Allelic variation of serotonin transporter function modulates the brain electrical response for error processing.

A functional length variation in the transcriptional control region of the serotonin transporter gene (5-HTTLPR) influences brain function, personality traits, and susceptibility to psychiatric disorders. Here we measured prefrontal brain function by means of event-related potentials during an error processing paradigm. Physiologically, occurrence of an error elicits two specific electrical responses in the prefrontal cortex, the early error related negativity (Ne/ERN) and the later occurring error positivity (Pe), reflecting different components of error processing.

Source localization (LORETA) of the error-related-negativity (ERN/Ne) and positivity (Pe).

We investigated error processing of 39 subjects engaging the Eriksen flanker task. In all 39 subjects a pronounced negative deflection (ERN/Ne) and a later positive component (Pe) were observed after incorrect as compared to correct responses. The neural sources of both components were analyzed using LORETA source localization.

Sensory gating deficit in a subtype of chronic schizophrenic patients.

The dual click P50 paradigm has been established as a neurophysiological method to detect gating mechanisms. Studies of schizophrenic patients have shown that an insufficient reduction of the P50 amplitude after the second relative to the first stimulus indicates a deficient sensory gating mechanism. The aim of this study was to compare the P50 responses in the dual click paradigm of healthy volunteers to those of patients with different psychotic disorders, especially with regard to psychopathology and nosology according to ICD-10 and DSM-IV and to the classification system of Leonhard.

Face-specific event-related potential in humans is independent from facial expression.

A face-specific brain EEG potential at approximately 160 ms after stimulus presentation has recently been described by various research groups. Most of these studies analysed this face-specific brain potential using smiling faces as stimuli. In electrophysiological studies, however, differences in amplitude due to the emotional valence of the stimuli were described as early as 100 ms after stimulus presentation.