Name: measuring sensitivity to viewpoint change with and without stereoscopic cues
Uploaded: 2013-12-04T18:30:00
Description: Watch this Scientific Journal Video about Measuring Sensitivity to Viewpoint Change with and without Stereoscopic Cues at JoVE.com

This research was supported by the Australian Research council. ARC Grant # DP110101511 given to JB; National Sciences and Engineering Research Council, NSERC of Canada Grant # RGPIN121713-11 given to FK ; ARC grant # DP130102580 and DP110104553 to DRB.

1. Prescreening
<ol>
	<li>Prior to testing, obtain written and informed consent from each participant.</li>
	<li>Ask the subject if they have normal or corrected-to-normal acuity (i.e. glasses).</li>
	<li>Verify the stereo acuity of the participant using a simple handheld stereo test.</li>
</ol>
2. Achieving Binocular Fusion in the Stereoscope
<ol>
	<li>Seat the participant at the desk in front of the mirror stereoscope and adjust the height of their chair for comfort.</li>
	<li>Turn ...

<ol>
	<li>Bennett, D. J., Vuong, Q. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+stereo+advantage+in+generalizing+over+changes+in+viewpoint+on+object+recognition+tasks.">A stereo advantage in generalizing over changes in viewpoint on object recognition tasks.</a> Percep. Psychophys. 68, 1082-1093 (2006).</li><li>Bulthoff, H. H., Edelman, S. Y., Tarr, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+are+three-dimensional+objects+represented+in+the+brain?.">How are three-dimensional objects represented in the brain?.</a> Cereb. Cortex. 5, 247-260 (1995).</li><li>Burke, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+disparate+views+of+objects:+Viewpoint+costs+are+reduced+by+stereopsis.">Combining disparate views of objects: Viewpoint costs are reduced by stereopsis.</a> Vis. Cogn. 12, 705-719 (2005).</li><li>Burke, D., Taubert, J., Higman, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+face+representations+viewpoint+dependent?+A+stereo+advantage+for+generalising+across+different+views+of+faces.">Are face representations viewpoint dependent? A stereo advantage for generalising across different views of faces.</a> Vis. Res. 47, 2164-2169 (2007).</li><li>Edelman, S., Bulthoff, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orientation+dependence+in+the+recognition+of+familiar+and+novel+views+of+three-dimensional+objects.">Orientation dependence in the recognition of familiar and novel views of three-dimensional objects.</a> Vis. Res. 32, 2385-2400 (1992).</li><li>Lim Lee, Y., Saunders, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereo+improves+3D+shape+discrimination+even+when+rich+monocular+shape+cues+are+available.">Stereo improves 3D shape discrimination even when rich monocular shape cues are available.</a> J. Vis. 11, (2011).</li><li>Parr, L. 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The methods discussed in this communication can be used by any researcher seeking to address questions related to discrimination and/or recognition of viewpoint rotated objects. Importantly, the method of perspective projection is not limited to the stimuli demonstrated here; instead it can be applied to a wide range of experimental stimuli, from lines to pictures of complex objects. Our introduction describes ways to apply this transformation using custom software, or library software such as MATLAB.
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Many studies have shown that the speed and accuracy of object recognition is compromised by a change in viewpoint1-7. For example, face recognition is best when the face is viewed in the fronto-parallel plane, i.e. &#34;front on&#34;, and declines systematically as the face is rotated in depth away from the fronto-parallel plane. Changes in viewpoint can occur either when the observer, or the viewed object, moves. Importantly, the viewpoint cost is often reduced by the introduction of stereoscopic cues to the observer1-4,6,8. It is, however, important to distinguish between the rotation of 3D and planar objects. The former may reveal new textures or structural information under rotation while this does not occur with planar objects. In this communication we discuss a method for simulating the appearance of planar shapes and objects that have been subject to rotation-in-depth, or RID. We describe an apparatus for turning the two-dimensional projection of a RID image into a vivid 3D (three-dimensional) percept of RID that is based on the Wheatstone mirror stereoscope9. Finally, we report a psychophysical method for determining whether stereoscopic (3D) cues influence our sensitivity to viewpoint change. Movie 1 demonstrates how the appearance of a shape is altered by a viewpoint change/RID.
Simulating a Viewpoint Change
