(a) Mice exhibit bouts of approach and retreat when investigating novel objects (left). Frequency of approach to objects (mean ± s.e.m. across n = 10 animals) (right; novel × familiar: t = 3.67, p = 0.001, n = 10 animals, paired t-test; novel × no object: t = 4.41, p = 0.0017, n = 10 animals, paired t-test). Solid dots indicate mean and transparent dots indicate each animal. (b) Example GCaMP trace from dopamine axons in TS (green) aligned to animal’s distance from the novel object (black), with dotted lines indicating nearest approach per bout. (c) Left: Example GCaMP signals aligned to onset of retreat. Bouts were sorted based on time of approach, shown as a grey line. Right: Average GCaMP responses across n = 6 animals to novel object (cyan), familiar object (magenta), and no object control (black). For novel × familiar: t = 3.04, p = 0.021, n = 6 animals, paired t-test. For novel × no object: t = 3.65, p = 0.015, n = 6 animals, paired t-test. Solid dots indicate mean and transparent dots indicate each animal. * P < 0.05 two-sided t-test, ** P < 0.01 two-sided t-test.