Nous remercions W. Ryu pour des conseils sur notre imagerie configuration initiale, Z. Gitaï à la suggestion d&#39;utiliser ImageJ 13 pour compter les vers, et J. Achraf pour les aider avec Google SketchUp. CTM est une bourse d&#39;études Pew dans les sciences biomédicales, un chercheur McKnight, et chercheur 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>

Le C. elegans apprentissage olfactif associatif et des dosages de mémoire présenté ici de distinguer entre les processus de l&#39;apprentissage massé, l&#39;apprentissage espacées, mémoire à court terme, et mémoire à long terme. Ces tests s&#39;appuient sur ​​les capacités des vers au sens des odeurs alimentaires et chimiques dans leur environnement et 1,2 pour former des associations positives entre les deux. 6 Par conséquent, les dosages sont très sensibles à la famine dans la population de départ des animaux, et un grand soin doit être prises pour s&#39;assurer que les vers sont bien nourris, avant et après la formation. Simple formation massés rendements à court terme la mémoire associative. L&#39;augmentation du nombre de périodes de conditionnement et le paradigme de formation espacées est essentiel pour parvenir à long terme la mémoire associative en C. elegans comme il est dans d&#39;autres organismes. Peut-être 6,8 ce test pourrait être modifié pour produire souvenirs à long terme des associations entre les différents stimuli conditionnés ou non conditionnés. Notre apprentissage associatif et les tests de mémoire peuvent être utilisées pour comparer les capacités d&#39;apprentissage et de mémoire de type sauvage au vieillissement ou génétique des animaux mutants. Par exemple, alors que les deux apprentissage associatif et à long terme la mémoire associative diminution des capacités dans le vieillissement vers de type sauvage, l&#39;apprentissage est maintenu plus longtemps avec l&#39;âge chez les animaux avec signalisation de l&#39;insuline réduite, et de l&#39;apprentissage et la mémoire est maintenue plus longtemps avec l&#39;âge chez les animaux calorique restreints 6. Ces tests sont également prête à l&#39;ARNi traitement ou la manipulation pharmacologique de C. elegans. Par exemple, le traitement des vers avec daf-2 améliore l&#39;ARNi à court et à long terme la mémoire associative, à l&#39;inverse, le blocage de la transcription génique et la synthèse des protéines avec des médicaments (actinomycine D et la cycloheximide, respectivement) pendant l&#39;entraînement espacés perturbe la formation de la mémoire à long terme. 6 Mémoire à long terme est un processus qui est crucial pour la survie de tous les animaux, et il semble que la plupart des machines moléculaires impliqués dans la mémoire d&#39;une association pavlovien est conservée par les vers pour les mammifères. 6 La capacité de distinguer et de tester l&#39;apprentissage associatif, court terme et mémoire à long terme l&#39;utilisation de ces tests olfactifs fait C. elegans un excellent système pour l&#39;étude plus approfondie de la mémoire, et peut donner un aperçu des processus neurodégénératifs qui conduisent à la perte de l&#39;apprentissage et la mémoire chez les humains.

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<td>Sodium Azide</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>S227</td>
<td>Prepare 1 M concentration in distilled water</td>
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<td>Ethyl Alcohol 190 Proof</td>
<td>&nbsp;</td>
<td>Pharmco-Aaper</td>
<td>DSP-CT-18</td>
<td>&gt;95% Ethanol may have impurities that interfere with chemotaxis assays</td>
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<td>2-Butanone 99+%</td>
<td>&nbsp;</td>
<td>Acros</td>
<td>14967-0010</td>
<td>&nbsp;</td>
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<td>Basler IEEE-1394/FireWire Area Scan CMOS Camera</td>
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<td>Edmund Optics</td>
<td>NT56-683</td>
<td>&nbsp;</td>
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<td>InfiniMite Video Lens &#x2013; Alpha Industrial</td>
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<td>Edmund Optics</td>
<td>NT56-202</td>
<td>&nbsp;</td>
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<td>Dolan-Jenner MI-150 Fiber Optic Illuminator</td>
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<td>Edmund Optics</td>
<td>NT55-718</td>
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<td>8&#x201D; x 8&#x201D; Backlight</td>
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<td>Schott Fostec</td>
<td>A08927</td>
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<td>Standard Boom Stand</td>
<td>&nbsp;</td>
<td>Edmund Optics</td>
<td>NT54-120</td>
<td>&nbsp;</td>
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<td>3/4&#x201D; Post Adaptor for Boom Stands</td>
<td>&nbsp;</td>
<td>Edmund Optics</td>
<td>NT54-124</td>
<td>&nbsp;</td>
<tr>
<td>Standard Fixed 1/4-20 Mounting Plate</td>
<td>&nbsp;</td>
<td>Edmund Optics</td>
<td>NT54-122</td>
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c. elegans positive butanone learning, short-term, and long-term associative memory assays

