O Brasil possui condições climáticas adequadas para o desenvolvimento de um grande número de frutas nativas e essa biodiversidade tem se tornado um caminho promissor para a descoberta de novos compostos bioativos capazes de ser utilizados na formulação de alimentos funcionais e medicamentos. Os compostos fenólicos apresentam ações específicas, podendo atuar como antioxidantes e anti-inflamatórios, assim prevenindo doenças crônicas. Diante do exposto, o objetivo deste trabalho foi avaliar o potencial antioxidante, antiinflamatório e a composição fenólica de dez frutas nativas brasileiras ainda pouco conhecidas: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassú (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruta-do-sabiá (Acnistus arborescens) e cajá (Spondias mombin L.). Os extratos etanólicos (80% v/v) das polpas foram analisados inicialmente quanto à capacidade de sequestro dos radicais ABTS&#8729+ e ROO&#8729. A atividade anti-inflamatória foi avaliada in vivo por meio do modelo de migração de neutrófilos induzida por carragenina, enquanto que a composição fenólica foi realizada por técnicas cromatográficas (CLAE-DAD e CG-EM). As 5 frutas com as maiores atividades biológicas foram ainda analisadas quanto à capacidade de sequestro de O2 &#8729-, HOCl e NO&#8729, atividade anti-inflamatória por meio do ensaio de ativação do fator nuclear-&kappa;B (NF-&kappa;B) e composição fenólica por espectrometria de massas de alta resolução (LC-ESI-QTOF-MS). Em relação ao sequestro do radical ABTS&#8729+ o cambuití-cipó apresentou a maior atividade (749,88 &mu;mol TE.g-1) e para o ROO&#8729 o murici vermelho apresentou a maior atividade antioxidante (559,09 &mu;mol TE.g-1). Os animais tratados com araçá-boi, cambuití-cipó, murici vermelho, cajá e morango silvestre apresentaram reduções no influxo de neutrófilos comparados ao grupo carragenina (p < 0,05). Por meio das técnicas de CLAE-DAD e CG-EM foi possível identificar compostos fenólicos pertencentes a classe dos flavonoides (catequina, epicatequina, rutina, quercetina glicosilada, kaempeferol glicosilado, quercetina, procianidina B1 e procianidina B2), sub-classe do ácido hidroxibenzóico (ácido gálico) e sub-classe dos ácidos hidrocinâmicos (ácido cumárico, ácido ferúlico e caféico). O araçá-boi, cambuití-cipó, murici vermelho, morango silvestre e cajá foram as cinco frutas que apresentaram as maiores atividades antioxidantes e/ou anti-inflamatórias, cujo perfil fenólico por LC-ESI-QTOF-MS indicou a presença de 18 compostos no araçá-boi, 32 no cambuitícipó, 26 no murici vermelho e 20 e 11 compostos no morango silvestre e cajá, respectivamente. Vários dos compostos fenólicos identificados foram encontrados pela primeira vez nessas espécies. O cambuiti-cipó e murici vermelho se destacaram em relação ao sequestro de HOCl (EC50 4,99 e 4,41 &mu;g mL-1, respectivamente) e o cambuití-cipó foi o mais ativo para desativar o radical O2 &#8729- (EC50 68,33 &mu;g mL-1) e NO&#8729 (EC50 0,78 &mu;g mL-1). Já os extratos de murici-vermelho, cambuití-cipó e morango silvestre inibiram significativamente a ativação do NF-&kappa;B. Portanto, as frutas nativas brasileiras são fontes de substâncias antioxidantes e anti-inflamatórias, bem como de uma grande diversidade de compostos fenólicos, os quais podem propiciar importantes benefícios para a saúde humana. / Brazil has favorable climatic conditions for the development of a large number of native fruits and this biodiversity has become a promising path towards the discovery of new bioactive compounds capable of being used in the formulation of functional foods and medicines. Phenolic compounds show specific action mechanisms, being able to act as antioxidants and anti-inflammatories, thus preventing chronic diseases. However, few Brazilian native fruits are well known and consumed by the population, undermining the investigation of chemical composition as well as the identification/quantification of bioactive compounds. In light of this, the objective of this work was to evaluate the antioxidant and anti-inflammatory potentials as well as the phenolic composition of ten underexploited Brazilian native fruits, namely: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassu (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruto-do-sabiá (Acnistus arborescens) and cajá (Spondias mombin L.). Pulps ethanolic extracts (80%, v/v) were initially analyzed regarding scavenging capacity of the ABTS&#8729+ and ROO&#8729 radicals. Antiinflammatory activity was evaluated in vivo using the carrageenan-induced neutrophil migration model, while phenolic composition was determined by chromatographic techniques (HPLC-PAD and GC-MS). The five fruits with the highest biological activities were analyzed for O2&#8729-, HOCl and NO&#8729 radicals scavenging capacities, for in vitro anti-inflammatory activity by nuclear factor-&kappa;B (NF-&kappa;B) activation, and