Non-telecentric two-photon microscopy for 3D random access mesoscale imaging.

Diffraction-limited two-photon microscopy permits minimally invasive optical monitoring of neuronal activity. However, most conventional two-photon microscopes impose significant constraints on the size of the imaging field-of-view and the specific shape of the effective excitation volume, thus limiting the scope of biological questions that can be addressed and the information obtainable. Here, employing a non-telecentric optical design, we present a low-cost, easily implemented and flexible solution to address these limitations, offering a several-fold expanded three-dimensional field of view. Moreover, rapid laser-focus control via an electrically tunable lens allows near-simultaneous imaging of remote regions separated in three dimensions and permits the bending of imaging planes to follow natural curvatures in biological structures. Crucially, our core design is readily implemented (and reversed) within a matter of hours, making it highly suitable as a base platform for further development. We demonstrate the application of our system for imaging neuronal activity in a variety of examples in zebrafish, mice and fruit flies.

Factores asociados al inicio de la lactancia materna y razones de la madre para la toma de su decisión / Predictors of breastfeeding initiation and maternal reasons for this decision

Introducción: Los beneficios de la lactancia materna (LM) son bien conocidos. En estudios previos se constata que aproximadamente un 20% de las madres deciden no iniciarla. Existe un escaso conocimiento de los factores que predicen tal decisión y los motivos maternos para ello. En este estudio analizamos la prevalencia de inicio de la LM, los factores asociados y las razones maternas al respecto. Método: Estudio de prevalencia de inicio de la LM de gestaciones ≥ 36 semanas. Recogida de variables mediante encuestas presenciales en las primeras 24 horas posparto. Estudio multivariante de los factores asociados al inicio de la LM. Resultados: Se estudió un total de 452 pares, madre-recién nacido. El 81% inició la LM. Los factores favorecedores fueron la opinión favorable de la pareja (odds ratio [OR]= 28,49; intervalo de confianza [IC] del 95%: 5,34-151,95), la opinión neutral de la abuela materna (OR= 4,79; IC del 95%: 0,99-23,76), haber dado LM al hijo previo (OR= 22,63; IC del 95%: 5,68-90,07) y residir en la misma provincia donde está ubicado el hospital (OR= 47,34; IC del 95%: 16,09-139,31). Los factores desfavorecedores fueron: el hábito tabáquico de la madre (OR= 0,37; IC del 95%: 0,15-0,92), haber tenido abortos previos (OR= 0,35; IC del 95%: 0,20-0,60) y precisar tratamiento farmacológico al iniciar la lactancia (OR= 0,25; IC del 95%: 0,08-0,74). Conclusiones: Aportamos ciertos factores conocidos y otros novedosos asociados al inicio de la LM y los motivos de la madre para la toma de su decisión. Los tratamientos farmacológicos maternos son un factor asociado para no iniciar la LM, corregible con un asesoramiento adecuado. Urge adoptar medidas correctoras para conseguir tasas de inicio de la LM cercanas al 100%. Es necesaria la unificación de criterios respecto a lo que se considera «inicio de la LM» para comparar resultados de futuras investigaciones (AU)

Introduction: Breastfeeding benefits have been clearly demonstrated, but nearly 20% of mothers don’t start breastfeeding. Related factors to this decision and maternal reasons have been poorly investigated. We asses initiation breastfeeding rate, maternal reasons and the factors linked to their decision. Method: This is a prevalence study of initiation breastfeeding rate in a sample of mothers who delivered after 36 weeks of gestation. Six trained investigators collected variables by structured questionnaires, asking the mothers in the hospital within the first 24 hours after delivery. Bivariate and multivariate analysis of the data were performed. Results: Eighty one percent of the mothers started breastfeeding. Positive associated factors were: a good opinion of mother’s partner about breastfeeding (OR= 28.49; CI 95%: 5.34-151.95), neutral opinion of grandmother about breastfeeding (OR= 4.79; CI 95%: 0.99-23.76), positive breastfeeding experience with previous sibling (OR= 22.63; CI 95%: 5.68-90.07) and coming from the same province where the hospital is located (OR= 47.34; CI 95%: 16.09- 139.31). Negative related factors were: maternal smoking habit (OR= 0.37; CI 95%: 0.15-0.92), previous abortions (OR= 0.35; CI 95%: 0.20-0.60) and maternal pharmacological treatment at the beginning of breastfeeding (OR= 0.25; CI 95%: 0.08-0.74). Conclusions: We have described not only known but other new factors associated with the breastfeeding initiation, and maternal reasons for making their decisions. Pharmacological treatment is one of the factors clearly implicated in the beginning of formula-feeding, and this decision is avoidable with a correct counselling. Increasing breastfeeding initiation rates is strongly recommended with new public health interventions. Common criteria of what consider as a “breastfeeding initiation” are required for future research (AU)

