The rapid screen of concussion: An evaluation of the non-word repetition test for use in mTBI research

Primary objectives: (1) To investigate the Nonword Repetition test (NWR) as an index of sub-vocal rehearsal deficits after mild traumatic brain injury (mTBI); (2) to assess the reliability, validity and sensitivity of the NWR; and (3) to compare the NWR to more sensitive tests of verbal memory. Research design: An independent groups design. Methods and procedures: Study 1 administered the NWR to 46 mTBI and 61 uninjured controls with the Rapid Screen of Concussion (RSC). Study 2 compared mTBI, orthopaedic and uninjured participants on the NWR and the Hopkins Verbal Learning Test (HVLT-R). Main outcomes and results: The NWR did not improve the diagnostic accuracy of the RSC. However, it is reliable and indexes sub-vocal rehearsal speed. These findings provide evidence that although the current form of the NWR lacks sensitivity to the impact of mTBI, the development of a more sensitive test of sub-vocal rehearsal deficits following mTBI is warranted.

Classic identity negative priming involves accessing semantic representations in the left anterior temporal cortex

Classic identity negative priming (NP) refers to the finding that when an object is ignored, subsequent naming responses to it are slower than when it has not been previously ignored (Tipper, S.P., 1985. The negative priming effect: inhibitory priming by ignored objects. Q. J. Exp. Psychol. 37A, 571-590). It is unclear whether this phenomenon arises due to the involvement of abstract semantic representations that the ignored object accesses automatically. Contemporary connectionist models propose a key role for the anterior temporal cortex in the representation of abstract semantic knowledge (e.g., McClelland, J.L., Rogers, T.T., 2003. The parallel distributed processing approach to semantic cognition. Nat. Rev. Neurosci. 4, 310-322), suggesting that this region should be involved during performance of the classic identity NP task if it involves semantic access. Using high-field (4 T) event-related functional magnetic resonance imaging, we observed increased BOLD responses in the left anterolateral temporal cortex including the temporal pole that was directly related to the magnitude of each individual's NP effect, supporting a semantic locus. Additional signal increases were observed in the supplementary eye fields (SEF) and left inferior parietal lobule (IPL). (c) 2006 Elsevier Inc. All rights reserved.

Affective priming - is it only affect that primes?

A target word is classified faster as pleasant or unpleasant if preceded by a prime that matches the target word’s valence. This affective priming phenomenon is currently popular as an implicit measure of stimulus valence. The present set of experiments investigated whether rated stimulus arousal will affect target classification as well. In three experiments, word targets were preceded by prime stimuli that differed in rated arousal and valence. The basic priming effect was replicated in all experiments, however, priming was largest after high arousal unpleasant and low arousal pleasant primes, and reduced after low arousal unpleasant and high arousal pleasant primes. This finding emerged for picture and word primes and does not reflect the effect of differences in stimulus complexity. The difference in the effectiveness of the primes was not affected by SOA and seemed to hold across a wide range (50-200 ms for words and 200-500 ms for pictures). The present results suggest that some failures to find affective priming may not reflect on prime valence, but on prime arousal. Moreover, it suggests that increases in stimulus arousal have differential effects for the processing of pleasant and unpleasant stimuli.

CONSCIÊNCIA E EMOÇÃO: O EFEITO DO PRIMING AFETIVO SUBLIMINAR EM TAREFAS DE ATENÇÃO

Esta tese revisou duas linhas de pesquisa, desenvolvidas nas últimas décadas: o estudo de efeitos de estimulação subliminar priming , e de desencadeamento de reações emocionais por estímulos controlados. Este estudo tem o objetivo de combinar tais linhas para o estudo da consciência com pré-preparo afetivo: efeito de estímulos de conteúdo aversivo, subliminares e supraliminares, sobre a cognição, pela análise do desempenho em tarefa de atenção. Três tarefas experimentais foram realizadas por 35 indivíduos em laboratório de neuropsicologia: a tarefa base onde testamos à detecção de alvo visual simples, e a mesma tarefa de base, porém com estímulos distratores aversivos intercalados, de forma supraliminar ou subliminar (500 ms ou 50 ms de duração), em blocos aleatorizados entre os indivíduos. Calcularam-se índices de detectabilidade e critério de resposta, que serviram para a comparação estatística entre condições (medidas repetidas). Os resultados mostram uma mudança significativa do índice critério , indicando mudança de estratégia na presença de distratores subliminares aversivos. Concluiu-se que a tarefa subliminar fez um efeito destruidor ou devastador na tarefa supraliminar, cometendo menos falso-alarmes protegendo a tarefa supraliminar, tendo um efeito protetor . Os resultados são discutidos no contexto da relevância de influências emocionais sobre o comportamento para a Psicologia da Saúde.

