The (Endo)-cannabinoid system and psycho-biological homeostasis
Both delta 9-THC and cannabidiol may be capable of reducing the neurotoxicity that is mediated in the rat brain by the NMDA-, AMPA-, and kainate receptors. Cannabinoids function as potent antioxidants in cultured neurons" R Lorenz - Neuro Endocrinol Lett, 2002 -" "Cannabinoids function as neuromodulators and enhance GABA transmission in the GPe , possibly by reducing GABA reuptake , although the exact mechanism remains unclear" C Zadikoff, PM Wadia, J Miyasaki, R Chen, AE Lang… - Basal Ganglia, 2011 - Elsevier A last example is that cannabinoids function as anxiolytics under certain conditions and doses, a main therapeutic indication of GABA A positive allosteric modulators JA Lile, TH Kelly, LR Hays - Drug and alcohol dependence, 2014 - europepmc.org Dopamine and endogenous cannabinoids function as neurotrans- mitters as well as neuromodulators in the brain, in which they often have opposing effects on nerve function S Fan, S Yazulla - Visual neuroscience, 2005 - Cambridge Univ Press Some studies describing the effects of cannabinoids on the system... now endocannanbinoids https://arxiv.org/abs/cond-mat/0208590 Dreams, endocannabinoids and itinerant dynamics in neural networks: re elaborating Crick-Mitchison unlearning hypothesis Dreams, endocannabinoids and itinerant dynamics in neural networks: re elaborating Crick-Mitchison unlearning hypothesis [cond-mat/0208590] Dreams, endocannabinoids and itinerant dynamics in neural networks: re elaborating Crick-Mitchison unlearning hypothesis In this work we reevaluate and elaborate Crick-Mitchison's proposal that REM-sleep corresponds to a self-organized process for unlearning attractors in neural networks. This reformulation is made at the face of recent findings concerning the intense activation of the amygdalar complex during REM-sleep, the role of endocannabinoids in synaptic weakening and neural network models with itinerant associative dynamics. We distinguish between a neurological REM-sleep function and a related evolutionary/behavioral dreaming function. At the neurological level, we propose that REM-sleep regulates excessive plasticity and weakens over stable brain activation patterns, specially in the amygdala, hippocampus and motor systems. At the behavioral level, we propose that dream narrative evolved as exploratory behavior made in a virtual environment promoting "emotional (un)learning", that is, habituation of emotional responses, anxiety and fear. We make several experimental predictions at variance with those of Memory Consolidation Hipothesis. We also predict that the "replay" of cells ensembles is done at an increasing faster pace along REM-sleep.