for phenolic composition by High Resolution Mass Spectrometry (LC-ESI-QTOF-MS). In relation to ABTS&#8729+ radical scavenging cambuiticipó showed the highest activity (749.88 &mu;mol TE.g-1), while for ROO&#8729 scavenging, murici vermelho had the highest antioxidant activity (559.09 &mu;mol TE.g-1). The animals treated with araçá-boi, cambuití-cipó, murici vermelho, cajá and morango silvestre reported decreases in neutrophils influx compared to carrageenan group (p <0.05). It was possible to identify by HPLC-DAD and GC-MS techniques phenolic compounds belonging to the class of flavonoids (catechin, epicatechin, rutin, glycosylated quercetin, glycosylated kaempeferol, quercetin, procyanidin B1 and procyanidin B2), subclass of hydroxybenzoic acid (gallic acid) and subclass of hydrocinnamic acids (coumaric, ferulic and caffeic acids). Araçá-boi, cambuitícipó, murici vermelho, morango silvestre and cajá were the five fruits with the highest antioxidant and / or anti-inflammatory activities. The phenolic profile analysis by LC-ESIQTOF- MS pointed the presence of 18 compounds in araçá-boi, 32 in cambuití-cipó, 26 in murici vermelho, 20 in morango silvestre and 11 in cajá. Several of the identified phenolic compounds were found for the first time in these fruit species. Cambuiti-cipó and murici vermelho stood out in relation to HOCl scavenging (EC50 4.99 and 4.41 &mu;g.mL-1, respectively) and cambuití-cipó was the most active to deactivate both O2 &#8729- radical (EC50 68.33 &mu;g.mL-1) as NO&#8729 (EC 500.78 &mu;g.mL-1). Murici vermelho, cambuití-cipó and morango silvestre extracts significantly inhibited the activation of NF- &kappa;B.Therefore, Brazilian native fruits are sources of antioxidant and anti-inflammatory substances, as well as a great diversity of phenolic compounds, which can provide important benefits for human health.

[pt] A perda de insight nas próprias habilidades cognitivas pode ser uma característica de uma ampla gama de distúrbios neurológicos e pode ser relevante para os resultados clínicos e a eficácia da reabilitação. Além disso, pesquisas recentes têm mostrado que alterações na metacognição também podem caracterizar o envelhecimento saudável e interferir nas atividades da vida cotidiana, aumentando a incidência de um conjunto de comportamentos que afetam a saúde e a tomada de decisões. Considerando a natureza subjetiva da autoconsciência e a falta de consenso sobre instrumentos de avaliação para medir habilidades metacognitivas, é importante elucidar a neuroarquitetura da consciência metacognitiva e identificar biomarcadores de funções metacognitivas. A presente tese explora este tema através de quatro artigos. De acordo com o Modelo de Consciência Cognitiva (CAM), diferentes tipos de comprometimento da autoconsciência dependem de diferentes perfis de disfunções neurocognitivas, como anosognosia mnemônica e executiva. O primeiro é discutido no Artigo 1, que se concentra nos mecanismos subjacentes à autoconsciência prejudicada na doença de Alzheimer. Especificamente, as evidências sugerem que os pacientes com Alzheimer dependem de informações desatualizadas sobre si mesmos e são incapazes de consolidar novas informações como consequência da amnésia anterógrada e retrógrada. Além disso, achados de neuroimagem mostram que a degeneração fronto-cingulada e temporal estão implicadas em deficiências de autoconsciência. O Artigo 2, por sua vez, concentrou-se nos mecanismos neurais subjacentes à anosognosia executiva. Foi realizada uma revisão sistemática de estudos potenciais relacionados a eventos que investigam o automonitoramento em distúrbios neurológicos foi realizada para entender a contribuição de diferentes estruturas cerebrais para o monitoramento de erros. Especificamente, o estudo concentrou-se na negatividade relacionada ao erro (ERN) e na positividade do erro (Pe), que indexam a detecção de erros e a consciência do erro, respectivamente. Os achados sugerem a presença de processamento de domínio geral de detecção de erros com base em áreas cingulo-operculares e gânglios da base, mas também foi levantada a hipótese de que lesões fora da rede de monitoramento fronto-basal podem levar a déficits específicos de domínio. Para testar a hipótese de especificidade de domínio, foi realizado um estudo de potencial relacionado a eventos (Artigo 3). Um grupo de adultos jovens e idosos completou uma tarefa de flanker perceptual e de memória, e os resultados demonstraram que é possível diferenciar processos de automonitoramento em domínios cognitivos. Além disso, os achados de Pe demonstraram um declínio global da consciência de erro no envelhecimento. Curiosamente, apenas em adultos mais velhos, o aumento de Pe dentro da tarefa foi específico para o domínio da memória, sugerindo a presença de efeitos de aprendizagem para a memória, mas não para as decisões perceptivas. Foi levantada a hipótese de que as