Your counterclaim is based on the unsupported assumption that a substance having relatively high neurotoxic potential means that it cannot induce neuroplasticit

Your counterclaim is based on the unsupported assumption that a substance having relatively high neurotoxic potential means that it cannot induce neuroplasticity. The two are not mutually exclusive, and in the case of the substance in question, it is well known to have both high neurotoxic potential, as all strong NMDA antagonists do, as well as the ability to induce increased neuroplasticity.