Sleep Deprivation impairs hippocampus-mediated contextual learning but not amygdala cued learning in rats.

Ruskin, D. N., Liu, C., Dunn, K. E., Bazan, N. G., & LaHoste, G. J. (2004). Sleep deprivation impairs hippocampus-mediated contextual learning but not amygdala-mediated cued learning in rats. European Journal of Neuroscience, 19(11), 3121-3124. doi:10.1111/j.0953-816X.2004.03426.x

Sleep is the ever vital process that we as humans need in order to make sense of the world around us and to be able to do such things as learn, recall, or cohabitate. Without it, even after one night, effectiveness and efficiency seem to decline. Sleep deprivation has often been studied to see how animals react to a lack of this needed process, and its effects. The reason I chose this particular article was out of desire and interest for specifics, and the fact that, as a college student I all too often suffer from sleep deprivation personally. I knew that sleep deprivation was harmful, but I curious to what degree and to which regions of the brain suffer the most. Contextual learning is one where the specimen of individual learns based on the surroundings (area) and this kind of learning takes place in the hippocampus. Cued learning takes root in the amygdale and is usually paired with a stimuli.  

The set up for this study was that the rats were split up into the control group (those without sleep deprivation) and the experimental group (those with sleep deprivation). The manner in which the rats were sleep deprived were that they were placed on planks that floated on water and whenever the rat was on the point of falling asleep, the plank would tip, waking the rat. This was effective for both REM and nREM. Immediately after to either control or manipulation rats were conditioned. The rats were conditioned for freezing movement but pairing a 2 minute sound with a 30 second shock.

Exactly one day from conditioning, two types of observations occurred: one where the rats were in the same room, the second being the rats were in a new room with the same tone. In both scenerios freezing behavior was watched for.

            The results indicate that for the control, both hippocampus and amygdale brought on healthy responses. The results also show that contextual learning was less effective in the experimental group than the cued learning. The study also found that increased conditioning did not help with hippocampus- mediated learning.