This work was funded by the Chinese Scholarship Council (CSC) to K. M., and an infrastructure grant of the Netherlands Research Organization (NWO) to B. H.

<ol>
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The authors have nothing to disclose.

In this article we described two detailed protocols for the virtual-hand and virtual-face illusion paradigms, in which our virtual-face study was the first to replicate the traditional stroking-induced face-ownership illusion in virtual reality, together with representative results from the two paradigms.
The significant synchrony effects indicate that we were successful in inducing illusory ownership for the virtual hand and the virtual face, similar to more traditional illusion paradigms. Being able to reproduce these effects by means of virtual reality techniques has considerable advantages11,24. Virtual-reality techniques are freeing the experimenter from the rather artificial and interruptive stroking procedure and opens new possibilities for experimental manipulations. For example, morphing virtual effectors allowed us to systematically manipulate the impact of the appearance of the virtual hand and the similarity between the virtual and the participant&#39;s real hand, or the facial expression of the virtual face. The impact of agency can also be systematically explored by varying the degree (e.g., immediacy) to which participants can control the movements of the artificial effector.
Another promising avenue for future virtual reality research are first person perspective (1PP) virtual reality experiences. 1PP experiences can create an immense sense of immersion and feeling of presence, on a completely different scale than a third person perspective virtual reality experience25,26,27,28. In 1PP experiences one can truly feel like one is the avatar, that one is literally embodying the avatar. This opens up possibilities for all kinds of manipulations such as detaching parts of a person&#39;s body28, elongating29, rescaling body parts30, or changing a person&#39;s skin color31,32.
As the present and many other findings demonstrate, controlling virtual events in a synchronous fashion strongly increases the perception of these events belonging to one&#39;s own body. For example, our findings from the hand study suggest that immediate control is an important cue for distinguishing between self-produced and other-produced events (i.e., personal agency) and between self-related and other-related events (i.e., body ownership). The findings presented here and elsewhere suggest that bottom-up information plays a decisive role in the emergence of phenomenal self-representation, even for body parts that are not as identity-related as one&#39;s own body part4.
The most critical part of the described protocols is the induction process, which introduces correlations between visual, tactile and motor (i.e., proprioceptive) information-these correlations allows the cognitive system to derive ownership and agency. As these correlations rely on the relative timing of the respective events, such as the delay between the participant&#39;s own movements and the movements of the artificial effector, it is crucial to keep processing delays (especially with regard to the translation of data from the dataglove to the motion of the virtual effector on the screen) to a minimum. With our experiment setup the maximum time delay is around 40 ms, which is hardly noticeable and does not hamper the perception of causality and agency. Shimada, Fukuda, and Hiraki33 have suggested that the critical time window for the occurrence of multisensory integration processes constituting the self-body representation is 300 ms, which means that longer delays are likely to reduce the perception of control over virtual events.
Another important aspect of the protocol is tight experimental control over the participant&#39;s hand or face movements, depending on the paradigm. During induction, active movements of the respective factor are essential, as the required intersensory correlations rely on active explorative movements on the side of the participant. It is thus important to encourage participants to move frequently and to engage in active exploration. In other phases of the experiment, movements can impair the measurement however. For instance, in the virtual-hand illusion paradigm, moving the left hand (from which SCR was recorded) is likely to render measurements of the SCR level noisy and unreliable.
A limitation of the virtual-hand illusion paradigm technique is that, for practical reasons, participants commonly wear a dataglove and orientation tracker during the entire experiment (so to minimize distraction). This may not be comfortable, which in turn may affect the mood or motivation of the participant. One possible solution for that problem would be the use of lighter equipment or custom-made wearables. Another limitation of our current virtual-face illusion paradigm technique is that the equipment only registers head movements but no changes in facial expression. Allowing participants to control the facial expressions of a virtual face is likely to contribute to ownership illusions, but this would require hardware and software that provides reliable detection and categorization of facial expressions in humans-which we do not yet have available in our lab. The use of for example real-time (facial) motion capture utilities would be of great benefit in overcoming these limitations and would allow us to increase sense of agency and ownership of avatars to significantly higher levels.
As suggested by the findings from our study8, people consider various sources of information and update their body representation continuously. They seem to use bottom-up information and top-down information in a compensatory fashion, in the sense that one source of information plays a stronger role in the absence of the other-similar to what has been assumed for the sense of agency34. This provides interesting avenues for future research, as it for instance suggests that ownership can be perceived even for artificial effectors in awkward postures, provided a sufficient degree of surface similarity, or vice versa (i.e., if the artificial effector perfectly aligns with the real effector but differs from it in terms of surface features). The available findings also suggest that the boundaries between self and others are rather plastic, so that features of another person or agent can be perceived as a feature of oneself, provided some degree of synchrony between one&#39;s own behavior and that of the other35,36.

