Schizophrenia Biological Research Center

West Haven, CT, United States

Schizophrenia Biological Research Center

West Haven, CT, United States
SEARCH FILTERS
Time filter
Source Type

Cavus I.,Yale University | Reinhart R.M.G.,Yale University | Roach B.J.,University of California at San Francisco | Roach B.J.,San Francisco Veterans Affairs Medical Center | And 12 more authors.
Biological Psychiatry | Year: 2012

Background: Impaired cortical plasticity may be part of the core pathophysiology of schizophrenia (SZ). Long-term potentiation is a form of neuroplasticity that has been recently demonstrated in humans by showing that repetitive visual stimulation produces lasting enhancement of visual evoked potentials (VEP). Using this paradigm, we examined whether visual cortical plasticity is impaired in SZ. Methods: Electroencephalographic data were recorded from 19 SZ and 22 healthy control (HC) subjects during a visual long-term potentiation paradigm. Visual evoked potentials were elicited by standard visual stimuli (∼.83 Hz, 2-minute blocks) at baseline and at 2, 4, and 20 minutes following exposure to visual high-frequency stimulation (HFS) (∼8.8 Hz, 2 minutes) designed to induce VEP potentiation. To ensure attentiveness during VEP assessments, subjects responded with a button press to infrequent (10%) target stimuli. Visual evoked potentials were subjected to principal components analysis. Two negative-voltage components prominent over occipital-parietal electrode sites were evident at 92 msec (C1) and at 146 msec (N1b). Changes in C1 and N1b component scores from baseline to the post-HFS assessments were compared between groups. Results: High-frequency stimulation produced sustained potentiation of visual C1 and N1b in HCs but not in SZs. The HCs and SZs had comparable HFS-driven electroencephalographic visual steady state responses. However, greater visual steady state responses to the HFS predicted greater N1b potentiation in HCs but not in SZs. Schizophrenia patients with greater N1b potentiation decreased their reaction times to target stimuli. Conclusions: Visual cortical plasticity is impaired in schizophrenia, consistent with hypothesized deficits in N-methyl-D-aspartate receptor function. © 2012 Society of Biological Psychiatry.


Addy P.H.,Schizophrenia Biological Research Center
Psychopharmacology | Year: 2012

Rationale Salvia divinorum has been used for centuries, and nontraditional use in modern societies is increasing. Inebriation and aftereffects of use are poorly documented in the scientific literature. Objectives This double-blind, placebo-controlled, randomized study analyzed subjective experiences of salvinorin A (SA) inebriation and consequences of use after 8 weeks. Methods Thirty middle-aged, well-educated, hallucinogen-experienced participants smoked either 1,017 or 100μg SA 2 weeks apart in counterbalanced order. Vital signs were recorded before and after inhalation. A researcher rated participants' behavior during sessions. Participants completed the Hallucinogen Rating Scale (HRS) assessing inebriation immediately after each session. Differences were analyzed between groups as functions of dose and time. After 8 weeks, participants were interviewed to determine reported consequences and aftereffects. Results Participants talked, laughed, and moved more often on an active dose. All six HRS clusters were significantly elevated on an active dose indicating hallucinogenic experiences. No significant adverse events were observed or reported by participants. Conclusions The present results indicate similarities as well as differences between the subjective effects of S. divinorum and other hallucinogens. As a selective kappa opioid receptor agonist, SA may be useful for expanding understanding of the psychopharmacology and psychology of hallucinogenic states beyond serotonergic mechanisms. © 2011 Springer-Verlag.


Sewell R.A.,Yale University | Sewell R.A.,VA Connecticut Healthcare System | Perry E.B.,Yale University | Perry E.B.,Schizophrenia Biological Research Center | And 23 more authors.
Schizophrenia Research | Year: 2010

Background: Nonlocalizing neurologic deficits detectable by clinical evaluation-"soft signs"-are a robust finding in patients diagnosed with schizophrenia, but their conceptual and neuroanatomical correlates remain unclear. The purpose of this study was to evaluate the organization of these deficits and their clinical correlates using the Neurological Evaluation Scale (NES). Methods: Ninety-three male veterans with schizophrenia and schizoaffective disorder were evaluated using a detailed clinical assessment that included the NES, the Extrapyramidal Symptom Rating Scale, the Abnormal Involuntary Movement Scale (AIMS), the Barnes Akathisia Scale, the Positive and Negative Syndrome Scale, the Wisconsin Card Sorting Test (WCST), the Schedule for the Deficit Syndrome (SDS), and the Digit Symbol Substitution Task (DSST). Results: Four factors explained 73% of the variance and had distinct clinical and neuropsychological correlates. Factor 1 reflected deficits involved with memory and sensory integration, and was associated with lower PANSS positive and higher AIMS scores. Factor 2 reflected impairments in motor control, and was associated with lower intelligence, more cognitive deficits, and deficit-syndrome schizophrenia. Factor 3 was related to lower intelligence and more perseverative errors on the WCST. Factor 4 was related to increasing age, more extrapyramidal symptoms, more perseverative errors, and worse scores on the DSST. Conclusions: Neurologic deficits in schizophrenia have an intrinsic organization that appears to have clinical significance, highlighting the continued utility of the NES in studies of neurological deficits in schizophrenia patients. The theoretical underpinning of this organization remains unclear. © 2010.


PubMed | Schizophrenia Biological Research Center
Type: Journal Article | Journal: Psychopharmacology | Year: 2012

Salvia divinorum has been used for centuries, and nontraditional use in modern societies is increasing. Inebriation and aftereffects of use are poorly documented in the scientific literature.This double-blind, placebo-controlled, randomized study analyzed subjective experiences of salvinorin A (SA) inebriation and consequences of use after 8 weeks.Thirty middle-aged, well-educated, hallucinogen-experienced participants smoked either 1,017 or 100g SA 2 weeks apart in counterbalanced order. Vital signs were recorded before and after inhalation. A researcher rated participants behavior during sessions. Participants completed the Hallucinogen Rating Scale (HRS) assessing inebriation immediately after each session. Differences were analyzed between groups as functions of dose and time. After 8 weeks, participants were interviewed to determine reported consequences and aftereffects.Participants talked, laughed, and moved more often on an active dose. All six HRS clusters were significantly elevated on an active dose indicating hallucinogenic experiences. No significant adverse events were observed or reported by participants.The present results indicate similarities as well as differences between the subjective effects of S. divinorum and other hallucinogens. As a selective kappa opioid receptor agonist, SA may be useful for expanding understanding of the psychopharmacology and psychology of hallucinogenic states beyond serotonergic mechanisms.

Loading Schizophrenia Biological Research Center collaborators
Loading Schizophrenia Biological Research Center collaborators