Análisis de conceptos básicos de memoria y aprendizaje: ¿hasta que punto los "dogmas" cognitivos son realmente "dogmas"?

El aprendizaje como proceso se puede considerar un avance evolutivo importante para todos los sistemas vivientes que lo adquirieron en las tempranas épocas del desarrollo de la vida. La percepción de un entorno que tiene “pasado” y “presente” permitió a los animales primitivos adquirir una visión más completa del mundo que los rodeaba. El uso cognitivo de la información que está disponible en un sistema viviente se le reconoce ahora como “aprendizaje”. A pesar que han pasado muchos años y muchos investigadores han estado muy comprometidos en el estudio de la memoria y el aprendizaje, su intrincada naturaleza todavía no se comprende bien. En este trabajo se amplían muchos términos comunes en la investigación de este tema, como memoria, aprendizaje y ensayo redefiniéndose en un contexto más acotado con la intención de uniformar su comprensión. Se vuelve a discutir el modelo de aprendizaje en términos de un “circuito de aprendizaje”. También se amplía el concepto unificador de “engrama de la unidad vectorial de la memoria” para el proceso de aprendizaje y el almacenamiento de la información, descrito con anterioridad. Finalmente, las implicaciones del modelo propuesto se consideran en el contexto de patologías que producen déficit de memoria, evaluándose las predicciones del modelo con la evidencia comportamental de pacientes con lesiones localizadas en ciertas partes del cerebro.Learning can be considered a process that gave to living systems a significant evolutionary advance in the history of life. The capacity to distinguish that events in the environment have “past” or “present” permitted the primitive evolving organisms to acquire a convenient enriched vision of the their surrounding world. The appropriate use of the information available as experience in an organism now it is known as learning. In spite of many years of intense research, the complete understanding of memory and learning still is not clear. Debate and disagreements about the intrinsic nature of this neural process in the scientific community did not help in these years to sediment a clear-cut knowledge about this important brain function. Part of these issues appears to be linked to the semantic use of some terms implying different meanings to different investigators, and the strong belief in interpretations about learning that in time has been considered dogmas. In the present work, intent to emphasize the meaning of many terms by limiting its significance and extending an alternative point of view previously presented elsewhere, about memory and learning is done.Fil: Alvarez Toro, Edgardo Orozimbo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Ratti, Silvia Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentin

The Altered Behavioural Responses Displayed by Litter Rats After Chronic Administration of Non-Toxic Concentrations of ZnTe to Parent Rats Are Reversed by Simultaneous Folic Acid Treatment

Trace elements are an omnipresent group of chemical elements that are present practically in all types of environments sustaining life. Since its principal characteristic is the very low concentration in ground and water, it was thought that its importance to metabolic processes to the living cell was minimal. However, in the past 15 years knowledge has been accumulated regarding that these chemical elements have important influences on the cell dynamic homeostatic mechanisms. Previous evidence from our laboratory has shown that chronic administration of ZnTe to pregnancy, delivery and subsequent juvenile stages in rats affected several of its behavioural parameters related to motivated, lateralized exploration, social and defensive behaviour. In the third part of this study, the possible effect of folic acid (FolA) on the Te-induced behavioural changes was studied. Three experimental groups were formed, Control, animals treated with tap water; ZnTe, animals treated with the trace elements, and ZnTe+FolA, animals treated with the combination of ZnTe and FolA, in the same way that of the previous experiments. Results show the folic acid treatment did not counteract the increase of motor activity observed in those animals treated with ZnTe. However, in the exploration induced by novelty measured in the Double Lateral Hole-board Labyrinth, the corridor behavioural activity displayed by animals under the combination of FolA and ZnTe was similar to control and significantly different from the ZnTe-treated group. The left exploration bias naturally present in control, and blocked in the ZnTe-treated animals, was restored to control values in the FolA+ZnTe treated animals. A similar observation was found with the percentage of animals with left-bias exploration, where those rats treated with the combination of FolA and ZnTe reached similar values to control and significantly greater than the ZnTe-treated rats which were statistically lower than control. Social behaviour, inhibited by ZnTe was restored to normal in the FolA treated animals. A similar observation was found in the defensive behaviour test. Results are compatible with the idea that FolA, which is known as a methyl donor reagent, can restore the behavioural effects of ZnTe, giving support to previous results suggesting that trace elements could act by molecular mechanisms involving epigenetical modulation of DNA.Fil: Ratti, Silvia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Alvarez Toro, Edgardo Orozimbo. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Rate coefficient for the reaction of Cl atoms with cis-3-hexene at 296 ± 2 K

