Medial superior olive in the rat: Anatomy, sources of input and axonal projections.

Although rats and mice are among the preferred animal models for investigating many characteristics of auditory function, they are rarely used to study an essential aspect of binaural hearing: the ability of animals to localize the sources of low-frequency sounds by detecting the interaural time difference (ITD), that is the difference in the time at which the sound arrives at each ear. In mammals, ITDs are mostly encoded in the medial superior olive (MSO), one of the main nuclei of the superior olivary complex (SOC). Because of their small heads and high frequency hearing range, rats and mice are often considered unable to use ITDs for sound localization. Moreover, their MSO is frequently viewed as too small or insignificant compared to that of mammals that use ITDs to localize sounds, including cats and gerbils. However, recent research has demonstrated remarkable similarities between most morphological and physiological features of mouse MSO neurons and those of MSO neurons of mammals that use ITDs. In this context, we have analyzed the structure and neural afferent and efferent connections of the rat MSO, which had never been studied by injecting neuroanatomical tracers into the nucleus. The rat MSO spans the SOC longitudinally. It is relatively small caudally, but grows rostrally into a well-developed column of stacked bipolar neurons. By placing small, precise injections of the bidirectional tracer biotinylated dextran amine (BDA) into the MSO, we show that this nucleus is innervated mainly by the most ventral and rostral spherical bushy cells of the anteroventral cochlear nucleus of both sides, and by the most ventrolateral principal neurons of the ipsilateral medial nucleus of the trapezoid body. The same experiments reveal that the MSO densely innervates the most dorsolateral region of the central nucleus of the inferior colliculus, the central region of the dorsal nucleus of the lateral lemniscus, and the most lateral region of the intermediate nucleus of the lateral lemniscus of its own side. Therefore, the MSO is selectively innervated by, and sends projections to, neurons that process low-frequency sounds. The structural and hodological features of the rat MSO are notably similar to those of the MSO of cats and gerbils. While these similarities raise the question of what functions other than ITD coding the MSO performs, they also suggest that the rat MSO is an appropriate model for future MSO-centered research.

The Relative Contribution of Cochlear Synaptopathy and Reduced Inhibition to Age-Related Hearing Impairment for People With Normal Audiograms.

Older people often show auditory temporal processing deficits and speech-in-noise intelligibility difficulties even when their audiogram is clinically normal. The causes of such problems remain unclear. Some studies have suggested that for people with normal audiograms, age-related hearing impairments may be due to a cognitive decline, while others have suggested that they may be caused by cochlear synaptopathy. Here, we explore an alternative hypothesis, namely that age-related hearing deficits are associated with decreased inhibition. For human adults (N = 30) selected to cover a reasonably wide age range (25-59 years), with normal audiograms and normal cognitive function, we measured speech reception thresholds in noise (SRTNs) for disyllabic words, gap detection thresholds (GDTs), and frequency modulation detection thresholds (FMDTs). We also measured the rate of growth (slope) of auditory brainstem response wave-I amplitude with increasing level as an indirect indicator of cochlear synaptopathy, and the interference inhibition score in the Stroop color and word test (SCWT) as a proxy for inhibition. As expected, performance in the auditory tasks worsened (SRTNs, GDTs, and FMDTs increased), and wave-I slope and SCWT inhibition scores decreased with ageing. Importantly, SRTNs, GDTs, and FMDTs were not related to wave-I slope but worsened with decreasing SCWT inhibition. Furthermore, after partialling out the effect of SCWT inhibition, age was no longer related to SRTNs or GDTs and became less strongly related to FMDTs. Altogether, results suggest that for people with normal audiograms, age-related deficits in auditory temporal processing and speech-in-noise intelligibility are mediated by decreased inhibition rather than cochlear synaptopathy.

The nuclei of the lateral lemniscus: unexpected players in the descending auditory pathway.