deficiências na percepção do erro podem estar associadas ao declínio sensorial no envelhecimento. Assim, o Artigo 4 investigou a associação entre Pe e potenciais bloqueados por estímulo em adultos jovens e idosos durante o desempenho da tarefa flanker de memória, a fim de entender a contribuição dos processos sensoriais ou de memória para mudanças relacionadas à idade na consciência de erro. Os resultados mostraram que a lembrança eficiente de estímulos foi associada a uma maior consciência de erro em adultos jovens e mais velhos e que a redução da consciência de erro em adultos mais velhos foi associada a deficiências no processamento perceptivo de estímulos. No geral, este trabalho contribui para nossa compreensão dos processos neurocognitivos subjacentes à consciência metacognitiva e correlatos neurais de diferentes tipos de anosognosia e apóia a conceituação multidimensional da consciência metacognitiva delineada pelo CAM. Os resultados do estudo oferecem novos insights sobre marcadores neurais de processos metacognitivos que podem servir para avaliação clínica e desenvolvimento de treinamento e reabilitação cognitiva. / [en] Loss of insight in own s cognitive abilities can be a feature of a wide range of neurological disorders and can be relevant for clinical outcomes and rehabilitation effectiveness. Furthermore, recent research has shown that changes in metacognition can also characterize healthy aging and interfere with everyday life activity, increasing the incidence of a set of behaviours affecting health and decision making. Considering the subjective nature of self-awareness and the lack of consensus on assessment instruments to measure metacognitive abilities, it is important to elucidate the neuroarchitecture of metacognitive awareness and identify biomarkers of metacognitive functions. The current thesis explores this topic through four articles. According to the Cognitive Awareness Model (CAM), different type of self-awareness impairments depends on different profiles of neurocognitive dysfunctions, such as mnemonic and executive anosognosia. The former is discussed in Article 1, which focuses on mechanisms underlying impaired self-awareness in Alzheimer s disease. Specifically, the evidence suggests that Alzheimer s patients rely on outdated information about the self and are unable to consolidate new information as consequence of anterograde and retrograde amnesia. Moreover, neuroimaging findings show that fronto-cingulate and temporal degeneration are implicated in self-awareness impairments. Article 2 focused instead on neural mechanisms underlying executive anosognosia. A systematic review of event-related potential studies investigating self-monitoring in neurological disorders was conducted to understand the contribution of different brain structures to error monitoring. Specifically, the study focused on the error-related negativity (ERN) and the error positivity (Pe), which index error detection and error awareness, respectively. The findings suggest the presence of domain-general processing of error detection relying on cingulo-opercular areas and basal ganglia, but it was also hypothesized that lesions outside the fronto-basal monitoring network may lead to domain-specific deficits. To test the domain- specificity hypothesis, an event-related potential study was conducted (Article 3). A group of young and older adults completed a perceptual and a memory flanker task and the findings demonstrated that it is possible to differentiate self-monitoring processes across cognitive domains. Moreover, Pe findings demonstrated a global decline of error awareness in aging. Interestingly, in older adults only, within-task increase in Pe was specific to the memory domain, suggesting the presence of learning effects for memory but not for perceptual decisions. It was hypothesized that error awareness impairments may be associated with sensory decline in aging. Thus, Article 4 investigated the association between Pe and stimulus-locked potentials in young and older adults during memory flanker task performance, in order to understand the contribution of sensory or memory processes to age-related changes in error awareness. The findings showed that efficient stimulus recollection was associated with higher error awareness in both young and older adults and that reduced error awareness in older adults was associated with impairments in perceptual processing of stimuli. Overall, this work contributes to our understanding of neurocognitive processes underlying metacognitive awareness and neural correlates of different types of anosognosia and supports the multidimensional conceptualization of metacognitive awareness delineated by the CAM. The study s results offer novel insights into neural markers of metacognitive processes that can serve clinical assessment and the development of cognitive training and rehabilitation.

