They are using voxels from visual areas V1, V2, and V4. These are levels in the visual regions of the cortex. What you call "thinking", would correlate with the IT (infero-temporal cortex) and the PFC (pre-frontal).
Also, they are using fMRI activations, which means they don't record from neurons directly, but look at cerebral blood flow (which is linked to neuronal activation; the more the neuron does, the more oxygen it needs).
This, while not directly relevant, might be helpful: http://www.scholarpedia.org/article/What_and_where_pathways
Also, they are using fMRI activations, which means they don't record from neurons directly, but look at cerebral blood flow (which is linked to neuronal activation; the more the neuron does, the more oxygen it needs).