Introduction: In the mammalian auditory pathway, the nuclei of the lateral lemniscus (NLL) are thought to be exclusively involved in the bottom-up transmission of auditory information. However, our repeated observation of numerous NLL neurons labeled after injection of retrograde tracers into the superior olivary complex (SOC) led us to systematically investigate with retrograde tracers the descending projections from the NLL to the SOC of the rat. Methods: We performed large injections of FluoroGold into the SOC to determine NLL contributions to descending projections, and focal injections of biotinylated dextran amine (BDA) to pinpoint the specific nuclei of the SOC innervated by each NLL. Results: The SOC is innervated by thousands of neurons distributed across four nuclei or regions associated with the lateral lemniscus: the ipsilateral ventral and intermediate nuclei of the lateral lemniscus (VNLL and INLL); the medial paralemniscal region (PL) of both sides; and the ipsilateral semilunar nucleus (SLN), a previously unrecognized nucleus that wraps around the INLL dorsally, medially, and caudally and consists of small, flat neurons. In some experiments, at least 30% of neurons in the VNLL and INLL were retrogradely labeled. All nuclei of the SOC, except the medial and lateral superior olives, are innervated by abundant lemniscal neurons, and each SOC nucleus receives a unique combination of lemniscal inputs. The primary target of the projections from the VNLL is the ventral nucleus of the trapezoid body (VNTB), followed by the superior paraolivary nucleus (SPON), and the medial nucleus of the trapezoid body (MNTB). The INLL selectively innervates the VNTB. The PL innervates dorsal periolivary regions bilaterally. The SLN preferentially innervates the MNTB and may provide the first identified non-calyceal excitatory input to MNTB neurons. Discussion: Our novel findings have strong implications for understanding acoustic information processing in the initial stages of the auditory pathway. Based on the proportion of lemniscal neurons involved in all the projections described, the NLL should be considered major players in the descending auditory pathway.

Descripción de las personas gestantes afiliadas a OSEP que solicitan una interrupción del embarazo / Description of pregnant people affiliated to osep who request a pregnancy interruption

En 2021 entró en vigencia en Argentina la Ley N.º 27.610. El objetivo es describir características de afiliadas a OSEP que solicitaron interrupción del embarazo (SIE).Trabajo observacional descriptivo. Se analizaron las variables del 0800 del Ministerio de Salud de la Nación de todas las personas que SIE con OSEP, entre el 24/01 y 31/12/2021. Los datos fueron analizados con SPSS Statistics. Se utilizaron moda, mediana, porcentaje, tasa y el chi2. Se recibieron 427 SIE, se concretaron 330 (77,3%). Solicitaron ive: media 28,59 años. Modo 19 y 33 años. Concretaron ive: modo 22 años. 84,5% se realizó ambulatorio con misoprostol. De las SIE, 50,4% eran solteras, 43,4% trabajaba, 59,1% tenía secundario completo. Se desconoce 32,8%. De las SIE, 52,7% refirió haber estado utilizando MAC (54,2% preservativo; 37,4% anticonceptivos orales; 2,8% métodos "naturales"; 2,2% DIU). La mayor cantidad fue de zonas urbanas del Gran Mendoza. Sin embargo, se observan tasas elevadas en zonas rurales respecto de algunas zonas urbanas y más pobladas. Se observó progresión de SIE a lo largo del año. Un 11% después de SIE decidió continuar con el embarazo. Aparentemente ninguna de las variables tuvo relación con esa decisión. El MAC utilizado fue mayormente preservativo y anticonceptivos orales. Esto podría indicar falta de educación y poco acceso a métodos de larga duración. La problemática de interrupción es transversal. En base a los resultados de este trabajo, las personas sin pareja conviviente, ante un embarazo no planificado serían las que SIE. Ninguna otra variable parece actuar como determinante. Tampoco del paso de la solicitud a la interrupción efectiva o a la continuación del embarazo. Hay que aumentar la accesibilidad a MAC en zonas rurales (AU)

In 2021, Law No. 27610 entered into force in Argentina. The objective is to describe characteristics of people with OSEP who requested termination of pregnancy (PWRTP). Descriptive observational work. The variables of the 0800 of the Ministry of Health of Argentina of all the PWRTP with OSEP, between 01/24 and 12/31/2021, were analyzed. Data were analyzed with SPSS Statistics. Mode, median, percentage, rate and chi2 were used. PWRTP: 427 requests were received, 330 (77.3%) were completed. PWRTP: mean 28.59 years. Mode 19 and 33 years. People who had an abortion: mode 22 years. 84.5% were performed on an outpatient basis with misoprostol. 50.4% of the PWRTP were single, 43.4% worked, 59.1% had completed high school, 32.8% unknown, 52.7% reported having been using contraceptive methods (CM): 54.2% condoms; 37.4% oral contraceptives; 2.8% "natural" methods; 2.2% IUDs. The largest amount was from urban areas of Mendoza. However, high rates are observed in rural areas. A progression of the amount of PWRTP was observed throughout the year. 11% after requesting an abortion decided to continue with the pregnancy. Apparently none of the variables was related to that decision. The CM used were mostly condoms and oral contraceptives. This may indicate a lack of education and poor access to long-acting CM. The problem of interruption is transversal. People without a cohabiting partner, faced with an unplanned pregnancy, are the ones who RTP. No other variable seems to act as a determinant. Nor from the transition from the request to the effective interruption or continuation of the pregnancy. We must increase the accessibility to CM in rural areas (AU)

