A parametric relief signal in human ventrolateral prefrontal cortex.

People experience relief whenever outcomes are better than they would have been, had an alternative course of action been chosen. Here we investigated the neuronal basis of relief with functional resonance imaging in a choice task in which the outcome of the chosen option and that of the unchosen option were revealed sequentially. We found parametric activation increases in anterior ventrolateral prefrontal cortex with increasing relief (chosen outcomes better than unchosen outcomes). Conversely, anterior ventrolateral prefrontal activation was unrelated to the opposite of relief, increasing regret (chosen outcomes worse than unchosen outcomes). Furthermore, the anterior ventrolateral prefrontal activation was unrelated to primary gains and increased with relief irrespective of whether the chosen outcome was a loss or a gain. These results suggest that the anterior ventrolateral prefrontal cortex encodes a higher-order reward signal that lies at the core of current theories of emotion.