According to Western philosophy, the human self consists of two aspects1: For one, we perceive our own body and our activities in the here and now, which creates a phenomenal self-representation (often called the minimal self). For another, we create more enduring representations of ourselves by storing information about our personal history, integrating new information into the emerging self-concept, and present ourselves to our social environment accordingly, which amounts to the creation of a so-called narrative self. The minimal or phenomenal self has been argued to emerge from two sources of information. One is top-down information about longer-lasting aspects of our body, such as information about the effectors we own or the shape of our face. The other is bottom-up information provided by self-perception in the current situation.
Investigations of the latter were strongly inspired by a clever study of Botvinick and Cohen2. These authors presented human participants with a rubber hand lying in front of them, close to one of their real hands, which however was hidden from view. When the real hand and the rubber hand were stroked in synchrony, so to create intermodal synchronous input, participants tended to perceive the rubber hand as part of their own body-the rubber-hand illusion. Further studies revealed that perceived ownership even went so far that participants would start sweating and trying to withdraw their real hand when the rubber hand was being attacked by a knife or otherwise being &#34;hurt&#34;3.
While Botvinick and Cohen have interpreted their findings to demonstrate that self-perception arises from the processing of bottom-up&#160;information, other authors have argued that the rubber-hand illusion results from the interaction between intermodal synchrony of input, a bottom-up source of information, and stored representations of one&#39;s own hands, a top-down source of information4. The idea is that the stimulus synchrony creates the impression that the real and the rubber hand are one and the same thing, and given that the rubber hand looks like a real hand, this impression is considered reality.
Later research by Kalckert and Ehrsson5 added a visuo-motor component to the rubber hand paradigm, which allows for the investigation of both perceived ownership (the impression that the artificial effector belongs to one&#39;s own body) and perceived agency (the impression that one is producing observed movements oneself). Participants were able to move the index finger of the rubber hand up and down by moving their own index finger, and the synchrony between real and rubber hand finger movements, the mode of movement (passive vs. active mode), and the positioning of the rubber hand (incongruous vs. congruous with regard to the participant&#39;s hand) were manipulated. The findings were taken to provide support for the notion that agency and ownership are functionally distinct cognitive phenomena: while synchrony of movement abolished both sense of ownership and agency, mode of movement only affected agency, and congruency of the rubber hand position had an effect on ownership only. The latter two result were replicated in a follow-up study in which the distance between real and rubber hand in the vertical plane varied6: ownership for the rubber hand decreased as its position increasingly mismatched the participant&#39;s real hand. However, agency was not affected by misplacements of the rubber hand in any condition.
However, recent research using virtual-reality techniques, which provide the participant with active control over the artificial effector, suggests that the role of the top-down part and the distinction between ownership and agency may have been overestimated7,8. These techniques have replaced the rubber hand by a virtual hand presented to participants on a screen in front of them or by means of virtual-reality glasses9. Participants commonly wear a dataglove that translates the movements of the participant&#39;s real hand into the movements of the virtual hand, either synchronously or asynchronously (e.g., with a noticeable delay). Similar to the rubber-hand illusion, synchronous translation strongly increases the participant&#39;s impression that the virtual hand becomes part of his or her own body10.
Employing virtual-reality techniques to create the rubber-hand illusion has several advantages over both the traditional rubber-hand paradigm and the combination of the rubber-hand paradigm with the visuo-motor components11. Moving one&#39;s hand and seeing an effector moving in synchrony with it creates a much more natural situation than facing a rubber hand and being stroked by an experimenter. Moreover, the virtual manipulation provides the experimenter with much more experimental flexibility and much more control over the perceptual relation between perceiving and moving one&#39;s real hand and one&#39;s perception of the event created by the artificial effector. In particular, using virtual techniques facilitates the manipulation of factors that are likely to influence perceived ownership and agency. For instance, the shape of the virtual hand can be modified much easier and faster than the shape of a rubber hand, and the movements of the virtual hand can be of any kind and for instance involve biologically impossible movements. Among other things, this facilitates exploring the limits of the illusion, as the artificial effector need not look like a hand but may be replaced by any kind of static or dynamic event. Of both practical and theoretical interest, a virtual effector is arguably a lot more immersive and feels a lot more real than a rubber hand, which is likely to reduce the necessity to invoke top-down interpretations to make sense of the present situation.
Ownership illusions have, however, not been restricted to hands. Tsakiris12 was the first to use the stroking technique to create the impression of participants that a static face in a picture presented in front of them is their own. Sforza et al.13 have also found evidence for this phenomenon, to which they refer as enfacement: participants incorporated facial features of a partner when their own and their partner&#39;s face were touched in synchrony. The neural mechanism underlying the enfacement illusion has recently been investigated by various researchers; for a comprehensive commentary and interpretation of the findings see Bufalari et al.14. We have recently turned the regular enfacement illusion design into a virtual-reality version (the virtual-face illusion), in which participants are controlling the movements of a virtual face in front of them by moving their own head15.
Here, we describe two experiments that used the virtual-hand illusion7 and the virtual-face illusion15 paradigms, respectively, to investigate self-representation. The virtual-hand experiment included three, completely crossed experimental factors: (a) the synchrony between (felt) real-hand and (seen) virtual-effector movements, which was either close to zero to induce ownership and agency or three seconds as a control condition; (b) the appearance of the virtual effector, which looked either like a human hand or like a rectangle (so to test the effect of real-virtual effector similarity on the ownership illusion); and (c) the opportunity to control the behavior of the virtual effector, which was either nonexistent in a passive condition or direct in an active condition. The virtual-face experiment included two, completely crossed experimental factors: (a) the synchrony between real-face and virtual-face movements, which was either close to zero to induce ownership and agency or three seconds as a control condition; and (b) the facial expression of the virtual face, which was either neutral or showing a smile, to test whether positive mood would lift the mood of the participant and improve his or her performance in a mood-sensitive creativity task.

