354 research outputs found

    P300 component in euthymic patients with bipolar disorder type I, bipolar disorder type II and healthy controls: a preliminary event-related potential study

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    The aim of the present study was to investigate P300 event-related potential components in euthymic bipolar disorder type I (BDI) and bipolar disorder type II (BDII) patients and matched controls. A total of 10 BDI patients, 10 BDII patients and 10 healthy individuals were enrolled in the study. Event-related potential data were collected according to a standard auditory 'oddball' paradigm. A significant groups effect in both the peak amplitude (P<0.001) and the mean amplitude (P<0.001) was observed; post-hoc comparisons showed that the peak and mean amplitudes of BDI and BDII patients were significantly lower than the peak and mean amplitudes of the healthy controls. The neurophysiological patterns found in the present study might at least partially reflect the presence of a mild selective cognitive impairment in euthymic BDI and BDII patients. From a clinical point of view, these evidences support the potential role of cognitive interventions in the treatment of BD

    Cerebellum in timing control: Evidence from contingent negative variation after cerebellar tDCS

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    Background and aims Timing control is defined as the ability to quantify time. The temporal estimation of supra-seconds range is generally seen as a conscious cognitive process, while the sub-seconds range is a more automatic cognitive process. It is accepted that cerebellum contributes to temporal processing, but its function is still debated. The aim of this research was to better explore the role of cerebellum in timing control. We transitorily inhibited cerebellar activity and studied the effects on CNV components in healthy subjects. Methods Sixteen healthy subjects underwent a S1-S2 duration discrimination motor task, prior and after cathodal and sham cerebellar tDCS, in two separate sessions. In S1-S2 task they had to judge whether the duration of a probe interval trial was shorter (Short-ISI-trial:800 ms), longer (long-ISI-trail:1600 ms), or equal to the Target interval of 1200 ms. For each interval trial for both tDCS sessions, we measured: total and W2-CNV areas, the RTs of correct responses and the absolute number of errors prior and after tDCS. Results After cathodal tDCS a significant reduction in total-CNV and W2-CNV amplitudes selectively emerged for Short (p &lt; 0.001; p = 0.003 respectively) and Target-ISI-trial (total-CNV: p &lt; 0.001; W2-CNV:p = 0.003); similarly, a significant higher number of errors emerged for Short (p = 0.004) and Target-ISI-trial (p = 0.07) alone. No differences were detected for Longer-ISI-trials and after sham stimulation. Conclusions These data indicate that cerebellar inhibition selectively altered the ability to make time estimations for second and sub-second intervals. We speculate that cerebellum regulates the attentional mechanisms of automatic timing control by making predictions of interval timing

    Mental flexibility in Parkinson's disease with central fatigue: Data from the frontal assessment battery

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    Background and aims Central fatigue is defined as a reduced energy level or an increased perception of effort, often associated to a failure in initiating and maintaining tasks that require self-motivation. It is common in Parkinson's disease population and it has been hypothesized to be related to a dysfunction in the striato-talamo- prefrontal loop. The aim of the present study was to explore the association between fatigue and executive functions as index of integrity of the striato-thalamo-prefrontal loop. Methods Twenty-nine non-demented PD patients without fatigue - PDnF, 28 non-demented PD patients with fatigue - PDF and 26 age and sex- matched controls underwent an evaluation with the Frontal Assessment Battery (FAB), MMSE, PSQI, BDI, STAI Y1-2, PDQ-39. Differences between groups in FAB scores (total and subitems) were analyzed by means of Kruskal-Wallis test. Moreover, a correlation between fatigue and FAB was also analyzed. Results Overall parkinsonian population displayed worse performance than controls in frontal scores especially inhibitory control (p = 0.008) and sensitivity to interference (p = 0.014). PDF displayed significantly worse than PDnF in verbal fluency (p = 0.05). Fatigue severity inversely correlated with executive performance (p b 0.001). Conclusions Phonemic fluency tasks are thought to reflect the simultaneous engagement of several executive functions such as attention, working memory, retrieval, information processing. The association of central fatigue with a deficit in mental flexibility, could support the hypothesis that central fatigue is a reliable index of the impairment of higher executive functions needed in order to effectively assess costs and benefits related to adaptive decision- making behavior