The rate coefficient of the cis-3-hexene + Cl atoms reaction at 296 ± 2 K and 750 ± 10 Torr was determined using the relative rate technique. The reaction was investigated using an 80 L Teflon reaction bag and a gas chromatograph coupled with flame-ionization detection. Chlorine atoms were produced by the photolysis of trichloroacetyl chloride. No previous experimental data was available in the literature, to the best of our knowledge. The mean second-order rate coefficient value found was (4.13 ± 0.51) × 10-10 cm3 molecule-1 s-1. The experimental value agrees with the rate coefficient estimated by structure-reactivity analysis, 4.27 × 10-10 cm3 molecule-1 s-1. Moreover, both addition and hydrogen abstraction channels contribute to the global kinetics, with branching ratios 70:30. Effective lifetime with respect to Cl atoms is predicted as 67.2 hours; however, the cis-3-hexene + Cl channel is suggested to be non-negligible at atmospheric conditions. Other atmospheric implications are discussed.Fil: Barbosa, Thaís S.. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Barrera, Javier Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Jara Toro, Rafael Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Bauerfeldt, Glauco F.. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Arbilla, Graciela. Universidade Federal do Rio de Janeiro; BrasilFil: Lane, Silvia Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Evaluation of microleakage and strength adhesive of composite resin restorations with total etch adhesive system in primary and permanent teeth

Indexación: Web of Science; Scielo.El presente estudio evaluó el grado de sellado marginal y resistencia adhesiva de restauraciones de resinas compuestas confeccionadas con un sistema adhesivo de grabado y lavado en dentición primaria y definitiva. Para realizar ambos test se utilizaron 20 piezas primarias y 20 piezas definitivas. En resistencia al cizallamiento, los dientes fueron seccionados longitudinalmente y se les adhirió un cilindro de resina compuesta, utilizando la técnica adhesiva de grabado y lavado para ambas denticiones. Posteriormente, fueron testeados en una máquina de ensayos universales Tinius Olsen, aplicando una fuerza de cizallamiento de 200 kg y a una velocidad de cabezal de 0,2 cm/min. Para el test de sellado marginal, se les realizó una preparación cavitaria clase V, por vestibular/palatino estandarizada. Luego se les confeccionaron restauraciones de resina compuesta con la técnica de grabado y lavado, y se sometieron al termociclado con azul de metileno al 2%; después fueron cortados y observados al microscopio óptico estereoscópico con aumento de lupa, para medir el porcentaje de microfiltración obtenido. El valor promedio de la resistencia adhesiva al cizallamiento para dentición primaria fue de 8,49 Mpa, y de 9,52 Mpa para dentición definitiva, no encontrándose diferencias estadísticamente significativas entre los grupos en estudio. En la investigación sobre el grado de sellado marginal se evaluó el porcentaje de microfiltración y tampoco se encontraron diferencias estadísticamente significativas, lo que señalaría que ambos tejidos son igualmente susceptibles de ser tratados adhesivamente mediante la técnica de hibridación.Abstract The present study evaluated the degree of marginal seal and adhesive resistance of composite resin restorations prepared with an etch and rinse adhesive system in primary and definitive dentition. To perform both tests, 20 primary pieces and 20 permanent pieces were used. In the shear strength resistance, the teeth were sectioned longitudinally and were adhered to composite resin cylinder, using the etch and rinse technique for both dentitions. They were then tested on a Tinius Olsen universal testing machine, applying a shear force of 200 kg and a head speed of 0.2 cm/min. For the margin seal test, a class V cavity preparation of standardised vestibular/palatine was made. The composite resin restorations were made with the etch and rinse technique and were subjected to thermocycling with 2% methylene blue. Later, they were cut and observed using a stereoscopic optical microscope with loop magnification to measure the percentage of microfiltration obtained. The mean value of the adhesive resistance to shearing for primary dentition was 8.49 Mpa, and 9.52 Mpa for permanent teeth, with no statistically significant differences being found between the groups studied. In the test on the degree of margin seal the percentage microfiltration was measured, with no statistically significant differences being found either. The results showed that both tissues are equally susceptible to being treated adhesively using the hybrid techniquehttp://ref.scielo.org/53nph

Bioinorganic chemistry of trace elements: Possible role in the epigenetic modulation of homoeostatic processes in complex organisms

Trace elements are well known in the geochemistry disciplines. However, its relationship to the biological and medical sciences is very recent. In spite that knowledge about the influence of environment in living processes is a traditional concept, until about the middle part of the 20 century, the possible influence on physiological functions of chemical elements present in waters and soil surrounding man habitat was not particularly investigated. Principal concern was concentrated to evaluate toxic actions of chemical elements on living systems. However, evidence showing that chemical elements are able to interact with enzymes, transcription factors and DNA in several living systems, put the inorganic elements into a new perspective. Higher concentrations of inorganic elements in the environment do not necessarily must be the only requirement for biological interactions in living systems. In the present paper historical aspects, some chemical properties of trace elements, an emphasized discussion about selenium and tellurium on functional processes in living systems are reviewed. In addition, hypothesis about the role of trace elements on epigenetic changes in the expression of gene action is also discussed.Fil: Ratti, Silvia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Laboratorio de Neuropsicofarmacología Experimental; Argentina;Fil: Cioccale, Marcela Alejandra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología Aplicada; Argentina;Fil: Carignano, Claudio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; Argentina; Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Geológicas Aplicadas; Argentina;Fil: Alvarez Toro, Edgardo Orozimbo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina

Surface Electromyography Study Using a Low-Cost System: Are There Neck Muscles Differences When the Passenger Is Warned during an Emergency Braking Inside an Autonomous Vehicle?

