For those of you not schooled in the history of sleep, the use of a cat as an animal model of sleep may seem novel. However, the cat was used as an animal model of sleep decades before rats, mice, hamsters, monkeys, and other non-human mammals. In fact, one of the first studies to identify sleep- versus wake-promoting centers in the brain was done in cats by Frechman, Michael Jouvet.

ResearchBlogging.orgIn 2012, the electrophysiological techniques available to better characterize sleep and wake states in the brain are certainly much more advanced than the tools available in the early 1900s. The researchers of this study used a single electrode to record from a distinctive cell population in the thalamus. The general idea was to see how the electrical firing of the neurons would change across different stages of sleep (NREM and REM) and wake and to see how transitions into specific sleep states impacted activation of the somatosensory cortex. In brief, this is a model of memory consolidation and to determine if a particular stage of sleep regulates such memory consolidation.

In order to record in the cats, the cats were trained to be restrained. I’m not sure how this was undertaken and how the cats would voluntarily become comfortable with such restraint let alone being prodded with electrodes. I envision the training being similar to that in one of the classic South Park episodes when the boys learn that cat urine can make them wicked high by restraining a cat and making it watch another video of aggressive cats: an activity known as “cheesing.”

Here is a snapshot of the data. Looks beautiful, doesn’t it. The main finding was that there was a temporal relationship between transitions into NREM sleep and the evoking of the somatasensory cortex. These experiments were also investigated in the slice and was one of the first instances of documenting sleep in the dish.

LFP recordings of sleep and wake

 

In conclusion, I was pleased to see that with all the technology that we have available today in basic biomedical research, researches still see value in historical model organisms and approaches. Both are equally as valuable for uncovering mechanism as any new technology.

Chauvette, S., Seigneur, J., & Timofeev, I. (2012). Sleep Oscillations in the Thalamocortical System Induce Long-Term Neuronal Plasticity Neuron, 75 (6), 1105-1113 DOI: 10.1016/j.neuron.2012.08.034