Table 2.

Neuronal classification in Task 2a

Seq #Time windows
1offer value A | AB +offer value A | BA +chosen value A +
2offer value A | ABoffer value A | BAchosen value A
3offer value B | BA +offer value B | AB +chosen value B +
4offer value B | BAoffer value B | ABchosen value B
5AB | BA +AB | BAchosen juice A
6AB | BAAB | BA +chosen juice B
7offer value1 +offer value2 +chosen value +
8offer value1offer value2chosen value
  • aBallesta and Padoa-Schioppa (2019) found that, under sequential offers, neurons in OFC encoded different variables in different time windows. However, focusing on three primary time windows, the vast majority of neurons presented 1 of 8 specific patterns of variables, referred to as variable “sequences.” The 8 sequences identified in that study are defined in this table, where + and – indicate the sign of the encoding. These sequences seem roughly analogous to the variables identified under simultaneous offers. For example, seq #1 encodes the value of juice A when the animal is offered that juice (post-offer1 in AB trials; post-offer2 in BA trials). Upon juice delivery, seq #1 encodes the value of juice A conditioned on juice A being chosen. Thus, neurons classified as seq #1 seem analogous to offer value A+ neurons found under simultaneous offers. Similarly, cells classified as seq #2, seq #3, and seq #4 seem analogous to offer value A–, offer value B+, and offer value B– cells found under simultaneous offers, respectively. Cells classified as seq #5 or seq #6 encode in a binary way the identity of the juice (A or B) offered to the animal or chosen by the animal. These neurons appear tentatively analogous to chosen juice cells identified under simultaneous offers. Finally, cells classified as seq #7 or seq #8 encode the value of either juice, provided that the animal focuses on it. They appear tentatively analogous to chosen value+ and chosen value– cells identified under simultaneous offers, with the understanding that the value encoded by these neurons is that upon which the animal places its mental focus and not necessarily the chosen one.