Sir

I thoroughly enjoy Nature's insightful columns and News and Views, and of course take a special satisfaction when researchers from my institution, the University of Pennsylvania (or U Penn) are featured. However, in a sidebar 'Body and mind' within the News Feature 'Brain craze' (Nature 447, 18–20; 2007), a researcher is reported to work at Pennsylvania State University (Penn State) in Philadelphia. There have been occasional other instances in your pages of confusion over Pennsylvania and its universities.

Neither Penn State nor the University of Pittsburgh (Pitt) is in Philadelphia, the state's largest city, located in its southeastern corner. U Penn is a private university in the city, founded by its most famous citizen, Benjamin Franklin.

Penn State is the state's (and maybe the country's) largest public university, and it has many campuses, the main one located in University Park, Pennsylvania. The legend is that the location of the university was chosen by drawing a large 'X' from the four corners of the state and placing the university at the centre of it — in order to make it equally accessible to all students.

The University of Pittsburgh (Pitt) is a public university that resides, as one might have guessed, in Pittsburgh, the second largest city in Pennsylvania and at the western edge of the state.