Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Mean active and inactive responding throughout self-administration and extinction training. Closed symbols represent active responses, while open symbols represent inactive responses. High drug-takers (n=22) are represented by triangles, while circles represent low drug-takers (n=20). * denotes statistical significance (p < 0.05).
