Feedback negativity is a negative component of the event-related brain potential observed 250-300 ms after feedback stimuli. The present study investigated the effects of value (correct or incorrect) and reward magnitude (no, small or large) on feedback negativity and P300. Feedback negativity was larger after incorrect feedback than after correct feedback, irrespective of reward magnitude. In contrast, P300 amplitude increased with reward magnitude, irrespective of value. The amplitude of feedback negativity was correlated with a trait score of negative affect and not positive affect, whereas P300 amplitude was correlated with positive affect and not negative affect. These results suggest that value and reward magnitude are processed separately in the brain.

The present study used functional magnetic resonance to examine the cerebral activity pattern associated with musical perception in musicians and non-musicians. Musicians showed left dominant secondary auditory areas in the temporal cortex and the left posterior dorsolateral prefrontal cortex during a passive music listening task, whereas non-musicians demonstrated right dominant secondary auditory areas during the same task. A significant difference in the degree of activation between musicians and non-musicians was noted in the bilateral planum temporale and the left posterior dorsolateral prefrontal cortex. The degree of activation of the left planum temporale correlated well with the age at which the person had begun musical training. Furthermore, the degree of activation in the left posterior dorsolateral prefrontal cortex and the left planum temporale correlated significantly with absolute pitch ability. The results indicated distinct neural activity in the auditory association areas and the prefrontal cortex of trained musicians. We suggest that such activity is associated with absolute pitch ability and the use-dependent functional reorganization produced by the early commencement of long-term training.

Background An international Delphi panel has defined a harmonized protocol (HarP) for the manual segmentation of the hippocampus on MR. The aim of this study is to study the concurrent validity of the HarP toward local protocols, and its major sources of variance. Methods Fourteen tracers segmented 10 Alzheimer's Disease Neuroimaging Initiative (ADNI) cases scanned at 1.5 T and 3T following local protocols, qualified for segmentation based on the HarP through a standard web-platform and resegmented following the HarP. The five most accurate tracers followed the HarP to segment 15 ADNI cases acquired at three time points on both 1.5 T and 3T. Results The agreement among tracers was relatively low with the local protocols (absolute left/right ICC 0.44/0.43) and much higher with the HarP (absolute left/right ICC 0.88/0.89). On the larger set of 15 cases, the HarP agreement within (left/right ICC range: 0.94/0.95 to 0.99/0.99) and among tracers (left/right ICC range: 0.89/0.90) was very high. The volume variance due to different tracers was 0.9% of the total, comparing favorably to variance due to scanner manufacturer (1.2), atrophy rates (3.5), hemispheric asymmetry (3.7), field strength (4.4), and significantly smaller than the variance due to atrophy (33.5%, P < .001), and physiological variability (49.2%, P < .001). Conclusions The HarP has high measurement stability compared with local segmentation protocols, and good reproducibility within and among human tracers. Hippocampi segmented with the HarP can be used as a reference for the qualification of human tracers and automated segmentation algorithms.

No abstract

To clarify the neural correlates and brain activity during the progression of human non-rapid eye movement (NREM) sleep, we examined the absolute regional cerebral blood flow (rCBF) during light and deep NREM sleep and during wakefulness in normal humans using positron emission tomography with H(2)(15)O. Relative changes in rCBF during light and deep NREM sleep in comparison to the rCBF during wakefulness were also analyzed. During light NREM sleep, the rCBF in the midbrain, in contrast to that in the pons and thalamic nuclei, did not decrease when compared to that during wakefulness, whereas rCBF decreased in the left medial frontal gyrus, left inferior frontal gyrus, and left inferior parietal gyrus of the neocortex. During deep NREM sleep, the rCBF in the midbrain tegmentum decreased, and there was a marked and bilateral decrease in the rCBF in all neocortical regions except for the perirolandic areas and the occipital lobe. There have been three groups of brain structures, each representing one type of deactivation during the progression of NREM sleep. The activity of the midbrain reticular formation is maintained during light NREM sleep and therefore represents a key distinguishing characteristic between light and deep NREM sleep. Selective deactivation of heteromodal association cortices, including those related to language, occurs with increasingly deep NREM sleep, which supports the recent theory that sleep is not a global, but it is a local process of the brain.