Is top-down control from prefrontal cortex necessary for visual categorization?

The brain mechanisms underlying visual object categorization remain unclear. In this issue of Neuron, Minamimoto and colleagues introduce a novel task that associates each category with a different incentive value, and they demonstrate that it can be learned within a single session even after ablation of the lateral prefrontal cortex. Copyright 2010 Elsevier Inc. All rights reserved.