We thank Joachim Erber for introducing us to the tactile learning paradigm in honey bees. This work was supported by the Cluster of Excellence 277 CITEC, funded in the framework of the German Excellence Initiative.

1. Preparing the Bees
<ol>
	<li>Nectar or Pollen foragers are caught in the field either from a sucrose feeder or directly from the hive entrance while returning from a foraging trip. Each single bee is captured into a glass vial that is closed with a foam plug and taken immediately into the laboratory for further handling.</li>
	<li>In the laboratory, the captured bees are briefly cooled in the refrigerator at 4 &deg;C until they show first signs of immobility.</li>
	<li>Each single immobilized bee is mounted in a small metal tube with adhesive tape between head and thorax and over the abdomen. Care should be taken that the proboscis and antennae are freely movable.</li>
	<li>Paint the compound eyes and ocelli of the fixed bee with white paint (e.g. solvent-free Tipp-Ex) to occlude vision.</li>
	<li>Add a small drop of melted wax behind the head of the bee to fix it to the tape between head and thorax to prevent head movements during recordings.</li>
	<li>Mark each single bee with a number on the tape for better identification and place the tube with the fixed bee into a humid atmosphere to prevent dehydration.</li>
	<li>Feed each single bee for 5 sec with droplets of a 30% sucrose solution presented with a syringe and let all bees recover for 30 min before starting with the tactile conditioning protocol.</li>
</ol>
2. Tactile Conditioning
<ol>
	<li>Before conditioning, each single bee has to be tested for the proboscis extension response (PER) to a 30% sucrose stimulus applied to the antennae. Thereby the tip of the proboscis has to cross a virtual line between the opened mandibles. Discard all bees that don't respond with a PER to the sucrose stimulus.</li>
	<li>For tactile conditioning use a brass cube (e.g. 3 x 5 mm) with a smooth or an engraved pattern, e.g., horizontal or vertical grooves forming a grating with 150 &mu;m wave length, as the conditioned stimulus (CS). For the unconditioned stimulus (US) use a 30% sucrose solution (household sugar, diluted in water).</li>
	<li>The brass cube (CS) is placed into a holder on a micromanipulator (e.g., M&auml;rzh&auml;user MM33) to ensure exact positioning during the conditioning procedure. The US is presented to the bee with a syringe filled with a 30% sucrose solution.</li>
	<li>The conditioning procedure consists of five pairings of the tactile stimulus (CS) and sucrose solution (US) with an inter-trial interval (ITI) of 5 min. Place a single bee in front of the micromanipulator with the mounted tactile stimulus (CS). Position the CS slowly, such that the surface of the tactile stimulus is parallel to the head of the bee (Figure 1 A and B). The distance between the animal and the tactile object should be in the range of the antennal working radius of the tested bee, i.e. the bee should be able to scan the tactile stimulus in a comfortable position with both antennae. In the example shown in Figure 1, the distance was 3 mm. Let the bee scan the tactile stimulus (CS) for 5 sec. After the first 3 sec, present a droplet of the 30% sucrose (US) solution with a syringe under the proboscis. Use the tip of the syringe to gently raise the proboscis. Sucrose stimulation under the proboscis will elicit the unconditioned PER15. Allow the bee to lick the sucrose reward. Use a stopwatch with an alarm signal to maintain the exact time intervals during conditioning.</li>
	<li>The conditioned PER is used as a measure for the learning success of a bee. After the first rewarded pairings, bees start to respond to CS presentation by extension of their proboscis, indicating that they expect the forthcoming reward. A fully extended proboscis observed anytime during the 3 sec time window of tactile stimulus presentation and before sucrose presentation is scored as a positive response. No response is counted negative. The occurrence of the PER has to be noted by the experimenter. The percentage of bees showing the PER during CS presentation is plotted for each trial.</li>
</ol>
3. Kinematic Recordings
<ol>
	<li>Antennal movements of a single harnessed bee are recorded with a digital video camera with a suitable macro lens (e.g. Basler A602f-2 equipped with TechSpec VZM 200, operated at 50 fps via a fire wire connection). The camera is positioned above the animal in a top-down view (Figure 1 A). In Figure 1, the spatial resolution of the recordings is 0.02 mm/pixel.</li>
	<li>Calibrate the camera by recording single pictures of a 10 x 10 mm checkerboard with an edge length of 1 mm from different orientations under the camera objective. The calibration can be done with the camera calibration tool box Matlab16.</li>
	<li>Place a single fixed bee below the camera lens. Present the tactile stimulus, fixed to a micromanipulator, to the animal. Proceed in the same way as described for tactile conditioning, and record the antennal movement while the bee is scanning the object. It is important that the full antennal working range and the tactile stimulus are visible. The choices of stimulus patterns tested and trial numbers depend on the experimental design.</li>
</ol>
4. Data Analysis
<ol>
	<li>The computation of the image background is done in Matlab. First, the median greyscale value over time has to be calculated for each pixel. Static objects, like the fixed head of the bee and the tactile stimulus, will constitute the image background. Moving objects, like the two antennae, will not be part of the background.</li>
	<li>Each frame of the recorded video has to be loaded sequentially, and the difference between the current frame and the image background has to be computed. The result of this subtraction emphasizes those parts of the image that are moving from frame to frame. Ideally, the antennae of the bee are the only areas of non-zero values (Figure 1C).</li>
	<li>For further processing, the two largest areas with non-zero pixel values are assumed to be the antennae. For both antennae a binary mask is to be generated containing for each pixel a value 1, if the pixel belongs to the antenna and value 0 otherwise. This mask serves as a basis for localizing the antennal tips later. To gain a preliminary mask for the entire image the grey-value of each pixel of the difference image is compared to a pre-defined threshold. Since we take care of noise later this threshold is chosen to be quite low. The preliminary mask then still carries two kinds of errors: Firstly, due to image noise small regions are still part of the mask. Secondly, areas that belong to the antenna might not necessarily be fully connected. The latter mostly occurs if the background has approximately the same luminescence as the antenna. To eliminate these artifacts, standard image processing morphological operation are applied, i.e. a combination of image erosion and dilatation, relying upon the standard Matlab functions imerode and imdilate respectively (see17 pp. 158-205 for further explanation). After the denoising process the antennae hypotheses are still contained within the same mask. Hence, as a next step the binary mask is clustered for disjoint areas using the standard Matlab function bwlabel (see17 pp. 40-48 for further details on the image segmentation algorithm).</li>
	<li>The number of pixels per cluster is counted and the two largest clusters are selected. The center of gravity is calculated to distinguish between the left and right antenna (Figure 1D).</li>
	<li>The antennal tip for each antenna can be defined as the pixel in a cluster with the highest value in the proximal-to-distal direction (see Figure 1D).</li>
</ol>

