Frontiers in Neuroscience
January 1, 2013
547 citations
Meditation practice appears to improve attentional functions by enhancing how attentional resources are allocated during early processing phases, which then improves subsequent cognitive processing. This review presents a theoretical framework emphasizing attentional control mechanisms as central to developing mindfulness skills. It discusses the phenomenological experience during meditation, the attentional functions involved, and the brain networks supporting them. Neural changes from pure mindfulness practice may serve as a reference for future research. The review also considers possible links between improved attentional control and emotion regulation skills, with implications for refining mindfulness-based interventions for conditions like eating disorders and ADHD.
Frontiers in Neuroscience
March 26, 2018
Darrin J. Lee, Edwin Kulubya, Philippe R. Goldin et al.
256 citations
Different forms of meditation—focused attention, open-monitoring, transcendental, and loving-kindness—produce distinct patterns of brainwave activity. Meditators show greater overall oscillatory activity than meditation-naïve adults, with larger changes as training increases. Focused attention and open-monitoring both increase anterior theta activity, but only focused attention affects posterior theta. Alpha power rises in posterior regions during both practices; in anterior regions, focused attention bilaterally increases alpha, while open-monitoring decreases left-sided alpha. Gamma activity is similar in frontal areas across practices but varies in parietal and occipital regions. These distinct neural signatures may help explain the cognitive and therapeutic benefits of each practice and guide neuromodulation targets.
Frontiers in Neuroscience
January 1, 2010
201 citations
The 5-HT(2A) subtype of serotonin receptor is strongly expressed in the cerebral cortex and is linked to mental disorders and the effects of hallucinogens. Using genetically modified mice, three main neuronal populations expressing the Htr2a gene were identified: layer V pyramidal cells in the anterior cortex, GABAergic interneurons in middle layers, and non-pyramidal cells in the subplate/Layer VIb. 5-HT(2A) receptors are concentrated in a diffuse band over layer Va, with a strong anteroposterior gradient matching the pyramidal cell distribution. Most middle-layer GABAergic interneurons are parvalbumin-expressing fast-spiking cells that are depolarized and excited by serotonin, likely via 5-HT(2A) receptors.
Frontiers in Neuroscience
January 1, 2013
197 citations
During an fMRI task where people rated images of artworks, regions of the medial prefrontal cortex that are part of the default mode network (DMN) were more active on the highest-rated trials. This is notable because the DMN was originally characterized as more active during rest than during externally focused tasks. Although the task had no explicit self-referential aspect, observers were told that their individual tastes mattered and were asked how much each artwork moved them. The artworks were little-known and varied widely in style, leading to high individual variability in ratings, so neural responses reflected aesthetic experience rather than features of particular artworks.
Frontiers in Neuroscience
April 19, 2016
Cristina Miliano, Giovanni Serpelloni, Claudia Rimondo et al.
195 citations
New psychoactive substances (NPS) are a diverse and rapidly expanding group of molecules sold as substitutes for controlled drugs, often consumed with other substances or alcohol, and linked to rising overdose deaths and emergency admissions. Their chemical classes include phenethylamines, piperazines, cathinones, tryptamines, and synthetic cannabinoids, with the latter accounting for 50% of newly identified NPS. Many NPS show addictive properties. This review examines the rewarding and addictive effects of cannabimimetics (JWH, HU, CP series) and amphetamine-like stimulants, including recent lab data showing that JWH-018, a potent CB1/CB2 agonist, increases dopamine signaling in the nucleus accumbens shell, contributing to dependence associated with 'Spice' use.
Frontiers in Neuroscience
August 6, 2018
174 citations
This report reviews historical research on the endogenous hallucinogen N,N-dimethyltryptamine (DMT), covering its biosynthesis and metabolism in the brain and peripheral tissues, detection methods in body fluids and brain, new sites of action, and possible physiological and therapeutic roles. It also addresses evidence for DMT as a putative neurotransmitter. The authors propose future directions: brain mapping of DMT biosynthesis enzymes, further studies of its presence and role in the pineal gland, reconsideration of binding site data, and new administration and imaging studies. They emphasize the need to distinguish the natural role of an endogenous hallucinogen from effects of peripheral administration.