<table border="0" cellpadding="0" cellspacing="0" width="620">
	<tbody>
		<tr height="399">
			<td height="399" style="height:399px;width:163px;">Vizard (Software controlling the virtual reality environment)</td>
			<td style="width:163px;">Worldviz</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Vizard allows importing hand models and integrating the hand, dataglove and orientation tracker modules through self-written command scripts. These scripts can be run to control the presentation of the virtual hand in the virtual environment, the appearance of the hand and the way it moves; they also control vibrator activities.</td>
		</tr>
		<tr height="189">
			<td height="189" style="height:189px;width:163px;">Cybertouch (Dataglove)</td>
			<td style="width:163px;">CyberGlove&#160;Systems</td>
			<td style="width:127px;">Cybertouch</td>
			<td style="width:169px;">Participants wear this dataglove to control the movements of the virtual hand in the virtual environment. Measurement frequency = 100 Hz; Vibrator vibrational frequency = 0-125 Hz.</td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:163px;">Intersense (Orientation tracker)</td>
			<td style="width:163px;">Thales</td>
			<td style="width:127px;">InertiaCube3</td>
			<td style="width:169px;">Participants wear the Intersense tracker to permit monitoring the orientation of their real hand (data that the used dataglove does not provide). Update rate = 180 Hz.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:163px;">Biopac system (Physiological measurement device)</td>
			<td style="width:163px;">Biopac</td>
			<td style="width:127px;">MP100</td>
			<td style="width:169px;">The hardware to record skin conductance response.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:163px;">Acquisition unit (Physiological measurement device)</td>
			<td style="width:163px;">Biopac</td>
			<td style="width:127px;">BN-PPGED</td>
			<td style="width:169px;">The hardware to record skin conductance response.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:163px;">Remote transmitter (Physiological measurement device)</td>
			<td style="width:163px;">Biopac</td>
			<td style="width:127px;">BN-PPGED-T</td>
			<td style="width:169px;">Participants wear the remote transmitter on their left hand wrist; it sends signals to the Biopac acqusition unit.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:163px;">Electrode (Physiological measurement device)</td>
			<td style="width:163px;">Biopac</td>
			<td style="width:127px;">EL507</td>
			<td style="width:169px;">Participants wear&#160; the electrode on their fingers; it picks up skin conductance signals.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:163px;">AcqKnowledge (Software controlling acquisition of physiological data)</td>
			<td style="width:163px;">Biopac</td>
			<td style="width:127px;">ACK100W, ACK100M</td>
			<td style="width:169px;">The software to record skin conductance responses.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:163px;">Box</td>
			<td style="width:163px;">Custom-made</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Participants put their right hand into the box</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:163px;">Computer</td>
			<td style="width:163px;">Any standard PC + Screen (could be replaced by VR glasses/devive)</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Necessary to present the virtual reality environment, including the virtual hand.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:163px;">Cape</td>
			<td style="width:163px;">Custom-made</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Participants wear this cape on their right shoulder so they cannot see their right hand and arm.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:163px;">Kinect (Head position tracker)</td>
			<td style="width:163px;">Microsoft</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Kinect tracks the X-Y position of the participant&#39;s head. Recording frame rate = 30 Hz.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:163px;">FAAST (Head position tracker software)</td>
			<td style="width:163px;">MXR</td>
			<td style="width:127px;">FAAST 1.0</td>
			<td style="width:169px;">Software controls Kinect and is used to track the position of the participant&#39;s head.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:163px;">Intersense (Head orientation tracker)</td>
			<td style="width:163px;">Thales</td>
			<td style="width:127px;">InertiaCube3</td>
			<td style="width:169px;">Intersense tracks rotational orientation changes of the participant&#39;s head. Update rate = 180 Hz.</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:163px;">Facegen (Face-model generator software)</td>
			<td style="width:163px;">Singular Inversions</td>
			<td>FaceGen&#160;Modeller&#160;</td>
			<td style="width:169px;">Facegen allows creating various virtual faces by varying various parameters, such as male/female-ness or skin color.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:163px;">Cap</td>
			<td style="width:163px;">Any cap, e.g., baseball cap</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">The cap carries the Intersense orientation tracker.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:163px;">Computer</td>
			<td style="width:163px;">Any standard PC + Screen</td>
			<td style="width:127px;"></td>
			<td style="width:169px;">Necessary to present the virtual reality environment, including the virtual head.</td>
		</tr>
	</tbody>
</table>

creating virtual-hand and virtual-face illusions to investigate self-representation

Studies investigating how people represent themselves and their own body often use variants of &#34;ownership illusions&#34;, such as the traditional rubber-hand illusion or the more recently discovered enfacement illusion. However, these examples require rather artificial experimental setups, in which the artificial effector needs to be stroked in synchrony with the participants&#39; real hand or face&#8212;a situation in which participants have no control over the stroking or the movements of their real or artificial effector. Here, we describe a technique to establish ownership illusions in a setup that is more realistic, more intuitive, and of presumably higher ecological validity. It allows creating the virtual-hand illusion by having participants control the movements of a virtual hand presented on a screen or in virtual space in front of them. If the virtual hand moves in synchrony with the participants&#39; own real hand, they tend to perceive the virtual hand as part of their own body. The technique also creates the virtual-face illusion by having participants control the movements of a virtual face in front of them, again with the effect that they tend to perceive the face as their own if it moves in synchrony with their real face. Studying the circumstances that illusions of this sort can be created, increased, or reduced provides important information about how people create and maintain representations of themselves.

