There have been conflicting findings as to whether the P3 brain potential to targets in oddball tasks is reduced in depressed patients. The P3 to novel distracter stimuli in a three-stimulus oddball task has a more frontocentral topography than P3 to targets and is associated with different cognitive operations and neural generators. The novelty P3 potential was predicted to be reduced in depre...

BACKGROUND Patients with mild to moderate AD often are apathetic and fail to attend to novel aspects of their environment. OBJECTIVE To investigate the mechanisms underlying these changes by studying the novelty P3 response that measures shifts of attention toward novel events. METHODS While event-related potentials were recorded, mildly impaired AD patients and matched normal controls (NC)...

This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they w...

Performance of voluntary behavior requires the selection of appropriate movements to attain a desired goal. We propose that the selection of voluntary movements is often contingent on the formation of a movement heuristic or set of internal rules governing movement selection. We used event-related potentials (ERPs) to identify the electrophysiological correlates of the formation of movement heu...

Parkinson's disease (PD) is characterized by deficits in goal-directed behavior as well as mood and motivational symptoms, including apathy, depression, and anxiety. The present study investigated novelty processing in PD, using event-related potentials (ERPs) to characterize electrophysiological reflections of visual novelty processing. Since apathy has been associated with decreased novelty p...

Cross-cultural differences in Easterners and Westerners have been observed in different cognitive domains. Differential sensitivity to the relationship between objects and contexts might be an underlying cognitive mechanism for these differences. Twenty-one Chinese and 22 Germans participated in a three-stimulus event-related potential oddball task. They were instructed to monitor geometrical f...

We previously reported a novelty P3 reduction in depressed patients compared to healthy controls (n=20 per group) in a novelty oddball task using a 31-channel montage. In an independent replication and extension using a 67-channel montage (n=49 per group), reference-free current source density (CSD) waveforms were simplified and quantified by a temporal, covariance-based principal components an...

A P300 (P3)-evoked response is generated in a variety of mammalian species upon detection of significant environmental events. The P3 component has been proposed to index a neural system involved in attention and memory capacity. We investigated the contribution of anterior and posterior association cortex to somatosensory P3 generation. Somatosensory event-related potentials (ERPs) were record...

Background & Objective: In an oddball experiment, the context in which novel stimuli are presented affects characteristics of novelty P3, i.e. as long as there is a difficult task in which the difference between standard and target stimuli is small, recurrent presentation of a highly discrepant stimulus can lead to P300 highly similar to novelty P3. Effect of stimulus properties on P300 has als...

The differential expression of the dopamine transmitter through its prefrontostriatal pathway has been proposed to account for individual differences in the updating of higher order task representations. Here we examined the interaction between two polymorphic variations of genes involved in the regulation of prefrontal and striatal dopamine (catechol-O-methyltransferase-COMT and ANKK1) on the ...