Rehabilitación respiratoria en pacientes con SARS-CoV-2. Estado de conocimiento actual / Respiratory Rehabilitation in Patients with SARS-COV-2. Current State of Knowledge

En diciembre del año 2019, en la localidad china de Wuhan se detectó el primer caso de enfermedad por el virus SARS-Cov-2. A diferencia del carácter limitado de las dos últimas epidemias, la del Síndrome Respiratorio de Medio Oriente (MERS) y el Síndrome Respiratorio Agudo Grave por Coronavirus (SARS-CoV), la rápida expansión del SARS-CoV-2 obligó a la Organización Mundial de la Salud (OMS) a declarar la situación de pandemia en marzo de 2020

2D Quantitative Imaging of Magnetic Nanoparticles by an AC Biosusceptometry Based Scanning Approach and Inverse Problem.

The use of magnetic nanoparticles (MNPs) in biomedical applications requires the quantitative knowledge of their quantitative distribution within the body. AC Biosusceptometry (ACB) is a biomagnetic technique recently employed to detect MNPs in vivo by measuring the MNPs response when exposed to an alternate magnetic field. The ACB technique presents some interesting characteristics: non-invasiveness, low operational cost, high portability, and no need for magnetic shielding. ACB conventional methods until now provided only qualitative information about the MNPs' mapping in small animals. We present a theoretical model and experimentally demonstrate the feasibility of ACB reconstructing 2D quantitative images of MNPs' distributions. We employed an ACB single-channel scanning approach, measuring at 361 sensor positions, to reconstruct MNPs' spatial distributions. For this, we established a discrete forward problem and solved the ACB system's inverse problem. Thus, we were able to determine the positions and quantities of MNPs in a field of view of 5×5×1 cm3 with good precision and accuracy. The results show the ACB system's capabilities to reconstruct the quantitative spatial distribution of MNPs with a spatial resolution better than 1 cm, and a sensitivity of 1.17 mg of MNPs fixed in gypsum. These results show the system's potential for biomedical application of MNPs in several studies, for example, electrochemical-functionalized MNPs for cancer cell targeting, quantitative sensing, and possibly in vivo imaging.

An Energy-Based Method for Orientation Correction of EMG Bracelet Sensors in Hand Gesture Recognition Systems.

Hand gesture recognition (HGR) systems using electromyography (EMG) bracelet-type sensors are currently largely used over other HGR technologies. However, bracelets are susceptible to electrode rotation, causing a decrease in HGR performance. In this work, HGR systems with an algorithm for orientation correction are proposed. The proposed orientation correction method is based on the computation of the maximum energy channel using a synchronization gesture. Then, the channels of the EMG are rearranged in a new sequence which starts with the maximum energy channel. This new sequence of channels is used for both training and testing. After the EMG channels are rearranged, this signal passes through the following stages: pre-processing, feature extraction, classification, and post-processing. We implemented user-specific and user-general HGR models based on a common architecture which is robust to rotations of the EMG bracelet. Four experiments were performed, taking into account two different metrics which are the classification and recognition accuracy for both models implemented in this work, where each model was evaluated with and without rotation of the bracelet. The classification accuracy measures how well a model predicted which gesture is contained somewhere in a given EMG, whereas recognition accuracy measures how well a model predicted when it occurred, how long it lasted, and which gesture is contained in a given EMG. The results of the experiments (without and with orientation correction) executed show an increase in performance from 44.5% to 81.2% for classification and from 43.3% to 81.3% for recognition in user-general models, while in user-specific models, the results show an increase in performance from 39.8% to 94.9% for classification and from 38.8% to 94.2% for recognition. The results obtained in this work evidence that the proposed method for orientation correction makes the performance of an HGR robust to rotations of the EMG bracelet.

Temporal information in tones, broadband noise, and natural vocalizations is conveyed by differential spiking responses in the superior paraolivary nucleus.

