Agradecemos W. Ryu para aconselhamento sobre a nossa imagem inicial set-up, Z. Gitai para a sugestão de usar ImageJ 13 a contar worms, e J. Ashraf para ajudar com o Google SketchUp. CTM é um Scholar Pew em Ciências Biomédicas, um Scholar McKnight, e um Scholar Keck.

<ol>
	<li>Bargmann, C. I., Hartwieg, E., Horvitz, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant-selective+genes+and+neurons+mediate+olfaction+in+C.+elegans.">Odorant-selective genes and neurons mediate olfaction in C. elegans.</a> Cell. 74, 515-515 (1993).</li><li>Ward, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotaxis+by+the+nematode+Caenorhabditis+elegans:+identification+of+attractants+and+analysis+of+the+response+by+use+of+mutants.">Chemotaxis by the nematode Caenorhabditis elegans: identification of attractants and analysis of the response by use of mutants.</a> Proc Natl Acad Sci U S A. 70, 817-817 (1973).</li><li>Bono, M. d. e., Maricq, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+substrates+of+complex+behaviors+in+C.+elegans.">Neuronal substrates of complex behaviors in C. elegans.</a> Annu Rev Neurosci. 28, 451-451 (2005).</li><li>Mori, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+of+chemotaxis+and+thermotaxis+in+the+nematode+Caenorhabditis+elegans.">Genetics of chemotaxis and thermotaxis in the nematode Caenorhabditis elegans.</a> Annu Rev Genet. 33, 399-399 (1999).</li><li>Zhang, Y., Lu, H., Bargmann, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenic+bacteria+induce+aversive+olfactory+learning+in+Caenorhabditis+elegans.">Pathogenic bacteria induce aversive olfactory learning in Caenorhabditis elegans.</a> Nature. 438, 179-179 (2005).</li><li>Kauffman, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin+signaling+and+dietary+restriction+differentially+influence+the+decline+of+learning+and+memory+with+age.">Insulin signaling and dietary restriction differentially influence the decline of learning and memory with age.</a> PLoS Biol. 8, e1000372-e1000372 (2010).</li><li>Torayama, I., Ishihara, T., Katsura, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caenorhabditis+elegans+integrates+the+signals+of+butanone+and+food+to+enhance+chemotaxis+to+butanone.">Caenorhabditis elegans integrates the signals of butanone and food to enhance chemotaxis to butanone.</a> J Neurosci. 27, 741-741 (2007).</li><li>Silva, A. J., Kogan, J. H., Frankland, P. W., Kida, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CREB+and+memory.">CREB and memory.</a> Annu Rev Neurosci. 21, 127-127 (1998).</li><li>Meyer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iterative+image+transformations+for+an+automatic+screening+of+cervical+smears.">Iterative image transformations for an automatic screening of cervical smears.</a> J Histochem Cytochem. 27, 128-128 (1979).</li><li>Otsu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Threshold+Selection+Method+from+Gray-Level+Histograms.">A Threshold Selection Method from Gray-Level Histograms.</a> IEEE Transactions on Systems, Man, and Cybernetics. 9, 62-62 (1979).</li><li>Brenner, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+genetics+of+Caenorhabditis+elegans.">The genetics of Caenorhabditis elegans.</a> Genetics. 77, 71-71 (1974).</li><li>Stephens, G. J., Johnson-Kerner, B., Bialek, W., Ryu, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimensionality+and+dynamics+in+the+behavior+of+C.+elegans.">Dimensionality and dynamics in the behavior of C. elegans.</a> PLoS Comput Biol. 4, e1000028-e1000028 (2008).</li><li>Abramoff, M. a. g. e. l. h. a. e. s., Ram, P. J., J, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+Processing+with+ImageJ.">Image Processing with ImageJ.</a> Biophotonics International. 11, 36-36 (2004).</li></ol>

Não há conflitos de interesse declarados.

