  In human studies, how averaged activation in a brain region relates to human
behavior has been extensively investigated. This approach has led to the
finding that positive and negative facial preferences are represented by
different brain regions. However, using a multi-voxel pattern induction method
we found that different patterns of neural activations within the cingulate
cortex (CC) play roles in representing opposite emotional states. In the
present study, while neutrally-preferred faces were presented, activation
patterns in the CC that corresponded to higher (or lower) preference were
repeatedly induced by the pattern induction method. As a result, previously
neutrally-preferred faces became more (or less) preferred. We conclude that a
different activation pattern in the CC, rather than averaged activation in a
different area, represents and causally determines positive or negative facial
preference. This new approach may reveal importance in an activation pattern
within a brain region in many cognitive functions.
