Desenvolvimento e utilização de equipamentos da neurociência para subsidiar a descoberta científica por alunos do ensino básico à pós-graduação

A ciência e tecnologia andam juntas. A ciência fornece o conhecimento para a geração de novas tecnologias que, porsua vez, disponibiliza novas ferramentas para a geração de novos conhecimentos. Uma educação científica deve vir acompanhada de uma educação tecnológica permitindo então que o aluno entenda não só o experimento, mas também como os resultados foram obtidos, como os equipamentos, técnicas e protocolos funcionam. Para uma educação científica efetiva o aluno deve ir além de expectador, se colocando no papel de pesquisador, a fim de construir seu próprio conhecimento. No entanto, para essa tarefa, é necessário o uso de equipamentos adequados ao experimento a ser realizado. Essa tese visa suprir a necessidade de equipamentos para experimentos na área de neurociência focados no estudo de memória e aprendizado, utilizando roedores e peixes como modelos animais na tarefa de esquiva inibitória passiva. Esses equipamentos visam uma maior acessibilidade do ponto de vista operacional e financeiro, sendo mais precisos e com isso fornecendo dados mais confiáveis e robustos do que os equipamentos disponíveis. Possibilitando aos alunos, da alfabetização à pós-graduação, a realização de experimentos comportamentais, tanto de maneira simples quanto complexas, interagindo em todas as etapas experimentais, resultando em aprendizagem e desenvolvimento cognitivo além de possibilitar novas descobertas científicas.Science and technology walking together, science provides the knowledge to generate new technologies which in turn provides new tools for the generation of new knowledge. A science education must be accompanied by a technological education to enable students to understand not only the experiment, but also how the results were obtained, understanding how the equipment, techniques and protocols work. For effective science education the student must go beyond bystander, putting themselves in the researcher function in order to construct their own knowledge. However for this task, it is necessary to use suitable equipment to the experiment to be performed. This PhD Thesis aims to fill a need for equipment for experiments in neuroscience focused on the study of memory and learning, using rodents and fish as animal models in the passive inhibitory avoidance task. These devices achieve greater accessibility of the operational and financial point, being more accurate and thus providing more reliable and consistent data that current equipment. Enabling student’s literacy to post graduate conducting simple and complex behavioral experiments, interacting in all experimental steps, resulting in learning and cognitive development and enable new scientific discoveries

Desenvolvimento e utilização de equipamentos da neurociência para subsidiar a descoberta científica por alunos do ensino básico à pós-graduação

A ciência e tecnologia andam juntas. A ciência fornece o conhecimento para a geração de novas tecnologias que, porsua vez, disponibiliza novas ferramentas para a geração de novos conhecimentos. Uma educação científica deve vir acompanhada de uma educação tecnológica permitindo então que o aluno entenda não só o experimento, mas também como os resultados foram obtidos, como os equipamentos, técnicas e protocolos funcionam. Para uma educação científica efetiva o aluno deve ir além de expectador, se colocando no papel de pesquisador, a fim de construir seu próprio conhecimento. No entanto, para essa tarefa, é necessário o uso de equipamentos adequados ao experimento a ser realizado. Essa tese visa suprir a necessidade de equipamentos para experimentos na área de neurociência focados no estudo de memória e aprendizado, utilizando roedores e peixes como modelos animais na tarefa de esquiva inibitória passiva. Esses equipamentos visam uma maior acessibilidade do ponto de vista operacional e financeiro, sendo mais precisos e com isso fornecendo dados mais confiáveis e robustos do que os equipamentos disponíveis. Possibilitando aos alunos, da alfabetização à pós-graduação, a realização de experimentos comportamentais, tanto de maneira simples quanto complexas, interagindo em todas as etapas experimentais, resultando em aprendizagem e desenvolvimento cognitivo além de possibilitar novas descobertas científicas.Science and technology walking together, science provides the knowledge to generate new technologies which in turn provides new tools for the generation of new knowledge. A science education must be accompanied by a technological education to enable students to understand not only the experiment, but also how the results were obtained, understanding how the equipment, techniques and protocols work. For effective science education the student must go beyond bystander, putting themselves in the researcher function in order to construct their own knowledge. However for this task, it is necessary to use suitable equipment to the experiment to be performed. This PhD Thesis aims to fill a need for equipment for experiments in neuroscience focused on the study of memory and learning, using rodents and fish as animal models in the passive inhibitory avoidance task. These devices achieve greater accessibility of the operational and financial point, being more accurate and thus providing more reliable and consistent data that current equipment. Enabling student’s literacy to post graduate conducting simple and complex behavioral experiments, interacting in all experimental steps, resulting in learning and cognitive development and enable new scientific discoveries

A new device for step-down inhibitory avoidance task--effects of low and high frequency in a novel device for passive inhibitory avoidance task that avoids bioimpedance variations.

