The Bundle-imaging Fiber Photometry with Targeted Optogenetics (BFTO) is designed for multi-site experiments that combine photometry and optogenetics. Among all of Doric Lenses’ photometry systems, the BFTO provides the most flexibility, as it supports dual-color fiber photometry in 7-19 sites, while independently controlling the optogenetic timing and wavelength at each of those sites.

The BFTO is interchangeably compatible with either Fan-out or High Density output configuration. Both types of patch cords are available in 7, 9, or 19 fiber bundle patterns, and the connection of either patch cord with the BFTO is designed for a single, reproducible orientation. Note that the pattern of the high-density patch cords from the sample port must always match the pattern of the optogenetics port.

To record green and red photometry signals, the BFTO uses built-in LEDs to illuminate the entire sample port, and a CMOS sensor to simultaneously image the fluorescent signal from every fiber within the bundle. The fluorescent light collected from each fiber within the bundle creates circular spots on a CMOS sensor. The electrical read-out from pixels within each fiber image correlates with the calcium activity of the corresponding brain site.

To independently control each optogenetic stimulation, individual lasers (either blue or red) are connected to one of the Branching Box ports. The multi-site optogenetic stimulation pattern is transmitted through the high-density fiber of the Branching Box, to the BFTO and then through the cannula on the animal, conserving the spatiotemporal pattern.