Virtual-hand Illusion
We ran several experiments using the virtual-hand illusion paradigm, to investigate how people represent their bodies, in this case their hands. The number of tested participants depended on the amount of conditions, usually around 20 participants for each condition. Here we provide relevant results for one of the most elaborated studies we conducted in our lab. We will restrict our discussion to the subjective data, the average of the Likert-scale responses to the four ownership questions (O1-O4) and the Likert-scale response to the agency question (A1).
In this study8, we systematically investigated the effects of synchrony (synchronous vs. asynchronous), appearance of the virtual effector (virtual hand vs. rectangle), and activity (passive vs. active) on the participants&#39; sense of ownership and sense of agency (all conditions were tested within participants). The results were the same for ownership and agency. As indicated in Figure 2, perceived ownership and agency were stronger if real and virtual hand moved in synchrony [F(1,43) = 48.35; p &#60; 0.001; and F(1,43) = 54.64; p &#60; 0.001; for ownership and agency, respectively], if the virtual effector was a hand than if it was a rectangle [F(1,43)=14.85; p &#60; 0.001; and F(1,43) = 6.94; p &#60; 0.02], and if the participant was active rather than passive [F(1,43) = 9.32; p &#60; 0.005; and F(1,43) = 79.60; p &#60; 0.001]. The synchrony effect replicates the standard virtual-hand illusion.
<img alt="Figure 2" src="/files/ftp_upload/54784/54784fig2.jpg" /> 
Figure 2: Ownership and agency ratings as a function of synchrony, appearance of the virtual effector, and activity of the participant. <a href="http://cloudflare.jove.com/files/ftp_upload/54784/54784fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/54784/54784fig3.jpg" /> 
Figure 3: Ownership and agency ratings as a function of synchrony and activity of the participant. Note that the synchrony effect is more pronounced for active participants. <a href="http://cloudflare.jove.com/files/ftp_upload/54784/54784fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Even more interestingly, both ownership and agency showed a significant interaction between activity and synchrony [F(1,43) = 13.68; p = 0.001; and F(1,43) = 23.36; p &#60; 0.001; see Figure 3], but not between appearance and synchrony. This pattern suggests that activity plays a more dominant role for the ownership and the illusion than appearance does, it even showed that the illusory ownership perception is stronger in virtual than traditional rubber hand illusion paradigm. According to Hommel22, objective agency (i.e., the degree to which an external event can objectively be controlled) contributes to both subjective ownership and subjective agency, which explains why in this experiment, active, synchronous control over the virtual effector increased both subjective ownership and subjective agency.
While appearance failed to interact with synchrony, suggesting that the ownership illusion does not rely on appearance, it did produce a main effect. This indicates that appearance does have an impact on perceived ownership. It makes sense to assume that people have general expectations about what external objects might or might not be a plausible part of their body, which supports ownership perception in general but does not moderate the effect of synchrony. We thus conclude that multiple sources of information contribute to the sense of subjective ownership: general top-down expectations and bottom-up synchrony information. The relationship between these two informational sources does not seem to be interactive but compensatory, so that general expectations may dominate in the absence of synchrony, and vice versa.
Virtual-face Illusion
In another study, we investigated how people represent their face. We were able to replicate the traditional enfacement illusion in a virtual environment, which we refer to as the virtual-face illusion12. We further investigated whether people adopt the mood expressed by a virtual face they identify with. There was one within-participant factor-synchrony (synchronous vs. asynchronous) and one between-participant factor-facial expression (happy vs. neutral). The IOS ratings before the induction phase were subtracted from the IOS ratings after the induction phase, also the Affect Grid ratings before the induction phase were subtracted from the Affect Grid ratings after the induction phase, and these rating changes were used as the IOS and affect grid results.
The analysis of the ownership scores (O1-4), the agency scores (A1-2), and the IOS scale18 changes all showed main effects of synchrony [F(1,58) = 38.24; p &#60; 0.001; F(1,58) = 77.33; p &#60; 0.001; and F(1,58) = 43.63; p &#60; 0.001; respectively], showing that synchrony between one&#39;s own head movements and the movements of the virtual face increased perceived ownership and agency, and facilitated the integration of the other&#39;s face into one&#39;s own self (see Figure 4). Synchrony also improved mood, as indicated by a synchrony effect on the affect grid19 changes [F(1,58) = 7.99; p &#60; 0.01].
<img alt="Figure 4" src="/files/ftp_upload/54784/54784fig4.jpg" /> 
Figure 4: Ownership and agency ratings, as well as IOS changes, as a function of synchrony. Note that positive IOS changes imply an increase of integration of the other into one&#39;s self. <a href="http://cloudflare.jove.com/files/ftp_upload/54784/54784fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" src="/files/ftp_upload/54784/54784fig5.jpg" /> 
Figure 5: Affect grid changes (positive values imply positive-going affect) and flexibility scores in the AUT, as a function of synchrony and the expression of the virtual face. Note that the interactions between synchrony and expression are driven by more positive-going mood and particularly good flexibility performance for the combination of synchrony and happy virtual face. <a href="http://cloudflare.jove.com/files/ftp_upload/54784/54784fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
There were significant main effects of the facial expression on IOS changes, affect grid changes, and flexibility in the AUT20,21,23but more important was the fact that the affect grid changes and the flexibility score interacted with synchrony [F(1,58) = 4.40; p &#60; 0.05; and F(1,58) = 4.98; p &#60; 0.05; respectively]. As shown in Figure 5, participants reported improved mood and showed more creative behavior after enfacing (i.e., synchronously moving with) a happy face as compared to the conditions where they moved asynchronously with a happy face or synchronously with a neutral face.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>F/P/PES</td>
			<td>EFF</td>
			<td>ACT</td>
			<td>SYN</td>
			<td>EFF*ACT</td>
