Default Mode Network (DMN) and afterglow - what happens in the brain after the experience
Resting state network — what it is, what research says, and the legal status in Poland. u Bucha.
When you sit idle and let your thoughts wander, your brain is not resting. It is actively working in a network called the DMN - default mode network, the resting state network. Imaging studies show that this network is overactive in individuals with depression and PTSD, creating a loop of rumination that is hard to escape. Psychedelics break this loop - and this explains the mechanism of afterglow: a several-week window of mood improvement and brain plasticity following a psychedelic experience. This article explains what DMN is, how afterglow works, and what science says about the neurobiological underpinnings of these phenomena.
KEY INFORMATION
• Psilocybin reduces DMN activity by 10-20% and disrupts the coherence of this network - which correlates with the intensity of subjective effects (Carhart-Harris et al., PNAS, 2012).
• Afterglow is a biologically documented state of increased synaptic plasticity and reduced DMN activity lasting up to 4 weeks after a session.
• The neuroplasticity window after psychedelics is a critical moment for integration - psychotherapy and physical activity during this time can enhance long-lasting effects.
• This article is purely educational - it discusses scientific research and does not encourage the use of controlled substances.
What is the default mode network (DMN)?
The DMN is a vast network of brain areas active during rest, daydreaming, and self-reflection. Pioneering work by Buckner et al. (Buckner et al., Nature Reviews Neuroscience, 2008) showed that the DMN includes the medial prefrontal cortex, posterior cingulate cortex (PCC), precuneus, and inferior parietal lobule. These areas form a coherent functional network that is deactivated during tasks requiring focused attention on the external world.
This network plays a central role in constructing a narrative about oneself - recalling the past, planning for the future, and evaluating one's actions. These are important cognitive functions. The problem arises when the DMN becomes overactive and begins to dominate other networks, leading to rumination: recurring, negative thoughts about oneself and the future. fMRI studies have shown that DMN overactivity is characteristic of both depression (Sheline et al., PNAS, 2009) and PTSD (Lanius et al., Neuropsychopharmacology, 2010).
Importantly, the DMN and the executive network (CEN, central executive network) act antagonistically. When one is active, the other is quiet. In healthy individuals, this exchange occurs smoothly; in individuals with depression, the CEN is weakened, and the DMN shows 'creeping' activity even during tasks.
How do psychedelics turn off the DMN?
Psilocybin, LSD, and DMT primarily act through agonism of 5-HT2A receptors, which are densely distributed in DMN nodes - especially in the medial prefrontal cortex and posterior cingulate gyrus. A key study by Carhart-Harris et al. published in PNAS showed that psilocybin significantly reduced blood flow (measured by ASL-fMRI) in DMN nodes, and the degree of this reduction correlated with the intensity of ego dissolution - the experience of dissolving the sense of separate self (Carhart-Harris et al., PNAS, 2012).
Subsequent studies by Petit et al. (NeuroImage, 2020) confirmed that psilocybin not only suppresses the activity of individual DMN nodes but radically increases functional connectivity between networks that normally do not communicate with each other. This phenomenon has been termed 'brain entropy' - a state of increased flexibility and chaotic neural activity, which is the opposite of the rigid, habitual patterns characteristic of depression.
We noted in the literature review that the degree of DMN reduction during a psychedelic session is a relatively weak predictor of long-term clinical improvement - the effect of 'disconnection' of specific ruminative narrative loops may be more important than the total suppression of the network. This suggests that the psychological context and readiness to change the narrative about oneself may enhance the therapeutic effect of disrupting the DMN.
What is afterglow and how long does it last?
Afterglow is a psychobiological state described by participants in clinical studies as a feeling of lightness, openness, warmth, and clarity of thought lasting from a few days to several weeks after a psychedelic experience. It is not a residual effect of the substance - psilocybin is eliminated from the body within 24 hours. Afterglow reflects lasting neurobiological changes occurring after the session.
A study by Davis et al. conducted on 24 individuals with major depression showed that mood improvement measured by the DASS and QIDS questionnaires persisted in most participants for at least 4 weeks after psilocybin administration (Davis et al., Scientific Reports, 2021). Similar results were noted by Carhart-Harris et al. in a study from Imperial College - 67% of patients maintained remission for at least 4 weeks after a session with psilocybin.
The biological mechanisms of afterglow involve several processes. First, elevated levels of BDNF (brain-derived neurotrophic factor) persist for days after exposure to psychedelics, confirmed in preclinical studies (Ly et al., Cell Reports, 2018). BDNF is a key factor in neuron growth and the formation of new synaptic connections. Secondly, the sustained reduction in DMN activity observed in fMRI studies conducted 24 hours after the session - significantly lower than baseline values.
What is the neuroplasticity window and why is it important?
The neuroplasticity window is a biologically justified period of increased susceptibility of the brain to reconfigure neural connections, which opens after a psychedelic experience. Studies by Castrén and Bharde on animal models have shown that psychedelics trigger a kind of 'critical period' of neuroplasticity - similar to that which allows for intense language and visual perception learning in children (Castrén and Bharde, Cell Reports Medicine, 2023). The estimated duration of intense plasticity is 7-21 days.
Why does this have therapeutic significance? Because psychotherapy and new experiences acquired during this window are potentially 'inscribed' deeper into neuronal structures than in a state of normal plasticity. The MAPS Protocol - the standard protocol used in MDMA-assisted PTSD therapy studies - provides for at least two integration sessions within the first two weeks after each session with the substance for this reason (MAPS, 2021).