Frontiers in Neuroscience
August 22, 2014
Mark P. Mattson
167 citations
The human brain's superior pattern processing (SPP) is the fundamental basis for unique features such as intelligence, language, imagination, invention, and belief in imaginary entities like ghosts and gods. SPP involves the electrochemical, neuronal network-based encoding, integration, and transfer of perceived or mentally-fabricated patterns. During evolution, pattern processing became more sophisticated with expansion of the cerebral cortex, especially the prefrontal cortex and image-processing regions. Patterns are reinforced by emotional experiences, indoctrination, and psychedelic drugs. Impaired SPP is fundamental to cognitive and psychiatric disorders. Understanding SPP mechanisms may enable interventions that reduce irrational decisions and destructive behaviors.
Frontiers in Neuroscience
October 31, 2019
Andrea Nani, Jordi Manuello, Lorenzo Mancuso et al.
117 citations
Consciousness and attention, though often conflated, should be regarded as separate brain processes with overlapping but distinct neural activity. Phenomenal consciousness likely arises from synchronized networks in temporo-parietal-occipital areas, while attention, supported by fronto-parietal networks, later provides focal awareness of specific features. Advances in functional neuroimaging have improved understanding, but conceptual difficulties still hamper research and theory. A coherent model of the neural correlates of these functions requires careful interpretation of empirical findings.
Frontiers in Neuroscience
January 22, 2018
Camila Sanz, Federico Zamberlán, Earth Erowid et al.
112 citations
Subjective reports of experiences under hallucinogens like LSD are semantically most similar to reports of high-lucidity dreams, while Datura (a deliriant) resembles low-lucidity dreams. Sedatives, stimulants, antipsychotics, and antidepressants rank lowest in similarity to dream reports. Frequent words across both dreams and hallucinogen experiences include perception-related terms ("see," "visual," "color"), emotion ("fear"), setting ("inside," "outside"), and family members ("mom," "dad"). The analysis confirms that hallucinogens produce experiences with the highest semantic similarity to dreams among all psychoactive substances.
Frontiers in Neuroscience
October 10, 2019
109 citations
A 15-minute brief mindfulness meditation (BMM) called JW2016, based on Buddhist breath meditation and scientific reports, was tested against an emotional regulation education (ERE) control in 42 healthy adults aged 18–25 over 7 consecutive days. After the intervention, the BMM group showed significant decreases in emotional intensity toward both positive and negative stimuli, faster emotional memory response times, and reduced attention bias toward negative stimuli, while the ERE group showed negative effects on mood. The BMM method may improve emotion processing without adverse mood effects, offering a convenient, safe option for those with limited time or money.
Frontiers in Neuroscience
September 28, 2017
Michael Winkelman
105 citations
Psychedelics produce profound cognitive, emotional, and social effects that have historically inspired cultures and religions. They objectively and reliably induce classic mystical experiences, raising questions about the neuropharmacological mechanisms behind these effects. Hallucinatory experiences can also arise from non-drug mechanisms such as meditation, hypnosis, and epilepsy, suggesting a common underlying model. Disruption of normal prefrontal cortex and default mode network function appears central, releasing lower brain discharges that stimulate visual information processing and innate cognitive operators. Converging evidence points to the mirror neuron system as a source of these visionary experiences.
Frontiers in Neuroscience
February 26, 2020
Monika Kacela, Piotr Adamowicz, Jolanta B. Zawilska
79 citations
NBOMe compounds, a new class of psychedelic drugs derived from the 2C family, are ultrapotent and highly selective agonists of serotonin 5-HT2A and 5-HT2C receptors, with over 1000-fold selectivity for 5-HT2A compared to 5-HT1A. Sold in various forms and administered via multiple routes, they have caused numerous clinical intoxications and fatalities since the early 2010s. Adverse effects include hallucinations, agitation, seizures, and sympathomimetic signs like mydriasis and tachycardia. This survey reviews their pharmacology, use patterns, metabolism, and analytical detection methods.
Frontiers in Neuroscience
September 10, 2021
Divya Choudhury, Anita E. Autry, K. Tolias et al.
75 citations
Ketamine, a drug used as an anesthetic since the 1970s, has recently gained attention for its rapid antidepressant effects. In preclinical studies, it shows both neurotoxic and neuroprotective properties depending on context. At anesthetic doses during neurodevelopmental windows, it contributes to inflammation, autophagy, apoptosis, and increased reactive oxygen species. At subanesthetic doses, it activates neurotrophic signaling cascades with neuroprotective actions that are not always dependent on its primary receptor. This review summarizes the complex intracellular signaling pathways modulated by ketamine and contrasts its protective and harmful features.