<ol>
	<li>Page, R. E., Scheiner, R., Erber, J., Amdam, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+and+evolution+of+division+of+labor+and+foraging+specialization+in+a+social+insect+(Apis+mellifera++L.).">The development and evolution of division of labor and foraging specialization in a social insect (Apis mellifera L.).</a> Curr. Top. Dev. Biol. 74, 253-286 (2006).</li><li>Menzel, R., M&#252;ller, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+and+memory+in+honeybees:+From+behavior+to+neural+substrates.">Learning and memory in honeybees: From behavior to neural substrates.</a> Annu. Rev. Neurosci. 19, 379-404 (1996).</li><li>Seeley, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The wisdom of the hive. , (1995).</li><li>Staudacher, E., Gebhardt, M. J., D&#252;rr, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antennal+movements+and+mechanoreception:+neurobiology+of+active+tactile+sensors.">Antennal movements and mechanoreception: neurobiology of active tactile sensors.</a> Adv. Insect Physiol. 32, 49-205 (2005).</li><li>Martin, H., Lindauer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sinnesphysiologische+Leistungen+beim+Wabenbau+der+Honigbiene.">Sinnesphysiologische Leistungen beim Wabenbau der Honigbiene.</a> Z. Vergl. Physiol. 53, 372-404 (1966).</li><li>Kevan, P. G., Menzel, R., Mercer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Texture+sensitivity+in+the+life+of+honeybees.">Texture sensitivity in the life of honeybees.</a> Neurobiology and behavior of honeybees. , 96-101 (1987).</li><li>von Frisch, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Tanzsprache und Orientierung der Bienen. , (1965).</li><li>Waser, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flower+constancy:+definition,+cause,+and+ceasurement.">Flower constancy: definition, cause, and ceasurement.</a> Am. Nat. 127, 593-603 (1986).</li><li>Kevan, P. G., Lane, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flower+petal+microtexture+is+a+tactile+cue+for+bees.">Flower petal microtexture is a tactile cue for bees.</a> Proc. Natl. Acad. Sci. U.S.A. 82, 4750-4752 (1985).</li><li>Erber, J., Kierzek, S., Sander, E., Grandy, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+learning+in+the+honeybee.">Tactile learning in the honeybee.</a> J. Comp. Physiol. A. 183, 737-744 (1998).</li><li>Kisch, J., Erber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Operant+conditioning+of+antennal+movements+in+the+honey+bee.">Operant conditioning of antennal movements in the honey bee.</a> Behav. Brain. Res. 99, 93-102 (1999).</li><li>Scheiner, R., Erber, J., Page, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+learning+and+the+individual+evaluation+of+the+reward+in+honey+bees+(Apis+mellifera+L.).">Tactile learning and the individual evaluation of the reward in honey bees (Apis mellifera L.).</a> J. Comp. Physiol. A. 185, 1-10 (1999).</li><li>Erber, J., Scheiner, R., Adelman, G., Smith, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Honeybee+learning.">Honeybee learning.</a> Encyclopedia of Neuroscience. , (2004).</li><li>Bitterman, M. E., Menzel, R., Fietz, A., Sch&#228;fer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Classical+conditioning+of+proboscis+extension+in+honeybees+(Apis+mellifera).">Classical conditioning of proboscis extension in honeybees (Apis mellifera).</a> J. Comp. Psychol. 97, 107-119 (1983).</li><li>Dacher, M., Gauthier, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Involvement+of+NO-synthase+and+nicotinic+receptors+in+learning+in+the+honey+bee.">Involvement of NO-synthase and nicotinic receptors in learning in the honey bee.