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Victims of urban violence are at risk of developing Posttraumatic Stress Disorder (PTSD), one of the most debilitating consequences of violence. Considering that PTSD may be associated with inefficient selection of defensive responses, it is important to understand the relation between motor processing and PTSD. The present study aims to investigate the extent to which the severity of posttraumatic stress symptoms (PTSS) is related to motor preparation against visual threat cues in victims of urban violence. Participants performed a choice reaction time task while ignoring a picture that could be threating or neutral. The EEG indices extracted were the motor-related amplitude asymmetry (MRAA) in the alpha frequency range, and the lateralized readiness potential (LRP). We observed a linear relation between longer LRP latency and a slower reaction time, selectively during threat processing (compared to neutral) in low PTSS, but not in high PTSS participants. Alpha MRAA suppression and the PTSS were also linearly related: the smaller the alpha MRAA suppression in the threat condition relative to neutral, the greater the PTSS. These results provide evidence that threatening cues affect motor processing that is modulated by the severity of PTSS in victims of urban violence.

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A growing body of evidence suggests that the mode of movement selection is relevant for the readiness potential, namely, internal (or free) selection of movements is associated with increased readiness potential amplitudes compared to predetermined or externally guided selection. It is little acknowledged, however, that this finding may be ascribed to the different expression of volition (i.e., conscious experience of choice) rather than to the mode of movement selection per se. To probe this issue, we conducted two experiments: in Experiment 1, a mental task was employed to distract sixteen volunteers from the selection and performance of incidental movements, which consisted of pressing one of two buttons according to either free or externally guided modes of movement selection; in Experiment 2, another sixteen individuals performed the same motor task, however, they were encouraged to attend to their intention to act. As result, the increased readiness potential amplitude before freely selected movements was found exclusively in Experiment 2. More detailed analysis suggested that the attention to the initiation of movements was associated with greater readiness potential in its medial and late portion, while the attention to the movement selection, with more global increase of the component. The study suggests that much of the higher demands on motor preparatory activities ascribed to the internal selection of movements in previous studies actually depends on individual's attention and, thus, probably corresponds to volitional processes.

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The current study investigated the effect of conscious intention to act on the Bereitschaftspotential. Situations in which the awareness of acting is minimally expressed were generated by asking 16 participants to press a button after performing a mental imagery task based on animal pictures (automatic condition). The affective responses induced by the pictures were controlled by selecting the animals according to different valences, threatening and neutral. The Bereitschaftspotential associated with the button presses was compared to the observed when similar movements were performed under the basic instructions of the self-paced movement paradigm (willed condition). Enhanced Bereitschaftspotential amplitudes were observed in the willed condition with respect to the automatic condition. This effect was manifested as a negative slope at medial frontocentral sites during the last 500 ms before movement onset. The valence of the pictures did not affect the motor preparatory potentials. The results suggest that significant part of the NS' subcomponent of the readiness potential is associated with the attention to-and, presumably, awareness of-intention to move, possibly reflecting cortical activation from supplementary motor areas. Secondarily, our findings supports that the feeling of threat does not influence the Bereitschaftspotential associated with automatic movements. Regarding methodological issues, the behavioural model of spontaneous voluntary movements proposed in automatic condition can benefit investigations on purely motor (or non-cognitive) subcomponents of the Bereitschaftspotential.

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BACKGROUND AND AIM: Sleep deprivation (SD) may result in perceptual and cognitive alterations in healthy subjects. Our objective was to compare whether psychoacoustics and neurophysiological variables in healthy subjects were altered after SD of 30-36 h. METHOD: We examined 22 subjects by means of several psychoacoustics tests, P300 and mismatch negativity (MMN) recordings, and brainstem auditory evoked potentials (BAEP) before and after 30-36 h of SD. RESULTS: In the psychoacoustics tests, we found that after SD, difficulties were experienced by the left ear in the discrimination of words in noise and by the right ear in music discrimination. In the neurophysiological tests, we found delayed latencies of P300 and MMN wave; there was a delay of wave I in both ears, and wave V in the right ear in BAEP. We found significant correlations with positive direction between P300 latency and words in noise and music discrimination in the right ear. CONCLUSIONS: SD results in alterations of central auditory processing perception and delays of brain neurophysiological responses, with some correlations between the psychoacoustics and neurophysiological tests. These alterations may relate to other cognitive alterations that deserve more research in future studies.