La mémoire des expériences et des informations apprises est essentiel pour les organismes de faire des choix que l&#39;aide à leur survie. C. elegans navigue son environnement grâce à des neurones spécifiques de détection des odeurs de nourriture et de produits chimiques 1, 2, et peut associer des États nutritive avec 3 odeurs chimiques, température de 4, et la pathogénicité d&#39;une source de 5 nourriture. Ici, nous décrivons des dosages de C. elegans apprentissage associatif et à court et à long terme la mémoire associative. Nous avons modifié un paradigme d&#39;apprentissage aversif olfactive au lieu de 6 à produire une réponse positive, l&#39;épreuve consiste à affamer les vers ~ 400, puis nourrir les vers à la présence de l&#39;AWC neurone-butanone senti chimioattractive volatiles à une concentration qui provoque un index chimiotactique faible (similaires d&#39;Toroyama et al. 7). Une population standard chimiotactisme assay1 essais attrait des vers à l&#39;odorant immédiatement ou minutes à quelques heures après le conditionnement. Après chimiotactisme conditionné, animaux de type sauvage »aux augmentations de butanone ~ 0,6 unités Indice chimiotactisme, son« indice de l&#39;apprentissage &quot;. L&#39;apprentissage associatif est dépendante de la présence de la nourriture et le butanone pendant la formation. Accord mets et de butanone pour une période de conditionnement unique («formation massés&quot;) produit à court terme la mémoire associative, qui dure environ 2 heures. Périodes de conditionnement multiples avec des périodes de repos entre («formation espacées») des rendements à long terme la mémoire associative (&lt;40 heures), et est dépendante de la protéine AMPc Element Binding Réponse (CREB), 6 un facteur de transcription requis pour mémoire à long terme à travers espèces 8. Notre protocole comprend également des méthodes d&#39;analyse d&#39;image pour la détermination rapide et précise des indices de chimiotactisme. Haut contraste des images d&#39;animaux sur les plaques de dosage chimiotactisme sont capturés et analysés par un logiciel de comptage dans le ver MatLab. Le logiciel corrige pour le fond inégale en utilisant une transformation tophat morphologiques. Méthode 9 Otsu est ensuite utilisé pour déterminer un seuil pour les vers séparer de l&#39;arrière-plan. 10 très petites particules sont supprimés automatiquement et les grands non-ver régions (bords de la plaque ou de poinçons agar) sont enlevé par sélection manuelle. Le logiciel évalue alors la taille du seul ver, en ignorant les régions qui sont au-dessus d&#39;une taille maximale spécifiée et en prenant la taille médiane des autres régions. Le nombre de vers est alors estimée en divisant la superficie totale occupée par identifiés comme des vers par la taille estimée d&#39;un seul ver. Nous avons constaté que l&#39;apprentissage et à court terme et mémoire à long terme peuvent être distingués, et que ces processus partagent les mêmes molécules clés avec les organismes supérieurs. 6,8 Nos tests peuvent tester rapidement nouveaux gènes candidats ou des molécules qui affectent l&#39;apprentissage et à court ou à long terme de mémoire en C. elegans qui sont pertinents à travers les espèces.

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

Nous décrivons ici les méthodes d&#39;essais de C. elegans apprentissage associatif et à court et à long terme la mémoire associative. Ces dosages de la population utilisent les capacités des vers à chemotax vers odorants volatils, et de former des associations positives sur les accords mets butanone chimiotactique. Augmenter le nombre de périodes de conditionnement induit mémoire à long terme.

C. elegans à l&#39;apprentissage butanone, à court terme et à long terme Tests mémoire associative

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

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Neuroscience

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

29.0K vues.  Princeton University. Nous décrivons ici les méthodes d'essais de C. elegans apprentissage associatif et à court et à long terme la mémoire associative. Ces dosages de la population utilisent les capacités des vers à chemotax vers odorants volatils, et de former des associations positives sur les accords mets butanone chimiotactique. Augmenter le nombre de périodes de conditionnement induit mémoire à long terme.

