Torpor Does Not Influence Spatial Memory in Hibernating Golden-Mantled Ground Squirrels (<i>Spermophilus [Callospermophilus] lateralis</i>)

AbstractMammalian hibernation in ground squirrels is characterized by periods of torpor wherein body temperature approaches ambient temperature and metabolism is reduced to as low as 1/100th of active rates. It is unclear how hibernation affects long-term spatial memory, as tremendous remodeling of neurons is associated with torpor use. Given the suspected links between remodeling and memory formation and retention, we examined long-term spatial memory retention throughout a hibernation season. Animals were trained on a Barnes maze before entering torpor. Animals were tested for memory retention once a month throughout a hibernation season. Results indicate marked variation between individuals. Some squirrels retained memory across multiple torpor bouts, while other squirrels did not. No relationship was found between the number of torpor bouts, duration of bouts, or time spent torpid on long-term memory retention. However, that some squirrels successfully retain memory suggests that the profound remodeling of dendritic spines during torpor does not always lead to memory loss.