Auditory mismatch negativity in pre-manifest and manifest Huntington's disease.

AIM: The aim of this study was to investigate the characteristics of the electrophysiological brain response elicited in a passive acoustic oddball paradigm, i.e. mismatch negativity (MMN), in patients with Huntington's disease (HD) in the premanifest (pHD) and manifest (mHD) phases. In this regard, we correlated the results of event-related potentials (ERP) with disease characteristics. METHODS: This was an observational cross-sectional MMN study. In addition to the MMN recording of the passive oddball task, all subjects with first-degree inheritance for HD underwent genetic testing for mutant HTT, the Huntington's Disease Rating Scale, the Total Functional Capacity Scale, the Problem Behaviors Assessment short form, and the Mini-Mental State Examination. RESULTS: We found that global field power (GFP) was reduced in the MMN time window in mHD patients compared to pHD and normal controls (NC). In the pHD group, MMN amplitude was only slightly and not significantly increased compared to mHD, while pHD patients showed increased theta coherence between trials compared to mHD. In the entire sample of HD gene carriers, the main MMN traits were not correlated with motor performance, cognitive impairment and functional disability. CONCLUSION: These results suggest an initial and subtle deterioration of pre-attentive mechanisms in the presymptomatic phase of HD, with an increasing phase shift in the MMN time frame. This result could indicate initial functional changes with a possible compensatory effect. SIGNIFICANCE: An initial and slight decrease in MMN associated with increased phase coherence in the corresponding EEG frequencies could indicate an early functional involvement of pre-attentive resources that could precede the clinical expression of HD.

Reduction of anxiety symptoms during systemic family therapy results in a concurrent improvement of cognitive performance: a study on people with high anxiety.

Difficulties in various cognitive functions are common observations in people experiencing anxiety. However, limited research has investigated the effects of psychotherapy on abnormal cognitive functioning. This study assessed whether psychotherapy-related reductions of anxiety result in improvements of cognitive functioning as well. Fifty-four participants with high self-reported anxiety, divided into two experimental groups (N = 28 and N = 26), and 27 non-anxious control participants (N = 27) completed a battery of memory tasks and anxiety questionnaires in three consecutive time points. In experimental group 1, participants started systemic family therapy immediately after the first time point, while, in experimental group 2, participants begun the same type of therapy three months later at the second time point. The results showed that, compared to control participants, at the beginning of the experiment, participants in the experimental groups had significantly lower memory performance, along with higher anxiety. Psychotherapy had a beneficial effect on anxiety symptoms and cognitive performance, with significant changes occurring only after intervals of treatments. These results show that psychotherapy is effective not only in reducing anxiety symptoms but on cognitive functioning as well. This improvement might be linked to the release of cognitive resources previously absorbed by worrisome thoughts, facilitated by a heightened protection from interference.

Reduced magnetic mismatch negativity: a shared deficit in psychosis and related risk.

BACKGROUND: Abnormal auditory processing of deviant stimuli, as reflected by mismatch negativity (MMN), is often reported in schizophrenia (SCZ). At present, it is still under debate whether this dysfunctional response is specific to the full-blown SCZ diagnosis or rather a marker of psychosis in general. The present study tested MMN in patients with SCZ, bipolar disorder (BD), first episode of psychosis (FEP), and in people at clinical high risk for psychosis (CHR). METHODS: Source-based MEG activity evoked during a passive auditory oddball task was recorded from 135 patients grouped according to diagnosis (SCZ, BD, FEP, and CHR) and 135 healthy controls also divided into four subgroups, age- and gender-matched with diagnostic subgroups. The magnetic MMN (mMMN) was analyzed as event-related field (ERF), Theta power, and Theta inter-trial phase coherence (ITPC). RESULTS: The clinical group as a whole showed reduced mMMN ERF amplitude, Theta power, and Theta ITPC, without any statistically significant interaction between diagnosis and mMMN reductions. The mMMN subgroup contrasts showed lower ERF amplitude in all the diagnostic subgroups. In the analysis of Theta frequency, SCZ showed significant power and ITPC reductions, while only indications of diminished ITPC were observed in CHR, but no significant decreases characterized BD and FEP. CONCLUSIONS: Significant mMMN alterations in people experiencing psychosis, also for diagnoses other than SCZ, suggest that this neurophysiological response may be a feature shared across psychotic disorders. Additionally, reduced Theta ITPC may be associated with risk for psychosis.