When an object is subject to RID it does not of course physically change in identity or shape. However from the observer&#8217;s viewpoint, the shape does change. For instance, if you hold a sheet of paper directly in front of you in landscape view, the image of the paper in your eye, termed the retinal image, is a horizontal rectangle. If you then rotate the paper around its central vertical axis, the retinal image becomes foreshortened along the horizontal (see Figure 1 for a demonstration). Ultimately, if you rotate the paper through 90&#176; the retinal image is a thin strip the thickness of the paper. Thus the largest change to the image of the sheet of paper that has been subject to RID is a horizontal compression of its shape. A smaller change gradient of change occurs in the vertical extent with the image being taller for the nearest edge unchanged at the axis of rotation and shorter for the farther edge.
A RID can be simulated by appropriate transformation of images using software packages or by writing one&#8217;s own code8,10. Readers wishing to know more about RID can consult relevant texts and websites concerned with viewpoint transformations, or learn about built-in functions in the image processing software of packages such as those listed in our Materials. However, when transforming an image of a stimulus on a screen to represent a particular angle of RID there is an additional consideration: which type of projection to use, orthographic or perspective? When we view a scene, nearby objects produce larger retinal images than farther away objects. For a 2D (two-dimensional) object that is subject to RID this means that the far side is compressed more than the near side, as Figure 1 illustrates (see in particular the bottom right figure which has a RID of 60&#176;). The magnitude of the compression asymmetry is dependent upon the size of the object being subject to RID, and on our distance from it. Perspective projection incorporates this compression asymmetry whereas orthographic projection simply ignores it by assigning the same dimensions to the near and far sides of the RID object. Since an observer viewing a planar object rotate will be presented with this asymmetry we will use perspective projection here. Another advantage of our method is that the projection takes into account viewing distance from observer to screen. We have previously used our RID method to simulate viewpoint rotated shapes in both 2D perspective projection and in 3D8,10.
Simulating a 3D Viewpoint Change
In order to simulate stereoscopic RID one needs to present slightly different images to the left and right eyes. This difference between the two images is known as binocular disparity11, and is a function of both viewing distance and between-eye separation, specifically the inter-pupillary distance. Returning to the example of our sheet of paper in landscape view, if we rotate the piece of paper around the vertical center, clockwise by 45&#176; (so the left edge is receding), each eye&#8217;s view of the paper is slightly different. The image projected onto the left eye is slightly less than 45&#176; rotation while the image projected onto the right eye is slightly more than 45&#176; rotation (see Figure 2 for an illustration - observers who can free fuse the top two images will perceive a RID in 3D). If the appropriate RID angles are presented separately to the left and right eyes (the stereo condition) they will produce a disparity gradient and the observer is likely to report a vivid impression of a 3D RID. However if identical images, representing a 45&#176; rotation from the central viewing point, are presented to both eyes (the nonstereo condition) the observer will see a 2D representation of the RID stimuli. An established method for presenting separate images to the left and right eyes using a single monitor is to use a modification of the mirror stereoscope originally developed by Sir Charles Wheatstone in the mid 19th century12 &#8211; see Figure&#160;3. When the two stereo-half-images are positioned at corresponding locations in each eye&#8217;s view, they can be binocularly fused to produce a 3D percept (see Howard and Rogers12 for an extensive review of stereo methods and limitations).
By combining a simulated viewpoint change with stereoscopic presentation we can determine, for example, the role that stereoscopic cues play in our ability to detect changes in viewpoint. The demonstration results below reveal that when the size of a planar object, in this case a curved contour, is known or familiar to the observer, the change in the 2D width of the curve (sometimes termed its sag) is used to detect the change in RID, i.e. viewpoint (see Bell et al.10 for the full manuscript on this effect). Below we describe in detail a psychophysical method for measuring sensitivity to RID change for 2D- and 3D-defined planar shapes.

