Funny kittens: Positive mood induced via short video-clips affects error processing but not conflict control.

The interplay of performance monitoring functions and affective variables labeled as moods or emotions has been investigated within different theoretical frameworks including conflict adaptation and reinforcement learning. However, results regarding the electrophysiological underpinnings of performance monitoring such as the error-related negativity (ERN), the N200 or the error positivity (Pe) remain largely inconsistent. While some studies report ERN enhancements after positive mood induction, others find reductions due to positive affect. An additional source of complexity regards the manifold induction methods across studies. Here, we investigated whether performance-independent, blocked mood inductions via mini-clips alter electrophysiological markers of performance monitoring. Positive clips consisted of a pre-rated collection of human and animal funny/fail videos, while neutral clips showed natural scenes of humans and animals or sport events. The main task was a modified flanker paradigm. The effectivity of mood induction was confirmed via recorded skin conductance response (SCR), facial-muscle electromyogram (EMG) and intermittent subjective mood questionnaires. Regarding interference control neither reaction times nor error rates were influenced by mood induction, similarly no mood effects of the N2 component were observed. In contrast, we found enhanced ERN as well as Pe amplitudes in the positive compared to the neutral condition. Additional to post error slowing we found increased interference effects after errors in positive blocks on the behavioral level. The results suggest a specific receptiveness of evaluative control components to positive affect that will be discussed regarding their possible neuronal underpinnings.

Deep brain stimulation of the nucleus basalis of Meynert in Alzheimer's dementia.

Cholinergic neurons of the medial forebrain are considered important contributors to brain plasticity and neuromodulation. A reduction of cholinergic innervation can lead to pathophysiological changes of neurotransmission and is observed in Alzheimer's disease. Here we report on six patients with mild to moderate Alzheimer's disease (AD) treated with bilateral low-frequency deep brain stimulation (DBS) of the nucleus basalis of Meynert (NBM). During a four-week double-blind sham-controlled phase and a subsequent 11-month follow-up open label period, clinical outcome was assessed by neuropsychological examination using the Alzheimer's Disease Assessment Scale-cognitive subscale as the primary outcome measure. Electroencephalography and [(18)F]-fluoro-desoxyglucose positron emission tomography were, besides others, secondary endpoints. On the basis of stable or improved primary outcome parameters twelve months after surgery, four of the six patients were considered responders. No severe or non-transitional side effects related to the stimulation were observed. Taking into account all limitations of a pilot study, we conclude that DBS of the NBM is both technically feasible and well tolerated.

Mistakes that affect others: an fMRI study on processing of own errors in a social context.

In social contexts, errors have a special significance and often bear consequences for others. Thinking about others and drawing social inferences in interpersonal games engages the mentalizing system. We used neuroimaging to investigate the differences in brain activations between errors that affect only agents themselves and errors that additionally influence the payoffs of interaction partners. Activation in posterior medial frontal cortex (pMFC) and bilateral insula was increased for all errors, whereas errors that implied consequences for others specifically activated medial prefrontal cortex (mPFC), an important part of the mentalizing system. The results demonstrate that performance monitoring in social contexts involves additional processes and brain structures compared with individual performance monitoring where errors only have consequences for the person committing them. Taking into account how one's behavior may affect others is particularly crucial for adapting behavior in interpersonal interactions and joint action.

Subprocesses of performance monitoring: a dissociation of error processing and response competition revealed by event-related fMRI and ERPs.

Performance monitoring can be implemented in the brain by two possible systems, one monitoring for response competition or one detecting errors. Two current models of performance monitoring have different views on these monitoring subsystems. While the error detection model proposes a specific error detection system, the response competition model denies the necessity of a specific error detector and favors a more general unitary system evaluating response conflict. Both models suggest that the frontomedian wall in the vicinity of the anterior cingulate sulcus plays an important role in performance monitoring. The present study investigates the hemodynamic and electrophysiological correlates of response competition and error processing. Twelve young healthy participants performed a speeded, modified flanker task, while fMRI signals and ERPs were measured in separate sessions. The event-related fMRI shows that networks involving the frontomedian wall are activated during both response competition and error processing. However, an anatomical dissociation was found: while error processing preferentially activates the human homologue of the cingulate motor area (CMA, BA 24c') in the depth of the anterior cingulate sulcus, response competition is accompanied by activation of the pre-SMA and mesial BA 8. The ERP waveforms for erroneous trials exhibit a large error-related negativity, which is most likely generated in the CMA. These results suggest that the CMA plays a major role in error processing. Further fMRI activations in the lateral prefrontal and primary motor cortex are discussed with respect to performance monitoring and its influence on task set reconfiguration.

Transient global ischemia specifically modulates visual P300 scalp distribution.

OBJECTIVE: Latency, amplitude, and scalp topography of the visual P300 component was examined in patients who had suffered from transient global ischemia (TGI) due to cardiac arrest and in age matched clinical and healthy controls in order to investigate the diagnostic value of this component. METHOD: Event-related potentials (ERPs) were recorded from 19 scalp electrodes in a visual oddball paradigm. RESULTS: Mean latency of the P300 component was prolonged in both patient groups. Changes in scalp distribution of the P300, however, appear to be specific to anoxic-ischemic encephalopathy. In particular, a selective reduction of the P300 amplitudes at posterior recording sites was observed in TGI patients. Moreover, examination of the auditory P300 in TGI patients revealed that this selective change seems to be restricted to the visual modality. CONCLUSION: The results are discussed with respect to selective vulnerability of brain tissue to hypoxic-ischemic injury. After TGI a modality-specific subset of P300 generators, probably located in the transitional parieto-occipital and extrastriate occipital cortex, appears to be affected. It is also noted, that the visual P300 component could serve as an additional marker of TGI especially in patients who do not show neuropathological changes in structural brain images.

An electrophysiological test of directed forgetting: the role of retrieval inhibition.

A central issue in the research of directed forgetting is whether the differential memory performance for to-be-remembered (TBR) and to-be-forgotten (TBF) items is solely due to differential encoding or whether retrieval inhibition of TBF items plays an additional role. In this study, recognition-related event-related brain potentials (ERPs) were used to examine this issue. The spatio-temporal distributions of the old/new ERP effects obtained in Experiment 1 that employed a directed forgetting paradigm were compared with those recorded in Experiment 2 in which the level of processing was manipulated. In Experiment 1, participants were instructed to remember or to forget words by means of a cue presented after each word. ERPs recorded in the recognition test revealed early phasic frontal and parietal old/new effects for TBR items, whereas TBF items elicited only a frontal old/new effect. Moreover, a late right-frontal positive slow wave was more pronounced for TBF items, suggesting that those items were associated with a larger amount of post-retrieval processing. In Experiment 2, the same cueing method and the same stimulus materials were used, and memory encoding was manipulated by cueing participants to process the words either deeply or shallowly. Both deeply and shallowly encoded items elicited phasic frontal and parietal old/new effects followed by a late right-frontal positive slow wave. However, in contrast to TBR and TBF items, these effects differed only quantitatively. The results suggest that differential encoding alone cannot account for the effects of directed forgetting. They are more consistent with the view that items followed by an instruction to forget become inhibited and less accessible, and, therefore, more difficult to retrieve.