Wie bereits mehrfach in anderen Studien beschrieben (Falkenstein et al., 1991; Gehring et al., 1993; Holroyd & Coles, 2002) konnte ein signifikanter Unterschied im EEG nach richtigen Antworten im Vergleich zu Fehlern in einem Zeitfenster von -35 bis 108 ms und von 110 bis 450 ms gezeigt werden. Die als Differenz aus den negativsten beziehungsweise positivsten Peaks nach falschen und richtigen Antworten berechnete „error-related negativity“ (ERN) und „error positivity“ (Pe) als wichtigste Komponenten der Fehlerverarbeitung zeigten im Vergleich zu anderen Studien zwar geringere, aber trotzdem vergleichbare Werte. Um den Einfluss von genetischen Unterschieden auf die Fehlerverarbeitung deutlich zu machen, wurde in dieser Studie untersucht, inwieweit Polymorphismen des Dopamintransporters (DAT), der Catechol-O-Methyl-Transferase (COMT) und des Phosphoproteins Stathmin Einfluss auf die Ausprägung der ERN und der Pe nehmen. Bezüglich des DAT-Polymorphismus konnte ein signifikanter Einfluss weder auf die ERN noch auf die Pe nachgewiesen werden. Hier ist zu vermuten, dass der Polymorphismus den Dopaminhaushalt der Basalganglien nicht nennenswert beeinträchtigt und demnach keinen Einfluss auf die Fehlerverarbeitung hat. Im Hinblick auf den COMT – Polymorphismus zeigte sich zwar kein Effekt auf die ERN, bei der Pe konnte man allerdings signifikante Unterschiede zwischen den Gruppen feststellen. Hier zeigten die homozygoten Träger des „val“ – Allels signifikant höhere Pe – Amplituden als die homozygoten Träger des „met“ – Allels. Heterozygote Personen lagen hinsichtlich der Pe – Amplitude zwischen den beiden anderen Gruppen. Dieser Effekt entspricht zwar nicht den Ergebnissen von anderen Studien (Egan et al., 2005; Frank et al., 2007), sollte aber dennoch Gegenstand weiterführender Forschung sein. Der Polymorphismus im Gen des Phosphoproteins Stathmin beeinflusste zwar die Amplitude der Pe nicht, zeigte aber signifikante Auswirkungen auf die ERN, wobei hier Träger des T-Allels signifikant kleinere ERN-Amplituden aufwiesen als Probanden, die dieses Allel nicht trugen. Allerdings wurde deutlich, dass dieser Effekt nach genauerer Analyse nicht stabil gegenüber Veränderungen war. Trotzdem ist davon auszugehen, dass dieser Polymorphismus die Funktion des ACC und damit auch die Fehlerverarbeitung beeinflusst, wodurch die Notwendigkeit weiterer Untersuchungen auf dem Gebiet des Phosphoproteins Stathmin gegeben ist. / As already published in several studies (Falkenstein et al., 1991; Gehring et al., 1993; Holroyd & Coles, 2002) a significant difference after correct answers compared to errors could be shown in EEG in a time window of -35 to 108ms and 110 to 450ms. The error related negativity (ERN) and error positivity (Pe) showed comparable values to other studies. To demonstrate the influence of genetic difference to the error processing, this study researched the influence of dopamine transporter (DAT), catechol-o-methyl transferase (COMT) and Stathmine to ERN and Pe. The DAT polymorphism does not have any significant influence to ERN and Pe. The COMT polymorphism shows no significant influence to ERN, but there is a significant influence to Pe. The genetic polymorphism of Stathmine does not have any impact on the amplitude of Pe but shows significant influence to ERN.

