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hippocampus
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Effects of psychedelics on neurogenesis and broader neuroplasticity link.springer.com Dec 19, 2024 14 facts
measurementOral ingestion of ayahuasca at concentrations of 250, 500, and 800 mg/kg in adult rats elevated GABA and 5-HT levels in the hippocampus and reduced glycine and GABA levels in the amygdala in a dose-dependent manner, 40 minutes post-ingestion, according to Castro-Neto et al. (2013).
claimPetermann et al. (2021) demonstrated that the effects of the SSRI citalopram on BDNF protein concentrations in the hippocampus are largely separable from its effects on neurogenesis in the dentate gyrus.
referenceAyahuasca ingestion causes changes in aminoacidergic and monoaminergic neurotransmission in the hippocampus and amygdala of rats, according to a 2013 study by de Castro-Neto et al. published in the World Journal of Biological Chemistry.
claimIn rodents, adult neurogenesis is restricted to the olfactory bulb, driven by neural stem cells in the subventricular zone, and the dentate gyrus sub-region of the hippocampus, driven by radial glial-like cells.
claimLeishman et al. (2018) found that a single 3 mg/kg THC injection administered to female rats at ages P35, P60, and P90 resulted in reduced endocannabinoid levels across the brain, with the most significant impact observed in the adult hippocampus.
referenceM. Petermann et al. found that alterations in BDNF protein concentrations in the hippocampus do not explain the pro-neurogenic effect of Citalopram on adult neurogenesis, as published in Pharmacopsychiatry in 2021.
measurementOnly the highest dose of 800 mg/kg of ayahuasca reproduced the effect of increased monoamine levels in the hippocampus of adult rats, according to Castro-Neto et al. (2013).
measurementLiu and colleagues found that 20 mg/kg of harmine increased BDNF levels in the hippocampus and prefrontal cortex, as well as glutamate transporter 1 (GLT-1) expression levels in mice.
claimZuo and colleagues observed that administering 30 mg/kg/day of ketamine to male rats between postnatal days 35–42 resulted in a reduction of synapsin expression in the hippocampus.
claimChronic THC exposure during adolescence reduces BDNF levels via the CREB pathway in the hippocampus and prefrontal cortex of male rats, while paradoxically increasing BDNF in the nucleus accumbens of female rats.
claimCannabis users exhibit diminished gray matter in the hippocampus, though cannabidiol may have protective effects against this reduction.
accountWankhar et al. (2020) demonstrated that 1-Methylpsilocin treatment alleviated behavioral signs of anxiety and anhedonic phenotype by the seventh day post-CUS, rescued subjects from CUS-induced mitochondrial damage, balanced 5-HT/5-HT2CR levels in the PFC and hippocampus, and mitigated hippocampal cell morphological abnormalities and elevated corticosterone levels.
claimThompson et al. (2012) found that maternal ingestion of MDMA during the E14-E20 embryonic window increased fiber density in the prelimbic cortex and the CA1 region of the hippocampus in offspring.
claimHarmala alkaloids increase levels of brain-derived neurotrophic factor (BDNF) and promote the survival of newborn neurons in the hippocampus.
Self-awareness, self-regulation, and self-transcendence (S-ART) frontiersin.org 12 facts
claimIncreased gray matter concentration in the right hippocampus has been attributed to training in arousal regulation, which suggests a mechanism for regulating the self toward more adaptive trajectories of self-experience.
referenceLuders, E., Toga, A. W., Lepore, N., and Gaser, C. (2009) published 'The underlying anatomical correlates of long-term meditation: larger hippocampal and frontal volumes of gray matter' in Neuroimage, volume 45, pages 672–678, asserting that long-term meditation is associated with larger hippocampal and frontal gray matter volumes.
referenceIn both rodents and humans, the brain areas involved in conditioning and extinguishing fear include the hippocampus, amygdala, rhinal cortices, and the ventromedial prefrontal cortex (VMPFC).
referenceBrain areas critical for their interactions with the prefrontal cortex (PFC) in emotion regulation include the amygdala, hippocampus, striatum (including the nucleus accumbens), thalamus, and insula.
measurementAdept practitioners of Zen meditation show reduced activity in executive, evaluative, and emotion-related brain areas (prefrontal cortex, amygdala, hippocampus) during acute pain compared to control subjects, according to Grant et al. (2010b).
referenceThe retrosplenial cortex (RSP) and medial parietal cortex (MPC) facilitate the construction of identity in time and space through moment-to-moment episodic memory formation, supported by dense reciprocal projections with the anterior thalamus and hippocampus.
claimThe autobiographical self, defined as a set of memories comprising an individual's unique past, current state, and expected future, accumulates through interactions between the posterior medial cortex (PMC) and subcortical limbic structures such as the hippocampus and amygdala.
