Where the lock lives
A glass brain
▶ Play this chapter The script
Every line as it is spoken in the film, in order.
Now pull back. Your brain is packed with these locks. The brighter the glow, the more there are.
They're densest in the deep structures that start and stop your movements. In the cerebellum, which keeps your timing. In the hippocampus, where today becomes memory. And in the bulb that reads smells. Hold on to that one.
But in the brainstem, the part that keeps you breathing without you ever thinking about it, there are very few. An opioid overdose kills by shutting breathing down, because opioid locks sit right in those breathing centers. The scientists who mapped these locks in 1990 pointed out what that means. It may be why even huge doses of cannabis are not lethal.
Now let's zoom into one connection, and see what your keys are actually for.
Sources
Every claim in this chapter with its grade: E established · M emerging (one or two studies, or animals only) · F framework.
- EHerkenham M et al. Cannabinoid receptor localization in brain. PNAS 1990;87:1932–6. link
- EHerkenham M et al. Characterization and localization of cannabinoid receptors in rat brain. J Neurosci 1991;11:563–83. link
- EGlass M, Dragunow M, Faull RLM. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience 1997;77:299–318. link
- EPattinson KTS. Opioids and the control of respiration. Br J Anaesth 2008;100:747–58. (respiratory depression is what limits opioids, and what kills in an overdose) link
- EMontandon G et al. PreBötzinger complex neurokinin-1 receptor-expressing neurons mediate opioid-induced respiratory depression. J Neurosci 2011;31:1292–301. (rats: opioids at this brainstem breathing center cause respiratory depression or fatal apnea) link
- EFonov V et al. Unbiased average age-appropriate atlases for pediatric studies. NeuroImage 2011;54:313–27 (MNI ICBM152 2009 templates). Brain surface derived from the symmetric 2009a template; deep structures drawn at standard coordinates, illustrative. link