Activity sensors represent an area of great interest in neuroengineering. The voltage sensor Archon is an archaerhodopsin-based molecule with a high voltage sensitivity and brightness compared to its predecessors. The aforementioned cross talk problem also pertains to sensors: since cell-processes are touching cell bodies, the signal coming from a cell body could in principle originate from nearby cells. To solve this problem we developed a GCaMP6f molecule that is retained in the cell body only, called somaGCaMP6f. This molecule enables low crosstalk physiological imaging in mice and fish.
Lastly, we have developed a technology that greatly facilitates the mapping of the brain. Optical super-resolution techniques are slow and costly, and accordingly do not scale well to large-scale brain circuitry. Instead of improving the resolving power of the microscope, we have found a way to physically expand biological specimens 4x-20x in linear dimension, in an isotropic fashion. This method, which we call expansion microscopy (ExM), enables the mapping of molecules of interest across cells and tissues of extended scale, and thus facilitates the analysis of neural circuits across scales of relevance to understanding brain function.