A Dual Reward-Place Association Task to Study the Preferential Retention of relevant Memories in Rats

Abstract

Memories of past events and common knowledge are critical to flexibly adjust ones future behavior based on prior experiences. The formation and the transformation of these memories into a long-lasting form are supported by a dialog between the coordinated activity of population of neurons in the cortex and the hippocampus. Not all experiences are remembered equally well nor for equally long. It has been demonstrated experimentally in humans that memory strength positively depends on the behavioral relevance of the associated experience. Behavioral paradigms testing the selective retention of memory in rodents would enable to further investigate the neuronal mechanisms at play. We developed a novel paradigm to follow the repeated acquisition and retrieval of two contextually distinct, yet concurrently occurring, food-place associations in rats. We demonstrated the use of this paradigm by varying the amount of reward associated with the two locations. After delays of 2h or 20h, rats showed better memory performance for experiences associated with larger amount of reward. This effect depends on the level of spatial integration required to retrieve the associated location. Thus, this paradigm is suited to study the preferential retention of relevant experiences in rats.