Science
December 6, 2007
M. Margarita Behrens, Sameh S. Ali, Diep N. Dao et al.
590 citations
Abuse of the dissociative anesthetic ketamine can lead to a syndrome indistinguishable from schizophrenia. In animals, repetitive exposure to this N-methyl-d-aspartate-receptor antagonist induces the dysfunction of a subset of cortical fast-spiking inhibitory interneurons, with loss of expression of parvalbumin and the gamma-aminobutyric acid-producing enzyme GAD67. We show here that exposure...
Science
August 23, 2007
H. Henrik Ehrsson
964 citations
I report an illusion in which individuals experience that they are located outside their physical bodies and looking at their bodies from this perspective. This demonstrates that the experience of being localized within the physical body can be determined by the visual perspective in conjunction with correlated multisensory information from the body.
Science
August 1, 2007
Psychology. Out-of-body experiences enter the laboratory.
Science
March 2, 2007
Adrian M. Owen, Martin R. Coleman, Melanie Boly et al.
72 citations
Additional data, supported by relevant functional neuroimaging literature, confirm that the “normal” patterns of brain activity reported in a patient who was clinically diagnosed as vegetative could not have occurred “automatically” in the absence of conscious awareness. The most parsimonious explanation remains that this patient was consciously aware despite her diagnosis of vegetative state.
Science
September 7, 2006
Adrian M. Owen, Martin R. Coleman, Melanie Boly et al.
1,974 citations
We used functional magnetic resonance imaging to demonstrate preserved conscious awareness in a patient fulfilling the criteria for a diagnosis of vegetative state. When asked to imagine playing tennis or moving around her home, the patient activated predicted cortical areas in a manner indistinguishable from that of healthy volunteers.
Science
September 29, 2005
Marcello Massimini, Fabio Ferrarelli, Reto Huber et al.
1,603 citations
When we fall asleep, consciousness fades yet the brain remains active. Why is this so? To investigate whether changes in cortical information transmission play a role, we used transcranial magnetic stimulation together with high-density electroencephalography and asked how the activation of one cortical area (the premotor area) is transmitted to the rest of the brain. During quiet wakefulness,...
Science
April 14, 2005
Brian Vastag
38 citations
Despite potentially harsh side effects, an African plant extract is being tested in two public clinical trials--and many clandestine ones.
Science
November 21, 2003
Per Svenningsson, Eleni T. Tzavara, Robert Carruthers et al.
312 citations
Three distinct classes of drugs: dopaminergic agonists (such as D-amphetamine), serotonergic agonists (such as LSD), and glutamatergic antagonists (such as PCP) all induce psychotomimetic states in experimental animals that closely resemble schizophrenia symptoms in humans. Here we implicate a common signaling pathway in mediating these effects. In this pathway, dopamine- and an adenosine...
Science
June 1, 2003
Michael C Mithoefer, Lisa Jerome, Richard Doblin et al.
36 citations
MDMA ("ecstasy") and neurotoxicity.
Science
September 27, 2002
George A. Ricaurte, Jie Yuan, George Hatzidimitriou et al.
179 citations
Retracted
The prevailing view is that the popular recreational drug (±)3,4-methylenedioxymethamphetamine (MDMA, or “ecstasy”) is a selective serotonin neurotoxin in animals and possibly in humans. Nonhuman primates exposed to several sequential doses of MDMA, a regimen modeled after one used by humans, developed severe brain dopaminergic neurotoxicity, in addition to less pronounced serotonergic...
Science
October 13, 2000
Robert Stickgold, April Malia, Denise Maguire et al.
Participants playing the computer game Tetris reported intrusive, stereotypical, visual images of the game at sleep onset. Three amnesic patients with extensive bilateral medial temporal lobe damage produced similar hypnagogic reports despite being unable to recall playing the game, suggesting that such imagery may arise without important contribution from the declarative memory system. In...
Science
August 28, 1998
Bita Moghaddam, Barbara W. Adams
1,019 citations
Glutamatergic abnormalities have been associated with several psychiatric disorders, including schizophrenia and addiction. Group II metabotropic glutamate receptors were targeted to normalize glutamatergic disruptions associated with an animal model of schizophrenia, the phencyclidine model. An agonist of this group of receptors, at a dose that was without effects on spontaneous activity and...
Science
December 6, 1991
J. W. Olney, J. Labruyere, G. Wang et al.
850 citations
Antagonists of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor, including phencyclidine (PCP) and ketamine, protect against brain damage in neurological disorders such as stroke. However, these agents have psychotomimetic properties in humans and morphologically damage neurons in the cerebral cortex of rats. It is now shown that the morphological damage can be prevented by certain...
Science
September 6, 1985
George A. Ricaurte, Guy K. Bryan, L. Strauss et al.
367 citations
(±)-3,4-Methylenedioxyamphetamine (MDA), an amphetamine analog with hallucinogenic activity, produced selective long-lasting reductions in the level of serotonin, the number of serotonin uptake sites, and the concentration of 5-hydroxyindoleacetic acid in rat brain. Morphological studies suggested that these neurochemical deficits were due to serotonin nerve terminal degeneration. These results...