Factores asociados al abandono precoz de la lactancia materna en una región del este de España / Factors associated with early weaning in a Spanish region

INTRODUCCIÓN: La lactancia materna (LM) tiene indudables beneficios para el recién nacido. En estudios previos se constata un abandono precoz de la misma, existiendo escasa evidencia sobre los factores asociados. Nuestro objetivo ha sido conocer la prevalencia de LM durante los primeros 12 meses posparto y analizar los factores asociados a su abandono. MATERIAL Y MÉTODOS: Estudio prospectivo, con inclusión consecutiva de pares (madre y recién nacido) hasta muestra requerida. Recogida de variables mediante encuestas maternas según el programa de seguimiento. Análisis estadístico bivariado y multivariado. RESULTADOS: Se seleccionaron 452 pares en los que se constató el inicio de la LM en el 81% de los casos, persistiendo a los 3 y 6 meses el 39 y 21% total, respectivamente. Los factores asociados al abandono precoz fueron: gestación tras técnicas de reproducción asistida (OR = 5,58; IC 95%: 2,62-11,91), hábito tabáquico materno (OR = 1,56; IC 95%: 1,10-2,22), expectativas pobres sobre la duración de la lactancia (OR = 2,19; IC 95%: 1,49-3,23), utilización de pezoneras (OR = 2,57; IC 95%: 1,69-3,90), uso rutinario del chupete durante el primer mes posparto (OR = 1,39; IC 95%: 1,02-1,91), madre con estudios universitarios (OR = 0,59; IC 95%: 0,40-0,88), asistencia a clases prenatales (OR = 0,68; IC 95%: 0,49-0,94), y sensación materna de leche suficiente al alta (OR = 0,66; IC 95%: 0,47-0,92). CONCLUSIONES: Las tasas de abandono de la LM en nuestro medio son elevadas, sin alcanzarse los objetivos de las recomendaciones internacionales al respecto. Se describen factores implicados ya conocidos y otros novedosos. Se recomiendan estrategias de intervención encaminadas a prolongar la LM

INTRODUCTION: Breastfeeding has undoubtedly great benefits. Previous studies have found anearly dropout. Only a few studies have investigated related factors. Our aim was to find outon-going breastfeeding rates along the first 12 months after birth and analyse factors associated with early weaning. MATERIAL AND METHODS: This is a prospective study including consecutive pairs (mother and newborn) till completion of the required sample. Variables were collected performing a structured program of surveys to the mothers. Bivariate and multivariate analysis of the data was performed. RESULTS: A total of 452 pairs were recruited. It was found that 81% of them started breastfeeding, with a prevalence of breastfeeding of 39% and 21% at 3 and 6 months after birth, respectively. Factors associated with early discontinuation of breastfeeding were: pregnancy induced by assisted reproduction methods (OR = 5.58; 95% CI: 2.62-11.91), maternal smoking(OR = 1.56; 95% CI: 1.10-2.22), poor maternal expectations about the duration of breastfeeding(OR = 2.19; 95% CI: 1.49-3.23), use of nipple shields for breastfeeding (OR = 2.57; 95% CI:1.69-3.90), pacifier use on a regular basis during the first month after delivery (OR = 1.39; 95%CI: 1.02-1.91), maternal university educational level (OR = 0,59; 95% CI: 0,40-0,88), attending birth preparation programs during pregnancy (OR = 0,68; 95% CI: 0,49-0,94), and believing having enough milk output at the time of discharge (OR = 0,66; 95% CI: 0,47-0,92). CONCLUSIONS: International recommendations about duration of breastfeeding are not achieved in our country because of high rates of early weaning. We describe the known factors involved and other novel factors. The implementation of interventions to increase breastfeeding rates and to prevent early weaning are strongly recommended

[Factors associated with early weaning in a Spanish region]. / Factores asociados al abandono precoz de la lactancia materna en una región del este de España.

