As humans, rats were found to be dreaming of the future as they are strongly motivated by a goal, in a new experiment coming from the University College London.
The brain structure and functioning of rats is known to be similar to that of humans. The study coming from the University College London and funded by the Wellcome Trust and Royal Society was intended to take a peek into the functioning of the hippocampus related to dreaming.
The hippocampus activity of four rats was monitored during the research. The researchers placed four rats in a T-shaped maze. In one of the arms of the maze, they visibly placed a yummy treat for the rats to reach, but blocked the access to the desired snack.
After trying to find ways to reach the so-close yet unattainable treat, the rats were comfortably arranged in a cosy nest and encouraged to sleep. The furry subjects dosed off for one hour, dreaming of…food.
Upon their awakening and returning to the T-shaped maze where access the the food had been restored by the researchers, they immediately reached it based on calculations they had made during their nap.
Lead author of the study Hugo Spiers amusingly commented that the experiment was:
“It’s like looking at a holiday brochure for Greece the day before you go – that night you might dream about the picture.”
Just as humans do, rats were found to store mental maps of the environments they roam in their hippocampi. By overseeing neural activity with the use of electrodes, the research team found that places are both recorded by rats with an unique combination of neurons in the hippocampi firing together.
The most interesting detail is that these memories don’t only fire when the rat finds itself in a certain location, but also when it nods to sleep. Nothing too unusual so far, as human also dream of places they’ve been.
Yet, the research team led by Hugo Spiers wanted a closer peek into whether the rats are also using these mental recordings and maps to plan the future.
The 50 electrodes that recorded neural activity in the hippocampi of the four rats as they were sleeping saw these ‘place cells’ firing up repeatedly. As the rats were placed back in the T-shaped maze with all barriers to the food and the arms of the maze removed, they instantly crowded to the same spot where the food had been placed initially and could only be spotted.
The results of the research suggest that it is the hippocampus which is responsible for planning routes that have both happened or may happen. However, in the case of the latter, there a strong motivation has to trigger the planning in the land of dreams.
It thus seems rats and humans are quite similar in planning and dreaming of future events. Food included.
According to the authors of the study, the purpose of the neural hippocampi simulations is still undefined. Albeit this experiment’s final suggestion that neural activity in the hippocampi during sleep may be a way to thoroughly evaluate all possibilities of action to determine which results in the getting the big prize – in this case, food, researchers would like to take it one step further.
According to the Caswell Barry, co-lead researcher, the team would now like to focus on determining if there is a link between planning and the rats’ next actions.
This study was published in the eLife journal.
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