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Neuroscience

Modern Clinical Research on LSD

April 27, 2017 / LSD, Neuroscience, Papers, Psychology, Publications / By /

Abstract

All modern clinical studies using the classic hallucinogen lysergic acid diethylamide (LSD) in healthy subjects or patients in the last 25 years are reviewed herein. There were five recent studies in healthy participants and one in patients. In a controlled setting, LSD acutely induced bliss, audiovisual synesthesia, altered meaning of perceptions, derealization, depersonalization, and mystical experiences. These subjective effects of LSD were mediated by the 5-HT2A receptor. LSD increased feelings of closeness to others, openness, trust, and suggestibility. LSD impaired the recognition of sad and fearful faces, reduced left amygdala reactivity to fearful faces, and enhanced emotional empathy. LSD increased the emotional response to music and the meaning of music. LSD acutely produced deficits in sensorimotor gating, similar to observations in schizophrenia. LSD had weak autonomic stimulant effects and elevated plasma cortisol, prolactin, and oxytocin levels. Resting state functional magnetic resonance studies showed that LSD acutely reduced the integrity of functional brain networks and increased connectivity between networks that normally are more dissociated. LSD increased functional thalamocortical connectivity and functional connectivity of the primary visual cortex with other brain areas. The latter effect was correlated with subjective hallucinations. LSD acutely induced global increases in brain entropy that were associated with greater trait openness 14 day later. In patients with anxiety associated with life-threatening disease, anxiety was reduced for 2 months after two doses of LSD. In medical settings, no complications of LSD administration were observed. These data should contribute to further investigations of the therapeutic potential of LSD in psychiatry.

Liechti, M. E. (2017). Modern Clinical Research on LSD. Neuropsychopharmacology. 10.1038/npp.2017.86
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Prefrontal Connectivity and Glutamate Transmission: Relevance to Depression Pathophysiology and Ketamine Treatment

April 23, 2017 / Depressive Disorders, Ketamine, Neuroscience, Papers / By / , , , , , ,

Abstract

Background

Prefrontal global brain connectivity with global signal regression (GBCr) was proposed as a robust biomarker of depression and was associated with ketamine’s mechanism of action. Here, we investigated prefrontal GBCr in treatment-resistant depression (TRD) at baseline and following treatment. Then, we conducted a set of pharmacological challenges in healthy subjects to investigate the glutamate neurotransmission correlates of GBCr.

Methods

In the cohort A study, we used functional magnetic resonance imaging to compare GBCr between 22 patients with TRD and 29 healthy control subjects. Then, we examined the effects of ketamine and midazolam on GBCr in patients with TRD 24 hours posttreatment. In the cohort B study, we acquired repeated functional magnetic resonance imaging in 18 healthy subjects to determine the effects of lamotrigine (a glutamate release inhibitor), ketamine, and lamotrigine-by-ketamine interaction.

Results

In the cohort A study, patients with TRD showed significant reduction in dorsomedial and dorsolateral prefrontal GBCr compared with healthy control subjects. In patients with TRD, GBCr in the altered clusters significantly increased 24 hours following ketamine (effect size = 1.0, confidence interval = 0.3 to 1.8) but not following midazolam (effect size = 0.5, confidence interval = −0.6 to 1.3). In the cohort B study, oral lamotrigine reduced GBCr 2 hours postadministration, while ketamine increased medial prefrontal GBCr during infusion. Lamotrigine significantly reduced the ketamine-induced GBCr surge. Exploratory analyses showed elevated ventral prefrontal GBCr in TRD and significant reduction of ventral prefrontal GBCr during ketamine infusion in healthy subjects.

Conclusions

This study provides the first replication of the ability of ketamine to normalize depression-related prefrontal dysconnectivity. It also provides indirect evidence that these effects may be triggered by the capacity of ketamine to enhance glutamate neurotransmission.