    Overt and covert effects of cognitive fatigue on attention networks

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    Background and aims Cognitive fatigue refers to a variation of the psychophysiological state during or after prolonged periods of mental activity that requires work efficiency, and could lead to temporary deterioration of attentional functioning, especially top-down attention and cognitive control. The present study aims to verify the effects of cognitive fatigue on attention in the context of the three attentional networks described by Posner, by using behavioral and psychophysiological measures, to detect variations in overt and covert responses respectively. Methods Thirty young healthy subjects were enrolled in the study, 15 in the “fatigue” and 15 in the control group. Cognitive fatigue was provoked by a continuous arithmetic task lasting 1 h, and the EEG recordings were conducted before and after the task, while subjects were performing the attention network test. The N1, N2 and P3 components were analyzed for the alerting, orienting and conflict networks, in conformity with behavioral analysis. Results No difference emerged between groups in networks' efficiency scores and in N1 and P3 amplitudes related to the alerting network. As regards the orienting network, P3 amplitude was significantly reduced in the fatigue group alone (p = 0.02), while no differences emerged in N1 amplitude. As regards the conflict network, both N2 and P3 amplitudes were significantly reduced in the fatigue group alone and selectively for the incongruent target (p &lt; 0.001; p = 0.001 respectively). Conclusions Our results suggest that, in young healthy subjects, cognitive fatigue interferes with goal-driven attention especially when the task demand is higher, sparing the bottom-up attention control mechanisms and in absence of any overt observable effect

    Mineral content of young leaves of yerba mate.

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    A Erva-mate é muito usada para produção de bebidas para consumo humano. Na primavera, a planta desenvolve folhas jovens que podem representar um novo nicho de mercado na indústria de erva-mate; este período é chamado nesse estudo de prea-safrinha. Este estudo teve por objetivo investigar os teores nutricionais totais e hidrossolúveis de folhas jovens de erva-mate coletadas na primavera e seu potencial nutricional para o consumo humano. Para representar folhas jovens da pre-safrinha, o material vegetal recolhido foi limitado ao terceiro botão terminal. A análise química total e hidrossolúvel de folhas das procedências Cascavel (progênie 174), Ivaí (progênie 6), Barão de Cotegipe (progênies 68 e 69) incluiu os seguintes elementos: P, K, Ca, Mg, Na, Fe, Mn, Cu e Zn.O conteúdo dos elementos da bebida obtida a partir da infusão de folhas jovens de erva-mate na ingestão diária recomendada variou de 0,5 a 11,5 % e se apresentou na seguinte ordem: Cu > Mn > K > P > Mg > Fe > Zn > Ca > Na. Progênies e morfotipos de erva-mate mostraram pouca variação no conteúdo total de nutrientes e não diferiram quanto ao conteúdo de nutrientes hidrossolúveis avaliados nas folhas jovens. Sendo assim, o extrato obtido a partir de folhas jovens de erva-mate apresenta potencial de uso para o consumo humano

    Valor nutricional total e hidrossolúvel de folhas jovens de erva mate (Ilex paraguariensis) coletadas na época de pré-safrinha.

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    Morfotipos de erva-mate apresentam diferenças na composição mineral e no teor de compostos fitoquímicos como teobromina, cafeína e taninos. O aperfeiçoamento do conhecimento da variação química das folhas relativo às características de cada procedência, progênies e da época de colheita das folhas permite gerar produtos com características de interesse para o setor industrial. O objetivo desse trabalho foi verificar as diferenças na composição química das folhas de 4 progênies de erva-mate, colhidas na época de pré-safrinha. Foram coletadas folhas jovens de plantas adultas na Fazenda Experimental Caguiri, pertencente à UFPR, município de Pinhais em novembro de 2011. Foram quantificados os teores totais e hidrossolúveis de P (fósforo), K (potássio), Ca (cálcio), Mg (magnésio), Cu (cobre), Fe (ferro), Mn (manganês), Zn (zinco) e Na(sódio). O objetivo desse trabalho foi quantificar os teores totais e hidrossolúveis de macro e micro elementos em folhas de erva-mate colhidas na época de pré-safrinha. Conclui-se as progênies apresentaram diferentes teores totais de K, Ca, Mg, Mn, Fe, Na e hidrossolúveis de Mn; para aumentar os teores de P no chá produzido com erva mate, a progênie mais indicada é a Barão de Cotegipe 69, para K e Zn a progênie Ivai 4, para Ca a Barão de Cotegipe 68, para Mg a Barão de Cotegipe 68 e 69, para Mn a Barão de Cotegipe 68 e para Fe a Cascavel 174; os nutrientes mais disponíveis para alimentação humana em uma xícara de chá são em ordem decrescente: K, Cu, P, Mg, Ca, Fe, Mn, Zn e Na sendo a contribuição desses nutrientes na ingestão diária recomendada pela ANVISA em ordem decrescente: Cu, Mn, P, Mg, Fe, Zn e Ca.Resumo expandido
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