A rat experiment linked the time course of attention effects with plasma amphetamine exposure, but blood sampling and behavior were measured in separate groups. It did not directly correlate each animal’s concentration with its own performance.
Slezak and colleagues used six male rats for a five-choice serial reaction-time task and five additional male rats for plasma measurements. Behavioral testing examined several doses and post-injection intervals. Plasma amphetamine was measured after intraperitoneal 1.0 mg/kg using liquid chromatography–mass spectrometry. The matrix was plasma, and the drug was d-amphetamine, not methamphetamine.
At 1.0 mg/kg, accuracy improved at selected intervals, including 30, 60 and 120 minutes. The higher 1.7-mg/kg dose initially worsened accuracy and increased omissions, but improved accuracy later. Plasma exposure declined after its earliest measured peak. The paper compared exposure ranges with published clinical data, offering a translational modeling argument rather than a new clinical trial.
Separate cohorts permit alignment of average time courses but leave individual concentration–response relationships unmeasured. Route differences also matter: intraperitoneal exposure is not equivalent to an oral human regimen. A concentration range associated with better rat task performance is not a human safety window, and overlap with reported therapeutic exposure does not establish absence of impairment in a forensic case. The dose-by-time reversal is also incompatible with a simple assumption that more drug always means better attention. The study supports further pharmacokinetic–pharmacodynamic research while preserving the distinction between an animal model and individual clinical interpretation.
See a human plasma study with no detectable cognitive correlation.