Deaths and serious injuries caused by traffic accidents is a concerning public health problem. However, the problem can be mitigated by the Autonomous Emergency Braking (AEB) system, which can avoid the impact. The market penetration of AEB is exponentially growing, and non-impact situations are expected to become more frequent. Thus, new injury patterns must be analysed, and the neck is particularly sensitive to sudden acceleration changes. Abrupt braking would be enough to be a potential risk for cervical spine injury. There is controversy about whether or not there are differences in cervical behaviour depending on whether passengers are relaxed or contract their muscles before the imminent accident. In the present manuscript, 18 volunteers were subjected to two different levels of awareness during an emergency braking test. Cervical muscles (sternocleidomastoid and trapezius) were analysed by the sEMG signal captured by means of a low-cost system. The differences observed in the muscle response according to gender and age were notable when passengers are warned. Gender differences were more significant in the post-braking phase. When passengers were relaxed, subjects older than 35 registered higher sEMG values. Meanwhile, when passengers contract their muscles, subjects who were younger than or equal to 35 years old experienced an increment in the values of the sEMG signals

Study of the Emergency Braking Test with an Autonomous Bus and the sEMG Neck Response by Means of a Low-Cost System

This article belongs to the Special Issue Development of Innovative Sensor Platforms for Field AnalysisNowadays, due to the advances and the increasing implementation of the autonomous braking systems in vehicles, the non-collision accident is expected to become more common than a crash when a sudden stop happens. The most common injury in this kind of accident is whiplash or cervical injury since the neck has high sensitivity to sharp deceleration. To date, biomechanical research has usually been developed inside laboratories and does not entirely represent real conditions (e.g., restraint systems or surroundings of the experiment). With the aim of knowing the possible neck effects and consequences of an automatic emergency braking inside an autonomous bus, a surface electromyography (sEMG) system built by low-cost elements and developed by us, in tandem with other devices, such as accelerometers or cameras, were used. Moreover, thanks to the collaboration of 18 participants, it was possible to study the non-collision effects in two different scenarios (braking test in which the passenger is seated and looking ahead while talking with somebody in front of him (BT1) and, a second braking test where the passenger used a smartphone (BT2) and nobody is seated in front of him talking to him). The aim was to assess the sEMG neck response in the most common situations when somebody uses some kind of transport in order to conclude which environments are riskier regarding a possible cervical injury

Environmental Biosensors: A Microbiological View

In this mini-review, the potential of using microorganisms to design biosensors for detecting environmental pollutants is analyzed and discussed. A distinction is made between a classical biosensor (CB) and a whole-cell biosensor (WCB), emphasizing their structural components and the possibility of using whole microorganisms as their bioreceptor elements. The advantages and disadvantages of using prokaryotic microorganisms as opposed to eukaryotic microorganisms are described. Likewise, the advantages of using protozoa ciliates) over other eukaryotic microorganisms are also shown. We analyze the current bibliography on biosensors built on microorganisms as bioreceptors of pollutant molecules, such as inorganic (metal (loid)s) or organic (xenobiotics). New trends, such as the prokaryotic riboswitches, microbial two-component systems where the pollutant can be simultaneously detected and bioremediated, along with advances in synthetic biology, are shown as promising tools in the design of environmental biosensors

Estudio aerobiológico de la localidad de Antequera, Málaga, España: 1998 - 1999

Estudio aerobiológico de la localidad de Antequera (Málaga, España): 1998-1999. En el presente trabajo se ha realizado un estudio aerobiológico de la atmósfera de Antequera (Málaga, sur de España) y se propone un calendario polínico para esta localidad a partir de los datos obtenidos durante los años 1998 y 1999, en los que el muestreo se ha realizado mediante un captador volumétrico de tipo Hirst colocado en la zona norte del núcleo urbano. En el citado calendario sólo se representan los taxa que han alcanzado una concentración de polen media decenal igual o superior a 1 grano de polen/m3 de aire, quedando reflejados un total de 33 taxa, de los cuáles sólo los dos primeros (Olea europaea y Cupressaceae) constituyen aproximadamente el 57% del polen total anual. La mayor diversidad de tipos polínicos se produce durante la primavera y las mayores concentraciones de pólenes se producen siempre durante los meses de Febrero a Junio, ambos inclusive, periodo en que se registra aproximadamente el 93% del polen total anual. Aparecen varios picos a lo largo del año, que se deben fundamentalmente a Cupressaceae, Platanus y Pinus en Marzo, Quercus en Abril, Olea europaea en Mayo y Poaceae en Junio, si bien durante los meses de Abril y Mayo también se detectan importantes cantidades de polen de Urticaceae, Plan tago y Chenopodiaceae-Amaranthaceae. Existe en Antequera un elevada incidencia atmosférica de pólenes procedentes de taxa arbóreos, ya que se ha visto que los cuatro primeros, en orden de abundancia anual son Olea europaea, Cupressaceae, Quercus y Platanus