Meng-Tsen Ke, Yasuhiro Nakai, Satoshi Fujimoto, Rie Takayama, Shuhei Yoshida, Tomoya S Kitajima, Makoto Sato, Takeshi Imai (2016) Super-Resolution Mapping of Neuronal Circuitry With an Index-Optimized Clearing Agent., Cell reports, Volume 14, Number 11, pp. 2718-32
Published in 2016 Mar 22 (Electronic publication in March 10, 2016, midnight )
(Abstract) Super-resolution imaging deep inside tissues has been challenging, as it is extremely sensitive to light scattering and spherical aberrations. Here, we report an optimized optical clearing agent for high-resolution fluorescence imaging (SeeDB2). SeeDB2 matches the refractive indices of fixed tissues to that of immersion oil (1.518), thus minimizing both light scattering and spherical aberrations. During the clearing process, fine morphology and fluorescent proteins were highly preserved. SeeDB2 enabled super-resolution microscopy of various tissue samples up to a depth of >100 mum, an order of magnitude deeper than previously possible under standard mounting conditions. Using this approach, we demonstrate accumulation of inhibitory synapses on spine heads in NMDA-receptor-deficient neurons. In the fly medulla, we found unexpected heterogeneity in axon bouton orientations among Mi1 neurons, a part of the motion detection circuitry. Thus, volumetric super-resolution microscopy of cleared tissues is a powerful strategy in connectomic studies at synaptic levels.(MeSH Terms)