A soldier charged with giving US secrets to the WikiLeaks website is due to return to court for pre-trial proceedings.
Manning is expected to give evidence in a defence motion seeking dismissal of all charges.
His lawyers contend that he was illegally punished by being locked up alone in a small cell for nearly nine months and having to sleep naked for several nights.
The military contends that his treatment at the Marine Corps brig in Quantico, Virginia, was proper, given his classification as a maximum-security detainee who posed a risk of injury to himself or others.
Manning faces possible life imprisonment if convicted of aiding the enemy, the most serious of the 22 charges.