Intracranial recordings, lesion studies, and the combination of functional imaging with source analysis have produced a solid body of evidence about the generators of the P300 event-related potential. Although it is impossible to square all findings obtained across and within methodologies, a consistent pattern of generators has emerged, with target-related responses in the parietal cortex and the cingulate and novelty-related activations mainly in the inferior parietal and prefrontal regions. Stimulus modality-specific contributions come from the inferior temporal and superior parietal cortex for the visual and from the superior temporal cortex for the auditory modality. The P300 continues to be an important signature of cognitive processes such as attention and working memory and of its dysfunction in neurologic and mental disorders. It is increasingly being investigated as a potential genetic marker of mental disorders. Knowledge about the generators of the P300 will be crucial for a better understanding of its cognitive significance and its continuing clinical application.

In February of 2012, the first international conference on real time functional magnetic resonance imaging (rtfMRI) neurofeedback was held at the Swiss Federal Institute of Technology Zurich (ETHZ), Switzerland. This review summarizes progress in the field, introduces current debates, elucidates open questions, and offers viewpoints derived from the conference. The review offers perspectives on study design, scientific and clinical applications, rtfMRI learning mechanisms and future outlook

Constraints from functional magnetic resonance imaging (fMRI) were used to identify the sources of the visual P300 event-related potential (ERP). Healthy subjects performed a visual three-stimulus oddball paradigm with a difficult discrimination task while fMRI and high-density ERP data were acquired in separate sessions. This paradigm allowed us to differentiate the P3b component of the P300, which has been implicated in the detection of rare events in general (target and distractor), from the P3a component, which is mainly evoked by distractor events. The fMRI-constrained source model explained Ͼ99% of the variance of the scalp ERP for both components. The P3b was mainly produced by parietal and inferior temporal areas, whereas frontal areas and the insula contributed mainly to the P3a. This source model reveals that both higher visual and supramodal association areas contribute to the visual P3b and that the P3a has a strong frontal contribution, which is compatible with its more anterior distribution on the scalp. The results point to the involvement of distinct attentional subsystems in target and distractor processing.

Apart from being a common feature of mental illness, auditory hallucinations provide an intriguing model for the study of internally generated sensory perceptions that are attributed to external sources. Until now, the knowledge about the cortical network that supports such hallucinations has been restricted by methodological limitations. Here, we describe an experiment with paranoid schizophrenic patients whose on- and offset of auditory hallucinations could be monitored within one functional magnetic resonance imaging (fMRI) session. We demonstrate an increase of the blood oxygen level-dependent (BOLD) signal in Heschl's gyrus during the patients' hallucinations. Our results provide direct evidence of the involvement of primary auditory areas in auditory verbal hallucinations and establish novel constraints for psychopathological models.