Yamagata, M. | Search bioRxiv

bioRxiv2018

Wide-area all-optical neurophysiology in acute brain slices

Optical tools for simultaneous perturbation and measurement of neural activity open the possibility of mapping neural function over wide areas of brain tissue. However, spectral overlap of actuators and reporters presents a challenge for their simultaneous use, and optical scattering and out-of-focus fluorescence in tissue degrade resolution. To minimize optical crosstalk, we combined an optimized variant (eTsChR) of the most blue-shifted channelrhodopsin reported to-date with a nuclear-localized red-shifted Ca2+ indicator, H2B-jRGECO1a. To perform wide-area optically sectioned imaging in tissue, we designed a structured illumination technique that uses Hadamard matrices to encode spatial information. By combining these molecular and optical approaches we made wide-area maps, spanning cortex and striatum, of the effects of antiepileptic drugs on neural excitability and on the effects of AMPA and NMDA receptor blockers on functional connectivity. Together, these tools provide a powerful capability for wide-area mapping of neuronal excitability and functional connectivity in acute brain slices.

neuroscience↗

bioRxiv2017

RANbodies: reporter-nanobody fusions as versatile, small, sensitive immunohistochemical reagents

Sensitive and specific antibodies are essential for detecting molecules in cells and tissues. However, currently used polyclonal and monoclonal antibodies are often less sensitive than desired, difficult to produce, and available in limited quantities. A promising recent approach to circumvent these limitations is to employ chemically-defined antigen-combining sites called nanobodies, derived from single chain camelid antibodies. Here, we used nanobodies to prepare sensitive unimolecular detection reagents by genetically fusing cDNAs encoding nanobodies to enzymatic or antigenic reporters. We call these fusions between a reporter and a nanobody RANbodies. They can be used to localize epitopes and to amplify signals from fluorescent proteins. They be generated and purified simply and in unlimited amounts, and can be preserved safely and inexpensively in the form of DNA or digital sequence.

neuroscience↗