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.
In the top panel, the two stimuli appear on the 90°/270° meridian. In the bottom panel, the two stimuli appear along the 0°/180° meridian.
