 The primary objectives of this study are: To evaluate pharmacokinetics PK properties of BIIB074 administered as a single oral dose in healthy Japanese and Caucasian participants; and To evaluate the PK properties of BIIB074 administered as repeated oral doses in healthy Japanese participants. The secondary objective of this study is to assess the safety and tolerability of BIIB074 administered as a single oral dose Japanese and Caucasian participants and as repeated oral doses Japanese participants. 