Auditory Pattern Representations Under Conditions of Uncertainty-An ERP Study.

The auditory system is able to recognize auditory objects and is thought to form predictive models of them even though the acoustic information arriving at our ears is often imperfect, intermixed, or distorted. We investigated implicit regularity extraction for acoustically intact versus disrupted six-tone sound patterns via event-related potentials (ERPs). In an exact-repetition condition, identical patterns were repeated; in two distorted-repetition conditions, one randomly chosen segment in each sound pattern was replaced either by white noise or by a wrong pitch. In a roving-standard paradigm, sound patterns were repeated 1-12 times (standards) in a row before a new pattern (deviant) occurred. The participants were not informed about the roving rule and had to detect rarely occurring loudness changes. Behavioral detectability of pattern changes was assessed in a subsequent behavioral task. Pattern changes (standard vs. deviant) elicited mismatch negativity (MMN) and P3a, and were behaviorally detected above the chance level in all conditions, suggesting that the auditory system extracts regularities despite distortions in the acoustic input. However, MMN and P3a amplitude were decreased by distortions. At the level of MMN, both types of distortions caused similar impairments, suggesting that auditory regularity extraction is largely determined by the stimulus statistics of matching information. At the level of P3a, wrong-pitch distortions caused larger decreases than white-noise distortions. Wrong-pitch distortions likely prevented the engagement of restoration mechanisms and the segregation of disrupted from true pattern segments, causing stronger informational interference with the relevant pattern information.

Change detection of auditory tonal patterns defined by absolute versus relative pitch information. A combined behavioural and EEG study.

The human auditory system often relies on relative pitch information to extract and identify auditory objects; such as when the same melody is played in different keys. The current study investigated the mental chronometry underlying the active discrimination of unfamiliar melodic six-tone patterns by measuring behavioural performance and event-related potentials (ERPs). In a roving standard paradigm, such patterns were either repeated identically within a stimulus train, carrying absolute frequency information about the pattern, or shifted in pitch (transposed) between repetitions, so only relative pitch information was available to extract the pattern identity. Results showed that participants were able to use relative pitch to detect when a new melodic pattern occurred. Though in the absence of absolute pitch sensitivity significantly decreased and behavioural reaction time to pattern changes increased. Mismatch-Negativity (MMN), an ERP indicator of auditory deviance detection, was elicited at approximately 206 ms after stimulus onset at frontocentral electrodes, even when only relative pitch was available to inform pattern discrimination. A P3a was elicited in both conditions, comparable in amplitude and latency. Increased latencies but no differences in amplitudes of N2b, and P3b suggest that processing at higher levels is affected when, in the absence of absolute pitch cues, relative pitch has to be extracted to inform pattern discrimination. Interestingly, the response delay of approximately 70 ms on the behavioural level, already fully manifests at the level of N2b. This is in accordance with recent findings on implicit auditory learning processes and suggests that in the absence of absolute pitch cues a slowing of target selection rather than a slowing of the auditory pattern change detection process causes the deterioration in behavioural performance.

How regularity representations of short sound patterns that are based on relative or absolute pitch information establish over time: An EEG study.

The recognition of sound patterns in speech or music (e.g., a melody that is played in different keys) requires knowledge about pitch relations between successive sounds. We investigated the formation of regularity representations for sound patterns in an event-related potential (ERP) study. A pattern, which consisted of six concatenated 50 ms tone segments differing in fundamental frequency, was presented 1, 2, 3, 6, or 12 times and then replaced by another pattern by randomly changing the pitch of the tonal segments (roving standard paradigm). In an absolute repetition condition, patterns were repeated identically, whereas in a transposed condition, only the pitch relations of the tonal segments of the patterns were repeated, while the entire patterns were shifted up or down in pitch. During ERP measurement participants were not informed about the pattern repetition rule, but were instructed to discriminate rarely occurring targets of lower or higher sound intensity. EPRs for pattern changes (mismatch negativity, MMN; and P3a) and for pattern repetitions (repetition positivity, RP) revealed that the auditory system is able to rapidly extract regularities from unfamiliar complex sound patterns even when absolute pitch varies. Yet, enhanced RP and P3a amplitudes, and improved behavioral performance measured in a post-hoc test, in the absolute as compared with the transposed condition suggest that it is more difficult to encode patterns without absolute pitch information. This is explained by dissociable processing of standards and deviants as well as a back propagation mechanism to early sensory processing stages, which is effective after less repetitions of a standard stimulus for absolute pitch.