Abdallah, C. G., Averill, C. L., Salas, R., Averill, L. A., Baldwin, P. R., Krystal, J. H., … & Mathalon, D. H. (2017). Prefrontal Connectivity & Glutamate Transmission: Relevance to Depression Pathophysiology and Ketamine Treatment. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. 10.1016/j.bpsc.2017.04.006
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New Treatment Strategies of Depression: Based on Mechanisms Related to Neuroplasticity

April 11, 2017 / Depressive Disorders, Ketamine, Neuroscience, Papers, Psychology, Publications / By / , ,

Abstract

Major depressive disorder is a severe and complex mental disorder. Impaired neurotransmission and disrupted signalling pathways may influence neuroplasticity, which is involved in the brain dysfunction in depression. Traditional neurobiological theories of depression, such as monoamine hypothesis, cannot fully explain the whole picture of depressive disorders. In this review, we discussed new treatment directions of depression, including modulation of glutamatergic system and noninvasive brain stimulation. Dysfunction of glutamatergic neurotransmission plays an important role in the pathophysiology of depression. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has rapid and lasting antidepressive effects in previous studies. In addition to ketamine, other glutamatergic modulators, such as sarcosine, also show potential antidepressant effect in animal models or clinical trials. Noninvasive brain stimulation is another new treatment strategy beyond pharmacotherapy. Growing evidence has demonstrated that superficial brain stimulations, such as transcranial magnetic stimulation, transcranial direct current stimulation, cranial electrotherapy stimulation, and magnetic seizure therapy, can improve depressive symptoms. The antidepressive effect of these brain stimulations may be through modulating neuroplasticity. In conclusion, drugs that modulate neurotransmission via NMDA receptor and noninvasive brain stimulation may provide new directions of treatment for depression. Furthermore, exploring the underlying mechanisms will help in developing novel therapies for depression in the future.
Huang, Y. J., Lane, H. Y., & Lin, C. H. (2017). New Treatment Strategies of Depression: Based on Mechanisms Related to Neuroplasticity. Neural plasticity, 2017. 10.1155/2017/4605971
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Dreamlike effects of LSD on waking imagery in humans depend on serotonin 2A receptor activation

April 7, 2017 / LSD, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

RATIONALE:
Accumulating evidence indicates that the mixed serotonin and dopamine receptor agonist lysergic acid diethylamide (LSD) induces an altered state of consciousness that resembles dreaming.
OBJECTIVES:
This study aimed to test the hypotheses that LSD produces dreamlike waking imagery and that this imagery depends on 5-HT2A receptor activation and is related to subjective drug effects.
METHODS:
Twenty-five healthy subjects performed an audiorecorded guided mental imagery task 7 h after drug administration during three drug conditions: placebo, LSD (100 mcg orally) and LSD together with the 5-HT2A receptor antagonist ketanserin (40 mg orally). Cognitive bizarreness of guided mental imagery reports was quantified as a standardised formal measure of dream mentation. State of consciousness was evaluated using the Altered State of Consciousness (5D-ASC) questionnaire.
RESULTS:
LSD, compared with placebo, significantly increased cognitive bizarreness (p < 0.001). The LSD-induced increase in cognitive bizarreness was positively correlated with the LSD-induced loss of self-boundaries and cognitive control (p < 0.05). Both LSD-induced increases in cognitive bizarreness and changes in state of consciousness were fully blocked by ketanserin.
CONCLUSIONS:
LSD produced mental imagery similar to dreaming, primarily via activation of the 5-HT2A receptor and in relation to loss of self-boundaries and cognitive control. Future psychopharmacological studies should assess the differential contribution of the D2/D1 and 5-HT1A receptors to cognitive bizarreness.
Kraehenmann, R., Pokorny, D., Vollenweider, L., Preller, K. H., Pokorny, T., Seifritz, E., & Vollenweider, F. X. (2017). Dreamlike effects of LSD on waking imagery in humans depend on serotonin 2A receptor activation. Psychopharmacology, 1-16. 10.1007/s00213-017-4610-0
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Acute effects of LSD on amygdala activity during processing of fearful stimuli in healthy subjects

April 4, 2017 / LSD, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Lysergic acid diethylamide (LSD) induces profound changes in various mental domains, including perception, self-awareness and emotions. We used functional magnetic resonance imaging (fMRI) to investigate the acute effects of LSD on the neural substrate of emotional processing in humans. Using a double-blind, randomised, cross-over study design, placebo or 100 μg LSD were orally administered to 20 healthy subjects before the fMRI scan, taking into account the subjective and pharmacological peak effects of LSD. The plasma levels of LSD were determined immediately before and after the scan. The study (including the a priori-defined study end point) was registered at ClinicalTrials.gov before study start (NCT02308969). The administration of LSD reduced reactivity of the left amygdala and the right medial prefrontal cortex relative to placebo during the presentation of fearful faces (P<0.05, family-wise error). Notably, there was a significant negative correlation between LSD-induced amygdala response to fearful stimuli and the LSD-induced subjective drug effects (P<0.05). These data suggest that acute administration of LSD modulates the engagement of brain regions that mediate emotional processing.

