Treating rats with an experimental drug at three months following a traumatic brain injury (TBI) improves their learning memory ability, as reported in a new study published online today in the July edition of The Journal of Neuroscience. The drug, a selective phosphodiesterase 4 subtype inhibitor (PDE4B), is currently under development by Tetra Discovery Partners, a privately held biotechnology company and is being tested as a potential therapy for TBI by University of Miami / Miami Project researchers.