Tumor Carcinoide de testículo / Testicular carcinoid tumor

Los tumores carcinoides de testículo son extremadamente raros, representando el 0.23% de los tumores de dicha localización. Se dividen en tres grupos: tumor carcinoide primario de testículo, teratoma de testículo con áreas de carcinoide y tumor carcinoide metastásico de otra localización. Presentamos un paciente de 52 años que consultó por dolor y tumefacción testicular. Se realizó orquiectomía derecha. LDH, alfa feto proteína y beta HCG: normales. Anatomía patológica: tumor blanco amarillento, constituido por células neoplásicas. Inmunohistoquímica: inmunofenotipo correspondiente a tumor neuroendocrino. 5HIAA urinario: normal. Centellografía con (Tc99) octreotide: normal. Se decidió control. Los tumores carcinoides primarios de testículo son infrecuentes, es fundamental descartar localizaciones primarias intestinales para confirmar el diagnóstico. Las herramientas diagnósticas más utilizadas son 5HIAA en orina y centellografía con (TC99) octreotide. El tumor carcinoide primario de testículo presenta un pronóstico favorable luego de la orquiectomía (AU)

Testicular carcinoid tumors are extremely rare. They are divided into three groups: primary testicular carcinoid tumor, testicular teratoma with areas of carcinoid and metastatic carcinoid tumor from another location. We present a 52 years old patient that was admitted with testicular pain and swelling. Right orchiectomy was performed. Serum LDH and alpha, fetoprotein and beta human chorionic gonadotropin were normal. Pathology: white yellowish tumor consisting of neoplastic cells. Immunohistochemistry: immunophenotype corresponding to neuroendocrine tumor. 5HIAA urinary and somatostatin receptor scintigraphy were normal. It was decided to control the patient. Primary testicular carcinoid tumors are uncommon. It is essential to rule out intestinal primary locations to confirm the diagnosis. The diagnostic tools used are 5 HIAA urinary and somatostatin receptor scintigraphy. The primary carcinoid tumor of the testis presents a favorable prognosis after orchiectomy (AU)

Perception of 'Back-Channeling' Nonverbal Feedback in Musical Duo Improvisation.

In witnessing face-to-face conversation, observers perceive authentic communication according to the social contingency of nonverbal feedback cues ('back-channeling') by non-speaking interactors. The current study investigated the generality of this function by focusing on nonverbal communication in musical improvisation. A perceptual experiment was conducted to test whether observers can reliably identify genuine versus fake (mismatched) duos from musicians' nonverbal cues, and how this judgement is affected by observers' musical background and rhythm perception skill. Twenty-four musicians were recruited to perform duo improvisations, which included solo episodes, in two styles: standard jazz (where rhythm is based on a regular pulse) or free improvisation (where rhythm is non-pulsed). The improvisations were recorded using a motion capture system to generate 16 ten-second point-light displays (with audio) of the soloist and the silent non-soloing musician ('back-channeler'). Sixteen further displays were created by splicing soloists with back-channelers from different duos. Participants (N = 60) with various musical backgrounds were asked to rate the point-light displays as either real or fake. Results indicated that participants were sensitive to the real/fake distinction in the free improvisation condition independently of musical experience. Individual differences in rhythm perception skill did not account for performance in the free condition, but were positively correlated with accuracy in the standard jazz condition. These findings suggest that the perception of back-channeling in free improvisation is not dependent on music-specific skills but is a general ability. The findings invite further study of the links between interpersonal dynamics in conversation and musical interaction.

Salud pública en Valparaíso: de un acto de caridad a un derecho / Public health in Valparaíso: an act of charity to the right

Cómo la asistencia sanitaria pasa en nuestro país de ser un acto de caridad, y como tal a discreción de quien la ofrece, a un deber de la autoridad; luego que el médico Benjamín Manterola propusiera al gobierno local los lineamientos que rigen hasta hoy, la atención hospitalaria.

Salud pública en Valparaíso: de un acto de caridad a un derecho / Public health in Valparaíso: an act of charity to the right

Cómo la asistencia sanitaria pasa en nuestro país de ser un acto de caridad, y como tal a discreción de quien la ofrece, a un deber de la autoridad; luego que el médico Benjamín Manterola propusiera al gobierno local los lineamientos que rigen hasta hoy, la atención hospitalaria. (AU)