Frontiers in Physiology
February 11, 2020
Thomas A. W. Bolton, Diana Wotruba, Roman Buechler et al.
83 citations
Emerging evidence has attributed altered network coordination between the default mode, central executive, and salience networks (DMN/CEN/SAL) to disturbances seen in schizophrenia, but little is known for at-risk psychosis stages. Moreover, pinpointing impairments in specific network-to-network interactions, although essential to resolve possibly distinct harbingers of conversion to clinically...
Journal of Psychopharmacology
March 20, 2009
Jörg Daumann, Daniel Wagner, Karsten Heekeren et al.
62 citations
Deficits in attentional functions belong to the core cognitive symptoms in schizophrenic patients. Alertness is a nonselective attention component that refers to a state of general readiness that improves stimulus processing and response initiation. The main goal of the present study was to investigate cerebral correlates of alertness in the human 5HT(2A) agonist and N-methyl-D-aspartic acid...
Psychopharmacology
November 2008
Jörg Daumann, Karsten Heekeren, Anna Neukirch et al.
Attentional deficits are common symptoms in schizophrenia. Recent evidence suggests that schizophrenic patients show abnormalities in spatial orienting of attention, particularly a deficit of inhibition of return (IOR). IOR is mostly thought to reflect an automatic, inhibitory mechanism protecting the organism from redirecting attention to previously scanned, insignificant locations....
Psychopharmacology
May 16, 2008
Karsten Heekeren, Jörg Daumann, Anna Neukirch et al.
158 citations
RATIONALE: Many studies have reported deficits of mismatch negativity (MMN) in schizophrenic patients. Pharmacological challenges with hallucinogens in healthy humans are used as models for psychotic states. Previous studies reported a significant reduction of MMN after ketamine (N-methyl-D-aspartate acid [NMDA] antagonist model) but not after psilocybin (5HT2A agonist model). OBJECTIVES: The...
Journal of Psychopharmacology
May 1, 2007
Karsten Heekeren, Anna Neukirch, Jörg Daumann et al.
49 citations
Patients with schizophrenia exhibit diminished prepuLse inhibition (PPI) of the acoustic startle reflex and deficits in the attentional moduLation of PPI. Pharmacological challenges with hallucinogens are used as models for psychosis in both humans and animals. RemarkabLy, in contrast to the findings in schizophrenic patients and in animal hallucinogen modeLs of psychosis, previous studies with...
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
February 2006
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, Anna Neukirch et al.
Patients with schizophrenia exhibit disturbances of orienting of attention. However, findings have been inconsistent. Pharmacologic challenges with hallucinogens have been used as models for psychosis. The NMDA antagonist state (PCP, ketamine) resembles undifferentiated psychoses with positive and negative symptoms, while the 5-HT(2A) agonist state (LSD, dimethyltryptamine (DMT)) is thought to...
Pharmacopsychiatry
November 1, 2005
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, Anna Neukirch et al.
198 citations
INTRODUCTION: Pharmacological challenges with hallucinogens are used as models for psychosis in experimental research. The state induced by glutamate antagonists such as phencyclidine (PCP) is often considered as a more appropriate model of psychosis than the state induced by serotonergic hallucinogens such as lysergic acid diethylamide (LSD), psilocybin and N,N-dimethyltryptamine (DMT)....
Pharmacopsychiatry
September 1, 2005
Euphrosyne Gouzoulis‐mayfrank, Anna Neukirch, Karsten Heekeren
2 citations
Pharmacological challenges with hallucinogens are used as models for psychosis in experimental research. The state induced by glutamate antagonists such as phencyclidine (PCP) is often considered as a more appropriate model of psychosis than the state induced by serotonergic hallucinogens such as lysergic acid (LSD), psilocybin and dimethyltryptamine (DMT). However, so far, this question has...
Psychopharmacology
May 2004
Karsten Heekeren, Jörg Daumann, Mark A Geyer et al.
3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is neurotoxic upon central serotonin systems in experimental animals and probably also in humans. Serotonin is involved in the habituation, sensitization and prepulse inhibition (PPI) of the startle reflex. To study the plasticity of startle reflex in currently abstinent MDMA users. Electromyographic responses to acoustic startle stimuli (pulse...
Neuropsychobiology
2002
Euphrosyne Gouzoulis‐mayfrank, B. Thelen, Stefanie Maier et al.
69 citations
Hallucinogenic drug-induced states are considered as models for acute schizophrenic disorders (experimental psychoses). In a double-blind study with healthy volunteers we investigated the influence of the serotonergic hallucinogen psilocybin, the ecstasy-like drug 3,4-methylenedioxyethylamphetamine (MDE), the stimulant d- methamphetamine and placebo on covert orienting of spatial attention (n =...
Behavioural Pharmacology
November 1, 1998
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, B. Thelen et al.
79 citations
Schizophrenic patients exhibit deficits in indices of sensorimotor gating, such as habituation and prepulse inhibition (PPI) of the startle reflex. Hallucinogenic drug-induced states are putative models for the early and acute stages of schizophrenic and schizophrenia-spectrum disorders. Hallucinogenic drugs have been shown to disrupt PPI and/or retard habituation of the startle reflex in...