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Several problems challenge mesoscopic imaging in the brain: 1) Difficulty with positioning high-NA objectives near the brain; 2) Creating a flat imaging window against the surface of the brain; 3) Adjusting the imaging window in the face of changes in swelling and pressure in the brain; 4) Preventing growth of dura and biofilms that obscure the imaging window; 5) Follow-on MRI imaging of the animal post-implantation. We propose here an ultra-large window radiolucent implant to address these issues. Our approach provides a 2 cm diameter window for non-human primates (NHPs) that regulates pressure and employs a stable, strong, and thin design. The system is mechanically modeled and stress-tested to achieve access to the brain by large objectives, with design features that allow for manual repositioning of the imaging lens. To optimize the distance between the objective and the brain, we prioritize a thin implant design. A strong radiolucent implant is created using PEEK plastic, a strong, thermoresistant and biostable material. We heighten strength of the chamber’s attachment to the skull by using titanium screws that are normal to the surface of the bone at each point. The implant design has several parts and contemplates a potential method to maintain pressure on the brain. This method uses an engineered silicone mount to maintain even pressure of the imaging window on the brain’s surface, despite brain motion. The mechanical properties of the silicone are manipulated to closely resemble that of brain tissue to be more biomimetic and act as a cushion for motion. This method also allows for the manual repositioning of the cover slip to create a flat imaging window. Lastly, our approach prevents dural growth by blocking the migration of migratory biofilm-forming cells; we hypothesize that use of dynamic pressure maintenance on the brain is key to this method’s success. We are also investigating methods to elongate the longevity of the implant and imaging site, such as silver sputtering on implants and blue light therapy. These methods have produced an ultra-large field of view with 2P image results in <60,000 neurons. As such the chambers are expected to enhance recording window longevity and may prove to be a critical advance in NHP and human brain imaging.
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Diesel2p mesoscope with dual independent scan engines for flexible capture of dynamics in distributed neural circuitry
Abstract Imaging the activity of neurons that are widely distributed across brain regions deep in scattering tissue at high speed remains challenging. Here, we introduce an open-source system with Dual Independent Enhanced Scan Engines for Large field-of-view Two-Photon imaging (Diesel2p). Combining optical design, adaptive optics, and temporal multiplexing, the system offers subcellular resolution over a large field-of-view of ~25 mm 2 , encompassing distances up to 7 mm, with independent scan engines. We demonstrate the flexibility and various use cases of this system for calcium imaging of neurons in the living brain.
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- PAR ID:
- 10309085
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Several problems challenge mesoscopic imaging in the brain: 1) Difficulty with positioning high-NA objectives near the brain; 2) Creating a flat imaging window against the surface of the brain; 3) Adjusting the imaging window in the face of changes in swelling and pressure in the brain; 4) Preventing growth of dura and biofilms that obscure the imaging window; 5) Follow-on MRI imaging of the animal post-implantation. We propose here an ultra-large window radiolucent implant to address these issues. Our approach provides a 2 cm diameter window for non-human primates (NHPs) that regulates pressure and employs a stable, strong, and thin design. The system is mechanically modeled and stress-tested to achieve access to the brain by large objectives, with design features that allow for manual repositioning of the imaging lens. To optimize the distance between the objective and the brain, we prioritize a thin implant design. A strong radiolucent implant is created using PEEK plastic, a strong, thermoresistant and biostable material. We heighten strength of the chamber’s attachment to the skull by using titanium screws that are normal to the surface of the bone at each point. The implant design has several parts and contemplates a potential method to maintain pressure on the brain. This method uses an engineered silicone mount to maintain even pressure of the imaging window on the brain’s surface, despite brain motion. The mechanical properties of the silicone are manipulated to closely resemble that of brain tissue to be more biomimetic and act as a cushion for motion. This method also allows for themanual repositioning of the cover slip to create a flat imaging window. Lastly, our approach prevents dural growth by blocking the migration of migratory biofilm-forming cells; we hypothesize that use of dynamic pressure maintenance on the brain is key to this method’s success. We are also investigating methods to elongate the longevity of the implant and imaging site, such as silver sputtering on implants and blue light therapy. These methods have produced an ultra-large field of view with 2P image results in <60,000 neurons. As such the chambers are expected to enhance recording window longevity and may prove to be a critical advance in NHP and human brain imaging.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41467-021-26736-4
