The executive director of the European Union’s ambitious — but contentious — Human Brain Project (HPB) has left his post after a disagreement with the institution that coordinates the initiative.

The 10-year, €1-billion (US$1.1-billion) project aims to simulate the human brain using computers, and is a flagship science initiative of the EU. In a joint statement on 16 August , Chris Ebell and the HBP’s coordinating institution, the Swiss Federal Institute of Technology in Lausanne, said that they had decided to “separate by common agreement” following “differences of opinion on governance and on strategic orientations”.

Ebell became director of the project in 2015, after the HBP disbanded its small executive committee in favour of a 22-member governing board.

The HBP, which involves more than 100 partner institutions, had after its inception in 2013 been criticized by some neuroscientists for its scientific direction, its complicated structure and the lack of transparency surrounding its funding decisions.