No description available.

Für das zielgerichtete Verhalten des Menschen ist ein funktionierendes Handlungsüberwachungssystem eine wichtige Voraussetzung. Somit können Fehlhandlungen registriert und verarbeitet werden, um dann anschließend das Verhalten an die entsprechende Situation besser anzupassen. Ein wichtiges neuroanatomisches Korrelat dieses Handlungsüberwachungssystems ist der anteriore Anteil des mittleren cingulären Cortex (anterior midcingulate cortex, aMCC), der in der Funktion der Fehlerverarbeitung eng mit den Basalganglien und dem lateralen präfrontalen Cortex verknüpft ist. In der vorliegenden Arbeit wurde die Bedeutung des Thalamus im Netzwerk der Fehlerverarbeitung genauer untersucht. Es konnte mittels diffusionsgewichteter Traktografie bei 16 gesunden Probanden gezeigt werden, dass speziell der Nucleus ventralis anterior (VA) und der Nucleus ventralis lateralis anterior (VLa) quantitativ stärkere Faserverbindungen mit dem aMCC aufweisen, als die restlichen Thalamuskerne. Desweiteren zeigten 15 Patienten mit Läsionen im Thalamus im Vergleich zur gesunden Kontrollgruppe im Eriksen Flanker Task fehlerspezifische Verhaltensunterschiede. Obwohl die Fehlerrate zwischen diesen Patienten und den Kontrollprobanden nahezu identisch war, konnten die Patienten ihre Fehler als solche signifikant schlechter detektieren und ihr Verhalten nach einem Fehler daher auch schlechter anpassen. Die EEG Daten zeigten für die Patientengruppe eine in der Amplitude signifikant verminderte error-related negativity (ERN – ein ereignis-korreliertes Hirnpotential, ausgelöst durch Fehlhandlungen, z.B. in Flankierreizaufgaben) im Vergleich zur Kontrollgruppe. Bei 6 Patienten mit Läsionen der VA und VLa Kerngruppe war die ERN nahezu komplett erloschen, wohingegen bei den 9 Patienten, deren Läsionen nicht VA und VLa betrafen, die ERN lediglich vermindert war. / Performance monitoring is an essential prerequisite of successful goal-directed behavior. Research of the last two decades implicates the anterior midcingulate cortex (aMCC) in the human medial frontal cortex and frontostriatal basal ganglia circuits in this function. Here, we addressed the function of the thalamus in detecting errors and adjusting behavior accordingly. Using diffusion-based tractography we found that, among the thalamic nuclei, the ventral anterior and ventral lateral anterior nuclei (VA, VLa) have the relatively strongest connectivity with the RCZ. Patients with focal thalamic lesions showed diminished error-related negativity, behavioral error detection, and post-error adjustments. When the lesions specifically affected the thalamic VA/VLa nuclei these effects were significantly pronounced, which was reflected by complete absence of the error-related negativity. These results reveal that the thalamus, particularly its VA/VLa region, is a necessary constituent of the performance-monitoring network, anatomically well connected and functionally closely interacting with the aMCC.

