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Objective: Memory processes, as reflected by ‘old/new’ effects of event-related potentials (ERPs), have been shown to be impaired in depressed patients. This variability might be partly explained by biological factors. S100B is a glial calcium-binding protein with neuroplastic properties; S100B serum levels have been shown to be increased in depressive patients. The pathophysiologic role of S100B in depression, however, is not yet sufficiently understood. Methods: In the present study, ERPs recorded in a visual continuous word recognition paradigm were therefore investigated in patients with remitted major depression in relation to S100B serum levels. Results: Patients with moderately increased S100B serum levels (n = 6) showed a normal old/new effect in contrast to a reduced old/new effect in patients with normal S100B levels (n = 6) compared to aged-matched controls. Conclusions: These findings provide evidence of an association between S100B levels and memory processes in patients with recurrent depression and further suggest a neuroprotective role of moderately increased S100B serum levels in the course of affective disorders. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: Complex genetic mechanisms are involved in the vulnerability to depressive disorders and cognitive dysfunctions found in depression. This study was performed to explore the effect of the familial risk for depression on electrophysiological correlates of attentional functions as demonstrated by an event-related potential (ERP) go/no-go experiment. Methods: The component P3b as an indicator of target detection processing was investigated in two groups of healthy subjects with or without a family history of depression (n = 14 each). An electrophysiological source localization method (LORETA) was employed to allow a neuro-anatomical interpretation for the ERP data. Results: The group with a familial risk for depression showed a reduced P3b amplitude over left temporal areas in contrast to the control group. This two-dimensional effect was associated with a significantly reduced activation of the left middle temporal gyrus. Conclusions: The P3b amplitude decrement might represent a neurocognitive vulnerability marker for the development of depression. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This is the first neuropsychological study using the S-enantiomer of the noncompetetive N-methyl-D-aspartate antagonist ketamine. In 2 randomized placebo-controlled trials we studied effects of two different doses of (S)-ketamine (low dose/high dose) on neuropsychological functions and psychopathology in 12 healthy male volunteers. Impairment was measured via standardized neuropsychological tests. Results indicate that both subanaesthetic doses produce only nonsignificant impairment in most of the tasks. Tasks involving divided and sustained attention as well as scores for objective and subjective psychopathology show significant impairment in a dose-dependent manner. Implications of these findings for the neuropsychology of attention and schizophrenia are discussed. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective: Atypical neuroleptics seem to be more beneficial than typical ones with respect to long-term neuropsychological functioning. Thus, most studies focus on the long-term effects of neuroleptics. We were interested in whether atypical neuroleptic treatment is also superior to typical drugs over relatively short periods of time. Methods: We studied 20 schizophrenic patients [10 males, mean age 35.5 years, mean Brief Psychiatric Rating Scale (BPRS) score at entry 58.9] admitted to our hospital with acute psychotic exacerbation. Nine of them were treated with typical and 11 with atypical neuroleptics. In addition, 14 healthy drug-free subjects (6 males, mean age 31.2 years) were enrolled in the study and compared to the patients. As neuropsychological tools, a divided attention test, the Vienna reaction time test, the Benton visual retention test, digit span and a Multiple Choice Word Fluency Test (MWT-B) were used during the first week after admission, within the third week and before discharge (approximately 3 months). Results: Patients scored significantly worse than healthy controls on nearly all tests (except Vienna reaction time). Clinical ratings [BPRS and Positive and Negative Symptom Scale for Schizophrenia (PANSS)] improved markedly (p < 0.01), without a significant difference between typical and atypical medication. Clinical improvement (PANSS total score) correlated with less mistakes on the Benton test (r = 0.762, p = 0.017) and an improvement on the divided attention task (r = 0.705, p = 0.034). Neuropsychological functioning (explicit memory, p < 0.01; divided attention, p < 0.05) moderately improved for both groups under treatment but without a significant difference between atypical and typical antipsychotic drugs. Conclusions: Over short periods of time (3 months), neuropsychological disturbances in schizophrenia seem to be moderately responsive to both typical and atypical neuroleptics.