O C. elegans aprendizado olfativo associativo e ensaios de memória apresentado aqui distinguir entre os processos de aprendizagem massed, aprendendo espaçados, memória de curto prazo e memória de longo prazo. Estes ensaios contam com as habilidades dos worms &quot;para sentir os odores dos alimentos e produtos químicos em seus 1,2 ambiente e de formar associações positivas entre os dois. 6 Portanto, os ensaios são muito sensíveis à fome na população a partir de animais, e um grande cuidado deve ser tomadas para garantir que os worms são bem alimentados antes e após o treinamento. Treinamento massed única rendimentos de curto prazo memória associativa. O aumento do número de períodos de condicionamento e treinamento espaçados paradigma é fundamental para alcançar a longo prazo memória associativa em C. elegans como é em outros organismos. 6,8 Talvez este ensaio pode ser modificada para produzir memórias de longo prazo de associações entre diferentes estímulos condicionados e incondicionados. Nossa aprendizagem associativa e ensaios de memória pode ser usado para comparar as capacidades de aprendizagem e memória de tipo selvagem ao envelhecimento ou genética animais mutantes. Por exemplo, enquanto a aprendizagem associativa e de longo prazo de memória associativa declínio habilidades no envelhecimento do tipo selvagem worms, a aprendizagem é mantida durante mais tempo com a idade em animais com a sinalização de insulina reduzida, e aprendizagem e da memória é mantido mais tempo com a idade em animais sob restrição calórica. 6 Estes ensaios também são passíveis de tratamento RNAi ou manipulação farmacológica do C. elegans. Por exemplo, o tratamento de vermes com daf-2 RNAi melhora a curto ea longo prazo memória associativa e, inversamente, o bloqueio da transcrição de genes e síntese de proteínas com drogas (actinomicina D e cicloheximida, respectivamente) durante o treinamento espaçadas interrompe a longo prazo a formação da memória. 6 Memória de longo prazo é um processo que é crucial para a sobrevivência em todos os animais, e parece que grande parte da maquinaria molecular envolvida na memória de uma associação pavloviana é conservada a partir de vermes aos mamíferos. 6 A capacidade de distinguir e teste de aprendizagem associativa, de curto prazo e memória de longo prazo com estes testes olfativos faz C. elegans um excelente sistema para o estudo adicional de memória, e pode fornecer a introspecção em processos neurodegenerativos que levam à perda de aprendizagem e memória em humanos.

<table><tbody><tr><td>Sodium Azide</td><td>Fisher Scientific</td><td>S227</td><td>Prepare 1 M concentration in distilled water</td></tr><tr><td>Ethyl Alcohol 190 Proof</td><td>Pharmco-AAPER</td><td>DSP-CT-18</td><td>&amp;gt;95% Ethanol may have impurities that interfere with chemotaxis assays</td></tr><tr><td>2-Butanone 99+%</td><td>Acros Organics</td><td>14967-0010</td><td></td></tr><tr><td>Basler IEEE-1394/FireWire Area Scan CMOS Camera</td><td>Edmund Scientific</td><td>NT56-683</td><td></td></tr><tr><td>InfiniMite Video Lens &amp;#8211; Alpha Industrial</td><td>Edmund Scientific</td><td>NT56-202</td><td></td></tr><tr><td>Dolan-Jenner MI-150 Fiber Optic Illuminator</td><td>Edmund Scientific</td><td>NT55-718</td><td></td></tr><tr><td>8&amp;#8221; x 8&amp;#8221; Backlight</td><td>Schott AG</td><td>A08927</td><td></td></tr><tr><td>Standard Boom Stand</td><td>Edmund Scientific</td><td>NT54-120</td><td></td></tr><tr><td>3/4&amp;#8221; Post Adaptor for Boom Stands</td><td>Edmund Scientific</td><td>NT54-124</td><td></td></tr><tr><td>Standard Fixed 1/4-20 Mounting Plate</td><td>Edmund Scientific</td><td>NT54-122</td><td></td></tr></tbody></table>

c. elegans positive butanone learning, short-term, and long-term associative memory assays

