ERP correlates of error processing during performance on the Halstead Category Test.

The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT are lacking. This paper demonstrates the use of a methodology inspired on Singular Spectrum Analysis (SSA) applied to EEG signals, to remove high amplitude ocular and movement artifacts during performance on the test. This filtering technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly, the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified. This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential that coupling ERP information with behavioral performance data can bring to the specificity of the HCT in diagnosing different types of impairment in frontal brain function.

Efeito do gel da babosa (Aloe barbadensis Mill. ) associado ao ultrassom em processo inflamatório agudo / Effect of aloe (Aloe barbadensis Mill. ) gel combined with ultrasound in the acute inflammatory process

O presente trabalho teve por objetivo analisar a ação antiinflamatória do gel da Babosa a 2 por cento (Aloe barbadensis Mill.) associado ao Ultrassom pulsátil no modelo de edema de pata. Foram utilizados 25 ratos Wistar, (200-250 g), divididos em 5 grupos de 5 animais cada. Grupo1 (controle): ratos tratados com solução salina a 0,9 por cento; Grupo 2: ratos tratados topicamente com gel de A. barbadensis Mill. a 2 por cento; Grupo 3: animais tratados com Ultrassom; Grupo 4: ratos tratados com gel de A. barbadensis Mill. a 2 por cento associado ao Ultrassom; Grupo 5 (controle positivo): ratos tratados com Indometacina na dose de 5 mg Kg-1. Os animais dos grupos 1 e 5 receberam os respectivos tratamentos por via intra-peritoneal 30 minutos antes da injeção intra-plantar de carragenina e os grupos 2, 3 e 4 foram tratados por aplicação tópica de gel de A. barbadensis Mill. a 2 por cento, Ultrassom pulsátil e gel de A. barbadensis Mill. associado ao Ultrassom respectivamente 15 minutos após a indução do edema. Os animais do grupo 04 demonstraram redução significativa do edema quando comparados ao grupo controle, ao mesmo tempo, que se mostrou comparável à indometacina. Observou-se que o gel de aloe associado à fonoforose é capaz reduzir a formação do edema de pata em ratos.

This work aimed to evaluate the anti-inflammatory action of 2 percent aloe (Aloe barbadensis Mill.) gel combined with pulsed ultrasound in the paw edema model. Twenty-five Wistar rats (200-250 g) were divided into 5 groups of 5 animals each. Group1 (control): rats treated with 0.9 percent saline; Group 2: rats topically treated with 2 percent aloe gel; Group 3: rats treated with ultrasound; Group 4: rats treated with 2 percent aloe gel combined with ultrasound; Group 5 (positive control): rats treated with indomethacin at 5 mg Kg-1. Animals of groups 1 and 5 were intraperitoneally treated 30 min before intraplantar carrageenan injection and groups 2, 3 and 4 were treated by topical application of 2 percent aloe gel, pulsed ultrasound and aloe gel combined with ultrasound, respectively, 15 min after edema induction. Animals of group 4 had a significant reduction in edema relative to controls and showed to be comparable to indomethacin. Aloe gel combined with phonophoresis is capable of reducing paw edema formation in rats.