Science
April 30, 1982
Francis J. White, James B. Appel
67 citations
The nonhallucinogenic ergot derivative lisuride exerts many pharmacological effects that are similar to those of its hallucinogenic congener, lysergic acid diethylamide (LSD). Animals trained to discriminate between the presence of one drug and the other can be used to differentiate the actions of these compounds on a neuronal level. The discriminative stimulus effect of LSD (the LSD cue) is...
Science
July 24, 1981
Jeffrey Schaeffer, Therese Andrysiak, J. Thomas Ungerleider
Neuropsychological variables and urine cannabinoid metabolites were evaluated in ten subjects born, raised, and educated in the United States and having histories of heavy or prolonged use of cannabis. No impairment of cognitive function was found. Cannabinoid metabolites in excess of 50 nanograms per milliliter were present in the ten urine samples. The tetrahydrocannabinol content of cannabis...
Science
May 29, 1981
Bella T. Altura, Burton M. Altura
81 citations
Phencyclidine (PCP), lysergic acid diethylamide (LSD), and mescaline produced potent contractile responses on isolated basilar and middle cerebral arteries, where, in terms of potency, LSD > mescaline > PCP. All three drugs produced cerebrovasospasm in a concentration range which parallels that needed for their psychotomimetic and intoxicating actions. Specific receptors for PCP, which subserve...
Science
August 3, 1979
Michael E. Trulson, Barry L. Jacobs
44 citations
The hypothesis that the action of hallucinogenic drugs is mediated by a depression of the activity of brain serotonergic (raphe) neurons was tested by examining the behavioral effects of d -lysergic acid diethylamide (LSD) while studying the activity of raphe neurons in freely moving cats. Although the results provide general support for the hypothesis, there were several important...
Science
March 31, 1978
Jan G. Bruhn, J.‐e. Lindgren, Bo Holmstedt et al.
23 citations
Mescaline, anhalonine, lophophorine, pellotine, and anhalonidine have been identified in alkaloid extracts of a prehistoric specimen of Lophophora from a burial cave in west central Coahuila, Mexico. The specimen is associated with radiocarbon dates of A.D. 810 to 1070 and is one of the oldest materials ever submitted to alkaloid analysis.
Science
November 12, 1976
Barry L. Jacobs, Michael E. Trulson, Warren C. Stern
72 citations
Cats injected with LSD (d-lysergic acid diethylamide) exhibit a group of behaviors that appear to be specific to hallucinogenic drugs. Two of these behaviors, limb flick and abortive grooming, have an extremely low frequency of occurrence in normal cats, but often dominate the behavior of LSD-treated cats. The frequency of occurrence of this group of behaviors is related to the dose of LSD. The...
Science
June 18, 1976
Ruth R. Michaels, M. J. Huber, Daisy S. McCann
95 citations
Transcendental meditation is said to induce in its practitioners an altered state of consciousness resulting in relief of stress, an increased sense of awareness, and a sense of well-being. Release of catecholamines has been associated widely with stress and lends itself to quantitation. Plasma epinephrine and norephinephrine, as well as lactate, were measured in 12 volunteers before, during,...
Science
May 21, 1976
Ronald I. Schoenfeld
118 citations
At a dose as low as 1 microgram per kilogram of body weight, lysergic acid diethylamide (LSD) significantly decreased the suppressive effect of electric shock on licking behavior of the rat. Attenuation of punishment was also obtained with mescaline, but neither dimethyltryptamine nor Δ 9 -tetrahydrocannabinol was active in this test. Cyproheptadine and α-propyldopacetamide, drugs that...
Science
January 23, 1976
Robert R. Pagano, Richard M. Rose, Robert M. Stivers et al.
73 citations
Five experienced practitioners of transcendental meditation spent appreciable parts of meditation sesions in sleep stages 2, 3, and 4. Time spent in each sleep stage varied both between sessions for a given subject and between subjects. In addition, we compare electroencephalogram records made during meditation with those made during naps taken at the same time of day. The range of states...
Science
June 13, 1975
Ian R. Brown, C. C. Liew
Lysergic acid diethylamide increased acetylation of histones in rabbit cerebral hemispheres and midbrain 30 minutes after intravenous administration of the drug at doses of 10 and 100 micrograms per kilogram of body weight. Evidence for the stimulation of acetylation in individual histone bands was obtained after separation by electrophoresis on polyacrylamide gels.
Science
July 13, 1973
Alison Taunton-Rigby, S. Sher, Paul R. Kelley
50 citations
A radioimmnunoassay for d-lysergic acid diethylamide (LSD) is described. Antibodies to LSD were obtained by immunizing rabbits with a conjugate of LSD and human serum albumin. The specificity of the antibody was shown by competitive binding studies. The method has been used to detect the presence of LSD in human urines. Picogram amounts can be measured by this assay.