Lateralized deficits in covert shifts of visual attention in chronic and never-medicated schizophrenics compared to normal controls

Potkin, S.G.; Swanson, J.M.; Urbanchek, Melanie G.; Carreon, Daisy C.; Bravo, Gary

doi:10.1016/0920-9964(89)90131-x

Cited by 22 publications

(9 citation statements)

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“…Thus, our result does not replicate the lateralized asymmetry initially observed in schizophrenics by Posner et al (1988) and Potkin et al (1989). In these studies, the asymmetry was only seen in acutely ill patients and not patients in a remitted state.…”

Section: Discussioncontrasting

confidence: 74%

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Effects of atypical neuroleptics on alertness and visual orienting in stabilized schizophrenic patients: a preliminary study

Daban

Krebs

Bourdel

et al. 2004

Int. J. Neuropsychopharm.

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It has been shown that schizophrenic patients treated with conventional neuroleptics display a general slowness in latency in simple reaction-time tasks and a disengagement deficit in visual-orienting tasks. Yet, the influence of atypical neuroleptics on attention is still controversial. The purpose of our study was to investigate the effect of atypical neuroleptics in tasks requiring alertness, selective attention or visual orienting. Thirteen stabilized schizophrenic patients receiving atypical neuroleptics were compared to 13 healthy controls matched for age, gender, and study level, in a choice reaction time (CRT) task and a visual-orienting task cued target detection (CTD) task. The results showed that patients and controls obtained comparable reaction times (RTs) in the CRT task. In the CTD task, both groups had comparable RTs but the presence of invalid cues caused a greater attentional cost in both visual fields for patients compared to controls, indicating a symmetrical disengagement deficit. To conclude, patients treated with atypical neuroleptics had a phasic alertness ability similar to controls. By contrast, an impairment of disengagement was present in those patients. Thus, atypical neuroleptics could have a positive influence on certain but not all attentional domains.

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Section: Discussioncontrasting

confidence: 74%

“…Posner interpreted this result as a lefthemisphere disengagement deficit analogous to what was seen in patients with left parietal lesions . A similar pattern of response was found in chronic never-medicated schizophrenic patients (Potkin et al, 1989). However, this result is still controversial.…”

Section: Introductionmentioning

confidence: 53%

Effects of atypical neuroleptics on alertness and visual orienting in stabilized schizophrenic patients: a preliminary study

Daban

Krebs

Bourdel

et al. 2004

Int. J. Neuropsychopharm.

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show abstract

“…Early studies in patients with schizophrenia reported a particularly slow detection of targets in the right visual field following invalid cues and short SOAs of about 100 ms (Posner et al, 1988;Potkin et al, 1989;Maruff et al, 1995;Wigal et al, 1997). This finding was interpreted as a lateralized deficit in disengaging attention from the previously cued location.…”

Section: Introductionmentioning

confidence: 98%

Inhibition of Return in the Human 5HT2A Agonist and NMDA Antagonist Model of Psychosis

Gouzoulis-Mayfrank

Heekeren

Neukirch

et al. 2005

Neuropsychopharmacol

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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 be an appropriate model for psychoses with prominent positive symptoms. The aim of this study was to investigate orienting of attention in the human NMDA antagonist and 5-HT 2A agonist models of psychosis. A total of 15 healthy volunteers participated in a randomized, double-blind, crossover study with a low and a high dose of DMT and S-ketamine, which elicited subtle 'prepsychotic' or fullblown psychotic symptoms (low and high dose, respectively). Nine subjects completed both experimental days with the two doses of both drugs. Overall, both hallucinogens slowed down reaction times dose dependently (DMT 4S-ketamine) and DMT diminished the general response facilitating (alerting) effect of spatially neutral cues. Inhibition of Return (IOR), that is, the normal reaction time disadvantage for validly cued trials with exogenous cues and long cue target intervals, was blunted after both doses of DMT and the low dose of S-ketamine. IOR reflects an automatic, inhibitory mechanism of attention, which is thought to protect the organism from redundant, distracting sensory information. In conclusion, our data suggest a deficit of IOR in both hallucinogen models of psychosis, with the effect being clearer in the serotonin model. Blunted IOR may underlie or predispose to different psychotic manifestations, but particularly to those with prominent positive symptoms.

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“…Increased costs of invalid cueing for right visual field targets in schizophrenic patients was reported by several authors and was interpreted as an expression of a left hemispheric dysfunction in attentional networks [15,37,42]. However, others did not confirm this finding of a lateralized impairment in disengagement of spatial attention [14,[17][18][19][20].…”

Section: Discussionmentioning

confidence: 78%

Effects of the Hallucinogen Psilocybin on Covert Orienting of Visual Attention in Humans

et al. 2002

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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 = 8 in each group). Reaction times were prolonged after ingestion of psilocybin > MDE, but not after d-methamphetamine. In addition, subjects on psilocybin exhibited particularly slow reaction times in invalid trials at short cue target intervals and failure of response inhibition in valid trials at long cue target intervals for right visual field targets. Despite some methodological limitations, these results are in line with both bilateral impairment of disengagement of attention and a lateralized impairment of inhibition of return (IOR) in productive psychotic states. Additional investigations with larger samples, different hallucinogenic substances (serotonergic agonists vs. NMDA antagonists) and different dose regimens are needed in order to further explore the suggested relationship between visuospatial attentional dysfunction and acute psychotic conditions.

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Lateralized deficits in covert shifts of visual attention in chronic and never-medicated schizophrenics compared to normal controls

Cited by 22 publications

References 0 publications

Effects of atypical neuroleptics on alertness and visual orienting in stabilized schizophrenic patients: a preliminary study

Effects of atypical neuroleptics on alertness and visual orienting in stabilized schizophrenic patients: a preliminary study

Inhibition of Return in the Human 5HT2A Agonist and NMDA Antagonist Model of Psychosis

Effects of the Hallucinogen Psilocybin on Covert Orienting of Visual Attention in Humans

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