<table border="0" cellpadding="0" cellspacing="0" width="775">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Stereo testing</td>
			<td style="width:127px;">http://www.stereooptical.com/products/stereotests</td>
			<td style="width:152px;">Titmus stereofly test</td>
			<td style="width:280px;">Handheld testing devices</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Prebuilt stereo devices</td>
			<td style="width:127px;">http://www.stereoaids.com.au</td>
			<td style="width:152px;">prebuilt stereoscopes</td>
			<td>Suitable for desktop and laptop computers</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Mirror stereoscope</td>
			<td style="width:127px;">Custom made; or, Edmundoptics</td>
			<td style="width:152px;">8 mirror stereoscope</td>
			<td>www.edmundoptics.com</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Graphics card</td>
			<td style="width:127px;">NVidia</td>
			<td style="width:152px;"></td>
			<td>NVidia or ATI recommended</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Experimental control software</td>
			<td style="width:127px;">MATLAB</td>
			<td style="width:152px;"></td>
			<td>MATLAB, Python, C++, Visual Basic recommended</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Experimental control software</td>
			<td style="width:127px;">Psychtoolbox.org</td>
			<td style="width:152px;">Psychtoolbox</td>
			<td>Free to download but requires MATLAB</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Statistical software</td>
			<td style="width:127px;">Graphpad</td>
			<td style="width:152px;">Prism V5</td>
			<td>http://www.graphpad.com/</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Statistical software</td>
			<td style="width:127px;">Palamedes</td>
			<td style="width:152px;">Psychophysics guide</td>
			<td>http://www.palamedestoolbox.org</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">3D Projection documentation</td>
			<td style="width:127px;">Wikipedia</td>
			<td style="width:152px;"></td>
			<td>http://en.wikipedia.org/wiki/3D_projection</td>
		</tr>
	</tbody>
</table>

measuring sensitivity to viewpoint change with and without stereoscopic cues

The speed and accuracy of object recognition is compromised by a change in viewpoint; demonstrating that human observers are sensitive to this transformation. Here we discuss a novel method for simulating the appearance of an object that has undergone a rotation-in-depth, and include an exposition of the differences between perspective and orthographic projections. Next we describe a method by which human sensitivity to rotation-in-depth can be measured. Finally we discuss an apparatus for creating a vivid percept of a 3-dimensional rotation-in-depth; the Wheatstone Eight Mirror Stereoscope. By doing so, we reveal a means by which to evaluate the role of stereoscopic cues in the discrimination of viewpoint rotated shapes and objects.

Figure 4 plots example results obtained from such an experiment. The y-axis in each figure describes the proportion of times that the test pattern was chosen as having a greater RID. Rather than plotting the absolute number of times this occurred, this is given as a proportion. The x-axis describes the physical RID of the test pattern; remembering that here, the reference pattern was held at a constant 45&#176; RID. The data points represent the proportion of times that the observer chose the test curve ...

Watch this Scientific Journal Video about Measuring Sensitivity to Viewpoint Change with and without Stereoscopic Cues at JoVE.com

Measuring Sensitivity to Viewpoint Change with and without Stereoscopic Cues

We discuss a novel method forviewpoint-rotation of visual stimuli, and demonstrate using a mirror stereoscopethe three-dimensional percept of rotation-in-depth. The technique can be used to investigate the role of stereoscopic cues in encoding viewpoint-rotated figures.

The speed and accuracy of object recognition is compromised by a change in viewpoint; demonstrating that human observers are sensitive to this ...

measuring-sensitivity-to-viewpoint-change-with-without-stereoscopic

Research

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Behavior

A Method for Investigating Age-related Differences in the Functional Connectivity of Cognitive Control Networks Associated with Dimensional Change Card Sort Performance

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional Change Card Sort task, participants switch from sorting cards one way, such as shape, to sorting them a different way, such as color. Adjusting behavior in this way exacts a small performance cost, or switch cost, such that responses are typically slower and more error-prone on switch trials in which the sorting rule changes as compared to repeat trials in which the sorting rule remains the same. The ability to flexibly adjust behavior is often said to develop gradually, in part because behavioral costs such as switch costs typically decrease with increasing age. Why aspects of higher-order cognition, such as behavioral flexibility, develop so gradually remains an open question. One hypothesis is that these changes occur in association with functional changes in broad-scale cognitive control networks. On this view, complex mental operations, such as switching, involve rapid interactions between several distributed brain regions, including those that update and maintain task rules, re-orient attention, and select behaviors. With development, functional connections between these regions strengthen, leading to faster and more efficient switching operations. The current video describes a method of testing this hypothesis through the collection and multivariate analysis of fMRI data from participants of different ages.

This video presents a method of examining age-related changes in functional connectivity of cognitive control networks engaged by targeted tasks/processes. The technique is based on multi-variate analysis of fMRI data.

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional ...

Uncovering Beat Deafness: Detecting Rhythm Disorders with Synchronized Finger Tapping and Perceptual Timing Tasks

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson&#8217;s disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder).

Behavioral tasks that allow for the assessment of perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) are presented. Synchronization of finger tapping to the beat of an auditory stimuli and detecting rhythmic irregularities provides a means of uncovering rhythm disorders.