Step-down inhibitory avoidance task has been widely used to evaluate aversive memory, but crucial parameters inherent to traditional devices that may influence the behavior analysis (as stimulus frequency, animal's bioimpedance) are frequently neglected.We developed a new device for step-down inhibitory avoidance task by modifying the shape and distribution of the stainless steel bars in the box floor where the stimuli are applied. The bars are 2 mm wide, with rectangular shape, arranged in pairs at intervals of 1cm from the next pairs. Each pair makes an electrical dipole where the polarity inverts after each pulse. This device also presents a component that acquires and records the exact current received by the animal foot and precisely controls the frequency of stimulus applied during the entire experiment.Different from conventional devices, this new apparatus increases the contact surface with bars and animal's paws, allowing the electric current pass through the animal's paws only, drastically reducing the influence of animal's bioimpedance. The analysis of recorded data showed that the current received by the animal was practically the same as applied, independent of the animal's body composition. Importantly, the aversive memory was observed at specific stimuli intensity and frequency (0.35 or 0.5 mA at 62 and 125 Hz but not at 0.20 mA or 20 Hz). Moreover, with this device it was possible to observe the well-known step-down inhibitory avoidance task memory impairment induced by guanosine.This new device offers a substantial improvement for behavioral analysis in step-down inhibitory avoidance task and allows us to precisely compare data from different animals with distinct body composition

Effects of frequency (Hz) with 0.35mA current intensity in step-down inhibitory avoidance latencies.

<p>A- Effects of frequency (Hz) on step down latency in training session (T), latency for escape (E), step down latency in test session (24h), and score performance (B—the combination of the 3 parameters by applying the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116000#pone.0116000.e002" target="_blank">Equation 2</a>).**P<0.01; ***p<0.001, by Mann-Whitney, comparing to the same group in A. Data represent median with interquartile range (n = 10/group).</p

Plots of current intensity at 62Hz passing through the animal’s paws or resistor.

<p>Different groups were represented by white, light gray or dark gray bars: 150Kohms resistor (no animal in the apparatus), female rats (3 months; 280–320g) or male rats (3 months; 310–360g), respectively. In insert graphic the effective current passing by animal body in traditional apparatus of inhibitory avoidance, nominal current 0.4mA. The standard data represents mean±S.D. Analyses by Mann-Whitney test; n = 5 animals/group/current supplied and 5 measurements for each animal. No significant difference was observed among the groups. Insert graphic, 8 animals, 3 measurements for each animal.</p

Number of animals (n = 10 per group) receiving 3 consecutive bursts of current (0.35 or 0.8mA, 62 Hz), measured for 1 s.

<p>Number of animals (n = 10 per group) receiving 3 consecutive bursts of current (0.35 or 0.8mA, 62 Hz), measured for 1 s.</p

Positive phase of stimulus waveform for different frequencies (Hz) at 0.35mA current intensity.

<p>Positive phase of stimulus waveform for different frequencies (Hz) at 0.35mA current intensity.</p

Description of the observed behavioral responsesduring the test and training sessions.

<p>+ one episode,</p><p>++ between two and four episodes,</p><p>+++ more than four episodes; in test the absolute number during the session.</p><p>Description of the observed behavioral responsesduring the test and training sessions.</p

Platform exploration time in training (step-down latency in training) and time of stimulus (escape latency) influence on learning.

<p>The scale of colors indicates the animals score based in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116000#pone.0116000.e002" target="_blank">Equation 2</a>. (A) Saline group exposed at 0.35mA, 62Hz. (B) Guanosine group exposed at 0.35mA, 62Hz. (C) Saline group exposed at 0.35mA, 125Hz. (D) Guanosine group exposed at 0.35mA, 125Hz. (n = 20/group).</p

Schematic representation of the inhibitory avoidance apparatus.

<p>The inhibitory avoidance apparatus, including operating diagram with digital frequency control by microcontroller (PIC18F4520), an analog-digital (A/D) to measure and to control the intensity of stimulus and a data recorder on a SD card.</p