Communication sounds across all mammals consist of multiple frequencies repeated in sequence. The onset and offset of vocalizations are potentially important cues for recognizing distinct units, such as phonemes and syllables, which are needed to perceive meaningful communication. The superior paraolivary nucleus (SPON) in the auditory brainstem has been implicated in the processing of rhythmic sounds. Here, we compared how best frequency tones (BFTs), broadband noise (BBN), and natural mouse calls elicit onset and offset spiking in the mouse SPON. The results demonstrate that onset spiking typically occurs in response to BBN, but not BFT stimulation, while spiking at the sound offset occurs for both stimulus types. This effect of stimulus bandwidth on spiking is consistent with two of the established inputs to the SPON from the octopus cells (onset spiking) and medial nucleus of the trapezoid body (offset spiking). Natural mouse calls elicit two main spiking peaks. The first spiking peak, which is weak or absent with BFT stimulation, occurs most consistently during the call envelope, while the second spiking peak occurs at the call offset. This suggests that the combined spiking activity in the SPON elicited by vocalizations reflects the entire envelope, that is, the coarse amplitude waveform. Since the output from the SPON is purely inhibitory, it is speculated that, at the level of the inferior colliculus, the broadly tuned first peak may improve the signal-to-noise ratio of the subsequent, more call frequency-specific peak. Thus, the SPON may provide a dual inhibition mechanism for tracking phonetic boundaries in social-vocal communication.

Octopus Cells in the Posteroventral Cochlear Nucleus Provide the Main Excitatory Input to the Superior Paraolivary Nucleus.

Auditory streaming enables perception and interpretation of complex acoustic environments that contain competing sound sources. At early stages of central processing, sounds are segregated into separate streams representing attributes that later merge into acoustic objects. Streaming of temporal cues is critical for perceiving vocal communication, such as human speech, but our understanding of circuits that underlie this process is lacking, particularly at subcortical levels. The superior paraolivary nucleus (SPON), a prominent group of inhibitory neurons in the mammalian brainstem, has been implicated in processing temporal information needed for the segmentation of ongoing complex sounds into discrete events. The SPON requires temporally precise and robust excitatory input(s) to convey information about the steep rise in sound amplitude that marks the onset of voiced sound elements. Unfortunately, the sources of excitation to the SPON and the impact of these inputs on the behavior of SPON neurons have yet to be resolved. Using anatomical tract tracing and immunohistochemistry, we identified octopus cells in the contralateral cochlear nucleus (CN) as the primary source of excitatory input to the SPON. Cluster analysis of miniature excitatory events also indicated that the majority of SPON neurons receive one type of excitatory input. Precise octopus cell-driven onset spiking coupled with transient offset spiking make SPON responses well-suited to signal transitions in sound energy contained in vocalizations. Targets of octopus cell projections, including the SPON, are strongly implicated in the processing of temporal sound features, which suggests a common pathway that conveys information critical for perception of complex natural sounds.

Different tonotopic regions of the lateral superior olive receive a similar combination of afferent inputs.

The mammalian lateral superior olive (LSO) codes disparities in the intensity of the sound that reaches the two ears by integrating ipsilateral excitation and contralateral inhibition, but it remains unclear what particular neuron types convey acoustic information to the nucleus. It is also uncertain whether the known conspicuous morphofunctional differences and gradients along the tonotopic axis of the LSO relate to qualitative and/or quantitative regional differences in its afferents. To clarify these issues, we made small, single injections of the neuroanatomical tracer biotinylated dextran amine (BDA) into different tonotopic regions of the LSO of albino rats and analyzed the neurons labeled retrogradely in brainstem auditory nuclei. We demonstrate that the LSO is innervated tonotopically by four brainstem neuron types: spherical bushy cells and planar multipolar neurons of the ipsilateral ventral cochlear nucleus, principal neurons of the ipsilateral medial nucleus of the trapezoid body, and small multipolar neurons of the contralateral ventral nucleus of the trapezoid body. Unexpectedly, the proportion of labeled neurons of each type was virtually identical in all cases, thus indicating that all tonotopic regions of the LSO receive a similar combination of inputs. Even more surprisingly, our data also suggest that the representation of frequencies in the LSO differs from that of the nuclei that innervate it: compared to the latter nuclei, the LSO seems to possess a relatively larger portion of its volume devoted to processing frequencies in the lower-middle part of the spectrum, and a relative smaller portion devoted to higher frequencies. J. Comp. Neurol. 524:2230-2250, 2016. © 2015 Wiley Periodicals, Inc.