Working memory impairment in relation to the severity of anxiety symptoms.

A working memory (WM) deficit is a reliable observation in people experiencing anxiety. Whether the level of anxiety is related to the severity of WM difficulties is still an open question. In the present experiment, we investigated this aspect by testing the WM performance of people with different levels of anxiety symptoms. Participants were grouped according to self-report anxiety into a control group with low anxiety scores and an experimental group with clinically relevant anxiety. The experimental group was then divided into a high anxiety group and a severe anxiety group. Participants performed a battery of WM tasks tagging different WM processes. The results showed that, compared to participants with low anxiety, participants with clinically relevant anxiety scores had reduced accuracy in all the WM tasks. Interestingly, participants with high and severe anxiety did not present any significant difference. Anxious participants showed difficulties also in cognitive domains other than WM. Hence, these results supply reliable evidence that people with clinically relevant anxiety scores present WM difficulties, irrespective of symptoms severity. The observation that anxiety compromises performance also in cognitive domains other than WM suggests that the deficit might affect fluid cognition.

The Processing of Visual Signals in Major Depressive Disorder.

The balanced processing of the internal mental world and the external world is a crucial aspect of everyday well-being. An extensive control of the internal emotional and cognitive world that often results in an internal expression of distress is a common feature of internalizing disorders. However, how depression affects the processing of the external world is still an open question. We, therefore, tested the processing of visual signals in major depressive disorder (MDD). To this end, we recorded the electroencephalogram of 38 MDD patients and 38 controls, while they performed a response-choice task with informative feedback and a passive viewing task. MDD patients differed significantly from controls in the early information processing of visual stimuli. The vertex positive potential (VPP) evoked by feedback in the response-choice task and pictures in the passive viewing task were smaller in MDD patients than in controls. This outcome suggests that depression might subtract attentional resources from external signal processing, with potential consequences in various cognitive domains.

On the processing of optimal performances: Studying arousal evoked by being correct and fast.

INTRODUCTION: Responses are optimal when they are accurate and fast. The present experiment investigated whether optimal responses evoke physiological arousal and whether performance affects the processing and evaluation of subsequent emotional material. METHODS: Participants performed a response-choice task, where feedback was a colored square reflecting performance quality or a face whose expression (happy or angry) did not indicate any aspect of performance. In the occurrence of an emotional stimulus, participants had to express a judgment about the emotional strength. The experiment focused on differences in the electrodermal and brain electrophysiological activities evoked by optimal (correct-fast) and suboptimal (correct-slow) responses, along with modulations on the processing and interpretation of facial emotions. RESULTS: The results showed that, compared to correct responses, incorrect responses elicited an augmented phasic skin conductance response (SCR) and enhanced response-locked event-related potentials. Importantly, among correct responses, the SCR and the correct-related negativity (CRN) were larger for correct-fast than correct-slow responses. Performance also affected the processing of faces, irrespective of the emotion, but it did not change the subjective interpretation. The EPN evoked by angry and happy faces was less negative after optimal than suboptimal responses. CONCLUSION: These results indicate that the monitoring system is sensitive to detect correct-fast responses, resulting in a state of physiological arousal that might guide the reinforcement of optimal performances.

Treatment-related changes towards normalization of the abnormal external signal processing in panic disorder.

Despite the scientific consensus on the efficacy of psychotherapy for the treatment of psychological disorders, the evidence of treatment-related changes towards normalization of abnormal brain functions in patients is mixed. In the present experiment, we investigated whether treatment can affect early information processing, by testing abnormal event-related potentials (ERPs) evoked by internal and external signals in panic disorder. Sixteen patients with panic disorder and comorbid personality disorder and sixteen control participants performed a response-choice task and a passive viewing task in two testing sessions, separated by around 14 months. During this period, patients received psychological treatment. In agreement with previous studies of performance monitoring, the abnormal amplitude of the Ne/ERN-an index of error processing based on internal signals-did not change between the first and second testing session. However, treatment-related changes were evident for the abnormal vertex positive potential (VPP) evoked by external signals in the response-choice task and the passive viewing task. In patients, the VPP was smaller in the second session compared to the first session, whereas no significant changes occurred in controls. This result supplies evidence of treatment-related changes towards normalization in the early information processing of external visual stimuli in panic disorder.

Feedback processing in the context of social comparison.

