Are effects of emotion in single words non-lexical? Evidence from event-related brain potentials

Emotional meaning impacts word processing. However, it is unclear, at which functional locus this influence occurs and whether and how it depends on word class. These questions were addressed by recording event-related potentials (ERPs) in a lexical decision task with written adjectives, verbs, and nouns of positive, negative, and neutral emotional valence. In addition, word frequency (high vs. low) was manipulated. The early posterior negativity (EPN) in ERPs started earlier for emotional nouns and adjectives than for verbs. Depending on word class, EPN onsets coincided with or followed the lexicality effects. Main ERP effects of emotion overlapped with effects of word frequency between 300 and 550 ms but interacted with them only after 500 ms. These results indicate that in all three word classes examined, emotional evaluation as represented by the EPN has a post-lexical locus, starting already after a minimum of lexical access.     

Simultaneous measurement of glucose blood–brain transport constants and metabolic rate in rat brain using in-vivo 1H MRS

Cerebral glucose consumption and glucose transport across the blood–brain barrier are crucial to brain function since glucose is the major energy fuel for supporting intense electrophysiological activity associated with neuronal firing and signaling. Therefore, the development of noninvasive methods to measure the cerebral metabolic rate of glucose (CMR_glc) and glucose transport constants (K_T: half-saturation constant; T_max: maximum transport rate) are of importance for understanding glucose transport mechanism and neuroenergetics under various physiological and pathological conditions. In this study, a novel approach able to simultaneously measure CMR_glc, K_T, and T_max via monitoring the dynamic glucose concentration changes in the brain tissue using in-vivo¹H magnetic resonance spectroscopy (MRS) and in plasma after a brief glucose infusion was proposed and tested using an animal model. The values of CMR_glc, T_max, and K_T were determined to be 0.44±0.17 μmol/g per minute, 1.35±0.47 μmol/g per minute, and 13.4±6.8 mmol/L in the rat brain anesthetized with 2% isoflurane. The Monte-Carlo simulations suggest that the measurements of CMR_glc and T_max are more reliable than that of K_T. The overall results indicate that the new approach is robust and reliable for in-vivo measurements of both brain glucose metabolic rate and transport constants, and has potential for human application.     

Reduced early visual emotion discrimination as an index of diminished emotion processing in Parkinson’s disease? – Evidence from event-related brain potentials

Although Parkinson’s disease (PD) is defined by its motor symptoms, it is now well recognized that cognitive and affective domains, such as recognition of emotion from facial expressions, may also be impaired. To examine brain mechanisms involved in processing of emotion recognition from facial expressions, we obtained affective ratings and visual event-related potentials (ERPs) in response to facial expressions from 18 PD patients under dopamine-replacement therapy, and 17 healthy age- and sex-matched controls. In control subjects, the early posterior negativity (EPN) of the ERP, which is thought to reflect early perceptual emotion discrimination, was larger in response to emotional compared to neutral facial expressions. In contrast, this emotional modulation of the EPN was absent in PD patients indicating impaired early emotion discrimination. Behaviorally, PD patients showed no impairments in emotion recognition as measured by affective ratings. These findings suggest that facial emotion processing may be disrupted at an early stage of visual neural processing in PD. Absence of behavioral impairment may point to compensatory strategies of emotion recognition in medicated PD patients. Further research should clarify these dissociations between behavioral and neurophysiological levels of emotion processing in PD.     

Self-regulation of brain activity and its effect on cognitive function in patients with multiple sclerosis – First insights from an interventional study using neurofeedback

ObjectiveTo investigate the effects of EEG-based neurofeedback training, in which one can learn to self-regulate one’s own brain activity, on cognitive function in patients with multiple sclerosis (pwMS).MethodsFourteen pwMS performed ten neurofeedback training sessions within 3–4 weeks at home using a tele-rehabilitation system. The aim of the neurofeedback training was to increase voluntarily the sensorimotor rhythm (SMR, 12–15 Hz) in the EEG over central brain areas by receiving visual real-time feedback thereof. Cognitive function was assessed before and after all neurofeedback training sessions using a comprehensive standardized neuropsychological test battery.ResultsHalf of the pwMS (N = 7) showed cognitive improvements in long-term memory and executive functions after neurofeedback training. These patients successfully learned to self-regulate their own brain activity by means of neurofeedback training. The other half of pwMS (N = 7) did neither show any cognitive changes when comparing the pre- and post-assessment nor were they able to modulate their own brain activity in the desired direction during neurofeedback training.ConclusionsData from this interventional study provide first preliminary evidence that successful self-regulation of one’s own brain activity may be associated with cognitive improvements in pwMS.SignificanceThese promising results should stimulate further studies. Neurofeedback might be a promising and alternative tool for future cognitive rehabilitation.