</a> Physiol. Behav. 95, 200-207 (2008).</li><li>Haralick, R. M., Shapiro, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Computer and Robot Vision. I, (1992).</li><li>Erber, J., Galizia, C. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+antennal+learning+in+the+honey+bee.">Tactile antennal learning in the honey bee.</a> Honeybee Neurobiology and Behavior. , 439-455 (2012).</li><li>Pankiw, T., Page, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pheromones,+hormones,+and+handling+on+sucrose+response+thresholds+of+honey+bees+(Apis+mellifera+L.).">Effect of pheromones, hormones, and handling on sucrose response thresholds of honey bees (Apis mellifera L.).</a> J. Comp. Physiol. A. 189, 675-684 (2003).</li><li>Harris, J. W., Woodring, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+stress,+age,+season+and+source+colony+on+levels+of+octopamine,+dopamine+and+serotonine+in+the+honey+bee+(Apis+mellifera+L.)+brain.">Effects of stress, age, season and source colony on levels of octopamine, dopamine and serotonine in the honey bee (Apis mellifera L.) brain.</a> J. Insect. Physiol. 38, 29-35 (1992).</li><li>Scheiner, R., Kuritz-Kaiser, A., Menzel, R., Erber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensory+responsiveness+and+the+effects+of+equal+subjective+rewards+on+tactile+learning+and+memory+of+honeybees.">Sensory responsiveness and the effects of equal subjective rewards on tactile learning and memory of honeybees.</a> Learn. Mem. 12, 626-635 (2005).</li><li>Mujagic, S., Sarkander, J., Erber, B., Erber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sucrose+acceptance+and+different+forms+of+associative+learning+of+the+honey+bee+(Apis+mellifera+L.)+in+the+field+and+laboratory.">Sucrose acceptance and different forms of associative learning of the honey bee (Apis mellifera L.) in the field and laboratory.</a> Front. Behav. Neurosci. 4, 46 (2010).</li><li>Scheiner, R., Barnert, M., Erber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+water+and+sucrose+responsiveness+during+the+foraging+season+affects+proboscis+extension+learning+in+honey+bees.">Variation in water and sucrose responsiveness during the foraging season affects proboscis extension learning in honey bees.</a> Apidologie. 34, 67-72 (2003).</li><li>Mujagic, S., Erber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sucrose+acceptance,+discrimination+and+proboscis+responses+of+honey+bees+(Apis+mellifera+L.)+in+the+field+and+the+laboratory.">Sucrose acceptance, discrimination and proboscis responses of honey bees (Apis mellifera L.) in the field and the laboratory.</a> J. Comp. Physiol. A. 195, 325-339 (2009).</li><li>Friedrich, A., Thomas, U., M&#252;ller, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+at+different+satiation+levels+reveals+parallel+functions+for+the+cAMP-protein+kinase+A+cascade+in+formation+of+long-term+memory.">Learning at different satiation levels reveals parallel functions for the cAMP-protein kinase A cascade in formation of long-term memory.</a> J. Neurosci. 24, 4460-4468 (2004).</li><li>Erber, J., Pribbenow, B., Grandy, K., Kierzek, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+motor+learning+in+the+antennal+system+of+the+honeybee+(Apis+mellifera+L.).">Tactile motor learning in the antennal system of the honeybee (Apis mellifera L.).</a> J. Comp. Physiol. A. 181, 355-365 (1997).</li><li>Lambin, M., D&#233;glise, P., Gauthier, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antennal+movements+as+indicators+of+odor+detection+by+worker+honeybees.">Antennal movements as indicators of odor detection by worker honeybees.</a> Apidologie. 36, 119-126 (2005).</li></ol>