A memória de experiências e informações aprendidas é fundamental para os organismos de fazer escolhas que ajudam a sua sobrevivência. C. elegans navega seu ambiente através de neurônio-específica detecção de odores de alimentos e química 1, 2, e pode associar estados nutritivo com odores químicos 3, temperatura de 4, e à patogenicidade de uma fonte de alimento 5. Aqui, descrevemos ensaios de C. elegans aprendizagem associativa e de curto e longo prazo memória associativa. Nós modificamos um paradigma de aprendizado aversivo olfativa 6 a vez produzir uma resposta positiva, o ensaio envolve starving ~ 400 worms, então alimentar os vermes na presença do AWC neurônio-butanona sentiu chemoattractant volátil em uma concentração que provoca um índice quimiotático baixa (similar para Toroyama et al. 7). A população padrão quimiotaxia assay1 testes atração dos vermes para o odorant imediatamente ou minutos a horas após o condicionamento. Depois de quimiotaxia condicionado, do tipo selvagem dos animais aos aumentos butanona ~ 0,6 Quimiotaxia unidades Index, seu &quot;Índice de Aprendizagem&quot;. Aprendizagem associativa é dependente da presença de ambos os alimentos e butanona durante o treinamento. Alimentos emparelhamento e butanona por um período de condicionamento único (&quot;formação massed&quot;) produz curto prazo memória associativa que dura aproximadamente 2 horas. Períodos de condicionamento múltiplos com períodos de descanso entre (&quot;formação espaçadas&quot;) rendimentos de longo prazo memória associativa (&lt;40 horas), e é dependente da proteína Elemento cAMP encadernação Resposta (CREB), 6 um fator de transcrição necessários para memória de longo prazo através espécies. 8 Nosso protocolo também inclui métodos de análise de imagem para determinação rápida e precisa dos índices de quimiotaxia. Imagens de alto contraste de animais em placas de ensaio de quimiotaxia são capturados e analisados ​​por software verme contagem em MatLab. O software corrige para o fundo irregular usando uma transformação tophat morfológica. Método 9 Otsu é então usado para determinar um limite para worms separado do fundo. 10 partículas muito pequenas são removidos automaticamente e maior verme não-regiões (as bordas da placa ou socos agar) são removidas por seleção manual. O software então calcula o tamanho do verme única, ignorando as regiões que estão acima de um tamanho máximo especificado e tendo a dimensão média das demais regiões. O número de vermes é, então, calcula-se dividindo a área total ocupada pela identificado como worms pelo tamanho estimado de um worm único. Nós descobrimos que a aprendizagem e de curto e longo prazo de memória podem ser distinguidos, e que estes processos partes semelhantes moléculas chave com organismos superiores. 6,8 Nossos ensaios pode testar rapidamente genes candidatos romance ou moléculas que afetam a aprendizagem e de curto ou longo prazo de memória em C. elegans, que são relevantes em toda espécie.

Watch this Scientific Journal Video about C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays at JoVE.com

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

Aqui nós descrevemos métodos para testar C. elegans aprendizagem associativa e de curto e longo prazo memória associativa. Estes ensaios população empregar as habilidades worms para chemotax direção odores voláteis, e formar associações positivas sobre o emparelhamento de alimentos com a butanona chemoattractant. Aumentar o número de períodos de condicionamento induz memória de longo prazo.

C. elegans Aprender Butanona Positivo, de curto prazo e de longo prazo Ensaios Memória Associativa

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment ...

c-elegans-positive-butanone-learning-short-term-long-term-associative

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

29.2K visualizações.  Princeton University. Aqui nós descrevemos métodos para testar C. elegans aprendizagem associativa e de curto e longo prazo memória associativa. Estes ensaios população empregar as habilidades worms para chemotax direção odores voláteis, e formar associações positivas sobre o emparelhamento de alimentos com a butanona chemoattractant. Aumentar o número de períodos de condicionamento induz memória de longo prazo.