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

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of these diseases, including Alzheimer's, Parkinson's and Huntington's disease are characterized by age-dependent deterioration in learning and memory functions and movement coordination2. Here we use behavioral assays, including the negative geotaxis assay3 and the aversive phototaxic suppression assay (APS assay)4,5, to show that some of the behavior characteristics associated with human neurodegeneration can be recapitulated in flies. In the negative geotaxis assay, the natural tendency of flies to move against gravity when agitated is utilized to study genes or conditions that may hinder locomotor capacities. In the APS assay, the learning and memory functions are tested in positively-phototactic flies trained to associate light with aversive bitter taste and hence avoid this otherwise natural tendency to move toward light. Testing these trained flies 6 hours post-training is used to assess memory functions. Using these assays, the contribution of any genetic or environmental factors toward developing neurodegeneration can be easily studied in flies.

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Behavior assays for measuring locomotor functions, learning, and memory abilities in Drosophila.

Déficits locomoteur Dosage, apprentissage et mémoire dans Drosophile Modèles de la neurodégénérescence

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of ...

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In vivo Laser Axotomy in C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron is damaged by injury or disease, it may regenerate. Cell-intrinsic and extrinsic factors influence the ability of a neuron to regenerate and restore function. Recently, the nematode C. elegans has emerged as an excellent model organism to identify genes and signaling pathways that influence the regeneration of neurons1-6. The main way to initiate neuronal regeneration in C. elegans is laser-mediated cutting, or axotomy. During axotomy, a fluorescently-labeled neuronal process is severed using high-energy pulses. Initially, neuronal regeneration in C. elegans was examined using an amplified femtosecond laser5. However, subsequent regeneration studies have shown that a conventional pulsed laser can be used to accurately sever neurons in vivo and elicit a similar regenerative response1,3,7.
We present a protocol for performing in vivo laser axotomy in the worm using a MicroPoint pulsed laser, a turnkey system that is readily available and that has been widely used for targeted cell ablation. We describe aligning the laser, mounting the worms, cutting specific neurons, and assessing subsequent regeneration. The system provides the ability to cut large numbers of neurons in multiple worms during one experiment. Thus, laser axotomy as described herein is an efficient system for initiating and analyzing the process of regeneration.

In vivo Laser Axotomy in C. elegans

A protocol to cut neurons in C. elegans with a MicroPoint pulsed laser is presented. We describe setting up the system, immobilizing worms, and severing labeled neurons. Advantages include a relatively low-cost system and the ability to sever neuronal processes or ablate cells in vivo.

In vivo laser axotomie en C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron ...

Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution. Here we describe an optical method and a deconvolution algorithm to record neural activity from up to 100 neurons with single-cell and single-spike resolution. This method relies on detection of the transient increases in intracellular somatic calcium concentration associated with suprathreshold electrical spikes (action potentials) in cortical neurons. High temporal resolution of the optical recordings is achieved by a fast random-access scanning technique using acousto-optical deflectors (AODs)1. Two-photon excitation of the calcium-sensitive dye results in high spatial resolution in opaque brain tissue2. Reconstruction of spikes from the fluorescence calcium recordings is achieved by a maximum-likelihood method. Simultaneous electrophysiological and optical recordings indicate that our method reliably detects spikes (&gt;97% spike detection efficiency), has a low rate of false positive spike detection (&lt; 0.003 spikes/sec), and a high temporal precision (about 3 msec) 3. This optical method of spike detection can be used to record neural activity in vitro and in anesthetized animals in vivo3,4.

Understanding the function of the vertebrate central nervous system requires recordings from many neurons because cortical function arises on the level of populations of neurons. Here we describe an optical method to record suprathreshold neural activity with single-cell and single-spike resolution, dithered random-access scanning. This method records somatic fluorescence calcium signals from up to 100 neurons with high temporal resolution. A maximum-likelihood algorithm deconvolves the underlying suprathreshold neural activity from the somatic fluorescence calcium signals. This method reliably detects spikes with high detection efficiency and a low rate of false positives and can be used to study neural populations in vitro and in vivo.

D&#39;enregistrement optique de l&#39;activité neuronale supraliminaire avec une résolution à cellule unique et un seul pic

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also ...

C. elegans Tracking and Behavioral Measurement

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the surface of an agar plate. For the study of the genetic, biochemical, and neuronal basis of behavior, C. elegans is an ideal organism because it is genetically tractable, amenable to microscopy, and shows a number of complex behaviors, including taxis, learning, and social interaction1,2. Behavioral analysis based on tracking the movements of worms as they crawl on agar plates have been particularly useful in the study of sensory behavior3, locomotion4, and general mutational phenotyping5. Our system works by moving the camera and illumination system as the worms crawls on a stationary agar plate, which ensures no mechanical stimulus is transmitted to the worm. Our tracking system is easy to use and includes a semi-automatic calibration feature. A challenge of all video tracking systems is that it generates an enormous amount of data that is intrinsically high dimensional. Our image processing and data analysis programs deal with this challenge by reducing the worms shape into a set of independent components, which comprehensively reconstruct the worms behavior as a function of only 3-4 dimensions6,7. As an example of the process we show that the worm enters and exits its reversal state in a phase specific manner.

