The brain regions that encode attack and defense strategies are identified in a study published this week in Nature Neuroscience. The study, which monitored the brain activity of Japanese chess (shogi) players, may provide new insight into how we make complex decisions.
Numerous studies exploring decision-making in the brain have focused on choices between options that yield different payouts and involve different levels of risk. These choices depend on the overall strategy adopted, but it is unclear how the strategy itself is selected. Shogi lends itself particularly well to distinguishing between offense- and defense- minded strategies because there is a strong dichotomy between the two.
Keiji Tanaka and colleagues used functional magnetic resonance imaging to track the brain activity of 17 highly-ranked amateur shogi players as they decided whether particular board positions represented opportunities to go on the offensive or play defensively. During a second trial type, players were asked to select game moves for pre-determined board positions and strategies (defensive or offensive). This allowed the authors to identify the brain regions that specifically encoded strategy rather than move choice.
They found that strategy decisions were made before the moves were selected, supporting the idea that we first adopt a strategy and later select a particular action within those constraints. Offense- and defense- minded strategy values were encoded in two distinct brain regions: posterior cingulate cortex (PCC) and rostral anterior cingulate cortex (rACC), respectively. Furthermore, activity in the dorsolateral prefrontal cortex (dlPFC) was most strongly related to the difference in offense- and defense- minded strategies, suggesting that dlPFC is involved in strategy selection.