Vídeo: C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

Automated Analysis of a Nematode Population-based Chemosensory Preference Assay

The nematode, Caenorhabditis elegans' compact nervous system of only 302 neurons underlies a diverse repertoire of behaviors. To facilitate the dissection of the neural circuits underlying these behaviors, the development of robust and reproducible behavioral assays is necessary. Previous C. elegans behavioral studies have used variations of a "drop test", a "chemotaxis assay", and a "retention assay" to investigate the response of C. elegans to soluble compounds. The method described in this article seeks to combine the complementary strengths of the three aforementioned assays. Briefly, a small circle in the middle of each assay plate is divided into four quadrants with the control and experimental solutions alternately placed. After the addition of the worms, the assay plates are loaded into a behavior chamber where microscope cameras record the worms' encounters with the treated regions. Automated video analysis is then performed and a preference index (PI) value for each video is generated. The video acquisition and automated analysis features of this method minimizes the experimenter's involvement and any associated errors. Furthermore, minute amounts of the experimental compound are used per assay and the behavior chamber's multi-camera setup increases experimental throughput. This method is particularly useful for conducting behavioral screens of genetic mutants and novel chemical compounds. However, this method is not appropriate for studying stimulus gradient navigation due to the close proximity of the control and experimental solution regions. It should also not be used when only a small population of worms is available. While suitable for assaying responses only to soluble compounds in its current form, this method can be easily modified to accommodate multimodal sensory interaction and optogenetic studies. This method can also be adapted to assay the chemosensory responses of other nematode species.

We present a behavior recording setup and protocol that enables automated analysis of the nematode, Caenorhabditis elegans' preference for soluble compounds in a population-based assay. This article describes the construction of a behavior chamber, the behavioral assay protocol, and video analysis software usage.

Análise automatizada de um ensaio de preferência quimiossensorial baseado na população de um nematodo

The nematode, Caenorhabditis elegans' compact nervous system of only 302 neurons underlies a diverse repertoire of behaviors. To facilitate the dissection ...

Comportamento

Appetitive Associative Olfactory Learning in Drosophila Larvae

In the following we describe the methodological details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with genetic interference, provides a handle to analyze the neuronal and molecular fundamentals of specifically associative learning in a simple larval brain.
Organisms can use past experience to adjust present behavior. Such acquisition of behavioral potential can be defined as learning, and the physical bases of these potentials as memory traces1-4. Neuroscientists try to understand how these processes are organized in terms of molecular and neuronal changes in the brain by using a variety of methods in model organisms ranging from insects to vertebrates5,6. For such endeavors it is helpful to use model systems that are simple and experimentally accessible. The Drosophila larva has turned out to satisfy these demands based on the availability of robust behavioral assays, the existence of a variety of transgenic techniques and the elementary organization of the nervous system comprising only about 10,000 neurons (albeit with some concessions: cognitive limitations, few behavioral options, and richness of experience questionable)7-10.
Drosophila larvae can form associations between odors and appetitive gustatory reinforcement like sugar11-14. In a standard assay, established in the lab of B. Gerber, animals receive a two-odor reciprocal training: A first group of larvae is exposed to an odor A together with a gustatory reinforcer (sugar reward) and is subsequently exposed to an odor B without reinforcement 9. Meanwhile a second group of larvae receives reciprocal training while experiencing odor A without reinforcement and subsequently being exposed to odor B with reinforcement (sugar reward). In the following both groups are tested for their preference between the two odors. Relatively higher preferences for the rewarded odor reflect associative learning - presented as a performance index (PI). The conclusion regarding the associative nature of the performance index is compelling, because apart from the contingency between odors and tastants, other parameters, such as odor and reward exposure, passage of time and handling do not differ between the two groups9.