Mueller, F., Lenz, C., Dolder, P. C., Harder, S., Schmid, Y., Lang, U. E., … & Borgwardt, S. (2017). Acute effects of LSD on amygdala activity during processing of fearful stimuli in healthy subjects. Translational Psychiatry, 7(4), e1084. 10.1038/tp.2017.54
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Psychedelics As A New Anti-Inflammatory Therapeutic For Atherosclerosis

April 1, 2017 / Neuroscience, Papers, Psychiatry & Medicine / By / , ,

Abstract

Background and Objective We previously discovered that serotonin 5-HT2A receptor activation with psychedelics has potent anti-inflammatory activity in both cell culture and whole animals, which indicated potent anti-inflammatory effects in vascular tissues among others. More recently we found that the psychedelic (R)-DOI potently prevents the development of allergic asthma in a mouse model. The effects of (R)-DOI were found to not result from a generalized anti-inflammatory process, but due to specific inflammatory pathways inhibition in both innate and Th2 cells. In this work, we have examined the therapeutic effects of the psychedelic (R)-DOI in the ApoE −/− high-fat model of atherosclerosis.

Methods Osmotic minipumps were used to deliver very low doses of (R)-DOI to male ApoE −/− mice that were divided into four treatment groups [Saline, normal chow; (R)-DOI, normal chow; Saline, hi-fat diet; (R)-DOI, hi-fat diet]. After 16 weeks, mice were euthanized and tissues collected for analysis

Results Calculated steady state levels of ~0.0013 mg/kg (R)-DOI resulted in a significant reduction of mRNA expression for inflammatory markers like Il6 in vascular tissue, reduced levels of glucose, and a reduction in circulating cholesterol in the high fat fed animals. Additional ongoing studies are examining arterial plaque size and heart pathology.

Summary Extremely low levels of the psychedelic (R)-DOI were sufficient to significantly block the development of vascular inflammation, normalize glucose homeostasis, and prevent the increase in cholesterol associated with a hi-fat ‘western’ high diet. Activation of serotonin 5-HT2A receptor therefore represents a powerful new strategy to treat inflammatory-related vascular disease.

Nichols, C. D., Sebastian, M., & Flanagan, T. (2017). Psychedelics As A New Anti-Inflammatory Therapeutic For Atherosclerosis. The FASEB Journal, 31(1 Supplement), 825-3.
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Anti-inflammatory effects of serotonin 5-HT2A receptor activation in ovalbumin-induced allergic asthma models

April 1, 2017 / Neuroscience, Papers, Psychiatry & Medicine / By / , ,

Abstract

Only recently has the full therapeutic value of serotonin [5-hydroxytryptophan (5-HT)] receptor activation begun to be explored. Currently there are two 5-HT2A receptor agonists in human clinical trials for the treatment of depression and obesity. An exciting new therapeutic avenue in which 5-HT2A agonists might be employed is the modulation of inflammation in allergic airways disease. Our lab has previously used an ovalbumin (OVA)-induced asthma model to demonstrate that administration of (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] prior to allergen challenge prevents many of the symptoms of allergic asthma. Here we have utilized a modified protocol to test the effectiveness of (R)-DOI in treating persistent allergic asthma. We demonstrate that administration of (R)-DOI in a chronic model attenuates the elevated airway hyperresponsiveness (AHR) typically observed in an asthmatic response. We also have probed for the expression of inflammatory markers in the lung and BALF. We concurrently are testing for the impact psilocybin and other tryptamines have on AHR in rodents using our OVA model. Overall our strategy is to develop 5-HT2A receptor agonism as a viable treatment modality against asthma and other inflammatory disorders.
Flanagan, T. W., Sebastian, M. N., & Nichols, C. D. (2017). Anti-inflammatory effects of serotonin 5-HT2A receptor activation in ovalbumin-induced allergic asthma models. The FASEB Journal, 31(1 Supplement), 820-4.
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Classic Hallucinogens and Mystical Experiences: Phenomenology and Neural Correlates

March 26, 2017 / Anxiety Disorders / PTSD, Depressive Disorders, Mushrooms / Psilocybin, Neuroscience, Papers, Psychology, Publications, Substance Use Disorder / By / ,

