Endogenous context for choice making: A magnetoencephalographic study

Abstract

The question of how we make choices and decisions in real-life situations continues to pose important challenges for research. In particular, very little is known about the role endogenous states of the brain may have in such cognitive processes. Magnetoencephalography was used to measure the temporal dynamics of neural responses in 16 subjects choosing groceries while on a simulated supermarket visit. A total of 90 choice inducing stimuli prompted the subjects to buy one out of 3 products belonging to a given category of products. Pre-stimulus brain states were characterized using a nonlinear measure based on deterministic features in the dynamics of brain activity. Across all subjects, the brain state measure followed a statistical gamma-distribution. Low pre-stimulus brain states implied relatively slow choices with an emphasis on familiarity. In contrast, high states implied an increase in determinism over pre-frontal cortices temporarily predisposing an individual to choose faster and to emphasize novelty over familiarity of the items to be chosen from. For these high states, significant post-stimulus activity was observed over left orbito-frontal and left parietal cortices consistent with an evaluation of reward values. These findings suggest that the overall context defined by a given choice situation as well as past choices may require an individual to fluctuate between certain states of the brain in order to balance anticipation of or preparation for upcoming decision making.