Utilización de medicina complementaria en procesos degenerativos articulares / Use of complementary medicine in joint degenerative processes

En la clínica alopática vemos a diario el avance de nuevos tratamientos hacia diversas patologías. Sin embargo, se ha visto que en las terapias crónicas de enfermedades inflamatorias degenerativas asociadas a la edad del paciente, (gerontes) el margen terapéutico de sus medicamentos se torna cada vez más estrecho, debido a que con el paso del tiempo aparecen disfunciones orgánicas que limitan la aplicación de fármacos sintéticos, por sus efectos colaterales. Es en esta brecha donde la medicina complementaria comienza a jugar un papel importante en el arsenal terapéutico del médico veterinario. En esta tesina, se describirán tres herramientas terapéuticas dentro de las llamadas medicinas complementarias que se utilizan en la terapia de los procesos degenerativos del aparato osteoarticular y se comparará su efecto de acción con las drogas antiinflamatorias de síntesis que se usan habitualmente. Las terapias que se desarrollarán en este trabajo son: La acupuntura, la fitomedicina y la apiterapia a través de la aplicación de apitoxina.

Diabetes and Other Risk Factors for Multi-drug Resistant Tuberculosis in a Mexican Population with Pulmonary Tuberculosis: Case Control Study.

BACKGROUND AND AIMS: Multidrug resistant tuberculosis (MDR-TB) poses problems in treatment, costs and treatment outcomes. It is not known if classically described risk factors for MDR-TB in other countries are the same in Mexico and the frequency of the association between diabetes mellitus (DM) and MDR-TB in our country is not clear. We undertook this study to analyze risk factors associated with the development of MDR-TB, with emphasis on DM. METHODS: A case-control study in the state of San Luis Potosi (SLP), Mexico was carried out. All pulmonary MDR-TB patients diagnosed in the state of SLP between 1998 and 2013 (36 cases) evaluated at a state pharmacoresistant tuberculosis (TB) clinic and committee; 139 controls were randomly selected from all pulmonary non-multidrug-resistant tuberculosis (non-MDR-TB) cases identified between 2003 and 2008. Cases and controls were diagnosed and treated under programmatic conditions. RESULTS: Age, gender, malnutrition, being a health-care worker, HIV/AIDS status, and drug abuse were not significantly different between MDR-TB and non-MDR-TB patients. Significant differences between MDR-TB and non-MDR-TB patients were DM (47.2 vs. 28.1%; p = 0.028); previous anti-TB treatments (3 vs. 0, respectively; p <0.001), and duration of first anti-TB treatment (8 vs. 6 months, respectively; p <0.001). CONCLUSIONS: MDR-TB and DM are associated in 47.2% of MDR TB cases (17/36) in this study. Other recognized factors were not found to be significantly different in MDR-TB compared to non-MDR-TB in this study. Cost-feasible strategies must be implemented in the treatment of DM-TB in order to prevent the selection of MDR-TB.

Embryonic amygdalar transplants in adult rats with motor cortex lesions: a molecular and electrophysiological analysis.

Transplants of embryonic nervous tissue ameliorate motor deficits induced by motor cortex lesions in adult animals. Restoration of lost brain functions has been recently shown in grafts of homotopic cortical origin, to be associated with a functional integration of the transplant after development of reciprocal host-graft connections. Nevertheless little is known about physiological properties or gene expression profiles of cortical implants with functional restorative capacity but no cortical origin. In this study, we show molecular and electrophysiological evidence supporting the functional development and integration of heterotopic transplants of embryonic amygdalar tissue placed into pre-lesioned motor cortex of adult rats. Grafts were analyzed 3 months post-transplantation. Using reverse transcriptase quantitative polymerase chain reaction, we found that key glutamatergic, GABAergic, and muscarinic receptors transcripts were expressed at different quantitative levels both in grafted and host tissues, but were all continuously present in the graft. Parallel sharp electrode recordings of grafted neurons in brain slices showed a regular firing pattern of transplanted neurons similar to host amygdalar pyramidal neurons. Synaptic connections from the adjacent host cortex on grafted neurons were electrophysiologically investigated and confirmed our molecular results. Taken together, our findings indicate that grafted neurons from a non-cortical, non-motor-related, but ontogenetical similar source, not only received functionally effective contacts from the adjacent motor cortex, but also developed electrophysiological and gene expression patterns comparable to host pyramidal neurons; suggesting an interesting tool for the field of neural repair and donor tissue in adults.