Caustic, biting, daring—Shostakovich’s Symphony No. 4 was written at the height of Soviet Russia’s artistic censorship and shelved until well after Stalin’s death. It’s clear to hear why: Nelsons and the Boston Symphony Orchestra elucidate this defiant work’s every chilling detail, from the strings’ frenzied playing in the opening movement to the ironic majesty of the Largo. Nelsons ratchets up the tension at the start of Symphony No. 11, “The Year 1905,” which describes the uprising that anticipated the Revolution of 1917. Its second-movement sketch of Russia’s Bloody Sunday shootings is terrifying, and Nelsons pushes his musicians to their technical and emotional limits.