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here ...

Assessment of Murine Exercise Endurance Without the Use of a Shock Grid: An Alternative to Forced Exercise

Using laboratory mouse models, the molecular pathways responsible for the metabolic benefits of endurance exercise are beginning to be defined. The most common method for assessing exercise endurance in mice utilizes forced running on a motorized treadmill equipped with a shock grid. Animals who quit running are pushed by the moving treadmill belt onto a grid that delivers an electric foot shock; to escape the negative stimulus, the mice return to running on the belt. However, avoidance behavior and psychological stress due to use of a shock apparatus can interfere with quantitation of running endurance, as well as confound measurements of postexercise serum hormone and cytokine levels. Here, we demonstrate and validate a refined method to measure running endurance in na&#239;ve C57BL/6 laboratory mice on a motorized treadmill without utilizing a shock grid. When mice are preacclimated to the treadmill, they run voluntarily with gait speeds specific to each mouse. Use of the shock grid is replaced by gentle encouragement by a human operator using a tongue depressor, coupled with sensitivity to the voluntary willingness to run on the part of the mouse. Clear endpoints for quantifying running time-to-exhaustion for each mouse are defined and reflected in behavioral signs of exhaustion such as splayed posture and labored breathing. This method is a humane refinement which also decreases the confounding effects of stress on experimental parameters.

A method to assess exercise endurance in laboratory mice without the use of a shock grid is demonstrated. This method is a humane refinement that can decrease the confounding effects of stress on experimental parameters.

Using laboratory mouse models, the molecular pathways responsible for the metabolic benefits of endurance exercise are beginning to be defined. The most ...

A Treatment Package without Escape Extinction to Address Food Selectivity

Feeding difficulties and feeding disorders are a commonly occurring problem for young children, particularly children with developmental delays including autism. Behavior analytic interventions for the treatment of feeding difficulties oftentimes include escape extinction as a primary component of treatment. The use of escape extinction, while effective, may be problematic as it is also associated with the emergence of challenging behavior (e.g., extinction burst). Such challenging behavior may be an acceptable side effect in treatment cases where feeding problems are severe and chronic (e.g., failure to thrive). However, in more acute cases (e.g., selective eating), the negative side effect may be unwarranted and undesired. More recent research on the behavioral treatment of food selectivity has begun to evaluate treatments for feeding difficulties that do not include escape extinction (e.g., demand fading, behavioral momentum), with some success. However, research to date reveals individual differences in responsiveness to such treatments and no clear preferable treatment has emerged. This manuscript describes a multi-component treatment package that includes shaping, sequential presentation and simultaneous presentation, for the treatment of food selectivity in four young children with developmental delays. This treatment package extends the literature on the behavioral treatment for food selectivity and offers a multi-component treatment protocol that may be clinically applicable across a range of treatment scenarios and settings.

Feeding difficulties are a common problem for children with developmental disorders, including autism, and behavioral interventions often include escape extinction. Recent research has begun to evaluate treatments that do not include escape extinction. This manuscript describes a multicomponent treatment package that does not use escape extinction to treat feeding difficulties.

Feeding difficulties and feeding disorders are a commonly occurring problem for young children, particularly children with developmental delays including ...

A Method to Test the Effect of Environmental Cues on Mating Behavior in Drosophila melanogaster

An individual's sexual drive is influenced by genotype, experience and environmental conditions. How these factors interact to modulate sexual behaviors remains poorly understood. In Drosophila melanogaster, environmental cues, such as food availability, affect mating activity offering a tractable system to investigate the mechanisms modulating sexual behavior. In D. melanogaster, environmental cues are often sensed via the chemosensory gustatory and olfactory systems. Here, we present a method to test the effect of environmental chemical cues on mating behavior. The assay consists of a small mating arena containing food medium and a mating couple. The mating frequency for each couple is continuously monitored for 24 h. Here we present the applicability of this assay to test environmental compounds from an external source through a pressurized air system as well as manipulation of the environmental components directly in the mating arena. The use of a pressurized air system is especially useful to test the effect of very volatile compounds, while manipulating components directly in the mating arena can be of value to ascertain a compound's presence. This assay can be adapted to answer questions about the influence of genetic and environmental cues on mating behavior and fecundity as well as other male and female reproductive behaviors.