Frontiers in Neuroscience
September 20, 2021
Lauren Lepow, Hirofumi Morishita, Rachel Yehuda
70 citations
A framework is proposed for investigating how psychedelic-assisted psychotherapy (PAP) produces neurobiological changes that underlie recovery from illnesses like PTSD. The authors suggest that psychedelics may remove brakes on adult neuroplasticity, inducing a state similar to developmental critical periods (CPs) when the brain is exquisitely sensitive to environmental input. They highlight ocular dominance plasticity in the visual system as a model for characterizing CPs in limbic systems relevant to psychiatry. This CP framework may help integrate neuroscientific inquiry with the influence of the environment both in development and in PAP, moving beyond traditional focus on pharmacologic properties alone.
Frontiers in Neuroscience
February 4, 2020
Claire J. Foldi, Paul Liknaitzky, M.l. Williams et al.
52 citations
Anorexia nervosa has the highest mortality rate of any psychiatric disease, and current medications are largely ineffective partly because the neurobiological drivers are poorly understood. Recent research into psychedelic medicine suggests psilocybin may alleviate symptoms related to serotonin signaling and cognitive inflexibility. Clinical trials for treatment-resistant depression show promise but have methodological biases. The first clinical trial using psilocybin for anorexia nervosa began in 2019, highlighting the need to understand the neurobiological mechanisms. Animal models, such as the activity-based anorexia rodent model, allow detailed study of brain function and behavior without the confounds of expectancy and bias, and are argued to be crucial for informing which patient subpopulations may benefit most from psychedelic medicine.
Frontiers in Neuroscience
April 17, 2023
Marvin M. Urban, Moritz R. Stingl, Marcus W. Meinhardt
47 citations
Since the 1960s, psychedelics have shown potential for persistently treating substance use disorders, but the biological mechanisms behind their therapeutic effects remain unclear. Serotonergic hallucinogens are known to alter gene expression and neuroplasticity, especially in prefrontal brain regions, yet how these changes specifically counteract the neuronal circuit alterations that develop during addiction is largely unknown. This narrative mini-review synthesizes established addiction research with findings and theories on the neurobiological effects of psychedelics, providing an overview of potential mechanisms underlying treatment of substance use disorders with classical hallucinogens and identifying gaps in current understanding.
Frontiers in Neuroscience
January 24, 2020
Nirit Soffer‐dudek
45 citations
Lucid dreaming—being aware that one is dreaming while still asleep—offers a unique experimental window into consciousness that is distinct from both waking and non-lucid dreaming. The article argues that studying lucid dreaming can advance understanding of consciousness by allowing direct communication between dreamers and researchers. This approach enables real-time investigation of neural correlates of conscious states, self-awareness, and volition during sleep. The authors suggest that lucid dreaming research may bridge gaps between subjective experience and objective measurement, potentially informing theories of consciousness and clinical applications for nightmares and psychiatric disorders.
Frontiers in Neuroscience
August 11, 2021
Pieter J. Vis, Anneke E. Goudriaan, Bastiaan C. Ter Meulen et al.
40 citations
Hallucinogen-persisting perception disorder (HPPD) involves perceptual symptoms and flashbacks after psychedelic use, but its phenomenology is poorly understood. A systematic review of 66 case reports and series covering 97 people identified 64 unique symptoms. Of these, 76% were characteristic of Alice in Wonderland syndrome, over 50% were non-visual, and 38% were not clearly linked to prior intoxication, contrasting with DSM-5 criteria. Fewer than half of patients had a protracted course over a year, and a third achieved remission. Co-occurring depression with or without anxiety was associated with longer symptom persistence and more negative treatment outcomes. HPPD involves changes in the content of consciousness and an attentional shift from external to internal phenomena, rather than the altered states seen in acute intoxication. The authors recommend expanding diagnostic criteria.
Frontiers in Neuroscience
April 23, 2018
Jon G. Dean
39 citations
N,N-dimethyltryptamine (DMT) is a potent serotonergic psychedelic whose exogenous administration produces striking effects in humans. DMT and related compounds, along with the enzyme indolethylamine-N-methyltransferase (INMT) that synthesizes DMT from tryptamine, have been found in human and other mammalian tissues. Hypotheses for endogenous DMT's physiological role include immunomodulation and involvement in naturally occurring altered states of consciousness, but no clear relationship has been established from in vivo assays. The authors propose that genetic screening of single nucleotide polymorphisms (SNPs) in INMT, which may affect DMT synthesis and levels, could overcome limitations of bodily fluid assays and help clarify whether DMT has a physiological role.
