Amphibians don't lose memories during hibernation

LINCOLN, England, Jan. 12 (UPI) -- New research suggests the memory formation and storage processes aren't interrupted in amphibians that settle down for the winter. Previous studies have shown some of the memories of hibernating mammals don't survive the long winter's nap.

The new findings -- detailed in the journal Scientific Reports -- suggest brumation, the period of winter inactivity, affects cognition differently in cold-blooded and warm-blooded animals.

"Long-term torpor is an adaptive strategy that allows animals to survive harsh winter conditions. However, the impact that this has on cognitive function is poorly understood," Anna Wilkinson, a researcher at the University of Lincoln, said in a news release. "We know that in mammals, hibernation causes reduced synaptic activity and can cause them to lose some of the memories they formed prior to hibernation, but the effect of brumation on memory has been unexplored, until now."

For the study six lizards were put in brumation for 100 days, triggered by turning down the temperature. Another six remained in normal conditions. Both groups proved equally adept at recalling a maze route after the 100-day waiting period.

"We demonstrated that each of the animals solved the task using memory, rather than sensory cues such as smell of the reward, and we're therefore confident that the period of brumation did not impact on their ability to remember," explained co-author Anne Hloch. "For these animals, memory retention is essential for survival as it allows them to recall important information about the environment, such as the location of food and the presence of predators."

Scientists aren't yet sure whether the differences between mammals and amphibians are a result of divergent learning and memory formation processes or the nature of their hibernation.