Name: visualization method for proprioceptive drift on a 2d plane using support vector machine
Uploaded: 2016-10-27T13:00:00
Description: Watch this Scientific Journal Video about Visualization Method for Proprioceptive Drift on a 2D Plane Using Support Vector Machine at JoVE.com

This research was supported by the Center of Innovation Program from the Japan Science and Technology Agency, JST.

All aspects of the experiment were approved by the Ethical Committee of Tokyo Institute of Technology.
1. Experimental Setup
<ol>
	<li>Material and Setup for Measuring Proprioceptive Drift.
	<ol>
		<li>Obtain a stand that can hold a 100 x 100 cm plate vertically (Figure 1).</li>
		<li>Obtain a chair on which the participant can sit comfortably during the experiment.</li>
		<li>Obtain a 100 x 100 cm acrylic mirror and matte blackboard.</li>
		<li>Obtain the position tracker (for example, SLC-C02,...

<ol>
	<li>Alimardani, M., Nishio, S., Ishiguro, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanlike+robot+hands+controlled+by+brain+activity+arouse+illusion+of+ownership+in+operators.">Humanlike robot hands controlled by brain activity arouse illusion of ownership in operators.</a> Sci. Rep. 3, 2396 (2013).</li><li>Fernando, C. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+TELESAR+V+for+transferring+bodily+consciousness+in+telexistence.">Design of TELESAR V for transferring bodily consciousness in telexistence.</a> , 5112-5118 (2012).</li><li>Ramachandran, V. S., Rogers-Ramachandran, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synaesthesia+in+phantom+limbs+induced+with+mirrors.">Synaesthesia in phantom limbs induced with mirrors.</a> Proc. Biol. Sci. 263, 377-386 (1996).</li><li>Chan, B. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mirror+therapy+for+phantom+limb+pain.">Mirror therapy for phantom limb pain.</a> N.Engl.J.Med. 357 (21), 2206-2207 (2007).</li><li>Michielsen, M. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motor+recovery+and+cortical+reorganization+after+mirror+therapy+in+chronic+stroke+patients:+a+phase+II+randomized+controlled+trial.">Motor recovery and cortical reorganization after mirror therapy in chronic stroke patients: a phase II randomized controlled trial.</a> Neurorehabil. Neural Repair. 25 (3), 223-233 (2010).</li><li>Lamont, K., Chin, M., Kogan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mirror+box+therapy:+seeing+is+believing.">Mirror box therapy: seeing is believing.</a> Explore (NY). 7 (6), 369-372 (2011).</li><li>Becker-Asano, C., Gustorff, S., Arras, K. O., Nebel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+effect+of+operator+modality+on+social+and+spatial+presence+during+teleoperation+of+a+human-like+robot.">On the effect of operator modality on social and spatial presence during teleoperation of a human-like robot.</a> , (2014).</li><li>Ros&#233;n, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Referral+of+sensation+to+an+advanced+humanoid+robotic+hand+prosthesis.">Referral of sensation to an advanced humanoid robotic hand prosthesis.</a> Scand. J. Plast. Reconstr. Surg. Hand Surg. 43 (5), 260-266 (2009).</li><li>Limerick, H., Coyle, D., Moore, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+experience+of+agency+in+human-computer+interactions:+a+review.">The experience of agency in human-computer interactions: a review.</a> Frontiers Hum. Neurosci. 8, 643 (2014).</li><li>Botvinick, M., Cohen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rubber+hands+'feel'+touch+that+eyes+see.">Rubber hands 'feel' touch that eyes see.