"The EPM was constructed from pine boards, painted black and sealed with polyurethane. It consisted of two opposing open arms (length: 40 cm, width: 9 cm) and two opposing wall-enclosed arms (wall height: 15 cm) extending off of a center square (9 cm per side) to form a plus shape. The maze was placed on a pedestal (70 cm high) in the center of a rectangular room (3 × 3.7 meters) with white walls containing large black painted shapes. A video camera was hung from the ceiling (2.7 meters high), directly above the center of the maze."

Front. Behav. Neurosci., 17 February 2015 | https://doi.org/10.3389/fnbeh.2015.00031

Behavior in the elevated plus maze is differentially affected by testing conditions in rats under and over three weeks of age

Your definition can be like this: Presently we define open arm initial heading errors in the elevated plus maze in the following way:

Thank you very much.

I want to under stand more about open arm initial heading errors in EPM?

I does it mean?

For example, stretching : elongation of body maintaining the hind paws fixed; in closed arm correlates positively with anxiety.

I want to under stand open arm initial heading errors like stretching

Can you help me?

I am very grateful for your.

Thanks once again and have a great day!