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Distribution and Morphology of Calcium-Binding Proteins Immunoreactive Neurons following Chronic Tungsten Multielectrode Implants.

Freire MA, Faber J, Lemos NA, Santos JR, Cavalcanti PF, Lima RH, Morya E - PLoS ONE (2015)

Bottom Line: Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation.Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted.On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.

View Article: PubMed Central - PubMed

Affiliation: Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil.

ABSTRACT
The development of therapeutic approaches to improve the life quality of people suffering from different types of body paralysis is a current major medical challenge. Brain-machine interface (BMI) can potentially help reestablishing lost sensory and motor functions, allowing patients to use their own brain activity to restore sensorimotor control of paralyzed body parts. Chronic implants of multielectrodes, employed to record neural activity directly from the brain parenchyma, constitute the fundamental component of a BMI. However, before this technique may be effectively available to human clinical trials, it is essential to characterize its long-term impact on the nervous tissue in animal models. In the present study we evaluated how chronic implanted tungsten microelectrode arrays impact the distribution and morphology of interneurons reactive to calcium-binding proteins calbindin (CB), calretinin (CR) and parvalbumin (PV) across the rat's motor cortex. Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation. Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted. Moreover, restricted microglial activation was observed on the implanted sites. On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.

No MeSH data available.


Related in: MedlinePlus

General pattern of implant sites.(a). Nissl staining shows the well-defined location of the electrode track (arrow), revealing a small loss of tissue. (b). It was possible to attest the absence of vacuolization and pyctonic profiles in all time points evaluated. The tissue around electrode implants presented a similar aspect to their contralateral counterpart. Black squares in lower magnification pictures indicate the regions where enlargements were obtained in all groups. Left column of the figure: implanted hemisphere; right column of the figure: contralateral hemisphere, adopted as control. Scale bar: 100 μm (lower magnification); 200 μm (enlargements).
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pone.0130354.g003: General pattern of implant sites.(a). Nissl staining shows the well-defined location of the electrode track (arrow), revealing a small loss of tissue. (b). It was possible to attest the absence of vacuolization and pyctonic profiles in all time points evaluated. The tissue around electrode implants presented a similar aspect to their contralateral counterpart. Black squares in lower magnification pictures indicate the regions where enlargements were obtained in all groups. Left column of the figure: implanted hemisphere; right column of the figure: contralateral hemisphere, adopted as control. Scale bar: 100 μm (lower magnification); 200 μm (enlargements).

Mentions: The precise location of the microwire array implants was identified in all animals at all survival times (Fig 3). Nissl staining revealed a minimal tissue loss in the implant site, restricted to the exact location of electrodes, with preservation of cell bodies near the microelectrode track and the absence of vacuolization, an event usually observed after milieu alterations (Fig 3).


Distribution and Morphology of Calcium-Binding Proteins Immunoreactive Neurons following Chronic Tungsten Multielectrode Implants.

Freire MA, Faber J, Lemos NA, Santos JR, Cavalcanti PF, Lima RH, Morya E - PLoS ONE (2015)

General pattern of implant sites.(a). Nissl staining shows the well-defined location of the electrode track (arrow), revealing a small loss of tissue. (b). It was possible to attest the absence of vacuolization and pyctonic profiles in all time points evaluated. The tissue around electrode implants presented a similar aspect to their contralateral counterpart. Black squares in lower magnification pictures indicate the regions where enlargements were obtained in all groups. Left column of the figure: implanted hemisphere; right column of the figure: contralateral hemisphere, adopted as control. Scale bar: 100 μm (lower magnification); 200 μm (enlargements).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476592&req=5

pone.0130354.g003: General pattern of implant sites.(a). Nissl staining shows the well-defined location of the electrode track (arrow), revealing a small loss of tissue. (b). It was possible to attest the absence of vacuolization and pyctonic profiles in all time points evaluated. The tissue around electrode implants presented a similar aspect to their contralateral counterpart. Black squares in lower magnification pictures indicate the regions where enlargements were obtained in all groups. Left column of the figure: implanted hemisphere; right column of the figure: contralateral hemisphere, adopted as control. Scale bar: 100 μm (lower magnification); 200 μm (enlargements).
Mentions: The precise location of the microwire array implants was identified in all animals at all survival times (Fig 3). Nissl staining revealed a minimal tissue loss in the implant site, restricted to the exact location of electrodes, with preservation of cell bodies near the microelectrode track and the absence of vacuolization, an event usually observed after milieu alterations (Fig 3).

Bottom Line: Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation.Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted.On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.

View Article: PubMed Central - PubMed

Affiliation: Edmond and Lily Safra International Institute of Neurosciences (ELS-IIN), Santos Dumont Institute, Macaiba, RN, Brazil.

ABSTRACT
The development of therapeutic approaches to improve the life quality of people suffering from different types of body paralysis is a current major medical challenge. Brain-machine interface (BMI) can potentially help reestablishing lost sensory and motor functions, allowing patients to use their own brain activity to restore sensorimotor control of paralyzed body parts. Chronic implants of multielectrodes, employed to record neural activity directly from the brain parenchyma, constitute the fundamental component of a BMI. However, before this technique may be effectively available to human clinical trials, it is essential to characterize its long-term impact on the nervous tissue in animal models. In the present study we evaluated how chronic implanted tungsten microelectrode arrays impact the distribution and morphology of interneurons reactive to calcium-binding proteins calbindin (CB), calretinin (CR) and parvalbumin (PV) across the rat's motor cortex. Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation. Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted. Moreover, restricted microglial activation was observed on the implanted sites. On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.

No MeSH data available.


Related in: MedlinePlus