Extended Data 1. Retinotopic mapping and motion direction tuning is consistent with the anatomical organization and tuning preferences of marmoset MT.

(a) Receptive fields for recorded units were measured by reverse correlation. Monkeys held fixation on a marmoset face while visual probes (drifting Gabors) appeared at random locations in the visual hemifield contralateral to the recording array. Each probe would appear, drift for 200ms, and disappear after which a new probe would appear in a new random location and the process would repeat until the monkey broke fixation. (b) The estimated position and orientation of Utah arrays in area MT based on retinotopy and histological examination for monkey W (blue) and monkey T (red). (c) Example receptive fields and their preference for motion direction are consistent with previous reports of marmoset MT⁵⁸.