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METHODS: Ten PD patients in stages 1 and 2 of the Hoehn & Yahr classification were compared to 18 healthy controls. Artifact-free EEG segments of two seconds preceding the onset of the blink potential were averaged and analyzed, and the statistical significance of the measured amplitudes were evaluated by analysis of variance models. RESULTS: The presence of a BP in the PD patients was demonstrated. The mean amplitudes at 0 ms were respectively 0.6 µV and 3.3 µV for the BP patients and the normal controls, respectively. CONCLUSIONS: The BP amplitudes were significantly smaller in PD patients than normal participants. The amplitudes of the BP were not modified by levodopa.

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ABSTRACT The Bereitschaftspotential (BP) is a negative wave observed in EEG retrograde averaging, preceding a motor act. The objective was to study the BP preceding voluntary eyelid blinks in Parkinson's disease (PD) patients during off and on phases of levodopa. Methods Ten PD patients in stages 1 and 2 of the Hoehn & Yahr classification were compared to 18 healthy controls. Artifact-free EEG segments of two seconds preceding the onset of the blink potential were averaged and analyzed, and the statistical significance of the measured amplitudes were evaluated by analysis of variance models. Results The presence of a BP in the PD patients was demonstrated. The mean amplitudes at 0 ms were respectively 0.6 µV and 3.3 µV for the BP patients and the normal controls, respectively. Conclusions The BP amplitudes were significantly smaller in PD patients than normal participants. The amplitudes of the BP were not modified by levodopa.

RESUMO O Potencial de Bereitschafts (PB) é uma onda negativa observada retrogradamente no EEG precedendo um ato motor. Objetivo Estudar o PB precedendo o piscamento palpebral voluntário em pacientes com doença de Parkinson (DP) durante as fases off e on da levodopa. Foram comparados dez pacientes com DP nos estágios 1 e 2 de Hoehn & Yahr com 18 controles saudáveis. Os segmentos de EEG livres de artefatos 2 segundos antes do início do potencial foram calculados e analisados e a significância estatística das amplitudes foi medida por modelos de análise de variância. Resultados A presença de PB nos pacientes com DP foi demonstrada. As amplitudes médias a 0 ms foram respectivamente 0,6 μV e 3,3 μV para os pacientes com DP e controles respectivamente. Conclusões As amplitudes do PB foram significativamente menores nos pacientes com DP do que controles. As amplitudes do PB não foram modificadas pela levodopa.

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Music represents a complex form of human cognition. To what extent our auditory system is attuned to music is yet to be clearly understood. Our principal aim was to determine whether the neurophysiological operations underlying pre-attentive auditory change detection (N1 enhancement (N1e)/Mismatch Negativity (MMN)) and the subsequent involuntary attentional reallocation (P3a) towards infrequent sound omissions, are influenced by differences in musical content. Specifically, we intended to explore any interaction effects that rhythmic and pitch dimensions of musical organization may have over these processes. Results showed that both the N1e and MMN amplitudes were differentially influenced by rhythm and pitch dimensions. MMN latencies were shorter for musical structures containing both features. This suggests some neurocognitive independence between pitch and rhythm domains, but also calls for further address on possible interactions between both of them at the level of early, automatic auditory detection. Furthermore, results demonstrate that the N1e reflects basic sensory memory processes. Lastly, we show that the involuntary switch of attention associated with the P3a reflects a general-purpose mechanism not modulated by musical features. Altogether, the N1e/MMN/P3a complex elicited by infrequent sound omissions revealed evidence of musical influence over early stages of auditory perception.

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Objective. This study identified the personal characteristics that affect Chilean health care providers’ readiness to adopt HIV Oral Rapid Testing (ORT) in Chile as a new clinical evidence- based practice (EBP). Methods. Using a cross-sectional research design, the study sampled 150 nurses, midwives, and physicians employed at four clinics within the Pontifícia Universidad Católica de Chile Health Network in Santiago. Participants completed a self-administered survey asking about their demographic background, EBP attitudes and experience, personal beliefs related to HIV, the importance of HIV testing, and perceived self-comfort in performing a rapid HIV test. Results. Of the participants, 90% believed that incorporating ORT would make a positive difference in their practice and said that they would be willing to adopt the technology for that reason. Nonetheless, the providers reported a mean “readiness to implement ORT” score of 15.1 out of a possible value of 20, suggesting only moderate self-perceived readiness to adopt the EBP. Education, beliefs about evidence-based practice, perceived comfort in performing ORT, and perceived importance of HIV testing explained 43.6% of the variance in readiness to adopt ORT. Conclusion. The findings of this first ORT pre-implementation study in Chile can help guide policy makers and HIV stakeholders to prepare for and increase primary health care providers’ readiness to successfully adopt this evidence-based technology. Successful adoption of ORT could increase Chile’s capacity to reach HIV-vulnerable Chileans for testing and referral to care if infected, thus helping the country to reduce further transmission of the virus and its medical complications.