Appetitive Associative Olfactory Learning in Drosophila Larvae

Drosophila larvae are able to associate odor stimuli with gustatory reward. Here we describe a simple behavioral paradigm that allows the analysis of appetitive associative olfactory learning.

Aprendizagem associativa apetitiva olfativa em<em&gt; Drosophila</em&gt; As larvas

In the following we describe the methodological  details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with ...

Neurociência

A Molecular Readout of Long-term Olfactory Adaptation in C. elegans

During sustained stimulation most sensory neurons will adapt their response by decreasing their sensitivity to the signal. The adaptation response helps shape attention and also protects cells from over-stimulation. Adaptation within the olfactory circuit of C. elegans was first described by Colbert and Bargmann1,2. Here, the authors defined parameters of the olfactory adaptation paradigm, which they used to design a genetic screen to isolate mutants defective in their ability to adapt to volatile odors sensed by the Amphid Wing cells type C (AWC) sensory neurons. When wildtype C. elegans animals are exposed to an attractive AWC-sensed odor3 for 30 min they will adapt their responsiveness to the odor and will then ignore the adapting odor in a chemotaxis behavioral assay for ~1 hr. When wildtype C. elegans animals are exposed to an attractive AWC-sensed odor for ~1 hr they will then ignore the adapting odor in a chemotaxis behavioral assay for ~3 hr. These two phases of olfactory adaptation in C. elegans were described as short-term olfactory adaptation (induced after 30 min odor exposure), and long-term olfactory adaptation (induced after 60 min odor exposure). Later work from L'Etoile et al.,4 uncovered a Protein Kinase G (PKG) called EGL-4 that is required for both the short-term and long-term olfactory adaptation in AWC neurons. The EGL-4 protein contains a nuclear localization sequence that is necessary for long-term olfactory adaptation responses but dispensable for short-term olfactory adaptation responses in the AWC4. By tagging EGL-4 with a green fluorescent protein, it was possible to visualize the localization of EGL-4 in the AWC during prolonged odor exposure. Using this fully functional GFP-tagged EGL-4 (GFP::EGL-4) molecule we have been able to develop a molecular readout of long-term olfactory adaptation in the AWC5. Using this molecular readout of olfactory adaptation we have been able to perform both forward and reverse genetic screens to identify mutant animals that exhibit defective subcellular localization patterns of GFP::EGL-4 in the AWC6,7. Here we describe: 1) the construction of GFP::EGL-4 expressing animals; 2) the protocol for cultivation of animals for long-term odor-induced nuclear translocation assays; and 3) the scoring of the long-term odor-induced nuclear translocation event and recovery (re-sensitization) from the nuclear GFP::EGL-4 state.

A Molecular Readout of Long-term Olfactory Adaptation in C. elegans

Here we describe a molecular readout of long-term olfactory adaptation in Caenorhabditis elegans. The Protein Kinase G, EGL-4, is necessary for stable adaptation responses in the primary sensory neuron pair called AWC. During prolonged odor exposure EGL-4 translocates from the cytosol to nucleus of the AWC.

A Leitura Molecular de adaptação a longo prazo olfativa em<em&gt; C. elegans</em

During sustained stimulation most sensory neurons will adapt their response by decreasing their sensitivity to the signal. The adaptation response helps ...