Die zugrunde liegenden Prozesse altersbedingter Veränderungen exekutiver Funktionen werden vielfach untersucht. Für eine flexible Anpassung ist die Überwachung von Handlungen und deren Konsequenzen notwendig. Handlungsüberwachung wird mit ereigniskorrelierten Potentialen (EKP) wie der error-related negativity/error negativity (ERN/Ne) und der correct-related negativity/correct negativity (CRN) gemessen. Die Arbeit untersucht die Handlungsüberwachung bei jüngeren und älteren Erwachsenen mit dem Ziel, das Wissen über kompensatorische Strategien bei Älteren und deren Auswirkung auf die EKP Befunde zu erweitern. Ältere zeigten reduzierte ERN/Ne und größere oder vergleichbar große CRN Amplituden im Vergleich zu Jüngeren. Während nur die Jüngeren eine Reduktion der ERN/Ne mit größerer Aufgabenschwierigkeit zeigten, zeigten beide Gruppen eine ERN/Ne Reduktion unter der Instruktion, die Geschwindigkeit anstatt Genauigkeit erforderte. Nur bei Jüngeren variierte die CRN mit der Kompatibilität der Trials, mit der Aufgabenschwierigkeit und Instruktion. Ältere wiesen geringere Fehlerraten und längere Reaktionszeiten als Jüngere auf. Dieses Muster deutet auf eine kompensatorische oder strategische Anpassung in Folge von Defiziten in der Nutzung einer erfolgreichen Kombination von proaktiver und reaktiver Kontrolle hin. Es wird postuliert, dass ERN/Ne und CRN einen gemeinsamen Prozess darstellen, der allgemeine Überwachungsfunktionen reflektiert. Die ERN/Ne beinhaltet zusätzlich einen Prozess, der Fehlerüberwachung signalisiert. Daraus ergibt sich die Vermutung, dass die reduzierte ERN/Ne bei Älteren entweder auf eine Verringerung spezifischer Fehlerprozesse oder auf eine Beeinträchtigung allgemeiner Überwachungsfunktionen zurückzuführen ist. Altersbezogene Veränderungen der EKP Befunde könnten den veränderten Einsatz von kompensatorischer Kontrolle bei Älteren im Vergleich zu Jüngeren reflektieren. Dieser Frage sollte in zukünftigen Studien nachgegangen werden. / Executive functions decline with age and a growing body of research aims at investigating age-related changes of the underlying processes. One important function is to monitor actions and action outcomes, which is necessary for flexible adjustments and learning. This so-called performance monitoring can be measured with event-related potentials (ERP), namely the error-related negativity/error negativity (ERN/Ne) and the correct-related negativity/correct negativity (CRN). This work examined performance monitoring in younger and older adults with the aim to advance knowledge about compensatory strategies in older adults and their implications for ERP results. Findings revealed reduced ERN/Ne and larger or similar-sized CRN in older compared to younger adults. While only younger adults showed a decrease of ERN/Ne with higher task difficulty, both age groups showed a reduction of ERN/Ne in the speed compared to the accuracy condition. Additionally, only younger adults showed variations, in that the CRN was smaller for compatible compared to incompatible trials, in the easy compared to the difficult condition, and in the speed compared to the accuracy condition. Behaviorally, older adults had less errors and longer response latencies than younger adults. This pattern may reflect compensatory or strategic adjustments with age which may be due to deficits in the use of a successful combination of proactive and reactive control. It was further assumed that ERN/Ne and CRN share a common process that reflects general monitoring functions and ERN/Ne includes an additional process that reflects error-specific monitoring. Accordingly, the ERN/Ne attenuation in older adults is either caused by reduced error-specific processing or compromised general monitoring functions. Age-related changes in ERP findings indicate altered engagement of compensatory cognitive control in older compared to younger adults. However, this question has to be further clarified in future studies.

The prevalence and sequelae of moderate-to-severe (M/S) traumatic brain injury (TBI) are significant and pervasive problems, and effective rehabilitation techniques are key. Errorless learning is regarded as a useful tool for memory impairments; however, the efficacy of errorless learning in a M/S TBI population is unclear. The primary goal (aim 1) of this study was to evaluate the efficacy of a single session of errorless vs. errorful learning in a group of M/S TBI survivors and matched controls. A secondary goal (aim 2) was to investigate the neural time course of errorless learning in participants with M/S TBI by analyzing the error-related negativity (ERN) component of the scalp-recorded event-related potential (ERP). The ERN is an electrophysiological measure of error processing that is disrupted in M/S TBI survivors. Measures of neuropsychological performance, self- and informant-report of executive functioning, and affect further informed both study aims. Data from 28 M/S TBI survivors (9 female) and 28 controls (9 female) were analyzed for aim 1, with data from 19 M/S TBI survivors (6 female) and 20 controls (8 female) analyzed for aim 2. There were significant differences between the TBI and control groups with regard to executive, mood, and neuropsychological functioning. Results from aim 1 indicated that TBI participants were slower across learning conditions, while both groups had significantly faster reaction times in the errorless condition. Regarding accuracy, there was not a statistically significant main effect of learning condition (p = .07), group (p = .06), or Group x Condition x Accuracy interaction (p = .33). Indices of memory and executive functioning, and group (TBI, Control) used in regressions predicted accuracy in both learning conditions (ps < .01). The memory composite was a significant independent predictor of errorless accuracy. Results from aim 2 indicated a reliable ERN was present across conditions, although there were no main effects of Condition, Group, or Group x Condition interactions on ERN amplitude or latency (ps > .22). ERN latency was not predictive of accuracy for either condition (ps > .08). Group was a significant independent predictor of accuracy in the errorless condition (p = .05), but not the errorful condition (p = .45). Findings indicate that memory functioning was a better predictor of accuracy than executive functioning or group membership. This suggests that the errorless learning benefit may be specific to memory functioning, rather than other cognitive variables. This conclusion aligns with research reporting that benefits of errorless learning depend upon the severity of memory impairments. Results from ERN analyses are only partially supported by previous research, and further work is needed to clarify the role of neural representations of errorless learning in M/S TBI.