Objetivo. En este estudio se determinaron las características personales que influyen sobre la disposición de los prestadores de atención de salud a adoptar la prueba oral rápida de detección del VIH en Chile como una nueva práctica clínica basada en la evidencia. Métodos. Con un diseño de investigación transversal, en el estudio se realizó un muestreo de 150 enfermeros, parteras y médicos que trabajaban en cuatro centros de la Red de Salud de la Pontifícia Universidad Católica de Chile, en Santiago. Los participantes llenaron una encuesta autoadministrada en la que se preguntaba sus características demográficas, actitudes y experiencia en relación con la práctica clínica basada en la evidencia, creencias personales respecto del VIH, importancia de las pruebas de detección del VIH y sensación de comodidad respecto de realizar una prueba oral rápida de detección del VIH. Resultados. El 90% de los participantes afirmó que creía que la incorporación de la prueba oral rápida significaría un cambio positivo en su práctica y que estaría dispuesto a adoptar la nueva tecnología por ese motivo. No obstante, de acuerdo con las respuestas, la "disposición a utilizar la prueba oral rápida" obtuvo una media de puntuación de 15,1 de un posible valor de 20, lo que sugiere solo una disposición autopercibida moderada a adoptar esta práctica basada en la evidencia. La educación, las creencias acerca de la práctica basada en la evidencia, la sensación de comodidad al realizar la prueba oral rápida y la percepción de la importancia de las pruebas de detección del VIH explican el 43,6% de la varianza de la disposición a adoptar la prueba oral rápida. Conclusiones. Los resultados de este estudio previo a la introducción de la prueba oral rápida de detección del VIH en Chile pueden ser útiles para orientar a los responsables de las políticas y a las partes interesadas en cuanto a la preparación de los prestadores de atención primaria de la salud para que aumente su disposición a adoptar con éxito esta tecnología basada en la evidencia. La adopción satisfactoria de la prueba oral rápida podría aumentar la capacidad de Chile para llegar a los chilenos vulnerables a la infección por el VIH para que se realicen la prueba y sean derivados para recibir atención si tienen un resultado positivo y, de este modo, podría contribuir a detener la transmisión del virus y reducir las complicaciones médicas.

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It is well established that the mental simulation of actions involves visual and/or somatomotor representations of those imagined actions. To investigate whether the total absence of vision affects the brain activity associated with the retrieval of motor representations, we recorded the readiness potential (RP), a marker of motor preparation preceding the execution, as well as the motor imagery of the right middle-finger extension in the first-person (1P; imagining oneself performing the movement) and in the third-person (3P; imagining the experimenter performing the movement) modes in 19 sighted and 10 congenitally blind subjects. Our main result was found for the single RP slope values at the Cz channel (likely corresponding to the supplementary motor area). No difference in RP slope was found between 1P and 3P in the sighted group, suggesting that similar motor preparation networks are recruited to simulate our own and other people's actions in spite of explicit instructions to perform the task in 1P or 3P. Conversely, reduced RP slopes in 3P compared with 1P found in the blind group indicated that they might have used an alternative, nonmotor strategy to perform the task in 3P. Moreover, movement imagery ability, assessed both by means of mental chronometry and a modified version of the Movement Imagery Questionnaire-Revised, indicated that blind and sighted individuals had similar motor imagery performance. Taken together, these results suggest that complete visual loss early in life modifies the brain networks that associate with others' action representations.

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Critical periods in language acquisition have been discussed primarily with reference to studies of people who are deaf or bilingual. Here, we provide evidence on the opening of sensitivity to the linguistic environment by studying the response to a change of phoneme at a native and nonnative phonetic boundary in full-term and preterm human infants using event-related potentials. Full-term infants show a decline in their discrimination of nonnative phonetic contrasts between 9 and 12 months of age. Because the womb is a high-frequency filter, many phonemes are strongly degraded in utero. Preterm infants thus benefit from earlier and richer exposure to broadcast speech. We find that preterms do not take advantage of this enriched linguistic environment: the decrease in amplitude of the mismatch response to a nonnative change of phoneme at the end of the first year of life was dependent on maturational age and not on the duration of exposure to broadcast speech. The shaping of phonological representations by the environment is thus strongly constrained by brain maturation factors.

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