About the Authors

Claus C Hilgetag

To whom correspondence should be addressed. E-mail: c.hilgetag@iu-bremen.de

Affiliations School of Engineering and Science, International University Bremen, Bremen, Germany , Boston University, Boston, Massachusetts, United States of America

Helen Barbas

Affiliations Boston University, Boston, Massachusetts, United States of America , Boston University School of Medicine, Boston, Massachusetts, United States of America , New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

CCH and HB conceived and designed the study. HB performed the anatomical experiments. CCH analyzed the data. CCH and HB wrote the paper.