			<td>EFF*SYN</td>
			<td>ACT*SYN</td>
			<td>EFF*ACT*SYN</td>
		</tr>
		<tr>
			<td rowspan="3">O1</td>
			<td>11.66</td>
			<td>10.11</td>
			<td>45.38</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>10.08</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.001</td>
			<td>0.003</td>
			<td>&#60;0.001</td>
			<td>0.003</td>
		</tr>
		<tr>
			<td>0.21</td>
			<td>0.19</td>
			<td>0.51</td>
			<td>0.19</td>
		</tr>
		<tr>
			<td rowspan="3">O2</td>
			<td rowspan="3"></td>
			<td>5.37</td>
			<td>47.65</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.025</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>0.11</td>
			<td>0.53</td>
		</tr>
		<tr>
			<td rowspan="3">O3</td>
			<td>10.75</td>
			<td rowspan="3"></td>
			<td>41.30</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>9.81</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.002</td>
			<td>&#60;0.001</td>
			<td>0.003</td>
		</tr>
		<tr>
			<td>0.20</td>
			<td>0.49</td>
			<td>0.19</td>
		</tr>
		<tr>
			<td rowspan="3">O4</td>
			<td>12.86</td>
			<td>17.17</td>
			<td>15.12</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>10.60</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.001</td>
			<td>&#60;0.001</td>
			<td>&#60;0.001</td>
			<td>0.002</td>
		</tr>
		<tr>
			<td>0.23</td>
			<td>0.29</td>
			<td>0.26</td>
			<td>0.20</td>
		</tr>
		<tr>
			<td rowspan="3">O1-4</td>
			<td>14.85</td>
			<td>9.32</td>
			<td>48.35</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>13.68</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>&#60;0.001</td>
			<td>0.004</td>
			<td>&#60;0.001</td>
			<td>0.001</td>
		</tr>
		<tr>
			<td>0.26</td>
			<td>0.18</td>
			<td>0.53</td>
			<td>0.24</td>
		</tr>
		<tr>
			<td rowspan="3">A1</td>
			<td>6.94</td>
			<td>79.60</td>
			<td>54.64</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>23.36</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.012</td>
			<td>&#60;0.001</td>
			<td>&#60;0.001</td>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>0.14</td>
			<td>0.65</td>
			<td>0.56</td>
			<td>0.37</td>
		</tr>
	</tbody>
</table>
Table 1: F, P and Partial Eta squared (PES) values for the effects of the questionnaire item ratings, with df = 43. Factors are EFF: virtual effector (virtual hand vs. rectangle); ACT: activity (active exploration vs. passive stimulation); and SYN: synchrony (synchronous vs. asynchronous). Only results for significant effects are shown.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>M/SE</td>
			<td>H-P-SY</td>
			<td>H-P-AS</td>
			<td>H-A-SY</td>
			<td>H-A-AS</td>
			<td>R-P-SY</td>
			<td>R-P-AS</td>
			<td>R-A-SY</td>
			<td>R-A-AS</td>
		</tr>
		<tr>
			<td rowspan="2">O1-4</td>
			<td>4.37</td>
			<td>3.44</td>
			<td>5.09</td>
			<td>3.50</td>
			<td>3.79</td>
			<td>3.14</td>
			<td>4.68</td>
			<td>3.05</td>
		</tr>
		<tr>
			<td>0.20</td>
			<td>0.23</td>
			<td>0.19</td>
			<td>0.25</td>
			<td>0.23</td>
			<td>0.23</td>
			<td>0.20</td>
			<td>0.21</td>
		</tr>
		<tr>
			<td rowspan="2">A1</td>
			<td>3.59</td>
			<td>3.11</td>
			<td>6.36</td>
			<td>4.36</td>
			<td>3.07</td>
			<td>2.57</td>
			<td>6.09</td>
			<td>3.80</td>
		</tr>
		<tr>
			<td>0.30</td>
			<td>0.32</td>
			<td>0.15</td>
			<td>0.33</td>
			<td>0.28</td>
			<td>0.27</td>
			<td>0.24</td>
			<td>0.33</td>
		</tr>
	</tbody>
</table>
Table 2: Means (M) and standard errors (SE) for the ownership and agency ratings in all eight conditions. H: hand; R: rectangle; A: active; P: passive; SY: synchronous; AS: asynchronous.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>F/P/PES</td>
			<td>Facial expression</td>
			<td>Synchrony</td>
			<td>Facial expression* Synchrony</td>
		</tr>
		<tr>
			<td rowspan="3">Ownership (O1-4)</td>
			<td rowspan="3"></td>
			<td>38.24</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>0.40</td>
		</tr>
		<tr>
			<td rowspan="3">Agency (A1-2)</td>
			<td rowspan="3"></td>
			<td>77.33</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>&#60;0.001</td>
		</tr>
		<tr>
			<td>0.57</td>
		</tr>
		<tr>
			<td rowspan="3">IOS Changes</td>
			<td>4.03</td>
			<td>43.63</td>
			<td rowspan="3"></td>
		</tr>
		<tr>
			<td>0.049</td>
			<td>0.001</td>
		</tr>
		<tr>
			<td>0.07</td>
			<td>0.43</td>
		</tr>
		<tr>
			<td rowspan="3">Affect Grid Valence Changes</td>
			<td>6.06</td>
			<td>7.99</td>
			<td>4.40</td>
		</tr>
		<tr>
			<td>0.017</td>
			<td>0.007</td>
			<td>0.041</td>
		</tr>
		<tr>
			<td>0.10</td>
			<td>0.13</td>
			<td>0.07</td>
		</tr>
		<tr>
			<td rowspan="3">AUT-Flexibility</td>
			<td>5.42</td>
			<td rowspan="3"></td>
			<td>4.98</td>
		</tr>
		<tr>
			<td>0.024</td>
			<td>0.03</td>
		</tr>
		<tr>
			<td>0.09</td>
			<td>0.08</td>
		</tr>
		<tr>
			<td rowspan="3">AUT-Fluency</td>
			<td rowspan="3"></td>
			<td rowspan="3"></td>
			<td>7.89</td>
		</tr>
		<tr>
			<td>0.007</td>
		</tr>
		<tr>
			<td>0.12</td>
		</tr>
	</tbody>
</table>
Table 3: F, P and Partial Eta squared (PES) values for relevant dependent measures, with df = 58 for questionnaire and IOS results, and df = 56 for the valence dimension of the affect grid mood and AUT results. Only results for significant effects are shown.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>M/SE</td>
			<td>Neutral-SY</td>
			<td>Neutral-AS</td>
			<td>Happy-SY</td>
			<td>Happy-AS</td>
		</tr>
		<tr>
			<td rowspan="2">Ownership (O1-4)</td>
			<td>2.88</td>
			<td>2.03</td>
			<td>3.38</td>
			<td>2.36</td>
		</tr>
		<tr>
			<td>0.27</td>
			<td>0.16</td>
			<td>0.23</td>
			<td>0.22</td>
		</tr>
		<tr>
			<td rowspan="2">Agency (A1-2)</td>
			<td>5.90</td>
			<td>4.25</td>
			<td>6.16</td>
			<td>4.08</td>
		</tr>
		<tr>
			<td>0.20</td>
			<td>0.25</td>
			<td>0.13</td>
			<td>0.32</td>
		</tr>
		<tr>
			<td rowspan="2">IOS Changes</td>
			<td>0.37</td>
			<td>-0.80</td>
			<td>1.00</td>
			<td>-0.40</td>
		</tr>
		<tr>
			<td>0.21</td>
			<td>0.25</td>
			<td>0.20</td>
			<td>0.24</td>
		</tr>
		<tr>
			<td rowspan="2">Affect Grid Valence Changes</td>
			<td>-1.07</td>
			<td>-1.33</td>
			<td>0.60</td>
			<td>-1.20</td>
		</tr>
		<tr>
			<td>0.42</td>
			<td>0.33</td>
			<td>0.39</td>
			<td>0.31</td>
		</tr>
		<tr>
			<td rowspan="2">AUT-Flexibility</td>
			<td>5.87</td>
			<td>6.07</td>
			<td>7.43</td>
			<td>6.10</td>
		</tr>
		<tr>
			<td>0.31</td>
			<td>0.37</td>
			<td>0.29</td>
			<td>0.39</td>
		</tr>
		<tr>
			<td rowspan="2">AUT-Fluency</td>
			<td>7.27</td>
			<td>8.27</td>
			<td>9.73</td>
			<td>7.37</td>
		</tr>
		<tr>
			<td>0.51</td>
			<td>0.68</td>
			<td>0.68</td>
			<td>0.49</td>
		</tr>
	</tbody>
</table>
Table 4: Means (M) and standard errors (SE) for relevant dependent measures in the four conditions. Neutral: neutral facial expression; Happy: happy facial expression; SY: synchronous; AS: asynchronous.