Frontiers in Neuroscience
March 15, 2022
Maria Bălăeţ
28 citations
Psychedelic compounds show promise for treating depression, anxiety, addiction, and PTSD, with positive trial results. Beyond medical use, healthy individuals increasingly use psychedelics for spiritual enhancement, productivity, and recreation, and microdosing is rising. Knowledge of psychedelic effects, especially on cognition in naturalistic settings, remains limited. Existing studies have limitations: disparate paradigms, small sample sizes, insufficient breadth of testing on both unhealthy and healthy volunteers, and confinement to laboratory settings without assessing multiple dosages or time points. This review summarizes how psychedelics acutely affect memory, attention, reasoning, social cognition, and creativity, compares findings, and proposes solutions to current limitations.
Frontiers in Neuroscience
April 30, 2021
E. Carboni, A. Carta, Elena Carboni et al.
28 citations
Ketamine, originally an anesthetic, is being repurposed as a fast-acting antidepressant for treatment-resistant depression, sparking interest in its mechanism of action and potential to reveal the etiology of depression. This review covers its clinical use in depression and suicidal behavior, potential pediatric applications, mechanism of action, involvement of specific brain areas, interaction with the hypothalamic-pituitary-adrenal axis, effects on neuronal transmission in the bed nucleus of stria terminalis, gender-dependent effects, interaction with inflammatory processes, effects of single versus repeated administration, and adverse cognitive effects or abuse potential. It assesses whether ketamine's use can improve understanding of depression's etiopathology and whether its therapeutic effect constitutes an actual cure rather than symptom control.
Frontiers in Neuroscience
January 31, 2023
Daniel Perkins, Kimberley Day, Jerome Sarris et al.
27 citations
Ayahuasca, a psychoactive Amazonian brew containing DMT and harmala alkaloids, is increasingly used worldwide in traditional and neo-shamanic settings. A review of existing literature and original qualitative data from a large cross-sectional study of ayahuasca drinkers proposes a model of five key psychotherapeutic processes inherent to the experience: somatic effects, introspection and emotional processing, increased self-connection, increased spiritual connection, and gaining insights and new perspectives. These processes, facilitated by neurobiological effects, are argued to lead to beneficial mental health and wellbeing outcomes. The model highlights differences from other classic psychedelics and implications for therapeutic use.
Frontiers in Neuroscience
July 10, 2024
Siyi Zheng, Rong Ma, Yang Yang et al.
23 citations
Psilocybin, the psychoactive alkaloid in hallucinogenic mushrooms, may offer a novel treatment for Alzheimer's disease (AD). Its active metabolite, psilocin, modulates the 5-HT2A receptor, leading to heightened neural plasticity, reduced inflammation, and improvements in cognitive functions such as creativity, cognitive flexibility, and emotional facial recognition. Psilocybin also shows promise in alleviating anxiety and depression symptoms in AD patients. The review discusses strategies to mitigate hallucinogenic side effects and addresses ethical and legal considerations, proposing therapeutic potential for psilocybin in managing Alzheimer's disease.
Frontiers in Neuroscience
October 6, 2023
Tobias Buchborn, Hannes S. Kettner, Laura Kärtner et al.
21 citations
The ego is central to psychedelic research and therapy but remains poorly defined. This theoretical review examines the ego through a psychodynamic lens, focusing on ego boundaries, defenses, and synthesis. Psychedelics can induce regressed ego states with reduced defenses, allowing early-life conflicts that created maladaptive patterns to emerge. The authors argue that lasting change requires psycholytic therapy to permeate the characterological core—the chronic, habitual patterns the ego uses to cope—not just transient ego regression. Emotional integration of formative early events is key to reshaping rigid character and defenses, aiming for more flexible ego patterns. This approach is compatible with third-wave cognitive behavioral therapies.
Frontiers in Neuroscience
March 17, 2022
Devon Stoliker, Gary F Egan, Adeel Razi
19 citations
Classic psychedelics are thought to reduce the precision of belief updating, allowing access to a wider range of hypotheses for making sense of the world. This process in higher cortices may explain their therapeutic effects on internalizing disorders. The authors argue that reduced precision also underlies changes in consciousness known as ego dissolution, and that alterations in consciousness and attention under psychedelics share a common mechanism of reduced precision in Bayesian belief updating. Evidence linking serotonergic receptors to large-scale connectivity changes in the cortex suggests that the precision of Bayesian belief updating may be a mechanism for modifying and investigating consciousness and attention.