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aim of this study was to delineate the influence of the emotional content of stimuli to be remembered on the recognition performance of normal subjects by means of the event-related potential (ERP) technique. When words are presented repeatedly, brain responses to repeated and recognized items are characterized by a more positive waveform, referred to as ‘old/new effect’. Words judged for their emotional connotation (‘negative’, ‘positive’ and ‘neutral’) were presented successively on a video monitor to subjects, who had the task to indicate whether a given word occurred for the first (‘new’) or second (‘old’) time within the list by pressing one of two buttons. For each word category, the ERPs of the old words were more positive compared to those of the new items from about 250 ms after stimulus. The old/new effect was significantly enhanced for the negative and positive items compared to the neutral stimuli between 450 and 650 ms after stimulus pointing to a significant influence of the emotional content of words on verbal memory processes. This paradigm appears to be feasible to investigate interactions of emotion and cognition in psychiatric patients. Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Acamprosate is effective in reducing alcohol intake in weaned alcoholics. We were interested if acamprosate had an effect on the excitability of cortical motoneurons determined by transcranial magnetic stimulation (TMS). We studied 12 male healthy volunteers (mean age 29.5 years, SD = 4.8) who were either treated with 6 tablets of acamprosate (each containing 333 mg verum) per day or placebo (randomized cross-over design) for 1 week. TMS was performed after each treatment session including a paired stimulation paradigm. Motor evoked potentials (MEPs) of the placebo and verum group did not differ with respect to paired stimulation. However, motor threshold increased in the acamprosate group (verum: 61.5% (SD = 7.9) vs. placebo: 58.9% (SD = 8.8), p = 0.036). We conclude that acamprosate leads to a hypoexcitability of the motor cortex. This might be due to subcortical mechanisms, e.g. thalamocortical pathways since intracortical inhibition and facilitation was not affected.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The effects of the opioid fentanyl and low doses of alcohol on neuropsychological functions in healthy volunteers were measured. Twenty-four healthy male volunteers participated in this study. Two randomised placebo-controlled cross-over trials were conducted. In group 1, 6 subjects received fentanyl (0.2 µg/kg body weight) in the order of fentanyl/placebo and 6 subjects in the order of placebo/fentanyl. Group 2 received alcohol in a similar procedure by continuous intravenous infusion, leading to a blood alcohol concentration (BAC) of 0.03%. Impairment was measured via different neuropsychological tests. The results indicate that fentanyl in concentrations commonly used in out-patient surgical procedures produces pronounced cognitive impairment (auditory reaction time, signal detection, sustained attention, recognition) in comparison to placebo. After application of low doses of alcohol (BAC 0.03%) only visual reaction time was impaired in comparison to placebo. [ABSTRACT FROM AUTHOR]

The effects of synthetic tetrahydrocannabinol (THC) on event-related brain potentials (ERPs) were assessed in 19 healthy male volunteers while they performed a visual continuous word recognition task. The study used a double-blind cross-over design. Specifically, word lists were manipulated to contain an equal number of emotionally neutral, negative, and positive words. Most words were repeated after several intervening items with the subject’s task to classify each word as old (previously seen) or new. Behaviorally, a decrease in recognition rate was observed under THC but no influence of the emotional charge of a word on recognition rate was seen. The ERPs showed a typical difference between old and new words taking the form of an enhanced positivity for old words beginning 250 ms poststimulus. The effects of THC were confined to the positive words, for which an enhancement of the positivity to the old words was seen. This effect was interpreted in terms of a congruity of the drug-induced mood state and the material to be recognized. The dissociation between ERPs and behavioral indices suggested that the former primarily reflect implicit memory processes. [ABSTRACT FROM AUTHOR]