A Method to Test the Effect of Environmental Cues on Mating Behavior in Drosophila melanogaster

We demonstrate an assay to analyze the environmental and genetic cues that influence mating behavior in the fruit fly Drosophila melanogaster.

An individual's sexual drive is influenced by genotype, experience and environmental conditions. How these factors interact to modulate sexual behaviors ...

A Method for Investigating Change Blindness in Pigeons (Columba Livia)

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. While many laboratory procedures have been developed that produce change blindness in humans, the flicker paradigm has emerged as a particularly effective method. In the flicker paradigm, two visual displays are presented in alternation with one another. If successive displays are separated by a short inter-stimulus interval (ISI), change detection is impaired. The simplicity of the procedure and the clear, performance-based operational definition of change blindness make the flicker paradigm well-suited to comparative research using nonhuman animals. Indeed, a variant has been developed that can be implemented in operant chambers to study change blindness in pigeons. Results indicate that pigeons, like humans, are worse at detecting the location of a change if two consecutive displays are separated in time by a blank ISI. Furthermore, pigeons&#39; change detection is consistent with an active, location-by-location search process that requires selective attention. The flicker task thus has the potential to contribute to investigations of the dynamics of pigeons&#39; selective spatial attention in comparison to humans. It also illustrates that the phenomenon of change blindness is not exclusive to humans&#39; visual perception, but may instead be a general consequence of selective attention. Finally, while the useful aspects of attention are widely appreciated and understood, it is also important to acknowledge that they may be accompanied by specific imperfections such as change blindness, and that these imperfections have consequences across a wide range of contexts.

A Method for Investigating Change Blindness in Pigeons Columba Livia

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. This protocol describes a variation on the flicker paradigm for investigating change blindness that is appropriate and effective for research with pigeons.

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. While many ...

Using Clicker Training and Social Observation to Teach Rats to Voluntarily Change Cages

Cage cleaning is a routinely performed husbandry procedure and is known to induce stress in laboratory rats. As stress can have a negative impact on well-being and can affect the comparability and reproducibility of research results, the amount of stress experienced by laboratory animals should be minimized and avoided when possible. Further, the direct contact between the rat and animal caretaker during the cage change bears hygiene risks and therefore possibly negatively impacts the well-being of the rats and the quality of the research. 
Our protocol aims to improve the routinely performed cage changing procedure. For this reason, we present a feasible protocol that enables rats to learn via clicker training and observation to voluntarily change to a clean cage. This training helps to reduce stress caused by the physical disturbance and handling associated with the cage changes and concurrently enables a reduction in direct contact between animal and animal caretaker after the training phase is completed.
The implementation of clicker training to rats is fast and easy. Rats are generally interested in the training and efficiently learn the desired behavior, which entails changing cages through a pipe. Even without training, the rats learn to perform the desired behavior by observation, as 80% of the observational learning group successfully changed cages when tested. The training further helps to establish a relationship of trust between trainer and animal. As hygiene and well-being are both very important in animal experiments, this protocol might also help to improve high-quality research.

This protocol introduces a method of cage change for rats via clicker training. Rats learn the desired behavior not only by direct training but also by observational learning. The implementation of this fast and easy protocol might help to improve well-being and hygiene in rodent facilities.

Cage cleaning is a routinely performed husbandry procedure and is known to induce stress in laboratory rats. As stress can have a negative impact on ...

Modified Blood Collection from Tail Veins of Non-anesthetized Mice with a Vacuum Blood Collection System and Eyeglass Magnifier

Blood sample collection is the basis of experimental animal research. It is of importance to obtain adequate blood samples for various research purposes. The tail veins of mice are small, and it is sometimes difficult to obtain the required blood volume by conventional puncture methods. This study investigates the superiority of repeated blood sample collection from tail veins of mice through use of a vacuum blood collection system and eyeglass magnifier (experimental group) compared to conventional blood sampling methods (conventional group), performed by beginners and experts, respectively. With the help of an eyeglass magnifier, a butterfly needle tip is inserted into the tail vein of each mouse in the experimental group. When the vein is penetrated successfully, a blood sample is collected in the vacuum collection tube by insertion of the rubber end of a butterfly needle into the vacuum blood collection tube. The plunger is then used to collect blood without the help of the eyeglass magnifier in the conventional group. Success rates of blood sample collection by the beginners and experts were shown to be 70% vs. 100% (p &#60; 0.01) in the experimental group and 35% vs. 85% (p &#60; 0.01) in the conventional group. For both beginners and experts, puncture times required for obtaining required blood sample were significantly lower in the experimental group compared to the conventional group (2.40 &#177; 0.75 vs. 2.90 &#177; 0.31, p &#60; 0.05; 1.15 &#177; 0.37 vs. 1.55 &#177; 0.76, p &#60; 0.05). In conclusion, the presented blood sampling technique is feasible and easy to practice and enables frequent sampling of adequate blood volumes from non-anesthetized mice.&#160;

This study reports blood sampling from tail vein in mice using a vacuum extraction tube system with eyeglass magnifier. Our method is easy to practice and could be used for repeat blood sampling in mice.

