Figure 4.

Agency credit assignment cartoon and striatal neurons coding social action and own reward. (A) Once the monkey receives a banana it needs to know which action produced reward to assign credit. The action can be its own (solid lines) or someone else's (dashed lines). Many actions take place before reward is delivered, therefore looking at a memory of each action or eligibility trace (brown arrows) can solve the agency credit assignment problem. (B) Task sequence for the actor: shape of conditioned cue predicted absence or presence of reward for each animal. Appearance of a subsequent blue go signal was followed by key release, stimulus touch and reward for actor, and later for conspecific. After the ITI the monkeys switched roles as actor and passive. (C) Single striatal neuron coding own action and own reward. Note the higher neuronal activity during own action and own reward compared to own reward absence and conspecific's actions. (D) Single striatal neuron coding social action and own reward. This neuron is active during conspecific's actions that will result in own reward, a complement to the neuron shown in (A). Monkey picture by smerikal (Flickr), reproduced with permission. Panels (B–D) based on Báez-Mendoza et al. (2013), reproduced with permission.