Save, E. (1997) The contribution of visual and inertial mechanisms to navigation in total darkness. Animal Learning and Behavior, 25, 324-334.
Rats were trained in the Morris water maze to
reach a platform in darkness after they have been provided with some information
on their initial location. They were given trials with (1) the light on
(light condition), and (2) light followed by darkness (dark condition).
In this latter condition, the dark period was preceded by either a brief
(short group) or a long (long group) initial light period. Although the
rats in the short group first oriented accurately toward the platform,
their trajectory rapidly deviated in darkness. In contrast, the rats in
the long group were able to navigate accurately over a longer distance
but finally also deviated. In transfer trials, the rats in the short group
were less accurate than the rats in the long group in the dark; however,
both groups performed well in light. This suggests that navigation in darkness
depends not only on the use of recent visual and locomotor memory but also
on the activation of an inertia-based navigation process.