A Low-Cost, Odor-Reward Association Task for Tests of Learning and Memory

Robust and simple behavioral paradigms of appetitive, associative memory are crucial for researchers interested in cellular and molecular mechanisms of memory. In this paper, an effective and low-cost mouse behavioral protocol is described for examining the effects of physiological manipulation (such as the infusion of pharmacological agents) on the learning rate and duration of odor-reward memory. Representative results are provided from a study examining the differential role of tyrosine kinase receptor activity in short-term (STM) and long-term memory (LTM). Male mice were conditioned to associate a reward (sugar pellet) with one of the two odors, and their memory for the association was tested 2 or 48 h later. Immediately prior to the training, a tyrosine kinase (Trk) receptor inhibitor or vehicle infusions were delivered into the olfactory bulb (OB). Although there was no effect of the infusion on the learning rate, blockade of the Trk receptors in the OB selectively impaired LTM (48 h), and not short-term memory (STM; 2 h). The LTM impairment was attributed to the diminished odor selectivity as measured by the length of the digging time. The culmination of the results of this experiment showed that Trk receptor activation in the OB is the key in olfactory memory consolidation.

An odor-reward, associative learning task was used to investigate the differential effects of physiological manipulation on long-term and short-term memory.

Robust and simple behavioral paradigms of appetitive, associative memory are crucial for researchers interested in cellular and molecular mechanisms of ...

Simultaneous Monitoring of Wireless Electrophysiology and Memory Behavioral Test as a Tool to Study Hippocampal Neurogenesis

Brainwaves amplitude obtained from electroencephalography (EEG) has been well-recognized as a basis for cognitive capacity, memory, and learning on animals and humans. Adult neurogenesis mechanism is also linked to memory and learning improvement. Traditionally, researchers used to assess learning and memory parameters in rodent models by behavioral tasks. Therefore, the simultaneous monitoring of behavioral changes and EEG is particularly interesting in correlating data between brain activity and task-related behaviors. However, most of the equipment required to perform both studies are either complex, expensive, or uses a wired setup network that hinders the natural animals&#8217; movement. In this study, EEG was recorded with a wireless electrophysiology device along with the execution of a novel object recognition task (NORT). The animal&#8217;s behavior was monitored simultaneously by a video tracking system. Both recordings were analyzed offline by their timestamps which were synched to link EEG signals with the animal&#8217;s actions. Subjects consist of adult Wistar rats after medium-term environmental enrichment treatment. Six skull screw electrodes were fixed in pairs on both hemispheres over frontal, central, and parietal regions and were referenced to an electrode located posterior of the nasal bone. NORT protocol consists of exposing the animal to two identical objects for 10 min. After 2 h and 24 h, one of the objects was replaced with a novel one. Exploration time for each object was monitored by a behavioral tracking software (BTS) and EEG data recording. The analysis of the EEG synced with behavioral data consists of estimations of alpha and beta relative band power and comparisons between novel object recognition versus familiar object exploration, between three experimental stages. In this manuscript, we have discussed electrodes manufacturing process, epidural electrodes implantation surgery, environmental enrichment protocol, NORT protocol, BTS setup, EEG &#8211; BTS coupling for simultaneous monitoring in real-time, and EEG data analysis based on automatic events detection.

The protocol presented here provides information on the simultaneous electroencephalography (EEG) and behavioral assessment in real-time. We have discussed all steps involved in this protocol as an attractive solution for researchers in many fields of neuroscience, particularly in learning and memory areas.

Monitoramento Simultâneo da Eletrofisiologia Wireless e Teste Comportamental de Memória como Ferramenta para Estudo da Neurogênese do Hipocampo

Brainwaves amplitude obtained from electroencephalography (EEG) has been well-recognized as a basis for cognitive capacity, memory, and learning on ...