No conflicts of interest declared.

Preparation of bees: Collecting and fixing the bees should be done quickly, in order to keep the stress level of the animal low. Stress has an effect on the PER-responsiveness and, therefore, could have an indirect effect on the learning performance in bees19, 20. The stress level can be decreased by placing the glass vials with the bees directly on ice immediately after collection to immobilize them quickly. It has to be taken into account that bees need more time to recover the longer the an...

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Pollen foragers, Apis mellifera L.</td>
 <td></td>
			<td></td>
			<td>Private hives</td>
		</tr>
		<tr>
			<td>Glass vials (22 x 45 mm)</td>
			<td>Carl Roth GmbH &amp; Co</td>
			<td>X655.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Brass tubes, 10 x 30 mm</td>
			<td></td>
			<td></td>
			<td>Self-produced</td>
		</tr>
		<tr>
			<td>Brass cube, 3 x 5 mm</td>
			<td></td>
			<td></td>
			<td>Self-produced</td>
		</tr>
		<tr>
			<td>Tipp-Ex (solvent-free)</td>
			<td>Tipp-Ex GmbH &amp; Co KG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose solution (30%)</td>
			<td></td>
			<td></td>
			<td>Household suger diluted in water</td>
		</tr>
		<tr>
			<td>Ethanol (70%)</td>
			<td>Carl Roth GmbH &amp; Co</td>
			<td>9065.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe (1 ml) and needle (0.6 x 25)</td>
			<td>Carl Roth GmbH &amp; Co</td>
			<td>59.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Stop Watch</td>
			<td>Carl Roth GmbH &amp; Co</td>
			<td>L423.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>M&auml;rzh&auml;user MM33</td>
			<td>00-42-101-0000</td>
			<td></td>
		</tr>
		<tr>
			<td>Digital video camera</td>
			<td>Basler A602f-2</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Macro lens for camera</td>
			<td>TechSpec VZM 200</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matlab R2009b</td>
			<td>The MathWorks</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

tactile conditioning and movement analysis of antennal sampling strategies in honey bees (apis mellifera l.)

Honey bees (Apis mellifera L.) are eusocial insects and well known for their complex division of labor and associative learning capability1, 2. The worker bees spend the first half of their life inside the dark hive, where they are nursing the larvae or building the regular hexagonal combs for food (e.g. pollen or nectar) and brood3. The antennae are extraordinary multisensory feelers and play a pivotal role in various tactile mediated tasks4, including hive building5 and pattern recognition6. Later in life, each single bee leaves the hive to forage for food. Then a bee has to learn to discriminate profitable food sources, memorize their location, and communicate it to its nest mates7. Bees use different floral signals like colors or odors7, 8, but also tactile cues from the petal surface9 to form multisensory memories of the food source. Under laboratory conditions, bees can be trained in an appetitive learning paradigm to discriminate tactile object features, such as edges or grooves with their antennae10, 11, 12, 13. This learning paradigm is closely related to the classical olfactory conditioning of the proboscis extension response (PER) in harnessed bees14. The advantage of the tactile learning paradigm in the laboratory is the possibility of combining behavioral experiments on learning with various physiological measurements, including the analysis of the antennal movement pattern.

