Neural dynamics and their relationship to learning behavior in response tot stimulation with a cortical neuroprosthesis

Sensory cortex, neuroprosthetics, brain-machine-interfaces, neurodynamics, learning, perception, embodied cognition

Influence of agrochemicals fipronil and imidacloprid on the learning behavior of Apis mellifera L. honeybees

Agrochemicals on crop cultivated areas is a source of contamination for bees and may cause physiological and behavioral disorders and mortality. The LD50 of the pesticides fipronil and imidacloprid was determined and their effect on the learning behavior of Apis mellifera L. honeybee evaluated. LD50 was determined by the ingestion of contaminated food with different concentrations of insecticide concentrations: Fipronil (0, 0.8, 0.4, 0.2, 0.1 and 0.05 µg bee-1) and imidacloprid (0, 0.4, 0.2, 0.1, 0.05 and 0.025 µg bee-1). The method of proboscis extension reflection (PER) and learning through citral odor evaluated their responses to food stimulation. LD50 obtained were 0.28 ± 0.11 and 0.10 ± 0.04 µg bee-1 for fipronil and imidacloprid, respectively. The PER test showed no significant difference (p < 0.05) although agrochemicals affected the learning of bees. Insecticides fipronil and imidacloprid are extremely harmful to foraging Africanized Apis mellifera bees.

PUE attack detection in CWSN using collaboration and learning behavior

Cognitive Wireless Sensor Network (CWSN) is a new paradigm which integrates cognitive features in traditional Wireless Sensor Networks (WSNs) to mitigate important problems such as spectrum occupancy. Security in Cognitive Wireless Sensor Networks is an important problem because these kinds of networks manage critical applications and data. Moreover, the specific constraints of WSN make the problem even more critical. However, effective solutions have not been implemented yet. Among the specific attacks derived from new cognitive features, the one most studied is the Primary User Emulation (PUE) attack. This paper discusses a new approach, based on anomaly behavior detection and collaboration, to detect the PUE attack in CWSN scenarios. A nonparametric CUSUM algorithm, suitable for low resource networks like CWSN, has been used in this work. The algorithm has been tested using a cognitive simulator that brings important results in this area. For example, the result shows that the number of collaborative nodes is the most important parameter in order to improve the PUE attack detection rates. If the 20% of the nodes collaborates, the PUE detection reaches the 98% with less than 1% of false positives.

Spatio-temporal credit assignment in population learning

Learning by reinforcement is important in shaping animal behavior, and in particular in behavioral decision making. Such decision making is likely to involve the integration of many synaptic events in space and time. However, using a single reinforcement signal to modulate synaptic plasticity, as suggested in classical reinforcement learning algorithms, a twofold problem arises. Different synapses will have contributed differently to the behavioral decision, and even for one and the same synapse, releases at different times may have had different effects. Here we present a plasticity rule which solves this spatio-temporal credit assignment problem in a population of spiking neurons. The learning rule is spike-time dependent and maximizes the expected reward by following its stochastic gradient. Synaptic plasticity is modulated not only by the reward, but also by a population feedback signal. While this additional signal solves the spatial component of the problem, the temporal one is solved by means of synaptic eligibility traces. In contrast to temporal difference (TD) based approaches to reinforcement learning, our rule is explicit with regard to the assumed biophysical mechanisms. Neurotransmitter concentrations determine plasticity and learning occurs fully online. Further, it works even if the task to be learned is non-Markovian, i.e. when reinforcement is not determined by the current state of the system but may also depend on past events. The performance of the model is assessed by studying three non-Markovian tasks. In the first task, the reward is delayed beyond the last action with non-related stimuli and actions appearing in between. The second task involves an action sequence which is itself extended in time and reward is only delivered at the last action, as it is the case in any type of board-game. The third task is the inspection game that has been studied in neuroeconomics, where an inspector tries to prevent a worker from shirking. Applying our algorithm to this game yields a learning behavior which is consistent with behavioral data from humans and monkeys, revealing themselves properties of a mixed Nash equilibrium. The examples show that our neuronal implementation of reward based learning copes with delayed and stochastic reward delivery, and also with the learning of mixed strategies in two-opponent games.