Moderate-to-severe traumatic brain injury (M/S TBI) is a growing public health concern with significant impact on the cognitive functioning of survivors. Cognitive control and deficits in awareness have been linked to poor recovery and rehabilitation outcomes. One way to research cognitive control is through awareness of errors using electroencephalogram and event-related potentials (ERPs). Both the error-related negativity and the post-error positivity components of the ERP are linked to error awareness and cognitive control processes. Attentional capacity and levels of apathy influence error awareness in those with M/S TBI. There are strong links between awareness, attention, and apathy. However, limited research has examined the role of attention, awareness, and apathy using electrophysiological indices of error awareness to further understand cognitive control in a M/S TBI sample. The current study sought to elucidate the role of apathy in error awareness in those with M/S TBI. Participants included 75 neurologically-healthy controls (divided randomly into two control groups) and 24 individuals with M/S TBI. All participants completed self-report measures of mood, apathy, and executive functioning, as well as a brief neuropsychological battery to measure attention and cognitive ability. To measure awareness, participants completed the error awareness task (EAT), a modified Stroop go/no-go task. Participants signaled awareness of errors committed on the previous trial. The M/S TBI group decreased accuracy while improving or maintaining error awareness compared to controls over time. There were no significant between-group differences for ERN and Pe amplitudes. Levels of apathy in the M/S TBI group were included in three multiple regression analyses predicting proportion of unaware errors, ERN amplitude, and Pe amplitude. Apathy was predictive of error awareness, although not in the predicted direction. Major analyses were replicated using two distinct control groups to determine potential sample effects. Results showed consistent results comparing both control groups to a M/S TBI group. Findings show variable levels of awareness and accuracy over time for those with M/S TBI when compared to controls. Conclusions include varying levels of attention and awareness from the M/S TBI group over time, evidenced by improving awareness of errors when they are happening, but an inability to regulate performance sufficiently to improve accuracy. Levels of apathy are playing a role in error awareness, however, not in predicted directions. The study provides support for the role of attentional impairments in error awareness and encourages future studies to look for varying levels of performance within a given task when using populations linked to elevated levels of apathy and attentional deficits.

Error related negativity (ERN) is a pronounced negative evoked response potential (ERP) that follows a known error. This neural pattern has the potential to communicate user awareness of incorrect actions within milliseconds. While the implications for human-machine interface and augmented cognition are exciting, the ERN has historically been evoked only in the laboratory using complex equipment while presenting simple visual stimuli such as letters and symbols. To effectively harness the applied potential of the ERN, detection must be accomplished in complex environments using simple, preferably single-electrode, EEG systems feasible for integration into field and workplace-ready equipment. The present project attempted to use static photographs to evoke and successfully detect the ERN in a complex visual search task: motorcycle conspicuity. Drivers regularly fail to see motorcycles, with tragic results. To reproduce the issue in the lab, static pictures of traffic were presented, either including or not including motorcycles. A standard flanker letter task replicated from a classic ERN study (Gehring et al., 1993) was run alongside, with both studies requiring a binary response. Results showed that the ERN could be clearly detected in both tasks, even when limiting data to a single electrode in the absence of artifact correction. These results support the feasibility of applied ERN detection in complex visual search in static images. Implications and opportunities will be discussed, limitations of the study explained, and future directions explored.

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