In the following experiment we studied how tactile learning affects antennal sampling behavior in honey bees. For this, we monitored the movement of the antennal tip in na&iuml;ve and conditioned bees before and during presentation of a tactile stimulus.
First, the spontaneous antennal movement of a group of pollen foragers (N = 42) was recorded for 1 min. One half of the bees (N = 21) was then conditioned by pairing five times a tactile stimulus with a 30% sucrose reward. This was the conditi...

Watch this Scientific Journal Video about Tactile Conditioning And Movement Analysis Of Antennal Sampling Strategies In Honey Bees Apis mellifera L. at JoVE.com

Tactile Conditioning And Movement Analysis Of Antennal Sampling Strategies In Honey Bees Apis mellifera L.

In this protocol we show how to condition harnessed honey bees to tactile stimuli and introduce a 2D motion capture technique for analyzing the kinematics of fine-scale antennal sampling pattern.

Tactile Conditioning And Movement Analysis Of Antennal Sampling Strategies In Honey Bees (Apis mellifera L.)

Honey bees (Apis mellifera L.) are eusocial insects and well known for their complex division of labor and associative learning capability1, 2. The worker ...

tactile-conditioning-movement-analysis-antennal-sampling-strategies

Research

JoVE Journal

Neuroscience

10.5K 조회수.  Bielefeld University. 이 프로토콜에서 우리는 상태로 촉각 자극에 꿀벌을 밝혀와 고급 규모의 antennal 샘플링 패턴의 운동학을 분석하는 차원 모션 캡처 기술을 소개하는 방법을 보여줍니다.

비디오: Tactile Conditioning And Movement Analysis Of Antennal Sampling Strategies In Honey Bees Apis mellifera L.

Behavioural Pharmacology in Classical Conditioning of the Proboscis Extension Response in Honeybees (Apis mellifera)

Honeybees (Apis mellifera) are well known for their communication and orientation skills and for their impressive learning capability1,2. Because the survival of a honeybee colony depends on the exploitation of food sources, forager bees learn and memorize variable flower sites as well as their profitability. Forager bees can be easily trained in natural settings where they forage at a feeding site and learn the related signals such as odor or color. Appetitive associative learning can also be studied under controlled conditions in the laboratory by conditioning the proboscis extension response (PER) of individually harnessed honeybees3,4. This learning paradigm enables the study of the neuronal and molecular mechanisms that underlie learning and memory formation in a simple and highly reliable way5-12. A behavioral pharmacology approach is used to study molecular mechanisms. Drugs are injected systemically to interfere with the function of specific molecules during or after learning and memory formation13-16.
Here we demonstrate how to train harnessed honeybees in PER conditioning and how to apply drugs systemically by injection into the bee flight muscle.

Behavioural Pharmacology in Classical Conditioning of the Proboscis Extension Response in Honeybees Apis mellifera

We demonstrate how to implement a behavioral pharmacology method in an appetitive olfactory conditioning paradigm in honeybees (Apis mellifera) by systemic application of drugs. This method allows investigation of the mechanisms underlying learning and memory formation in a simple and reliable way.

Honeybees (Apis mellifera) are well known for their communication and orientation skills and for their impressive learning capability1,2. Because the ...