C. elegans Tracking and Behavioral Measurement

We have developed a video-rate tracking microscope system that can record and quantify C. elegans behavior at high resolution and high speeds. We have also developed computational methods to reduce the dimensionality of the worm images to a fundamental set of measurements that completely describe the shape of the worm.

C. elegans Suivi et évaluation comportementale

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the ...

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.

Appétitive apprentissage olfactif associatif en<em&gt; Drosophila</em&gt; Les larves

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

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.

Un indicateur moléculaire de l&#39;adaptation à long terme olfactive dans<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 ...

Agarose Microchambers for Long-term Calcium Imaging of Caenorhabditis elegans

Behavior is controlled by the nervous system. Calcium imaging is a straightforward method in the transparent nematode Caenorhabditis elegans to measure the activity of neurons during various behaviors. To correlate neural activity with behavior, the animal should not be immobilized but should be able to move. Many behavioral changes occur during long time scales and require recording over many hours of behavior. This also makes it necessary to culture the worms in the presence of food. How can worms be cultured and their neural activity imaged over long time scales? Agarose Microchamber Imaging (AMI) was previously developed to culture and observe small larvae and has now been adapted to study all life stages from early L1 until the adult stage of C. elegans. AMI can be performed on various life stages of C. elegans. Long-term calcium imaging is achieved without immobilizing the animals by using short externally triggered exposures combined with an electron multiplying charge-coupled device (EMCCD) camera recording. Zooming out or scanning can scale up this method to image up to 40 worms in parallel. Thus, a method is described to image behavior and neural activity over long time scales in all life stages of C. elegans.

Agarose Microchambers for Long-term Calcium Imaging of Caenorhabditis elegans

Imaging behavior and neural activity over long time scales without immobilization of the animal is a prerequisite to understand behavior. Agarose microfluidic chambers imaging (AMI) can be used to image neural activity and behavior for all life stages of Caenorhabditis elegans.

Microchambres agarose à long terme de l&#39;imagerie calcique<em&gt; Caenorhabditis elegans</em

Behavior is controlled by the nervous system. Calcium imaging is a straightforward method in the transparent nematode Caenorhabditis elegans to measure ...

Assessing Spatial Learning and Memory in Small Squamate Reptiles

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, interest in the cognitive processes of nonmodel species, typically within an ecological context, has also become an emerging field of study. In particular, interest in the cognitive processes in reptiles is growing although experimental studies on reptilian cognition are sparse. The few reptilian studies that have experimentally tested for spatial learning and memory have used rodent paradigms modified for use in reptiles. However, ecologically important aspects of the physiology and behavior of this taxonomic group must be taken into account when testing for spatially based cognition. Here, we describe modifications of the dry land Barnes maze and associated testing protocol that can improve performance when probing for spatial learning and memory ability in small squamate reptiles. The described paradigm and procedures were successfully used with male side-blotched lizards (Uta stansburiana), demonstrating that spatial learning and memory can be assessed in this taxonomic group with an ecologically relevant apparatus and protocol.

This paper describes a modification of the Barnes maze, a standard rodent paradigm used to assess spatial memory and learning, for use in small squamate reptiles.

Évaluation de l&#39;apprentissage spatial et la mémoire dans les petits squamate Reptiles

Clinical research has leveraged a variety of paradigms to assess cognitive decline, commonly targeting spatial learning and memory abilities. However, ...

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 Conditionnement en tant que mesure de l&#39;apprentissage et de la mémoire

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

Long-term Sensory Conflict in Freely Behaving Mice

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning in mice. By permanently wearing a device fixed on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages. Therefore, this protocol readily enables the study of the visual system and multisensory interactions over an extended timeframe that would not be accessible otherwise. In addition to lowering the experimental costs of long-term sensory learning in naturally behaving mice, this approach accommodates the combination of in vivo and in vitro experiments. In the reported example, video-oculography is performed to quantify the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) before and after learning. Mice exposed to this long-term sensory conflict between visual and vestibular inputs presented a strong VOR gain decrease but exhibited few OKR changes. Detailed steps of device assembly, animal care, and reflex measurements are hereby reported.

The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning. By permanently wearing a fixed device on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages.

À long terme conflit sensoriel en comportement librement souris

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for ...