Blood sample collection is the basis of experimental animal research. It is of importance to obtain adequate blood samples for various research purposes. ...

Assessing the Influence of Personality on Sensitivity to Magnetic Fields in Zebrafish

To orient themselves in their environment, animals integrate a wide array of external cues, which interact with several internal factors, such as personality. Here, we describe a behavioral protocol designed for the study of the influence of zebrafish personality on their orientation response to multiple external environmental cues, specifically water currents and magnetic fields. This protocol aims to understand whether proactive or reactive zebrafish display different rheotactic thresholds (i.e., the flow speed at which the fish start swimming upstream) when the surrounding magnetic field changes its direction. To identify zebrafish with the same personality, fish are introduced in the dark half of a tank connected with a narrow opening to a bright half. Only proactive fish explore the novel, bright environment. Reactive fish do not exit the dark half of the tank. A swimming tunnel with low flow rates is used to determine the rheotactic threshold. We describe two setups to control the magnetic field in the tunnel, in the range of the earth&#8217;s magnetic field intensity: one that controls the magnetic field along the flow direction (one dimension) and one that allows a three-axial control of the magnetic field. Fish are filmed while experiencing a stepwise increase of the flow speed in the tunnel under different magnetic fields. Data on the orientation behavior are collected through a video-tracking procedure and applied to a logistic model to allow the determination of the rheotactic threshold. We report representative results collected from shoaling zebrafish. Specifically, these demonstrate that only reactive, prudent fish show variations of the rheotactic threshold when the magnetic field varies in its direction, while proactive fish do not respond to magnetic field changes. This methodology can be applied to the study of magnetic sensitivity and rheotactic behavior of many aquatic species, both displaying solitary or shoaling swimming strategies.

We describe a behavioral protocol designed to assess how zebrafish&#8217;s personalities influence their response to water currents and weak magnetic fields. Fishes with the same personalities are separated based on their explorative behavior. Then, their rheotactic orientation behavior in a swimming tunnel with a low flow rate and under different magnetic conditions is observed.

To orient themselves in their environment, animals integrate a wide array of external cues, which interact with several internal factors, such as ...

Measuring Biophysical and Psychological Stress Levels Following Visitation to Three Locations with Differing Levels of Nature

Visitation to natural environments has been linked to psychological stress reduction. Although most stress-related research has relied on self-report formats, a growing number of studies now incorporate biological stress-related hormones and catalysts, such as cortisol and &#945;-amylase, to measure levels of stress. Presented here is a protocol to examine the effects on levels of biophysical and psychological stress following visitation to three different locations with differing levels of nature. Biophysical and self-reported psychological stress levels are measured immediately upon entering the selected locations and just prior to the visitors leaving the site. Using a &#34;drool&#34;&#160;method, the biophysical measure consists of 1-2 mL samples of saliva provided by study subjects upon entry to one of three study locations. As prescribed by extant literature, the saliva is collected within a 45 minute time frame following the end of the visitor&#8217;s engagement at the location. Following saliva collection, the samples are labeled and transported to a biological lab. Cortisol is the biophysical variable of interest in this study and measured using an ELISA process with a TECAN plate reader. To measure self-reported stress, the Perceived Stress Questionnaire (PSQ), which reports levels of worry, tension, joy, and perceived demands. Data are collected at all three sites in the late afternoon through early evening. When compared across all three settings, stress levels, as measured by both the biological markers and self-reports, are significantly lower after visitation to the most natural setting.

The purpose of this paper is to identify changes in stress levels after visitation to three different settings and to describe the methods used in identifying stress levels based on measures of salivary cortisol, &#945;-amylase, and a psychological self-report instrument.&#160;

Visitation to natural environments has been linked to psychological stress reduction. Although most stress-related research has relied on self-report ...