Automated Sholl Analysis of Digitized Neuronal Morphology at Multiple Scales

Neuronal morphology plays a significant role in determining how neurons function and communicate1-3. Specifically, it affects the ability of neurons to receive inputs from other cells2 and contributes to the propagation of action potentials4,5. The morphology of the neurites also affects how information is processed. The diversity of dendrite morphologies facilitate local and long range signaling and allow individual neurons or groups of neurons to carry out specialized functions within the neuronal network6,7. Alterations in dendrite morphology, including fragmentation of dendrites and changes in branching patterns, have been observed in a number of disease states, including Alzheimer's disease8, schizophrenia9,10, and mental retardation11. The ability to both understand the factors that shape dendrite morphologies and to identify changes in dendrite morphologies is essential in the understanding of nervous system function and dysfunction.
Neurite morphology is often analyzed by Sholl analysis and by counting the number of neurites and the number of branch tips. This analysis is generally applied to dendrites, but it can also be applied to axons. Performing this analysis by hand is both time consuming and inevitably introduces variability due to experimenter bias and inconsistency. The Bonfire program is a semi-automated approach to the analysis of dendrite and axon morphology that builds upon available open-source morphological analysis tools. Our program enables the detection of local changes in dendrite and axon branching behaviors by performing Sholl analysis on subregions of the neuritic arbor. For example, Sholl analysis is performed on both the neuron as a whole as well as on each subset of processes (primary, secondary, terminal, root, etc.) Dendrite and axon patterning is influenced by a number of intracellular and extracellular factors, many acting locally. Thus, the resulting arbor morphology is a result of specific processes acting on specific neurites, making it necessary to perform morphological analysis on a smaller scale in order to observe these local variations12.
The Bonfire program requires the use of two open-source analysis tools, the NeuronJ plugin to ImageJ and NeuronStudio. Neurons are traced in ImageJ, and NeuronStudio is used to define the connectivity between neurites. Bonfire contains a number of custom scripts written in MATLAB (MathWorks) that are used to convert the data into the appropriate format for further analysis, check for user errors, and ultimately perform Sholl analysis. Finally, data are exported into Excel for statistical analysis. A flow chart of the Bonfire program is shown in Figure 1.

We have developed a computer program to analyze neuronal morphology. In combination with two existing open source analysis tools, our program performs Sholl analysis and determines the number of neurites, branch points, and neurite tips. The analyses are performed so that local changes in neurite morphology can be observed.

Neuronal morphology plays a significant role in determining how neurons function and communicate1-3.  Specifically, it affects the ability of neurons to ...

The Culture of Primary Motor and Sensory Neurons in Defined Media on Electrospun Poly-L-lactide Nanofiber Scaffolds

Electrospinning is a technique for producing micro- to nano-scale fibers. Fibers can be electrospun with varying degrees of alignment, from highly aligned to completely random. In addition, fibers can be spun from a variety of materials, including biodegradable polymers such as poly-L-lactic acid (PLLA). These characteristics make electrospun fibers suitable for a variety of scaffolding applications in tissue engineering. Our focus is on the use of aligned electrospun fibers for nerve regeneration. We have previously shown that aligned electrospun PLLA fibers direct the outgrowth of both primary sensory and motor neurons in vitro. We maintain that the use of a primary cell culture system is essential when evaluating biomaterials to model real neurons found in vivo as closely as possible. Here, we describe techniques used in our laboratory to electrospin fibrous scaffolds and culture dorsal root ganglia explants, as well as dissociated sensory and motor neurons, on electrospun scaffolds. However, the electrospinning and/or culture techniques presented here are easily adapted for use in other applications.

Aligned electrospun fibers direct the growth of neurons in vitro and are a potential component of nerve regeneration scaffolds. We describe a procedure for preparing electrospun fiber substrates and the serum-free culture of primary rat E15 sensory (DRG) and motor neurons. Visualization of neurons by immunocytochemistry is also included.

Electrospinning is a technique for producing micro- to nano-scale fibers. Fibers can be electrospun with varying degrees of alignment, from highly aligned ...

Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe

The antennal lobe is the primary olfactory center in the insect brain and represents the anatomical and functional equivalent of the vertebrate olfactory bulb1-5. Olfactory information in the external world is transmitted to the antennal lobe by olfactory sensory neurons (OSNs), which segregate to distinct regions of neuropil called glomeruli according to the specific olfactory receptor they express. Here, OSN axons synapse with both local interneurons (LNs), whose processes can innervate many different glomeruli, and projection neurons (PNs), which convey olfactory information to higher olfactory brain regions.
Optical imaging of the activity of OSNs, LNs and PNs in the antennal lobe - traditionally using synthetic calcium indicators (e.g. calcium green, FURA-2) or voltage-sensitive dyes (e.g. RH414) - has long been an important technique to understand how olfactory stimuli are represented as spatial and temporal patterns of glomerular activity in many species of insects6-10. Development of genetically-encoded neural activity reporters, such as the fluorescent calcium indicators G-CaMP11,12 and Cameleon13, the bioluminescent calcium indicator GFP-aequorin14,15, or a reporter of synaptic transmission, synapto-pHluorin16 has made the olfactory system of the fruitfly, Drosophila melanogaster, particularly accessible to neurophysiological imaging, complementing its comprehensively-described molecular, electrophysiological and neuroanatomical properties2,4,17. These reporters can be selectively expressed via binary transcriptional control systems (e.g. GAL4/UAS18, LexA/LexAop19,20, Q system21) in defined populations of neurons within the olfactory circuitry to dissect with high spatial and temporal resolution how odor-evoked neural activity is represented, modulated and transformed22-24.
Here we describe the preparation and analysis methods to measure odor-evoked responses in the Drosophila antennal lobe using G-CaMP25-27. The animal preparation is minimally invasive and can be adapted to imaging using wide-field fluorescence, confocal and two-photon microscopes.

Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe

We describe an established technique to measure and analyze odor-evoked calcium responses in the antennal lobe of living Drosophila melanogaster.

The antennal lobe is the primary olfactory center in the insect brain and represents the anatomical and functional equivalent of the vertebrate olfactory ...

Electrophysiological Measurements and Analysis of Nociception in Human Infants

Pain is an unpleasant sensory and emotional experience. Since infants cannot verbally report their experiences, current methods of pain assessment are based on behavioural and physiological body reactions, such as crying, body movements or changes in facial expression. While these measures demonstrate that infants mount a response following noxious stimulation, they are limited: they are based on activation of subcortical somatic and autonomic motor pathways that may not be reliably linked to central sensory processing in the brain. Knowledge of how the central nervous system responds to noxious events could provide an insight to how nociceptive information and pain is processed in newborns.
The heel lancing procedure used to extract blood from hospitalised infants offers a unique opportunity to study pain in infancy. In this video we describe how electroencephalography (EEG) and electromyography (EMG) time-locked to this procedure can be used to investigate nociceptive activity in the brain and spinal cord.
This integrative approach to the measurement of infant pain has the potential to pave the way for an effective and sensitive clinical measurement tool.

The assessment and treatment of pain in infants is difficult because infants cannot verbally report their experience. In this video we describe quantitative electrophysiological methods and analysis techniques that can be used to measure the response to noxious events from the infant nervous system.

Pain is an unpleasant sensory and emotional experience. Since infants cannot verbally report their experiences, current methods of pain assessment are ...

Rapid Determination of the Thermal Nociceptive Threshold in Diabetic Rats

Painful diabetic neuropathy (PDN) is characterized by hyperalgesia i.e., increased sensitivity to noxious stimulus, and allodynia i.e., hypersensitivity to normally innocuous stimuli1. Hyperalgesia and allodynia have been studied in many different rodent models of diabetes mellitus2. However, as stated by B&ouml;lcskei et al, determination of "pain" in animal models is challenging due to its subjective nature3. Moreover, the traditional methods used to determine behavioral responses to noxious thermal stimuli usually lack reproducibility and pharmacological sensitivity3. For instance, by using the hot-plate method of Ankier4, flinch, withdrawal and/or licking of either hind- and/or fore-paws is quantified as reflex latencies at constant high thermal stimuli (52-55 &deg;C). However, animals that are hyperalgesic to thermal stimulus do not reproducibly show differences in reflex latencies using those supra-threshold temperatures3,5. As the recently described method of B&ouml;lcskei et al.6, the procedures described here allows for the rapid, sensitive and reproducible determination of thermal nociceptive thresholds (TNTs) in mice and rats. The method uses slowly increasing thermal stimulus applied mostly to the skin of mouse/rat plantar surface. The method is particularly sensitive to study anti-nociception during hyperalgesic states such as PDN. The procedures described bellow are based on the ones published in detail by Alm&aacute;si et al 5 and B&ouml;lcskei et al 3. The procedures described here have been approved the Laboratory Animal Care and Use Committee (LACUC), Wright State University.