Learning to recognize faces incrementally

[EN]Most face recognition systems are based on some form of batch learning. Online face recognition is not only more practical, it is also much more biologically plausible. Typical batch learners aim at minimizing both training error and (a measure of) hypothesis complexity. We show that the same minimization can be done incrementally as long as some form of ”scaffolding” is applied throughout the learning process. Scaffolding means: make the system learn from samples that are neither too easy nor too difficult at each step. We note that such learning behavior is also biologically plausible. Experiments using large sequences of facial images support the theoretical claims. The proposed method compares well with other, numerical calculus-based online learners.

The Intrahippocampal Infusion Of Crotamine From Crotalus Durissus Terrificus Venom Enhances Memory Persistence In Rats.

Previous research has shown that crotamine, a toxin isolated from the venom of Crotalus durissus terrificus, induces the release of acetylcholine and dopamine in the central nervous system of rats. Particularly, these neurotransmitters are important modulators of memory processes. Therefore, in this study we investigated the effects of crotamine infusion on persistence of memory in rats. We verified that the intrahippocampal infusion of crotamine (1 μg/μl; 1 μl/side) improved the persistence of object recognition and aversive memory. By other side, the intrahippocampal infusion of the toxin did not alter locomotor and exploratory activities, anxiety or pain threshold. These results demonstrate a future prospect of using crotamine as potential pharmacological tool to treat diseases involving memory impairment, although it is still necessary more researches to better elucidate the crotamine effects on hippocampus and memory.

El trabajo en equipo en el Proceso Administrativo y de Compras en OPL Carga de Bucaramanga

El proceso administrativo y de compras de OPL Carga tiene algunas falencias entre ellas: fallas en la Comunicación entre el personal operativo, no se realizan llamadas internas usando con frecuencia el email, produciendo la saturación de solicitudes las cuales terminan sin ser resueltas en cuanto a roles se refiere, no hay enfoque de procesos en vista que no se tiene claras las tareas de cada cargo, adicionalmente no hay claridad en los subprocesos, perjudicando el proceso con el aumento de costos, pérdida de tiempo, las responsabilidades de los funcionario no todas las veces se ejecutan en el tiempo asignado, el liderazgo compartido presenta ambigüedades. Objetivos: Definir el trabajo en equipo en el proceso administrativo y de compras en OPL carga de Bucaramanga. La investigación que a realizar es de tipo descriptivo, busca descubrir las falencias o características que permiten diseñar y desarrollar un modelo de solución para los problemas del equipo de OPL Carga S.A.S. Materiales y métodos: La investigación efectuada es de tipo descriptivo, el objetivo es definir el modelo del trabajo en equipo y describir las falencias en el proceso administrativo y de compras en OPL carga de Bucaramanga, que permitan obtener un diagnóstico integral que conlleve a la implementación de estrategias de solución. Resultados: Se identificaron las falencias en los siguientes aspectos: Variable comunicación, rendimiento, destrezas complementarias, propósito significativo y meta específicas de los funcionarios en OPL carga sección administrativa. Conclusiones: El modelo de trabajo en equipo que OPL aplica es jerárquico, en el que se ofrece estabilidad, seguridad, se toman decisiones en forma piramidal, mediante la planeación de tareas, la colaboración, igualdad y respeto por los miembros, trabajando en pro de la solución de problemas. Se construyó un plano conceptual que permitió exponer la interpretación que la estudiante tiene de las teorías, investigaciones y antecedentes válidos para la comprensión del problema investigado. Área comunicacional: Coordinar acciones tendientes para que los funcionarios respondan a tiempo los emails atenientes a su trabajo. Área condiciones de trabajo: Clarificar y diseñar las reglas de comportamiento al interior de los equipos de trabajo que redunden en el mejoramiento del mismo y la búsqueda de soluciones oportunas. Área metas específicas: Procurar mediante auditorías el cumplimiento de las metas y objetivos propuestos por cada equipo de trabajo.

