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.
Example of one trial. Two tones were drawn from two of four frequency ranges (indicated by the different colors). If a change occurred when the sequence was repeated, the new tone was drawn from the same frequency range as the corresponding tone in the first sequence. The maintenance period as well as ITI randomly varied in each trial (2 or 10 s).