INTRODUCTION: Breastfeeding has undoubtedly great benefits. Previous studies have foundan early dropout. Only a few studies have investigated related factors. Our aim was to find out on-going breastfeeding rates along the first 12 months after birth and analyse factors associated with early weaning. MATERIAL AND METHODS: This is a prospective study including consecutive pairs (mother and newborn) till completion of the required sample. Variables were collected performing a structured program of surveys to the mothers. Bivariate and multivariate analysis of the data was performed. RESULTS: A total of 452 pairs were recruited. It was found that 81% of them started breastfeeding, with a prevalence of breastfeeding of 39% and 21% at 3 and 6 months after birth, respectively. Factors associated with early discontinuation of breastfeeding were: pregnancy induced by assisted reproduction methods (OR=5.58; 95% CI: 2.62-11.91), maternal smoking (OR=1.56; 95% CI: 1.10-2.22), poor maternal expectations about the duration of breastfeeding (OR=2.19; 95% CI: 1.49-3.23), use of nipple shields for breastfeeding (OR=2.57; 95% CI: 1.69-3.90), pacifier use on a regular basis during the first month after delivery (OR=1.39; 95% CI: 1.02-1.91), maternal university educational level (OR=0,59; 95% CI: 0,40-0,88), attending birth preparation programs during pregnancy (OR=0,68; 95% CI: 0,49-0,94), and believing having enough milk output at the time of discharge (OR=0,66; 95% CI: 0,47-0,92). CONCLUSIONS: International recommendations about duration of breastfeeding are not achieved in our country because of high rates of early weaning. We describe the known factors involved and other novel factors. The implementation of interventions to increase breastfeeding rates and to prevent early weaning are strongly recommended.

Las múltiples facetas de la hipertrofia ventricular izquierda en la obesidad e hipertensión arterial / Left ventricular characteristics in obesity and hypertension

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Rapid development and plasticity of layer 2/3 maps in rat barrel cortex in vivo.

Cortical synaptic circuitry develops rapidly in the second postnatal week, simultaneous with experience-dependent turnover of dendritic spines. To relate the emergence of sensory maps to synaptogenesis, we recorded synaptic potentials evoked by whisker deflection in layer 2/3 neurons from postnatal day (P) 12 to 20. At P12, synaptic responses were undetectable. Only 2 days later in life (P14), receptive fields had mature organization. Sensory deprivation, if initiated before P14, disrupted receptive field structure. In layer 4, responses and maps were already mature by P12 and insensitive to deprivation, implying that barrel cortex develops from layer 4 to layer 2/3. Thus, P12-14 is a critical period shared by layer 2/3 synapses and their spines, suggesting that spine plasticity is involved in the refinement of maps.

Ca(2+) signaling in dendritic spines.

Dendritic spines are cellular microcompartments that are isolated from their parent dendrites and neighboring spines. Recently, imaging studies of spine Ca(2+) dynamics have revealed that Ca(2+) can enter spines through voltage-sensitive and ligand-activated channels, as well as through Ca(2+) release from intracellular stores. Relationships between spine Ca(2+) signals and induction of various forms of synaptic plasticity are beginning to be elucidated. Measurements of spine Ca(2+) concentration are also being used to probe the properties of single synapses and even individual calcium channels in their native environment.

Estimating intracellular calcium concentrations and buffering without wavelength ratioing.

We describe a method for determining intracellular free calcium concentration ([Ca(2+)]) from single-wavelength fluorescence signals. In contrast to previous single-wavelength calibration methods, the proposed method does not require independent estimates of resting [Ca(2+)] but relies on the measurement of fluorescence close to indicator saturation during an experiment. Consequently, it is well suited to [Ca(2+)] indicators for which saturation can be achieved under physiological conditions. In addition, the method requires that the indicators have large dynamic ranges. Popular indicators such as Calcium Green-1 or Fluo-3 fulfill these conditions. As a test of the method, we measured [Ca(2+)] in CA1 pyramidal neurons in rat hippocampal slices using Oregon Green BAPTA-1 and 2-photon laser scanning microscopy (BAPTA: 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid). Resting [Ca(2+)] was 32-59 nM in the proximal apical dendrite. Monitoring action potential-evoked [Ca(2+)] transients as a function of indicator loading yielded estimates of endogenous buffering capacity (44-80) and peak [Ca(2+)] changes at zero added buffer (178-312 nM). In young animals (postnatal days 14-17) our results were comparable to previous estimates obtained by ratiometric methods (, Biophys. J. 70:1069-1081), and no significant differences were seen in older animals (P24-28). We expect our method to be widely applicable to measurements of [Ca(2+)] and [Ca(2+)]-dependent processes in small neuronal compartments, particularly in the many situations that do not permit wavelength ratio imaging.

Sparsification from dilute connectivity in a neural network model of memory.

Several hypotheses concerning implementations of associative memory in the brain rely on analyses of the capabilities of simple network models. However, the low connectivity of cerebral networks imposes constraints which sometimes do not arise clearly from such analyses. We investigate an aspect of a simple, dilute network's operation that is sometimes overlooked, namely the setting of activation thresholds. An examination of several criteria for optimal threshold assignment affords several new insights. It becomes apparent that the network's capacity (which is simply derived) is insufficient to characterize the quality of its performance. We derive the degree of 'sparsification' or decrease in firing probability that arises from dilution, and also the consequent losses in representational ability, and propose that they should also be taken into account. To evaluate the model's performance and suitability, we argue that one should explicitly consider the trade-off that exists between storage of patterns and preservation of information, and its consequent constraints.