Prevalencia de factores de riesgo psicosocial en trabajadores de una empresa del sector salud, Yopal 2014

Antecedentes: Los factores de Riesgo psicosocial según la resolución 2646 de 2008 “comprenden los aspectos intralaborales, extralaborales o externos a la organización y las condiciones individuales o características intrínsecas al trabajador, los cuales en una interrelación dinámica, mediante percepciones y experiencias, influirían en la salud y el desempeño de las personas”. El objetivo del estudio es establecer la prevalencia de factores de riesgo psicosocial y la asociación existente en la población trabajadora del área administrativa y asistencial, en una empresa del sector salud nivel II, Yopal, 2014 Materiales y método: Se diseñó un estudio de corte transversal para establecer la prevalencia de los factores de riesgo psicosocial en una población de 92 trabajadores del área administrativa (50) y asistencial (42) en una empresa del sector salud nivel II en Yopal, por medio de la batería de Riesgo Psicosocial del Ministerio de la Protección Social. Resultados: Se realizó un análisis multivariado, se puede afirmar con un nivel de confianza del 95% que en la población de estudio, la prevalencia de riesgo intralaboral en la población administrativa está entre el 9,5% y 34,5% y en los trabajadores del área asistencial entre el 9,7% y el 37,9%. El riesgo extralaboral en el área administrativa está entre el 4,8% y el 27,2%, en el área asistencial la prevalencia está entre el 1,5% y el 19,5%. La prevalencia de Riesgo de Estrés se encuentra en la población administrativa entre el 29,2% y el 58,8% y en el área asistencial entre el 17,9% y el 48,8%. Se encontró una asociación (p = 0,007) entre estado civil y riesgo intralaboral en la población asistencial, entre tipo de vivienda y nivel de estres (p= 0,003) en la población administrativa, y entre número de personas a cargo económicamente y riesgo extralaboral (p=0,004) en el área asistencial. Discusión: La prevalencia de riesgo psicosocial es evidente en las dos áreas de trabajo tanto administrativos como asistenciales, sin embargo se encuentra una prevalencia mayor de riesgo en el área asistencial en la dimensión exigencias del rol dado a un incremento en la responsabilidad y tiempo extra que se debe realizar para el desarrollo de tareas y su cumplimiento ante el rol desempeñado; los resultados permiten implementar programas de vigilancia epidemiológica que permitan mitigar y controlar los hallazgos en este estudio.

Chronic administration of risperidone in a rat model of schizophrenia: A behavioural, morphological and molecular study

In the present work we analyzed the effect of the chronic administration of risperidone (2mg/kg over 65 days) on behavioural, morphological and molecular aspects in an experimental model of schizophrenia obtained by bilateral injection of ibotenic acid into the ventral hippocampus of new-born rats. Our results show that during their adult lives the animals with hippocampal lesions exhibit different alterations, mainly at behavioural level and in the gene expression of dopamine D2 and 5-HT2A receptors. However, at morphological level the study performed on the prefrontal cortex did not reveal any alterations in either the thickness or the number of cells immunoreactive for c-Fos, GFAP, CBP or PV. Overall, risperidone administration elicited a trend towards the recovery of the values previously altered by the hippocampal lesion, approaching the values seen in the animals without lesions. It may be concluded that the administration of risperidone in the schizophrenia model employed helps to improve the altered functions, with no significant negative effects. © 2013.

Contingências facilitadoras de comportamento verbal em crianças usuárias de implante coclear e práticas parentais: uma intervenção com mães

Pós-graduação em Psicologia do Desenvolvimento e Aprendizagem - FC

Segmentação interativa de imagens utilizando competição e cooperação entre partículas

Pós-graduação em Ciência da Computação - IBILCE

Latrepirdine improves cognition and arrests progression of neuropathology in an Alzheimer's mouse model

Latrepirdine (Dimebon) is a pro-neurogenic, antihistaminic compound that has yielded mixed results in clinical trials of mild to moderate Alzheimer's disease, with a dramatically positive outcome in a Russian clinical trial that was unconfirmed in a replication trial in the United States. We sought to determine whether latrepirdine (LAT)-stimulated amyloid precursor protein (APP) catabolism is at least partially attributable to regulation of macroautophagy, a highly conserved protein catabolism pathway that is known to be impaired in brains of patients with Alzheimer's disease (AD). We utilized several mammalian cellular models to determine whether LAT regulates mammalian target of rapamycin (mTOR) and Atg5-dependent autophagy. Male TgCRND8 mice were chronically administered LAT prior to behavior analysis in the cued and contextual fear conditioning paradigm, as well as immunohistological and biochemical analysis of AD-related neuropathology. Treatment of cultured mammalian cells with LAT led to enhanced mTOR- and Atg5-dependent autophagy. Latrepirdine treatment of TgCRND8 transgenic mice was associated with improved learning behavior and with a reduction in accumulation of Aβ42 and α-synuclein. We conclude that LAT possesses pro-autophagic properties in addition to the previously reported pro-neurogenic properties, both of which are potentially relevant to the treatment and/or prevention of neurodegenerative diseases. We suggest that elucidation of the molecular mechanism(s) underlying LAT effects on neurogenesis, autophagy and behavior might warranty the further study of LAT as a potentially viable lead compound that might yield more consistent clinical benefit following the optimization of its pro-neurogenic, pro-autophagic and/or pro-cognitive activities.