Abstract

This chapter begins with a brief review of descriptions and definitions of mystical-type experiences and the historical connection between classic hallucinogens and mystical experiences. The chapter then explores the empirical literature on experiences with classic hallucinogens in which claims about mystical or religious experiences have been made. A psychometrically validated questionnaire is described for the reliable measurement of mystical-type experiences occasioned by classic hallucinogens. Controlled laboratory studies show that under double-blind conditions that provide significant controls for expectancy bias, psilocybin can occasion complete mystical experiences in the majority of people studied. These effects are dose-dependent, specific to psilocybin compared to placebo or a psychoactive control substance, and have enduring impact on the moods, attitudes, and behaviors of participants as assessed by self-report of participants and ratings by community observers. Other studies suggest that enduring personal meaning in healthy volunteers and therapeutic outcomes in patients, including reduction and cessation of substance abuse behaviors and reduction of anxiety and depression in patients with a life-threatening cancer diagnosis, are related to the occurrence of mystical experiences during drug sessions. The final sections of the chapter draw parallels in human neuroscience research between the neural bases of experiences with classic hallucinogens and the neural bases of meditative practices for which claims of mystical-type experience are sometimes made. From these parallels, a functional neural model of mystical experience is proposed, based on changes in the default mode network of the brain that have been observed after the administration of classic hallucinogens and during meditation practices for which mystical-type claims have been made.
Barrett, F. S., & Griffiths, R. R. (2017). Classic Hallucinogens and Mystical Experiences: Phenomenology and Neural Correlates. 10.1007/7854_2017_474
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Chemistry and Structure-Activity Relationships of Psychedelics

March 26, 2017 / LSD, Mescaline / Cacti, Mushrooms / Psilocybin, Neuroscience, Papers, Publications / By /

Abstract

This chapter will summarize structure-activity relationships (SAR) that are known for the classic serotonergic hallucinogens (aka psychedelics), focusing on the three chemical types: tryptamines, ergolines, and phenethylamines. In the brain, the serotonin 5-HT2Areceptor plays a key role in regulation of cortical function and cognition, and also appears to be the principal target for hallucinogenic/psychedelic drugs such as LSD. It is one of the most extensively studied of the 14 known types of serotonin receptors. Important structural features will be identified for activity and, where possible, those that the psychedelics have in common will be discussed. Because activation of the 5-HT2A receptor is the principal mechanism of action for psychedelics, compounds with 5-HT2A agonist activity generally are quickly discarded by the pharmaceutical industry. Thus, most of the research on psychedelics can be related to activation of 5-HT2A receptors. Therefore, much of the discussion will include not only clinical or anecdotal studies, but also will consider data from animal models as well as a certain amount of molecular pharmacology where it is known.
Nichols, D. E. (2017). Chemistry and Structure–Activity Relationships of Psychedelics. 10.1007/7854_2017_475
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Type A monoamine oxidase and serotonin are coordinately involved in depressive disorders: from neurotransmitter imbalance to impaired neurogenesis

March 14, 2017 / Ayahuasca, Depressive Disorders, Neuroscience, Papers / By / , ,

Abstract

Type A monoamine oxidase (MAOA) catabolizes monoamine transmitters, serotonin, norepinephrine and dopamine, and plays a major role in the onset, progression and therapy of neuropsychiatric disorders. In depressive disorders, increase in MAOA expression and decrease in brain levels of serotonin and norepinephrine are proposed as the major pathogenic factors. The functional polymorphism of MAOA gene and genes in serotonin signal pathway are associated with depression. This review presents recent advance in studies on the role of MAOA in major depressive disorder and related emotional disorders. MAOA and serotonin regulate the prenatal development and postnatal maintenance of brain architecture and neurocircuit, as shown by MAOA-deficient humans and MAO knockout animal models. Impaired neurogenesis in the mature hippocampus has been proposed as “adult neurogenesis” hypothesis of depression. MAOA modulates the sensitivity to stress in the stages of brain development and maturation, and the interaction of gene–environmental factors in the early stage regulates the onset of depressive behaviors in adulthood. Vice versa environmental factors affect MAOAexpression by epigenetic regulation. MAO inhibitors not only restore compromised neurotransmitters, but also protect neurons from cell death in depression through induction of anti-apoptotic Bcl-2 and prosurvival neurotrophic factors, especially brain-derived neurotrophic factor, the deficiency of which is detected in depression. This review discusses novel role of MAOA and serotonin in the pathogenesis and therapy of depressive disorders.

Naoi, M., Maruyama, W., & Shamoto-Nagai, M. (2017). Type A monoamine oxidase and serotonin are coordinately involved in depressive disorders: from neurotransmitter imbalance to impaired neurogenesis. Journal of Neural Transmission, 1-14. 10.1007/s0070
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