Watch this Scientific Journal Video about Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation at JoVE.com

Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation

Here, we describe virtual-hand and virtual-face illusion paradigms that can be used to study body-related self-perception/-representation. They have already been used in various studies to demonstrate that, under specific conditions, a virtual hand or face can be incorporated into one&#39;s body representation, suggesting that body representations are rather flexible.

Studies investigating how people represent themselves and their own body often use variants of &#34;ownership illusions&#34;, such as the traditional ...

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13.1K Views.  Leiden University. Here, we describe virtual-hand and virtual-face illusion paradigms that can be used to study body-related self-perception/-representation. They have already been used in various studies to demonstrate that, under specific conditions, a virtual hand or face can be incorporated into one's body representation, suggesting that body representations are rather flexible.

Video: Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation

Creating Dynamic Images of Short-lived Dopamine Fluctuations with lp-ntPET:  Dopamine Movies of Cigarette Smoking

We describe experimental and statistical steps for creating dopamine movies of the brain from dynamic PET data. The movies represent minute-to-minute fluctuations of dopamine induced by smoking a cigarette. The smoker is imaged during a natural smoking experience while other possible confounding effects (such as head motion, expectation, novelty, or aversion to smoking repeatedly) are minimized.
We present the details of our unique analysis. Conventional methods for PET analysis estimate time-invariant kinetic model parameters which cannot capture short-term fluctuations in neurotransmitter release. Our analysis - yielding a dopamine movie - is based on our work with kinetic models and other decomposition techniques that allow for time-varying parameters 1-7. This aspect of the analysis - temporal-variation - is key to our work. Because our model is also linear in parameters, it is practical, computationally, to apply at the voxel level. The analysis technique is comprised of five main steps: pre-processing, modeling, statistical comparison, masking and visualization. Preprocessing is applied to the PET data with a unique 'HYPR' spatial filter 8 that reduces spatial noise but preserves critical temporal information. Modeling identifies the time-varying function that best describes the dopamine effect on 11C-raclopride uptake. The statistical step compares the fit of our (lp-ntPET) model 7 to a conventional model 9. Masking restricts treatment to those voxels best described by the new model. Visualization maps the dopamine function at each voxel to a color scale and produces a dopamine movie. Interim results and sample dopamine movies of cigarette smoking are presented.

We present a novel PET imaging approach for capturing dopamine fluctuations induced by cigarette smoking. Subjects smoke in the PET scanner. Dynamic PET images are modeled voxel-by-voxel in time by lp-ntPET, which includes a time-varying dopamine term. The results are 'movies' of dopamine fluctuations in the striatum during smoking.

We describe experimental and statistical steps for creating dopamine movies of the brain from dynamic PET data. The movies represent minute-to-minute ...

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 ...

