📝 SummarXiv

Abstract

My findings show, for the first time, what causes loss of awareness, anesthesia, memory replay, opioids induced respiratory depression (OIRD), and slow wave sleep. Opiates are fast pain relievers and anesthetics that can cause respiratory arrest. I found how mu-opioids and other medial habenula activators slowdown respiration during SWS and anesthesia. Using DTI method I observed that human hippocampus is connected to MHb via posterior septum, while amygdala via anteromedial BNST. MHb projected to pineal gland and contralateral MHb (Vadovi\v{c}ov\'a, 2014). MHb has dense mu-opioids receptors (Gardon and Faget, 2014) and strong projections to IPN. Herkenham (1981) found increased glucose intake during anesthesia in MHb and IPN. The IPN projects to serotonergic MRN/DRN, and pain/interoception/arousal linked PAG. The question is: What is the MHb-IPN circuit doing? This extended circuit model explains role of the dentate gyrus >posterior septum >MHb >IPN >MRN >hippocampus + BF + claustrum >cortical slow-wave activity (SWA) in memory replay, loss of awareness, anesthesia and SWS. It proposes new neural mechanisms for anesthetic ketamine, nitrous oxide, and phencyclidine effects: activation of the IPN >MRN >claustrum >cortical SWA circuit by the 5-HT2a receptors in the IPN and claustrum. This brain model shows why are ketamine and psychedelics anxiolytic and antidepressant. How they by activating the 5-HT2a receptors in vACC/infralimbic cortex increase safety, well-being signal, socializing, and cognitive flexibility, and attenuate fear, worries, anger, impulsivity, self-defence and wanting. This model suggests that mu-opioids, acetylcholine, nicotine, cannabinoids, adenosine, GLP-1RA, neuropeptide Y, and substance P activate the MHb-IPN-MRN circuit which promotes rest, recovery, repair, serotonin-BDNF-proteins production-spines/synapses growth-anti-inflammatory state.