Brain Freeze

Known for never following a conventional artistic path, Bjork's challenging new Elektra album, "Medulla," finds the Icelandic artist singing over rhythms fashioned by such beatboxers as former Roots member Rahzel, Shlomo and Dokaka. The 14-track set was produced by Bjork, with assistance on four tracks by longtime collaborator Mark Bell.

Other guests include Fantomas/Mr. Bungle principal Mike Patton, singer/songwriter Robert Wyatt (on the duet "Submarine"), classical vocalist Gregory Purnhagen, Inuit throat singer Tagaq and the Icelandic and London Choirs. Programming was supplied by Matmos, Mum's Valgeir Sigurdsson, Olivier Alary and Jake Davies.

A limited edition of "Medulla" will sport expanded artwork and a 16-panel poster. It's the follow-up to 2001's "Vespertine," which debuted at No. 19 on The Billboard 200 and has sold more than 368,000 copies in the United States, according to Nielsen SoundScan.