Journal of Psychopharmacology
May 20, 2006
Marc Wittmann, Olivia Carter, Felix Hasler et al.
245 citations
Hallucinogenic psilocybin is known to alter the subjective experience of time. However, there is no study that systematically investigated objective measures of time perception under psilocybin. Therefore, we studied dose-dependent effects of the serotonin (5-HT) 2A/1A receptor agonist psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) on temporal processing, employing tasks of temporal...
Neuropsychopharmacology
January 26, 2005
Olivia Carter, John D. Pettigrew, Felix Hasler et al.
122 citations
Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of...
Schizophrenia Research
January 1, 2005
Georg Northoff, Andre Richter, Felix Bermpohl et al.
Based on animal data, NMDA receptor hypofunction has been suggested as a model for positive symptoms in schizophrenia. NMDA receptor hypofunction affects several corticolimbic brain regions, of which the posterior cingulate seems to be the most sensitive. However, empirical support for a crucial role of posterior cingulate NMDA hypofunction in the pathophysiology of positive symptoms is still...
Human Brain Mapping
August 27, 2001
Edi Frei, Alex Gamma, Roberto D Pascual-Marqui et al.
175 citations
Abstract 3,4‐Methylenedioxymethamphetamine (MDMA; 'Ecstasy') is a psychostimulant drug producing heightened mood and facilitated social communication. In animal studies, MDMA effects are primarily mediated by serotonin (5‐HT), but also by dopamine (DA) and possibly noradrenaline (NA). In humans, however, the neurochemical and neurophysiological basis of acute MDMA effects remains unknown. The...
Archives of General Psychiatry
December 1, 2000
Daniel Umbricht, Liselotte Schmid, Rene Koller et al.
590 citations
BACKGROUND: In patients with schizophrenia, deficient generation of mismatch negativity (MMN)-an event-related potential (ERP) indexing auditory sensory ("echoic") memory-and a selective increase of "context dependent" ("BX") errors in the "A-X" version of the Continuous Performance Test (AX-CPT) indicate an impaired ability to form and use transient memory traces. Animal and human studies...
Neuroreport
2000
Alex Gamma, Edi Frei, Dietrich Lehmann et al.
81 citations
Resting EEG during open and closed eyes and subsequent mood ratings were obtained from 15 Ecstasy users and 14 Ecstasy-naive controls. Absolute spectral power on the scalp, and the three-dimensional, intracerebral distribution of neuroelectric activity using low resolution brain electromagnetic tomography (LORETA) were computed. LORETA revealed global increases of theta, alpha 1 and beta 2/3...
Neuropsychopharmacology
May 1999
Franz X. Vollenweider, P Vontobel, Daniel Hell et al.
The modulating effects of serotonin on dopamine neurotransmission are not well understood, particularly in acute psychotic states. Positron emission tomography was used to examine the effect of psilocybin on the in vivo binding of [11C]raclopride to D2-dopamine receptors in the striatum in healthy volunteers after placebo and a psychotomimetic dose of psilocybin (n = 7). Psilocybin is a potent...
Neuroreport
December 1, 1998
Franz X. Vollenweider, M. F. I. Vollenweider-Scherpenhuyzen, Andreas Bäbler et al.
1,023 citations
Psilocybin, an indoleamine hallucinogen, produces a psychosis-like syndrome in humans that resembles first episodes of schizophrenia. In healthy human volunteers, the psychotomimetic effects of psilocybin were blocked dose-dependently by the serotonin-2A antagonist ketanserin or the atypical antipsychotic risperidone, but were increased by the dopamine antagonist and typical antipsychotic...