Correction to: Bot Stud (2019) 60:9 https://doi.org/10.1186/s40529-019-0258-x

In the publication of this article (Liu et al. 2019), there was an error in the method and ethics declarations sections which were published with incorrect animal experiment approval number. The error: ‘These animal experimental protocols have been reviewed and approved by the Institutional Animal Care and Use Committee of Taipei Medical University (LAC-99-0142).’ Should instead read: These animal experimental protocols have been reviewed and approved by the Institutional Animal Care and Use Committee of Taipei Medical University (LAC-2016-0340).