</a> Nature. 391 (6669), 756-756 (1998).</li><li>Tsakiris, M., Haggard, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+rubber+hand+illusion+revisited:+visuotactile+integration+and+self-attribution.">The rubber hand illusion revisited: visuotactile integration and self-attribution.</a> J. Exp. Psychol. Hum. Percept. Perform. 31 (1), 80-91 (2005).</li><li>Rohde, M., Di Luca, M., Ernst, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+rubber+hand+illusion:+feeling+of+ownership+and+proprioceptive+drift+do+not+go+hand+in+hand.">The rubber hand illusion: feeling of ownership and proprioceptive drift do not go hand in hand.</a> PloS One. 6 (6), e21659 (2011).</li><li>Kalckert, A., Ehrsson, 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=Moving+a+rubber+hand+that+feels+like+your+own:+a+dissociation+of+ownership+and+agency.">Moving a rubber hand that feels like your own: a dissociation of ownership and agency.</a> Frontiers Hum. Neurosci. 6, 40 (2012).</li><li>Holmes, N. P., Crozier, G., Spence, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=When+mirrors+lie:+'visual+capture'+of+arm+position+impairs+reaching+performance.">When mirrors lie: 'visual capture' of arm position impairs reaching performance.</a> Cog. Affect. Behav. Neurosci. 4 (2), 193-200 (2004).</li><li>Snijders, H. J., Holmes, N. P., Spence, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direction-dependent+integration+of+vision+and+proprioception+in+reaching+under+the+influence+of+the+mirror+illusion.">Direction-dependent integration of vision and proprioception in reaching under the influence of the mirror illusion.</a> Neuropsychologia. 45 (3), 496-505 (2007).</li><li>Tajima, D., Mizuno, T., Kume, Y., Yoshida, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mirror+illusion:+does+proprioceptive+drift+go+hand+in+hand+with+sense+of+agency.">The mirror illusion: does proprioceptive drift go hand in hand with sense of agency.</a> Front. Psychol. 6, 200 (2015).</li><li>Gallagher, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Philosophical+conceptions+of+the+self:+implications+for+cognitive+science.">Philosophical conceptions of the self: implications for cognitive science.</a> Trends Cog. Sci. 4 (1), 14-21 (2000).</li><li>Farmer, H., Tajadura-Jim&#233;nez, A., Tsakiris, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+the+colour+of+my+skin:+how+skin+colour+affects+the+sense+of+body-ownership.">Beyond the colour of my skin: how skin colour affects the sense of body-ownership.</a> Conscious. Cogn. 21 (3), 1242-1256 (2012).</li><li>Boucsein, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electrodermal Activity. , (2012).</li><li>Bishop, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Pattern recognition and machine learning. , (2006).</li><li>Karatzoglou, A., Smola, A., Hornik, K., Zeileis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=kernlab+-+An+S4+Package+for+Kernel+Methods+in+R.">kernlab - An S4 Package for Kernel Methods in R.</a> J. Stat. Software. 11 (9), 1-2 (2004).</li><li>Jenkinson, P. M., Haggard, P., Ferreira, N. C., Fotopoulou, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Body+ownership+and+attention+in+the+mirror:+insights+from+somatoparaphrenia+and+the+rubber+hand+illusion.">Body ownership and attention in the mirror: insights from somatoparaphrenia and the rubber hand illusion.</a> Neuropsychologia. 51 (8), 1453-1462 (2013).</li></ol>