Drosophila Courtship Conditioning As a Measure of Learning and Memory

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model organisms such as the fruit fly, Drosophila melanogaster. Drosophila is useful for understanding the basic neurobiology underlying cognitive deficits resulting from mutations in genes associated with human cognitive disorders, such as intellectual disability (ID) and autism. This work describes a methodology for testing learning and memory using a classic paradigm in Drosophila known as courtship conditioning. Male flies court females using a distinct pattern of easily recognizable behaviors. Premated females are not receptive to mating and will reject the male&#39;s copulation attempts. In response to this rejection, male flies reduce their courtship behavior. This learned reduction in courtship behavior is measured over time, serving as an indicator of learning and memory. The basic numerical output of this assay is the courtship index (CI), which is defined as the percentage of time that a male spends courting during a 10 min interval. The learning index (LI) is the relative reduction of CI in flies that have been exposed to a premated female compared to na&#239;ve flies with no previous social encounters. For the statistical comparison of LIs between genotypes, a randomization test with bootstrapping is used. To illustrate how the assay can be used to address the role of a gene relating to learning and memory, the pan-neuronal knockdown of Dihydroxyacetone phosphate acyltransferase (Dhap-at) was characterized here. The human ortholog of Dhap-at, glyceronephosphate O-acyltransferase (GNPT), is involved in rhizomelic chondrodysplasia punctata type 2, an autosomal-recessive syndrome characterized by severe ID. Using the courtship conditioning assay, it was determined that Dhap-at is required for long-term memory, but not for short-term memory. This result serves as a basis for further investigation of the underlying molecular mechanisms.

Drosophila Courtship Conditioning As a Measure of Learning and Memory

This protocol describes a Drosophila learning and memory assay called courtship conditioning. This classic assay is based on a reduction of male courtship behavior after sexual rejection by a non-receptive premated female. This natural form of behavioral plasticity can be used to test learning, short-term memory, and long-term memory.

Drosophila Courtship Acondicionamento Como Medida de Aprendizagem e Memória

Many insights into the molecular mechanisms underlying learning and memory have been elucidated through the use of simple behavioral assays in model ...

A Caenorhabditis elegans Nutritional-status Based Copper Aversion Assay

To ensure survival, organisms must be capable of avoiding unfavorable habitats while ensuring a consistent food source. Caenorhabditis elegans alter their locomotory patterns upon detection of diverse environmental stimuli and can modulate their suite of behavioral responses in response to starvation conditions. Nematodes typically exhibit a decreased aversive response when removed from a food source for over 30 min. Observation of behavioral changes in response to a changing nutritional status can provide insight into the mechanisms that regulate the transition from a well-fed to starved state.
We have developed an assay that measures a nematode&#39;s ability to cross an aversive barrier (i.e. copper) then reach a food source over a prolonged period of time. This protocol builds upon previous work by integrating multiple variables in a manner that allows for continued data collection as the organisms shift towards an increasingly starved condition. Moreover, this assay permits an increased sample size so that larger populations of nematodes can be simultaneously evaluated.
Organisms defective for the ability to detect or respond to copper immediately cross the chemical barrier, while wild type nematodes are initially repelled. As wild type worms are increasingly starved, they begin to cross the barrier and reach the food source. We designed this assay to evaluate a mutant that is incapable of responding to diverse environmental cues, including food sensation or detection of aversive chemicals. When evaluated via this protocol, the defective organisms immediately crossed the barrier, but were also incapable of detecting a food source. Hence, these mutants repeatedly cross the chemical barrier despite temporarily reaching a food source. This assay can straightforwardly test populations of worms to evaluate potential pathway defects related to aversion and starvation.

A Caenorhabditis elegans Nutritional-status Based Copper Aversion Assay

Here, we present a Caenorhabditis elegans-specific assay designed to evaluate changes in copper aversion behavior and the ability to locate a common food source, as the organism progresses from a well-fed to starved nutritional state.

UMA<em&gt; Caenorhabditis elegans</em&gt; Ensaio de Aversão ao Cobre Baseado em Status Nutricional

To ensure survival, organisms must be capable of avoiding unfavorable habitats while ensuring a consistent food source. Caenorhabditis elegans alter their ...

