A proposed common neural mechanism for categorization and perceptual decisions.

One of the most fascinating issues in neuroscience is how the brain makes decisions. Recent evidence points to the parietal cortex as an important locus for certain kinds of decisions. Because parietal neurons are also involved in movements, it has been proposed that decisions are encoded in an intentional, action-based framework based on the movements used to report decisions. An alternative or complementary view is that decisions represent more abstract information not linked to movements per se. Parallel experiments on categorization suggest that parietal neurons can indeed represent abstract categorical outcomes that are not linked to movements. This could provide a unified or complementary view of how the brain decides and categorizes.