In many situations, social comparison calls for the evaluation of one´s own performance in relative terms by taking into account the performances of other people. Here, we investigated the effects of social comparison on performance monitoring with the help of ERPs. Two participants performed two identical experiments at the same time and in the same room. Instructions created a social context of cooperation by suggesting that participants were performing the same task for the maximization of a shared bonus. The experiment was a response-choice task with two feedback signals presented in sequence after each response: one feedback described the personal performance (personal feedback) and one reflected the other participant's performance (nonpersonal feedback). In the present experiment, social comparison should induce interpretations of the second feedback in relative terms (e.g., "I performed better") according to the quality of the first feedback. ERP results showed that the first nonpersonal feedback affected the fronto-central P3 component (P3a) evoked by the second personal feedback but did not modulate the feedback-related negativity (FRN). The P3a component evoked by the personal feedback was larger when the comparison against the preceding nonpersonal feedback signaled that the personal performance was worse than the other participant's performance. Interestingly, the effect was prominent over bilateral fronto-central electrodes (FC3, FC4). The observed P3a effect might indicate the recruitment of attentional resources when the comparison between personal and nonpersonal performance shows that the personal performance was not as good as the performance of others.

Internal and external signal processing in patients with panic disorder: An event-related potential (ERP) study.

Self-absorption describes a pathological tendency towards the internal mental world (internalization) that often conflicts with the accurate monitoring of the external world. In performance monitoring, an augmented electrophysiological response evoked by internal signals in patients with anxiety or depressive disorder seems to reflect this tendency. Specifically, the error-related negativity (Ne/ERN), an index of error processing based on internal signals, is larger in patients compared to controls. In the present experiment, we investigated whether the preferential processing of internal signals in patients is linked to diminished and inflexible external signal processing. To this end, the electrophysiological response evoked by external signals was analysed in patients with panic disorder and healthy controls. Participants performed a choice-response task, where informative or uninformative feedback followed each response, and a passive viewing task. As a replication of previous studies, patients presented an augmented Ne/ERN, indexing enhanced processing of internal signals related to errors. Furthermore, the vertex positive potential (VPP) evoked by visual stimuli was larger in patients than in controls, suggesting enhanced attention to external signals. Moreover, patients and controls showed similar sensitivity to the feedback information content, indicating a normal flexibility in the allocation of monitoring resources to external signals depending on how informative these signals are for performance monitoring. These results suggest that the tendency towards internal signals in patients with panic disorder does not hinder the flexible processing of external signals. On the contrary, external signals seem to attract enhanced processing in patients compared to controls.

Linking internal and external signals for performance monitoring: An event-related potential study.

The present study explored the relevance of internal signals for the dynamics of personal and nonpersonal feedback processing. To this end, pairs of participants performed concurrently a choice-response task and received external signals in four feedback contexts. In two contexts, feedback was informative about the personal performance (personal/private and personal/public); in the other two contexts, instructions suggested that feedback was informative about the other participant's performance (nonpersonal/other) or that it was random (nonpersonal/random). Since personal feedback was contingent on performance, the two contexts with personal feedback allowed a reference between internal and external signals. This reference significantly affected personal feedback processing. On the one hand, in the processing of personal feedback, the feedback-related negativities (FRNs) evoked by feedback associated with distinctively fast or slow responses were less negative than the FRN elicited by feedback related to responses made with average speed. On the other hand, feedback signals evoked FRNs with similar amplitudes in the two contexts with nonpersonal feedback. Furthermore, personal and nonpersonal feedback elicited ERPs with different strength. Starting with the P2 potential, personal feedback evoked a more positive electrophysiological response than nonpersonal feedback. Based on these results, we conclude that a link between internal and external signals, as for personal feedback, is a key factor influencing the dynamics of feedback processing.

Processing genuine and nongenuine smiles as social response to personal performance: An event-related brain potential (ERP) study.