Aversive Associative Learning and Memory Formation by Pairing Two Chemicals in Caenorhabditis elegans

The nematode Caenorhabditis elegans is an attractive model organism to study learning and memory at molecular and cellular levels because of the simplicity of its nervous system, whose chemical and electrical wiring diagrams were completely reconstructed from serial electron micrographs of thin sections. Here, we describe detailed protocols for the conditioning of C. elegans by massed and spaced training for the formation of short-term memory (STM) and long-term memory (LTM), respectively. By pairing 1-propanol and hydrochloric acid as conditioned and unconditioned stimuli, respectively, C. elegans was successfully trained to form aversive associative STM and LTM. While na&#239;ve animals were attracted to 1-propanol, the trained animals were no longer or very weakly attracted to 1-propanol. Like in other organisms such as Aplysia and Drosophila, "learning and memory genes" play essential roles in memory formation. Particularly, NMDA-type glutamate receptors, expressed in only six pairs of interneurons in C. elegans, are required for the formation of both STM and LTM, possibly as a coincidence factor. Therefore, the memory trace may reside among the interneurons.

Aversive Associative Learning and Memory Formation by Pairing Two Chemicals in Caenorhabditis elegans

We have previously developed protocols for Caenorhabditis elegans to form short- and long-term associative memories by massed and spaced training, respectively. Here, detailed protocols are described for the conditioning of C. elegans by pairing 1-propanol and hydrochloric acid as conditioned and unconditioned stimuli, respectively, to form aversive associative memory.

Aprendizagem associativa aversiva e formação de memória emparelhando dois produtos químicos em Caenorhabditis elegans

The nematode Caenorhabditis elegans is an attractive model organism to study learning and memory at molecular and cellular levels because of the ...

C. elegans Chemotaxis Assay

Chemotaxis is a process in which cells or organisms move in response to a chemical stimulus. In nature, chemotaxis is important for organisms to sense and move toward food sources and move away from stimuli that may be toxic or harmful. Chemotaxis is also important at the cellular level. For example, chemotaxis is required for the movement of sperm toward an egg prior to fertilization. In the lab, chemotaxis is frequently examined in the nematode, C. elegans, which is known to migrate towards food sources in soil, but away from toxins such as heavy metals, substances with a low pH, and detergents. This video demonstrates how to perform a chemotaxis assay, which includes preparing the chemotaxis plates and the worms, running the assay, and analyzing the data. Then, we discuss examples of how chemotaxis assays can be used in C. elegans as a tool to understand learning and memory, olfactory adaptation, and neurological disease such as Alzheimer&quot;s disease. Chemotaxis experiments in C. elegans have near-limitless possibilities for learning more about the cellular and genetic mechanisms of many biological processes, and may lead to a greater understanding of human biology, development, and disease.

Chemotaxis Assay in Caenorhabditis elegans

Ensaio de quimiotaxia com C. elegans

Chemotaxis is a process in which cells or organisms move in response to a chemical stimulus. In nature, chemotaxis is important for organisms to sense and ...

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Biologia Básica

Biologia I: levedura, Drosophila e C. elegans

C. elegans Survival Assay: A Short-Term Toxicity Test

Source: Possik, E. and Pause, A. <a href="https://jove.unicartagenaproxy.elogim.com/video/2496/measuring-caenorhabditis-elegans-life-span-96-well-microtiter">Measuring Oxidative Stress Resistance of&#160;Caenorhabditis elegans&#160;in 96-well Microtiter Plates.</a>&#160;J. Vis. Exp. (2015).
This video introduces a short-term survival assay that tests a treatment for acute toxicity or tests a genetic strain for resistance to a toxic condition.&#160; The example protocol shows an example survival assay in which worms are tested for their ability to&#160; resist oxidative stress induced by paraquat (PQ).

C. elegans Ensaio de sobrevivência: um teste de toxicidade de curto prazo

Source: Possik, E. and Pause, A. Measuring Oxidative Stress Resistance of&#160;Caenorhabditis elegans&#160;in 96-well Microtiter Plates.&#160;J. Vis. Exp. ...

C. elegans Aprender Butanona Positivo, de curto prazo e de longo prazo Ensaios Memória Associativa

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