"D", "M2", ""M3"", ""M4"" and ""M5"" Positions 1st Gear

The forward brake and the forward One-way Clutch regulate reverse rotation of the mid sun gear.
The 1st One-way Clutch regulates reverse rotation of the rear sun gear.
The 3rd One-way Clutch regulates reverse rotation of the front sun gear.
During deceleration, the mid sun gear turns forward, so the forward One-way Clutch idles and the engine brake is not activated.

Fig 1: Shift Component Application In "D1" Position
Courtesy of NISSAN MOTOR CO., U.S.A.