claimMultiple Mindfulness-Based Intervention (MBI) studies, including research by Lazar et al. (2005), Pagnoni and Cekic (2007), Holzel et al. (2008, 2010, 2011b), Luders et al. (2009), Vestergaard-Poulsen et al. (2009), and Grant et al. (2010a), have found increases in gray matter (GM) volume and density in the hippocampus and posterior cingulate cortex (PCC) compared to non-meditating controls using voxel-based morphometry (VBM).
referenceMilad et al. (2007) demonstrated that the recall of fear extinction in humans activates the ventromedial prefrontal cortex and the hippocampus in concert.
referencePeters et al. (2009) demonstrated that associations evoked during memory encoding recruit the context-network in the hippocampus.
referenceCortical thickness of the ventromedial prefrontal cortex (VMPFC) positively correlates with extinction recall, and functional connectivity between the VMPFC and the hippocampus is related to learned safety, as reported by Milad et al. (2007).
claimMeditators exhibit greater gray matter (GM) concentration in the hippocampus compared to non-meditators, which suggests enhanced circuitry for extinction learning and retention, according to studies by Holzel et al. (2008) and Luders et al. (2009).
The Mechanisms of Psychedelic Visionary Experiences - Frontiers frontiersin.org Sep 27, 2017 4 facts
referenceThe ventral anterior cingulate cortex (ACC) has strong connections to limbic structures (amygdala, hippocampus), cortical areas mediating limbic structures (orbitofrontal cortex and anterior insula), the periaqueductal gray, the nucleus accumbens, and the hypothalamus, giving it a central role in assessing and mediating emotionally salient stimuli, as stated by Washington and VanMeter (2015).
claimEgoless experiences, measured as 'oceanic boundlessness,' are associated with alterations in the frontolimbic-parieto-striatal network and are positively correlated with cerebral glucose metabolism in Default Mode Network regions (anterior cingulate cortex, hippocampus, inferior parietal cortex) and prefrontal cortex areas (frontomedial superior, frontolateral, and left inferolateral).
referenceThe Default Mode Network primarily involves connections among the thalamus, posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC), and areas of the limbic system (parahippocampal cortex and the hippocampus) that function as a network for information routing and integration, as described by Buckner et al. (2008).
claimThe hippocampus is the focal point of mechanisms that reduce inhibitory serotonin regulation of temporal lobe limbic function, which results in a reduction of the gating of emotional responses and an enhancement of activity in the dopaminergic circuitry.
The function(s) of consciousness: an evolutionary perspective frontiersin.org Nov 25, 2024 3 facts
claimThe hypothesis that conscious sensations of affect act directly on the hippocampus is problematic because it would imply the hippocampus is a central hub for all conscious signals, which contradicts findings from lesion studies by Squire (2004) and Squire and Wixted (2011).
claimHabitat navigation is linked to olfactory centers through connections to the hippocampus, memory, and the amygdala via the orbitofrontal complex, as noted by Jacobs (2012).
procedureThe MDIS model describes a process for modulating behavior based on odor: (1) an animal encounters an odor associated with fear based on memory, (2) the feeling of fear co-occurs with a specific location coded by hippocampal place cells, and (3) a link forms between the hippocampus and the center responsible for the sensation, causing the sensation to be evoked upon future arrival at that location.
Ancient Roots of Today's Emerging Renaissance in ... link.springer.com 1 fact
claimClassic psychedelics initiate a cascade of altered neural connectivity and blood-flow across brain regions including the default-mode network (medial prefrontal cortex, posterior cingulate cortex, inferior parietal lobule, lateral temporal cortex, hippocampus, and precuneus), the amygdala, the thalamus, and the claustrum.
Global workspace theory: consciousness as brain wide information ... selfawarepatterns.com Dec 29, 2019 1 fact
claimBoth Bernard Baars and Stanislas Dehaene agree that subcortical regions generally cannot contribute directly to the global workspace, though Bernard Baars considers the hippocampus a possible exception.
GWT: A Leading Consciousness Theory Depends on Information ... mindmatters.ai Oct 15, 2021 1 fact
referenceMorten L. Kringelbach and Gustavo Deco identify the global workspace as a core subset of brain regions including the precuneus, the posterior and isthmus cingulate, nucleus accumbens, putamen, hippocampus, and amygdala.
A Survey of Incorporating Psychological Theories in LLMs - arXiv arxiv.org 1 fact
claimHippocampal indexing theory, as proposed by Teyler & DiScenna (1986), views the hippocampus as a pointer to neocortical memory and is used to enhance retrieval-augmented generation (Gutierrez et al., 2024) and counterfactual reasoning (Miao et al., 2024a) in LLMs.
Neuroimaging in psychedelic drug development: past, present, and ... nature.com Sep 27, 2023 1 fact
claimPatients with treatment-resistant depression treated with psilocybin showed differences in the functional connectivity of the medial pre-frontal cortex and hippocampus.