A Cognitive Paradigm to Investigate Interference in Working Memory by Distractions and Interruptions

Goal-directed behavior is often impaired by interference from the external environment, either in the form of distraction by irrelevant information that one attempts to ignore, or by interrupting information that demands attention as part of another (secondary) task goal. Both forms of external interference have been shown to detrimentally impact the ability to maintain information in working memory (WM). Emerging evidence suggests that these different types of external interference exert different effects on behavior and may be mediated by distinct neural mechanisms. Better characterizing the distinct neuro-behavioral impact of irrelevant distractions versus attended interruptions is essential for advancing an understanding of top-down attention, resolution of external interference, and how these abilities become degraded in healthy aging and in neuropsychiatric conditions. This manuscript describes a novel cognitive paradigm developed the Gazzaley lab that has now been modified into several distinct versions used to elucidate behavioral and neural correlates of interference, by to-be-ignored distractors versus to-be-attended interruptors. Details are provided on variants of this paradigm for investigating interference in visual and auditory modalities, at multiple levels of stimulus complexity, and with experimental timing optimized for electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) studies. In addition, data from younger and older adult participants obtained using this paradigm is reviewed and discussed in the context of its relationship with the broader literatures on external interference and age-related neuro-behavioral changes in resolving interference in working memory.

A novel cognitive paradigm is developed to elucidate behavioral and neural correlates of interference by to-be-ignored distractors versus interference by to-be-attended interruptors during a working memory task. In this manuscript, several variants of this paradigm are detailed, and data obtained with this paradigm in younger/older adult participants is reviewed.

Goal-directed behavior is often impaired by interference from the external environment, either in the form of distraction by irrelevant information that ...

The Deese-Roediger-McDermott (DRM) Task: A Simple Cognitive Paradigm to Investigate False Memories in the Laboratory

The Deese,&#160;Roediger and McDermott&#160;(DRM) task is a false memory paradigm in which subjects are presented with lists of semantically related words (e.g., nurse, hospital, etc.) at encoding. After a delay, subjects are asked to recall or recognize these words. In the recognition memory version of the task, subjects are asked whether they remember previously presented words, as well as related (but never presented) critical lure words (&#39;doctor&#39;). Typically, the critical word is recognized with high probability and confidence. This false memory effect has been robustly demonstrated across short (e.g., immediate, 20 min) and long (e.g., 1, 7, 60 d) delays between encoding and memory testing. A strength of using this task to study false memory is its simplicity and short duration. If encoding and retrieval components of the task occur in the same session, the entire task can take as little as 2 - 30 min. However, although the DRM task is widely considered a &#39;false memory&#39; paradigm, some researchers consider DRM illusions to be based on the activation of semantic memory networks in the brain, and argue that such semantic gist-based false memory errors may actually be useful in some scenarios (e.g., remembering the forest for the trees; remembering that a word list was about &#34;doctors&#34;, even though the actual word &#34;doctor&#34; was never presented for study). Remembering the gist of experience (instead of or along with individual details) is arguably an adaptive process and this task has provided a great deal of knowledge about the constructive, adaptive nature of memory. Therefore, researchers should use caution when discussing the overall reach and implications of their experiments when using this task to study &#39;false memory&#39;, as DRM memory errors may not adequately reflect false memories in the real world, such as false memory in eyewitness testimony, or false memories of sexual abuse.

The Deese-Roediger-McDermott DRM Task: A Simple Cognitive Paradigm to Investigate False Memories in the Laboratory

Here we present the Deese,&#160;Roediger and McDermott&#160;(DRM) task, a tool to study false memories in the laboratory. Subjects study lists of semantically related words (e.g.,&#160;nurse, sick, etc.), and later falsely remember an unstudied word (doctor) that represents the gist, or theme, of the word list.

The Deese,&#160;Roediger and McDermott&#160;(DRM) task is a false memory paradigm in which subjects are presented with lists of semantically related words ...

Using a Virtual Store As a Research Tool to Investigate Consumer In-store Behavior

People&#39;s responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various approaches (e.g., surveys or laboratory settings) to study in-store behaviors, but the external validity of these is limited by their poor capability to resemble realistic choice environments. In addition, building a real store to meet experimental conditions while controlling for undesirable effects is costly and highly difficult. A virtual store developed by virtual reality techniques potentially transcends these limitations by offering the simulation of a 3D virtual store environment in a realistic, flexible, and cost-efficient way. In particular, a virtual store interactively allows consumers (participants) to experience and interact with objects in a tightly controlled yet realistic setting. This paper presents the key elements of using a desktop virtual store to study in-store consumer behavior. Descriptions of the protocol steps to: 1) build the experimental store, 2) prepare the data management program, 3) run the virtual store experiment, and 4) organize and export data from the data management program are presented. The virtual store enables participants to navigate through the store, choose a product from alternatives, and select or return products. Moreover, consumer-related shopping behaviors (e.g., shopping time, walking speed, and number and type of products examined and bought) can also be collected. The protocol is illustrated with an example of a store layout experiment showing that shelf length and shelf orientation influence shopping- and movement-related behaviors. This demonstrates that the use of a virtual store facilitates the study of consumer responses. The virtual store can be especially helpful when examining factors that are costly or difficult to change in real life (e.g., overall store layout), products that are not presently available in the market, and routinized behaviors in familiar environments.

This paper describes the use of a desktop virtual store to create virtual shopping environments to investigate in-store consumer behavior. A description of the protocol to build and run experiments, example results from an experiment concerning store layout, and important considerations when conducting virtual store experiments are presented.

People&#39;s responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various ...

Creating and Applying a Reference to Facilitate the Discussion and Classification of Proteins in a Diverse Group

Related proteins that have been studied in different labs using varying organisms may lack a uniform system of nomenclature and classification, making it difficult to discuss the group as a whole and to place new sequences into the appropriate context. Developing a reference that prioritizes important sequence features related to structure and/or activity can be used in addition to established names to add some coherency to a diverse group of proteins. This paper uses the cysteine-stabilized alpha-helix (CS-&#945;&#946;) superfamily as an example to show how a reference generated in&#160;spreadsheet software can clarify relationships between existing proteins in the superfamily, as well as facilitate the addition of new sequences. It also shows how the reference can help to refine sequence alignments generated in commonly used software, which impacts the validity of phylogenetic analyses. The use of a reference will likely be most helpful for protein groups that include highly divergent sequences from a broad spectrum of taxa, with features that are not adequately captured by molecular analyses.