Desarrollo de un proceso de razonamiento visual para la valoración del patrimonio

El tema de la presente tesis es la valoración del patrimonio y en ella se considera que el patrimonio es un proceso cultural interesado en negociar, crear y recrear recuerdos, valores y significados culturales. Actualmente el patrimonio como proceso se está consolidando en la literatura científica, aunque la idea de que es una ‘cosa’ es dominante en el debate internacional y está respaldada tanto por políticas como prácticas de la UNESCO. El considerar el patrimonio como un proceso permite una mirada crítica, que subraya la significación. Es decir, supone el correlato que conlleva definir algo como ‘patrimonio’, o hacer que lo vaya siendo. Esta visión del concepto permite la posibilidad de comprender no sólo lo que se ha valorado, sino también lo que se ha olvidado y el porqué. El principal objetivo de esta investigación es explorar las características de un proceso de razonamiento visual para aplicarlo en el de valoración del patrimonio. Éste que se presenta, implica la creación de representaciones visuales y sus relaciones, además su meta no está centrada en producir un ambiente que sea indiferenciado de la realidad física. Con él se pretende ofrecer la posibilidad de comunicar la dimensión ‘poliédrica’ del patrimonio. Para que este nuevo proceso que propongo sea viable y sostenible, existe la necesidad de tener en cuenta el fin que se quiere lograr: la valoración. Es importante considerar que es un proceso en el cual las dinámicas de aprendizaje, comportamientos y exploración del patrimonio están directamente relacionadas con su valoración. Por lo tanto, hay que saber cómo se genera la valoración del patrimonio, con el fin de ser capaces de desarrollar el proceso adaptado a estas dinámicas. La hipótesis de esta tesis defiende que un proceso de razonamiento visual para la valoración del patrimonio permite que las personas involucradas en el proceso inicien un proceso de interacción con un elemento patrimonial y su imagen mental para llegar a ciertas conclusiones con respecto a su valor y significado. El trabajo describe la metodología que da lugar al proceso de razonamiento visual para el patrimonio, que ha sido concebido sobre un modelado descriptivo de procesos, donde se han caracterizado tres niveles: meta-nivel, de análisis y operacional. En el modelado del proceso los agentes, junto con el patrimonio, son los protagonistas. El enfoque propuesto no es sólo sobre el patrimonio, sino sobre la compleja relación entre las personas y el patrimonio. Los agentes humanos dan valor a los testimonios de la vida pasada y les imbuyen de significado. Por lo tanto, este enfoque de un proceso de razonamiento visual sirve para detectar los cambios en el valor del patrimonio, además de su dimensión poliédrica en términos espaciales y temporales. Además se ha propuesto una nueva tipología de patrimonio necesaria para sustentar un proceso de razonamiento visual para su valoración. Esta tipología está apoyada en la usabilidad del patrimonio y dentro de ella se encuentran los siguientes tipos de patrimonio: accesible, cautivo, contextualizado, descontextualizado, original y vicarial. El desarrollo de un proceso de razonamiento visual para el patrimonio es una propuesta innovadora porque integra el proceso para su valoración, contemplando la dimensión poliédrica del patrimonio y explotando la potencialidad del razonamiento visual. Además, los posibles usuarios del proceso propuesto van a tener interacción de manera directa con el patrimonio e indirecta con la información relativa a él, como por ejemplo, con los metadatos. Por tanto, el proceso propuesto posibilita que los posibles usuarios se impliquen activamente en la propia valoración del patrimonio. ABSTRACT The subject of this thesis is heritage valuation and it argues that heritage is a cultural process that is inherited, transmitted, and transformed by individuals who are interested in negotiating, creating and recreating memories and cultural meanings. Recently heritage as a process has seen a consolidation in the research, although the idea that heritage is a ‘thing’ is dominant in the international debate and is supported by policies and practice of UNESCO. Seeing heritage as a process enables a critical view, underscoring the significance. That is, it is the correlate involved in defining something as ‘heritage’, or converting it into heritage. This view of the concept allows the possibility to understand not only what has been valued, but also what has been forgotten and why. The main objective of this research is to explore the characteristics of a visual reasoning process in order to apply it to a heritage valuation. The goal of the process is not centered on producing an environment that is undifferentiated from physical reality. Thus, the objective of the process is to provide the ability to communicate the ‘polyhedral’ dimension of heritage. For this new process to be viable and sustainable, it is necessary to consider what is to be achieved: heritage valuation. It is important to note that it is a process in which the dynamics of learning, behavior and exploration heritage are directly related to its valuation. Therefore, we need to know how this valuation takes place in order to be able to develop a process that is adapted to these dynamic. The hypothesis of this thesis argues that a visual reasoning process for heritage valuation allows people involved in the process to initiate an interaction with a heritage and to build its mental image to reach certain conclusions regarding its value and meaning. The thesis describes the methodology that results in a visual reasoning process for heritage valuation, which has been based on a descriptive modeling process and have characterized three levels: meta, analysis and operational -level. The agents are the protagonists in the process, along with heritage. The proposed approach is not only about heritage but the complex relationship between people and heritage. Human operators give value to the testimonies of past life and imbue them with meaning. Therefore, this approach of a visual reasoning process is used to detect changes in the value of heritage and its multifaceted dimension in spatial and temporal terms. A new type of heritage required to support a visual reasoning process for heritage valuation has also been proposed. This type is supported by its usability and it covers the following types of heritage: available, captive, contextualized, decontextualized, original and vicarious. The development of a visual reasoning process for heritage valuation is innovative because it integrates the process for valuation of heritage, considering the multifaceted dimension of heritage and exploiting the potential of visual reasoning. In addition, potential users of the proposed process will have direct interaction with heritage and indirectly with the information about it, such as the metadata. Therefore, the proposed process enables potential users to be actively involved in their own heritage valuation.