Here, we describe a rapid reliable and simple procedure to determine the lowest temperature at which rats or mice show nocifensive behavior, i.e. the thermal nociceptive threshold (TNT). This method applies a slowly increasing thermal stimulus allowing precise and reproducible estimation of TNTs with minimum, if any, stress to the animals.

Painful diabetic neuropathy (PDN) is characterized by hyperalgesia i.e., increased sensitivity to noxious stimulus, and allodynia i.e., hypersensitivity ...

RNAi-mediated Double Gene Knockdown and Gustatory Perception Measurement in Honey Bees (Apis mellifera)

This video demonstrates novel techniques of RNA interference (RNAi) which downregulate two genes simultaneously in honey bees using double-stranded RNA (dsRNA) injections. It also presents a protocol of proboscis extension response (PER) assay for measuring gustatory perception.	
	RNAi-mediated gene knockdown is an effective technique downregulating target gene expression. This technique is usually used for single gene manipulation, but it has limitations to detect interactions and joint effects between genes. In the first part of this video, we present two strategies to simultaneously knock down two genes (called double gene knockdown). We show both strategies are able to effectively suppress two genes, vitellogenin (vg) and ultraspiracle (usp), which are in a regulatory feedback loop. This double gene knockdown approach can be used to dissect interrelationships between genes and can be readily applied in different insect species.	
	The second part of this video is a demonstration of proboscis extension response (PER) assay in honey bees after the treatment of double gene knockdown. The PER assay is a standard test for measuring gustatory perception in honey bees, which is a key predictor for how fast a honey bee's behavioral maturation is. Greater gustatory perception of nest bees indicates increased behavioral development which is often associated with an earlier age at onset of foraging and foraging specialization in pollen. In addition, PER assay can be applied to identify metabolic states of satiation or hunger in honey bees. Finally, PER assay combined with pairing different odor stimuli for conditioning the bees is also widely used for learning and memory studies in honey bees.

RNAi-mediated Double Gene Knockdown and Gustatory Perception Measurement in Honey Bees Apis mellifera

In this protocol, we describe two strategies that simultaneously suppress two genes (double gene knockdown) in honey bees. Then we present how to use the proboscis extension response (PER) assay to study the effect of double gene knockdown on honey bee gustatory perception.

This video demonstrates novel techniques of RNA  interference (RNAi) which downregulate two genes simultaneously in honey bees  using double-stranded RNA ...

Neuropharmacological Manipulation of Restrained and Free-flying Honey Bees, Apis mellifera

Honey bees demonstrate astonishing learning abilities and advanced social behavior and communication. In addition, their brain is small, easy to visualize and to study. Therefore, bees have long been a favored model amongst neurobiologists and neuroethologists for studying the neural basis of social and natural behavior. It is important, however, that the experimental techniques used to study bees do not interfere with the behaviors being studied. Because of this, it has been necessary to develop a range of techniques for pharmacological manipulation of honey bees. In this paper we demonstrate methods for treating restrained or free-flying honey bees with a wide range of pharmacological agents. These include both noninvasive methods such as oral and topical treatments, as well as more invasive methods that allow for precise drug delivery in either systemic or localized fashion. Finally, we discuss the advantages and disadvantages of each method and&#160;describe common hurdles and how to best overcome them. We conclude with a discussion on the importance of adapting the experimental method to the biological questions rather than the other way around.

Neuropharmacological Manipulation of Restrained and Free-flying Honey Bees, Apis mellifera

This manuscript describes several protocols for administering pharmacological agents to honey bees, including simple noninvasive methods for free-flying bees, as well as more invasive variants that allow precise localized treatment of restrained bees.

Honey bees demonstrate astonishing learning abilities and advanced social behavior and communication. In addition, their brain is small, easy to visualize ...

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain.

Trace eyeblink classical conditioning (ECC) was used to assess hippocampal-dependent associative learning in adult rats that were administered a high concentration (11.9% v/v) of alcohol during early neonatal brain development. In general, ECC procedures are sound diagnostic tools for detecting brain dysfunction across many psychological and biomedical settings.

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain ...

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.

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