The goal of this protocol is to develop a reference for divergent proteins in a group that lacks coherent criteria for nomenclature and classification. This reference will facilitate analyses and discussion of the group as a whole and can be used in addition to established names.

Related proteins that have been studied in different labs using varying organisms may lack a uniform system of nomenclature and classification, making it ...

Elevated Plus Maze Test Combined with Video Tracking Software to Investigate the Anxiolytic Effect of Exogenous Ketogenic Supplements

The overall goal of this study is to describe the methodology of the elevated plus maze (EPM) test in combination with a video tracking software. The purpose of the method is to document the effect of various potential anxiolytic treatments on laboratory rodent models. The EPM test is based on the rodents&#39; proclivity toward protected, enclosed dark spaces and unconditioned fear of open spaces and heights, and their innate intense motivation to explore novel environments. The EPM test is a widely used behavioral test for investigating the anxiolytic or anxiogenic responses of rodents given drugs that are known to affect behavior. Observation demonstrating a decreased proportion of time spent on closed arms, an increased proportion of time spent on open arms, a reduced number of entries to closed arms, and an elevated number of entries to open arms measured by the EPM test may reflect reduced anxiety levels. Using this method, the effect of exogenous ketone supplements on anxiety-related behavior is tested in Sprague Dawley (SPD) rats. Exogenous ketone supplements are chronically fed to the rats for 83 days or subchronically and acutely orally gavaged, daily for 7 days, before conducting the EPM test. Behavioral data collection is performed using the SMART video tracking system by a blinded observer at the end of the treatments. The main findings indicate that the EPM test is an effective method to detect the ketone supplement-induced anxiolytic effect and can be considered a sensitive measure to assess changes in anxiety behavior associated with drug- or metabolic-based therapies.

Here, we present a protocol to investigate changes in the anxiety level of rodent animal models. The elevated plus maze (EPM) test, used together with a video tracking software, provides a reliable method to document the effect of various potential anxiolytic treatments in preclinical laboratory scenarios.

The overall goal of this study is to describe the methodology of the elevated plus maze (EPM) test in combination with a video tracking software. The ...

Using the FishSim Animation Toolchain to Investigate Fish Behavior: A Case Study on Mate-Choice Copying In Sailfin Mollies

Over the last decade, employing computer animations for animal behavior research has increased due to its ability to non-invasively manipulate the appearance and behavior of visual stimuli, compared to manipulating live animals. Here, we present the FishSim Animation Toolchain, a software framework developed to provide researchers with an easy-to-use method for implementing 3D computer animations in behavioral experiments with fish. The toolchain offers templates to create virtual 3D stimuli of five different fish species. Stimuli are customizable in both appearance and size, based on photographs taken of live fish. Multiple stimuli can be animated by recording swimming paths in a virtual environment using a video game controller. To increase standardization of the simulated behavior, the prerecorded swimming path may be replayed with different stimuli. Multiple animations can later be organized into playlists and presented on monitors during experiments with live fish.
In a case study with sailfin mollies (Poecilia latipinna), we provide a protocol on how to conduct a mate-choice copying experiment with FishSim. We utilized this method to create and animate virtual males and virtual model females, and then presented these to live focal females in a binary choice experiment. Our results demonstrate that computer animation may be used to simulate virtual fish in a mate-choice copying experiment to investigate the role of female gravid spots as an indication of quality for a model female in mate-choice copying.
Applying this method is not limited to mate-choice copying experiments but can be used in various experimental designs. Still, its usability depends on the visual capabilities of the study species and first needs validation. Overall, computer animations offer a high degree of control and standardization in experiments and bear the potential to &#39;reduce&#39; and &#39;replace&#39; live stimulus animals as well as to &#39;refine&#39; experimental procedures.

Using the FishSim Animation Toolchain to Investigate Fish Behavior: A Case Study on Mate-Choice Copying In Sailfin Mollies

Using the novel FishSim Animation Toolchain, we present a protocol for non-invasive visual manipulation of public information in the context of mate-choice copying in sailfin mollies. FishSim Animation Toolchain provides an easy-to-use framework for the design, animation and presentation of computer-animated fish stimuli for behavioral experiments with live test fish.

Over the last decade, employing computer animations for animal behavior research has increased due to its ability to non-invasively manipulate the ...

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. ...

Using a Virtual Reality Walking Simulator to Investigate Pedestrian Behavior

To cross a road successfully, individuals must coordinate their movements with moving vehicles. This paper describes use of a walking simulator in which people walk on a treadmill to intercept gaps between two moving vehicles in an immersive virtual environment. Virtual reality allows for a safe and ecologically varied investigation of gap crossing behavior. Manipulating the initial starting distance can further the understanding of a participant&#8217;s speed regulation while approaching a gap. The speed profile may be assessed for various gap crossing variables, such as initial distance, vehicle size, and gap size. Each walking simulation results in a position/time series that can inform how velocity is adjusted differently depending on the gap characteristics. This methodology can be used by researchers investigating pedestrian behavior and behavioral dynamics while employing human participants in a safe and realistic setting.

This protocol describes use of a walking simulator that serves as a safe and ecologically valid method to study pedestrian behavior in the presence of moving traffic.

To cross a road successfully, individuals must coordinate their movements with moving vehicles. This paper describes use of a walking simulator in which ...