Fiber Photometry Acquisition

One-month post-surgery, mice were habituated to head-mounted equipment for 2 days.

On day 1, an actual or mock wireless inertial sensor(~2.5 cm H x 1 cm L x 0.5 cm W with ~ 2.5-3.0 cm antennae, ~1.8 g weight)glued to the 4-position connector(Harwin Inc., M52-040023V0445) was attached to the implanted receptacle connector on the skull cap.

Individual mice roamed freely in the home cage for 1 hour.

On day 2, a multi-fiber bundled patch cord (3 fiber bundle, 400/440μm diameter for a maximum of inner diameter at 900 μm, 0.37 NA, 3.5 m long, 1.25 mm fiber tip diameter, low-autofluorescence; Doric, BBP(3)_400/440/900-0.37_3.5m_FCM-3xMF1.25_LAF) was attached to individual mice in addition to the wireless sensor and optogenetic patchcord.

Individual mice were allowed to habituate to the equipment for 1 hour in its home cage.

Mice were attached to the head-mounted equipment and subjected to 30 frames per second photometry recording (FP3002, Neurophotometrics), with 75-150 μW 560 nm LED illuminating rDA1m, and equivalent closed loop optogenetic parameters described in Guidelines section.

To test for DA release in the context of closed loop optogenetic setup, an average of 30 hits of blue light were delivered randomly within the span of 30 minutes.

To evaluate DA release in the context of food reward, mice were placed on an IACUC approved food deprivation protocol and kept within 85% of original weight. Mice were placed in an operant chamber with a nosepoke linked to a lick detector (PyControl). Each lick detection triggers dispensing 2 μl 10% sucrose.

Note: Since animals tend to accidentally trigger lick detector at the beginning of sessions, between 40-50 sucrose dispensing events were gathered per animal and rDA1m activities associated with the last 35 rewards of the session were used for analysis.