: An array of eight separated gold leads (4 × 10 μm), individually flexible in 3D, were cut from a gold sheet using laser milling and insulated with Parylene C. To provide structural support during implantation into rat cortex, the electrode array was embedded in a hard gelatin based material, which dissolves after implantation. Recordings were made during 3 weeks. At termination, the animals were perfused with fixative and frozen to prevent dislocation of the implanted electrodes. A thick slice of brain tissue, with the electrode array still in situ, was made transparent using methyl salicylate to evaluate the conformation of the implanted electrode array.

Results: Median noise levels and signal/noise remained relatively stable during the 3 week observation period; 4.3-5.9 μV and 2.8-4.2, respectively. The spike amplitudes were often quite stable within recording sessions and for 15% of recordings where single-units were identified, the highest-SNR unit had an amplitude higher than 150 μV. In addition, high correlations (>0.96) between unit waveforms recorded at different time points were obtained for 58% of the electrode sites. The structure of the electrode array was well preserved 3 weeks after implantation.

Conclusions: A new implantable multichannel neural interface, comprising electrodes individually flexible in 3D that retain its architecture and functionality after implantation has been developed. Since the new neural interface design is adaptable, it offers a versatile tool to explore the function of various brain structures.

No MeSH data available.


Related in: MedlinePlus