Citation capsule - afterglow and neuroplasticity: Studies on animal models have shown that psilocybin and other psychedelics activate a 'critical period' of neuroplasticity, during which the brain is exceptionally susceptible to reconfiguring synaptic connections (Castrén and Bharde, Cell Reports Medicine, 2023). This effect lasts 7-21 days and explains why therapeutic integration immediately after the session is considered an essential element of therapeutic protocols.
Table: DMN, afterglow, and neurobiological mechanisms
The following summary organizes the stages of psychedelic action on the brain - from the acute effect, through afterglow, to stabilization.
| Phase | Time | Mechanism | Therapeutic implication |
|---|---|---|---|
| Acute | 4-8 h | DMN suppression, brain entropy, 5-HT2A agonism | Breaking rumination loops; 'softening' rigid beliefs |
| Early afterglow | 1-7 dni | Elevated BDNF, reduced DMN activity at rest | Integrative psychotherapy, working with new thinking patterns |
| Plasticity window | 7-21 dni | Enhanced synaptogenesis, 'critical period' of neuroplasticity | Building new habits; physical exercise as a BDNF booster |
| Stabilization | 3-12 tygodni | Consolidation of new connections, DMN returning to new baseline levels | Follow-up sessions; assessment of clinical effects |
How does neuroplasticity after psychedelics relate to BDNF?
BDNF - brain-derived neurotrophic factor - is a protein that acts as 'fertilizer' for neurons. It supports the survival of nerve cells, the formation of new synaptic connections, and learning processes. Low levels of BDNF are associated with depression and anxiety disorders; SSRI antidepressants raise BDNF, but the effect only manifests after several weeks of use.
Psychedelics act faster. Studies by Ly et al. on neuronal cultures have shown that psilocybin and DMT stimulate dendritic growth and synaptogenesis within 24 hours - the effect was comparable to ketamine, which acts as a 'fast antidepressant' (Ly et al., Cell Reports, 2018). Importantly, this effect was observed at concentrations insufficient to induce full psychoactive effects, suggesting that neuroplasticity is a distinct mechanism from the hallucinogenic action.
We noted in the analyses of clinical literature that participants' reports of afterglow often describe it as 'clarity' and 'calm' - not euphoria. This distinguishes it from the effects of psychostimulant drugs and suggests that the mechanism is more of a 'reset' of the rumination loop than a stimulation of the reward system.
What do studies say about the durability of DMN effects after psilocybin?
One of the most important long-term studies was conducted at Johns Hopkins University. Griffiths et al. (Psychopharmacology, 2016) demonstrated that improvements in mood and self-rated well-being were maintained in 80% of participants 12 months after sessions with psilocybin - with 67% rating this experience as one of the five most significant in their lives (Griffiths et al., Psychopharmacology, 2016). The study did not include DMN measurement in fMRI, but the results correlate with the hypothesis of a lasting change in the baseline activity level of this network.
Direct evidence from neuroimaging came from the study by Smigielski et al. (NeuroImage, 2019): they measured the coherence of brain networks before and 7 days after a session with psilocybin. The results indicated a sustained reduction in internal coherence of the DMN after 7 days, which correlated with a lasting change in self-perception (Smigielski et al., NeuroImage, 2019). This is one of the few direct pieces of evidence - aside from behavioral analysis and self-reports - on the biological basis of afterglow.
Frequently Asked Questions
What is the default mode network (DMN)?
DMN (default mode network) is a network of brain areas active during rest and daydreaming - it includes the medial prefrontal cortex, posterior cingulate gyrus, and parietal lobe. It is responsible for rumination, self-narrative, and retrospective thinking. Overactivity of the DMN is linked to depression and PTSD (Buckner et al., Nature Reviews Neuroscience, 2008).
How do psychedelics affect the DMN?
Psychedelics (psilocybin, LSD, DMT) strongly suppress DMN activity and disrupt its internal coherence. A study by Carhart-Harris et al. (PNAS, 2012) showed that psilocybin reduces blood flow in DMN nodes by 10-20%, which correlates with the intensity of subjective effects. This effect underlies the feeling neuroplasticity induced by psychoplastogens.
What is afterglow after psychedelics?
Afterglow is a period of improved mood, openness, and clarity of thought lasting from a few days to a few weeks after a psychedelic experience. Biologically, it is associated with elevated levels of BDNF and increased synaptic plasticity. The study by Davis et al. (Scientific Reports, 2021) confirmed an improvement in well-being lasting up to 4 weeks after a session with psilocybin.
How long does the neuroplasticity window last after psychedelics?
It is estimated that the window of enhanced plasticity lasts from 2 to 4 weeks after a psychedelic experience. Studies on animal models (Castrén and Bharde, Cell Reports Medicine, 2023) indicates that the critical period for reforming synaptic connections lasts most intensely for the first 7-14 days after the session.
How to best utilize the afterglow window?
Researchers recommend: psychotherapy and integration within 1-2 weeks after the session, regular physical activity supporting BDNF, meditation enhancing rumination reduction, avoiding alcohol and excessive stress. The MAPS program includes at least two integration sessions immediately after each administration of the substance (MAPS, 2021).
Does the afterglow look the same after every psychedelic?
No. Psilocybin, LSD, and MDMA have different pharmacological profiles and induce somewhat different afterglow patterns. MDMA, primarily acting serotoninergically, can lead to a "secondary crash" a few days after the session related to transient serotonin depletion - unlike classic serotoninergic psychedelics. However, long-term mood improvement is documented for all these substances in therapeutic protocols.
This article is for informational and educational purposes and does not replace consultation with a doctor. If you are pregnant, breastfeeding, taking medications, or have chronic conditions, consult the use of supplements or herbs with a specialist.
Author: Michał Waluk · Published: 2026-05-04 · Updated: 2026-05-04
