Recalling memories in reverse, it appears, helps us trace the good or rewarding stuff. This sheds some light on our biological capacity in learning through one-of-a-kind experiences.
A study conducted on rats showed through rewinding a memory, the rodents were able to retrace where they found a treat. This makes going back to the rewarding area easier for the rats.
A team of researchers studied around 120 place cells in five rats by implanting electrodes on each of their brain’s hippocampus. To study the animals’ simultaneous activity, the researchers let the rats run on a straight path.
As they run back and forth, there is chocolate awaiting them on the end of each direction. After a while, the researchers put more chocolate on one end. The rats responded by mentally retracing their way more on the end with more chocolate as compared to the other.
David Foster from Johns Hopkins University in Baltimore, Maryland says through getting a “nice big fat reward,” one learns all the areas leading to the certain treat or reward are “great places to be.” He adds this trajectory is, of course, “a good one.”
They were also able to observe the rats retracing their steps using a reverse pattern. While there are also forward replays, the number of instances where the rats rewind their memories are double compared to the other method.
Just like humans, rats store their recollections in their hippocampus. What helps rats in charting certain routes and environments during its exploration is the firing of “place cells” in the hippocampus.
These place cells are what creates the patterns and combinations in the mental map. According to Hopkins, while moving around, the place cells are inactive. But while not in motion, like during sleeping, they are active.
They fire in a sequence that shows how the route is mentally replayed by the rats. The step-by-step process also allows the rats to remember the early stages towards the route of a rewarding spot.
According to Massachusetts Institute of Technology’s Matthew Wilson, the findings of “reverse reactivation” is “important” and “critical” in knowing more about our ability of biologically learning through particular experiences. This gives more information on how our brain’s hippocampus store memories and important information from a certain event, and how we can retrieve them.