I've just come across pubbrain.org. It looks like a fantastic tool for cognitive neuroscience.

Search for a term (e.g. "working memory") and find out how many PubMed papers have referred to different brain regions (a "heat map" is provided), together with a list of citations. For example, Pubmed find 161 papers linking "working memory" and "inferior frontal gyrus". Of course this is only the first step in understanding the brain basis of a given function, but I think it should be very useful for gaining a quick overview.

Tom