The bilateral origin of movement-related potentials preceding unilateral actions

It is as yet unclear why a unilateral self-paced movement in human and nonhuman primates is preceded by a bilateral Bereitschaftspotential (BP) or readiness potential (RP). The RP consists of an early symmetrical part (termed BP1 or RP), presumably of supplementary motor area (SMA) origin, and a later contralaterally dominant part (termed BP2 or NS'), to which the primary motor cortex (M1) is thought to contribute. Apart from the SMA there are other motor areas in the mesial cortex, which might provide additional sources for these slow waves. Although bilateral intracortical sources of the RP are found in the premotor cortex (Sasaki & Gemba, 1991), they play nearly any role in most discussions on the RP. Recently the very existence of the ipsilateral RP over MI has been doubted. RP recordings of two patients with an intracerebral electrode in the ventro-intermedius nucleus (Vim) of the thalamus are shown, suggesting that the ipsilateral RP is not the consequence of volume conduction or signal transmission via the corpus callosum. Rather they point to a subcortical source, from where the ipsilateral cortex is activated. Anatomical and recent RP recordings from Vim and subthalamic nucleus seem to support this interpretatio

An event-related potential study on the early processing of crying faces

Crying is an attachment behavior, which in course of evolution had survival value. This study examined the characteristics of the face-sensitive N170, and focused on whether crying expressions evoked different early event-related potential waveforms than other facial expressions. Twenty-five participants viewed photographs of six facial expressions, including crying, and performed an implicit processing task. All stimuli evoked the N170, but the facial expression modulated this component in terms of latency and amplitude to some extent. The event-related potential correlates for crying faces differed mostly from those for neutral and fear faces. The results suggest that facial expressions are processed automatically and rapidly. The strong behavioral and emotional responses to crying appear not to be reflected in the early brain processes of face recognition

Are subjective benefits of mindfulness‑based stress reduction related to changes in cardiac and cortical responses to a stress task?

AbstractObjectives Mindfulness-Based Stress Reduction (MBSR) has been shown to decrease general feelings of distress. It is not known to what extent such beneficial effects are associated with attenuation of physiological responses to challenging psychological situations. The aim of the present study was to examine potential associations between general decreases in subjective distress and changes in acute cardiac and cortical responses during recall of a recent stressful episode between pre- and post-MBSR.MethodFifty-eight MBSR participants (77.6% female, mean age 43.8 years, SD = 13.1) took part in a laboratory examination before and after MBSR. Measurements of the electrocardiogram (ECG) and electroencephalogram (EEG) were performedduring the whole protocol including the stress recall task.ResultsThe MBSR group showed overall decreases in general negative affect and an increase in heart rate variability from pre- to post-intervention. Out of six physiological outcomes (heart rate, heart rate variability, theta, alpha, beta, and gamma power at Fz), only a decreased response of gamma power during the stress task was significant. The subjective and physiological changes were unrelated.ConclusionsThe present results suggest that the favourable effects of MBSR on general stress reduction may not be clearly reflected in cortical electrical wave activity or vagal cardiac response during recall of a recent stressful episode. The few changes found in cardiac and cortical activity may be due to either effects independent of general subjective feelings or independent of the intervention altogether