Effects of syllabic complexity in predicting accuracy of repetition and direction of errors in patients with articulatory and phonological difficulties

The purpose of this paper is to demonstrate the existence of a strong and significant effect of complexity in aphasia independent from other variables including length. Complexity was found to be a strong and significant predictor of accurate repetition in a group of 13 Italian aphasic patients when it was entered in a regression equation either simultaneously or after a large number of other variables. Significant effects were found both when complexity was measured in terms of number of complex onsets (as in a recent paper by Nickels & Howard, 2004) and when it was measured in a more comprehensive way. Significant complexity effects were also found with matched lists contrasting simple and complex words and in analyses of errors. Effects of complexity, however, were restricted to patients with articulatory difficulties. Reasons for this association and for the lack of significant results in Nickels and Howard (2004) are discussed. © 2005 Psychology Press Ltd.

Pearl-chain waveguides written at megahertz repetition rate

Waveguides in the form of connected pearls, written with sub-30 fs pulses centered at 800 nm at a repetition rate of 10 MHz, show high changes of the refractive index and, as a consequence, simple in-coupling. The value of the refractive index modification of these waveguides is as high as 10-2, optical losses are 6 dB/cm (at 1.55 µm) and the mode field diameter is 8 µm at 670 nm.

Low-loss waveguides in borosilicate glass fabricated by high-repetition-Rate femtosecond chirp-pulsed oscillator

We describe fabrication and characterisation of smooth low-loss waveguides in BK7 optical glass bymeans of direct femtosecond inscription with chirp-pulse oscillator, operating at 800 nm and 11 MHz repetition rate.

Gingipains from Porphyromonas gingivalis increase the chemotactic and respiratory burst-priming properties of the 77-amino-acid interleukin-8 variant

Porphyromonas gingivalis, a gram-negative anaerobe which is implicated in the etiology of active periodontitis, secretes degradative enzymes (gingipains) and sheds proinflammatory mediators (e.g., lipopolysaccharides [LPS]). LPS triggers the secretion of interleukin-8 (IL-8) from immune (72-amino-acid [aa] variant [IL-8(72aa)]) and nonimmune (IL-8(77aa)) cells. IL-8(77aa) has low chemotactic and respiratory burst-inducing activity but is susceptible to cleavage by gingipains. This study shows that both R- and K-gingipain treatments of IL-8(77aa) significantly enhance burst activation by fMLP and chemotactic activity (P < 0.05) but decrease burst activation and chemotactic activity of IL-8(72aa) toward neutrophil-like HL60 cells and primary neutrophils (P < 0.05). Using tandem mass spectrometry, we have demonstrated that R-gingipain cleaves 5- and 11-aa peptides from the N-terminal portion of IL-8(77aa) and the resultant peptides are biologically active, while K-gingipain removes an 8-aa N-terminal peptide yielding a 69-aa isoform of IL-8 that shows enhanced biological activity. During periodontitis, secreted gingipains may differentially affect neutrophil chemotaxis and activation in response to IL-8 according to the cellular source of the chemokine.

Inscription and characterization of waveguides written into borosilicate glass by a high-repetition-rate femtosecond laser at 800 nm

A series of waveguides was inscribed in a borosilicate glass (BK7) by an 11 MHz repetition rate femtosecond laser operating with pulse energies from 16 to 30 nJ and focused at various depths within the bulk material. The index modification was measured using a quantitative phase microscopy technique that revealed central index changes ranging from 5×10-3 to 10-2, leading to waveguides that exhibited propagation losses of 0.2 dB/cm at a wavelength of 633 nm and 0.6 dB/cm at a wavelength of 1550 nm with efficient mode matching, less than 0.2 dB, to standard optical fibers. Analysis of the experimental data shows that, for a given inscription energy, the index modification has a strong dependence on inscription scanning velocity. At higher energies, the index modification increases with increasing inscription scanning velocity with other fabrication parameters constant.

Repetition-rate multiplication using a single all-pass optical cavity

We demonstrate a simple lossless method for the implementation of repetition-rate multiplication of a periodic pulse train. As it is showed, a single all-pass optical cavity (APOC) can increase the repetition rate of the output pulse train by factors of 2, 3, and 4. Two different APOC implementations, based on a Gires-Tournois interferometer and an all-pass ring resonator, are proposed and numerically demonstrated.

Repetition rate multiplication using all-pass optical structures

Optical Engineering: New waveform generation provides the experimentalist with interesting new tools.