The Science of Sleep: Localized Brain Control and the TRN Pathway

News Brief by Kanika Kamal

      Neuroscientists in MIT may have just discovered a breakthrough pathway that will revolutionize modern sleep medicine and anesthesia. Previously, it was thought that when one sleeps, the entire brain falls asleep in an “everything off” state. However, this is not the case. Instead, only small regions of the brain “fall asleep,” while the rest remain alert. MIT scientists figured out that this was a result of a pathway that originates in the Thalamic Reticular Nucleus (TRN). The TRN send signals to the thalamus and the cortex, thus stimulating release of the neurotransmitter GABA, which calms nervous activity in specific brain regions. Small, oscillating brain waves can be observed in these localized areas, representing decreased arousal of the brain regions, a.k.a sleep. The TRN pathway could also be linked to the sensation of “zoning out,” a phenomenon every college student has experienced at least once, when sleep deprived. When one “zones out,” the TRN activates the circuit to decrease arousal in some parts of the brain, making you feel sluggish. With this newfound information of the brain’s ability to “locally control” arousal and drowsiness, there are many implications for developing more naturally effective anesthetic and sleep-inducing drugs. As TRN releases GABA, a common anesthetic drug target, a new door has been opened that could greatly affect modern-day sleep science and medicine for the best.

Massachusetts Institute of Technology. (2015, October 13). How the brain controls sleep: Brain structure generates pockets of sleep within the brain.ScienceDaily. Retrieved October 19, 2015 from