N-methyl-D-aspartate receptors (NMDAR) are involved in neuronal plasticity. To assess their role simultaneously in spatial working memory and non-cognitive learning, we used NMDAR antagonists and the Allothetic Place Avoidance Alternation Task (APAAT). In this test rats should avoid entering a place where shocks were presented on a rotating arena which requires cognitive coordination for the segregation of stimuli.
View Article and Find Full Text PDFTranscranial direct current stimulation (tDCS) of the prefrontal cortex, which non-invasively alters cortical activity, has been established to affect executive functions in humans. We hypothesized that changes in excitability by tDCS, found to improve cognitive functions dependent on moderate prefrontal cortex activity, would operate similarly in animals as in humans. To verify this we performed experiments using a rat behavioral model of visuospatial working memory and skill learning paired with tDCS of the frontal cortex.
View Article and Find Full Text PDFWe present a paradigm for assessing visuospatial working memory and skill learning in a rodent model, based on the place avoidance test. In our allothetic place avoidance alternation task (APAAT) the paradigm is comprised of minimal training sessions, tests various aspects of learning and memory and provides a rich set of parameters. A single working memory session consists of four conditions: habituation (no shock), two place avoidance training intervals (shock activated) and a retrieval test (shock inactivated).
View Article and Find Full Text PDFThe functional neuroanatomy of executive function critically involves the dorsolateral prefrontal cortex. Transcranial direct current stimulation (tDCS) has been established as a noninvasive tool for transient modulation of cortical function. Here, we examined the effects of tDCS of the left dorsolateral prefrontal cortex on planning function by using the Tower of London task to evaluate performance during and after anodal, cathodal (1 mA, 15 min), and sham tDCS in 24 healthy volunteers.
View Article and Find Full Text PDFAim: Previous studies have suggested altered structural and functional asymmetry of the brain in schizophrenia.
Methods: Functional MRI was used to assess differences in cortical activation during a verbal task in Broca's area and its contralateral homologue in four pairs of right-handed monozygotic (MZ) twins discordant and concordant for schizophrenia with low and high familial loading for the illness and four healthy control MZ twin pairs.
Results: Pooled data from all subjects with schizophrenia showed increased activation in the right homologue of Broca's area in contrast to healthy individuals.
Objectives: With the aim to indicate the functional anatomical substrate of cognitive dysfunction in schizophrenia we evaluated the relationship between resting brain metabolism and performance on the Trail Making Test (TMT). As the prerequisite analysis we compared the performance in Part A and B of the TMT between schizophrenic patients and controls. Resting brain metabolism was investigated by (18)FDG positron emission tomography (PET) as the probe for the relative regional synaptic strength and density.
View Article and Find Full Text PDFThe aim of the study was to assess the 6-months treatment efficacy and 24-month follow up of three different therapeutic programs (A. moclobemide and supportive guidance, B. group cognitive-behavioral therapy and pill placebo, and C.
View Article and Find Full Text PDFAtypical antipsychotics have greatly enhanced the treatment of schizophrenia. The mechanisms underlying the effectiveness and adverse effects of these drugs are, to date, not sufficiently explained. This article summarises the hypothetical mechanisms of action of atypical antipsychotics with respect to the neurobiology of schizophrenia.
View Article and Find Full Text PDFThe high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) over the prefrontal cortex is a promising method for the treatment of negative symptoms of schizophrenia. Using double-blind sham-controlled parallel design, we evaluated the effect of HF-rTMS over the left dorsolateral prefrontal cortex (DLPFC) on negative symptoms in patients with schizophrenia. Sixteen schizophrenia patients with predominantly negative symptoms on stable antipsychotic medication were treated with 20 Hz rTMS (90% of motor threshold, 2000 stimuli per session) over ten days within 2 weeks with six weeks follow-up.
View Article and Find Full Text PDFInjecting tetrodotoxin (TTX) into one hippocampus impaired avoidance of a place defined by distal cues while rats were on a slowly rotating arena. The impairment could be explained by a deficit in memory, navigation, or behavioral inhibition. Here, we show that the TTX injection abolished the ability of rats to organize place-avoidance behavior specifically when distal room and local arena cues were continuously dissociated.
View Article and Find Full Text PDFObjectives: Amisulpride in antipsychotic doses can induce hyperprolactinemia. The aim of this study was to prove whether the same is true for low doses of amisulpride.
Methodology: Plasma prolactin levels were measured in 5 males and 5 females with depressive symptoms who were treated with 50 mg of amisulpride per day as an augmentation to antidepressants (n=5), benzodiazepine anxiolytics (n=8) or in monotherapy (n=1).
T1 and T2 relaxation times were examined in four pairs of monozygotic (MZ) twins discordant and concordant for schizophrenia with low and high genetic loading for the illness and five healthy control MZ twin pairs. Patients with schizophrenia (n = 11) showed significant prolongation in T1 relaxation times in the globus pallidus (GP) bilaterally (P < 0.005, Bonferroni corrected) when compared to 14 healthy MZ twins.
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