School bus safety belts: their use, carryover effects and administrative issues. Final report.

National Highway Traffic Safety Administration, Office of Driver and Pedestrian Safety, Washington, D.C.

Functional near infrared spectroscopy study of language, joint attention and motor skills

Near infrared spectroscopy (NIRS) is an emerging non-invasive optical neuro imaging technique that monitors the hemodynamic response to brain activation with ms-scale temporal resolution and sub-cm spatial resolution. The overall goal of my dissertation was to develop and apply NIRS towards investigation of neurological response to language, joint attention and planning and execution of motor skills in healthy adults. Language studies were performed to investigate the hemodynamic response, synchrony and dominance feature of the frontal and fronto-temporal cortex of healthy adults in response to language reception and expression. The mathematical model developed based on granger causality explicated the directional flow of information during the processing of language stimuli by the fronto-temporal cortex. Joint attention and planning/ execution of motor skill studies were performed to investigate the hemodynamic response, synchrony and dominance feature of the frontal cortex of healthy adults and in children (5-8 years old) with autism (for joint attention studies) and individuals with cerebral palsy (for planning/execution of motor skills studies). The joint attention studies on healthy adults showed differences in activation as well as intensity and phase dependent connectivity in the frontal cortex during joint attention in comparison to rest. The joint attention studies on typically developing children showed differences in frontal cortical activation in comparison to that in children with autism. The planning and execution of motor skills studies on healthy adults and individuals with cerebral palsy (CP) showed difference in the frontal cortical dominance, that is, bilateral and ipsilateral dominance, respectively. The planning and execution of motor skills studies also demonstrated the plastic and learning behavior of brain wherein correlation was found between the relative change in total hemoglobin in the frontal cortex and the kinematics of the activity performed by the participants. Thus, during my dissertation the NIRS neuroimaging technique was successfully implemented to investigate the neurological response of language, joint attention and planning and execution of motor skills in healthy adults as well as preliminarily on children with autism and individuals with cerebral palsy. These NIRS studies have long-term potential for the design of early stage interventions in children with autism and customized rehabilitation in individuals with cerebral palsy.