We investigated the processing of faces with different smile expressions according to a context of personal performance. Individual judgments of smile happiness were collected to assess the processing of different types of smile when these were presented as a social response in a cognitive conflict task. Two main factors were considered: (a) Expression characteristics of the smile were manipulated: that is, happy (happy-happy), neutral (neutral-happy), or sad (sad-happy) eyes were morphed in faces with smiling mouth; (b) The performance context in which the smiling face appeared as social response (after fast, average, or slow correct response). Participants rated happy-happy faces the happiest followed by neutral-happy faces, then sad-happy faces (happy-happy > neutral-happy > sad-happy). Moreover, faces were rated more happy after fast responses as compared with average or slow responses (fast > average > slow). In addition to subjective ratings, we recorded the electroencephalography (EEG) and calculated event-related brain potentials (ERPs). The ERPs showed modulations of early visual potentials according to the expression characteristics of the face. The P1 was larger for sad-happy than neutral-happy faces. Moreover, the relationship between performance and face had a significant impact on the early posterior negativity (EPN), an ERP component associated with emotion processing. Faces elicited the largest EPN amplitude after average and slow responses as compared with fast responses. These results show that smile processing and interpretation are determined both by the distinctive perceptual features of the smile expression and by the performance context in which the smiling face occurs. (PsycINFO Database Record

Processing of Internal and External Signals for Performance Monitoring in the Context of Emotional Faces.

Performance monitoring can be based on internal or external signals. We recorded event-related potentials (ERPs) to investigate whether relating performance to external signals affects internal performance monitoring. Thirty participants performed a task in which responses were followed by faces whose expressions were partially contingent upon performance. Instructions given to half of the participants mentioned a link between task performance and the upcoming face expression. Instructed participants showed smaller error-related negativity (Ne/ERN) to erroneous responses and larger N170 to faces as compared to participants in the not-instructed group. In addition, we observed a correlation between ΔNe/ERN and P1-latency benefit for angry faces after errors. Taken together, processing of internally generated signals for performance monitoring is reduced by instructions referring to an emotional face. Furthermore, we relate the correlation between the magnitude of internal monitoring and facilitation in processing angry faces to priming induced by the negative affective meaning of errors.

Early response activation in repetition priming: an LRP study.

According to recent interpretations of repetition priming, response codes are automatically bound to a stimulus and retrieved during successive presentations of the stimulus, hence, affecting its current processing. Despite a solid corpus of behavioural evidence in line with this interpretation, electrophysiological studies have reported contrasting results regarding the nature and the timing of response code retrieval. The present experiment aims to establish at which stage of information processing decision and action codes are retrieved in repetition priming. To this end, the lateralized readiness potential (LRP) was analysed for primed faces to monitor motor cortex activity related to response preparation. Congruent and incongruent responses were obtained by having identical or reversed tasks between study and test. Primed stimuli presented LRP activations with opposite polarities for the two congruency conditions in the time-window 250-300 ms, indicating response-related motor cortex activity resulting from the retrieval of correct and incorrect decision/action codes for congruent and incongruent trials, respectively. This result indicates that decision and action codes bound to a primed stimulus are retrieved at early stages of stimulus processing and that these codes are transmitted to the motor cortex.

On the correct side of performance: Processing of internal and external signals in response speed evaluation.

Response appropriateness is not exclusively limited to accuracy. Nevertheless, the processing of parameters other than accuracy for response monitoring has been mostly neglected. The present experiment explored how the cognitive system processes response speed based on internal and external signals. Participants performed a response-choice task where correct responses were classified as fast, average, or slow. External signals informative about performance quality were presented after the response in most of the trials; in some trials, instead, participants had to judge their own performance. Event-related brain potentials (ERPs) of response and feedback processing were analysed to investigate how the cognitive system monitors correct responses. Response quality affected the processing of internal signals. That is, both the response-related negativity (correct-related negativity, CRN) and positivity (correct positivity, Pc) showed modulations related to speed: with the largest and the smallest amplitudes associated with fast and slow responses, respectively. We ascribe these modulations to positive arousal associated with the optimal nature of correct fast responses. Response quality, also affected feedback processing. Here, response speed significantly modulated the feedback-related negativity (FRN) and had an effect on the latency and the magnitude of the preceding positive peak. These effects in feedback processing seem related to feedback expectation in a context where awareness of feedback quality is vague and average performance, although more difficult to detected, is generally expected.

Dissociation of rapid response learning and facilitation in perceptual and conceptual networks of person recognition.

Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition. Here, we addressed the relevance of network facilitation and rapid response learning for priming of person recognition with a view to advance general theories of priming. In four experiments, participants performed conceptual decisions like occupation or nationality judgments for famous faces. The magnitude of rapid response learning varied across experiments, and rapid response learning co-occurred and interacted with facilitation in perceptual and conceptual networks. These findings indicate that rapid response learning and facilitation in perceptual and conceptual networks are complementary rather than competing theories of priming. Thus, future memory theories need to incorporate both rapid response learning and network facilitation as individual facets of priming.