We demonstrate a method to estimate proprioceptive drift in a 2D plane during the mirror illusion using SVM and to compare the result with questionnaire responses for sense of ownership and agency. This novel method revealed that the required offset between visual and proprioceptive feedback to maintain proprioceptive drift is approximately 10 cm and that this offset closely overlaps with the offset required to maintain the feeling of ownership and agency.
Note that the most critical step of t...

In recent years, research about the sense or experience of the self-body, that is, one&#39;s own body, has increased in the context of embodiment. Embodiment refers to the idea or concept of having a physical or virtual body that can interact with the environment, such as reaching, grasping, and touching. For instance, humans can touch an object or another human positioned in the environment by moving their own body, in this case their own arm and hand. Nowadays, this interaction or communication is not limited to using one&#39;s own natural body. Due to inventions and development of human-like robots or avatars in the virtual world, the natural human body can be substituted by an artificial body, such as a humanoid, remote control robot, electric prosthesis, or computer-graphics avatar in virtual reality. For example, researchers developed a robot whose operator can &#34;grasp&#34; an object placed in front of the robot via its mechanical body, even if the robot is placed far away from the operator&#39;s body position1,2. Similar to this example, if a human could perform an action via an artificial body, which body would hold the attribution of the operator&#39;s self-body?
We can easily find topics related to this discussion on the attribution or projection of &#34;self&#34; from our own natural body to an artificial, non-flesh-and-bone body. One example can be found in the medical field; for example, in the field of medical rehabilitation, treatments that &#34;trick&#34; the patient&#39;s self-body sensation using mirrors are being explored for reducing pain and improving motor function of a missing or paralyzed limb, called mirror therapy3-6. In this therapy, the mirrored image of the unaffected body part or limb can mislead the patient&#39;s brain into believing that the missing or paralyzed limb corresponds to the one displayed in the mirror and lead to the feeling that it is still in its former condition (i.e., before the accident). It is still under discussion how this illusion affects the brain&#39;s resilience related to body representation. In addition to this type of discussion on our natural body, we can find similar discussions on embodiment, especially of human-system interaction design issues in the field of engineering. The sense of self for an artificial or virtual body has been well investigated in the context of telepresence, brain-machine interface, and brain-computer interface1,2,7-9. Some researchers reported that a humanlike robot, which can transfer the tactile sensation from its robot hand to the operator&#39;s hand, can capture the operator&#39;s sense of self-body to the robot as well as the sense of being at a place where the robot is positioned rather than where the operator actually exists, called tele-existence1. Other researchers reported that a virtual avatar reflecting the operator&#39;s body movements strongly transfers the operator&#39;s sense of self-body from the operator&#39;s own body to the virtual body9. These findings indicate how users can project their sense of self-body into an artificial body, such as a humanoid, remote control robot, electric prosthesis, or computer-graphics avatar in virtual reality, even if the artificial body is not directly connected to their brain and body.
Basic scientific research on this type of self-body sensation for non-flesh-and-blood, artificial body-like objects examined the underlying brain mechanisms for the experience of self-body using the rubber hand illusion (RHI)10-13 and mirror illusion (MI)14-16 in the medical and engineering fields as well as in psychophysics and neuropsychology. The RHI is the sensation that a rubber hand belongs to one&#39;s own body and is evoked by simultaneously stroking a visible rubber hand and the participant&#39;s obscured hand. In the MI, a hand image in a mirror positioned along the midsagittal axis visually captures the participant&#39;s perceived position of the unseen opposite hand. Moreover, synchronous movements of the reflected and unseen hand evoke the strong sensation as if the reflected hand image were the unseen opposite hand. According to the research on these illusions, the consistency between multimodal information and the prediction and sensory feedback about body movements seems to play an important role for the judgment of self-body attribution. Thus, these two illusions can be simple but powerful evidence and tools for scientists to investigate the brain mechanisms underlying our sensation of being tricked or believing that some artificial object or image can subjectively be our own body part, and that our self-body sensation does not have to be tied to our natural physical body.
In all these studies listed above, the discussion has been based on the concept of &#34;self&#34; consisting of two types of sensation proposed by the philosopher Gallagher17: the sense of ownership and the sense of agency. The sense of ownership refers to the sensation that an observed body part is one&#39;s own. The sense of agency corresponds to the sensation that body movement is self-caused. These two sensations are defined as the minimal self, that is, an immediate sense of the self16. According to this concept, the attribution of the &#34;self&#34; for the natural, damaged, virtual, and mechanical bodies can be evaluated by the same indexes: the sense of ownership and agency. In order to use this sensation for scientific evaluation, the question arises of how to measure the sense of ownership and agency robustly. Currently, the estimation of the sense of ownership and agency mainly relies on questionnaires, originally proposed by Botvinick9. In addition to questionnaires, we can attempt to measure them in quantitative ways. For instance, the skin conductance response (SCR) has been used as a physiological index of ownership in cases where the rubber hand is suddenly cut by a knife18. The SCR is calculated by measuring the electrical characteristics of the skin and is a sensitive and valid indicator for arousal19. Since this method is typically applied for single trials per participant, measuring SCR is not suitable as a physical index during psychophysics experiments that require repetitive measurements within participants. One of the most successful behavioral indexes for the sense of ownership is proprioceptive drift. Proprioceptive drift is the change in the perceived position of the unseen real hand toward the position of an object that looks like a hand, such as the rubber-made prosthesis or computer graphics10-13. Since this change can be estimated repetitively and robustly by measuring the distance between the unseen real hand and the visual image of the hand, proprioceptive drift is a suitable physical index for psychophysical measurements. However, this usage needs to be evaluated carefully, because recent discussions have questioned whether proprioceptive drift can always be used as a behavioral index of ownership12.
Typically, proprioceptive drift is measured in only one of the three directions, such as height, width, or depth. Proprioceptive drift has rarely been measured in multiple directions due to the difficulty of estimating and visualizing multi-dimensional data. This metrological limitation is not critical for basic research exploring the mechanisms that process multisensory information, because experimental conditions can be easily designed and controlled to limit the measured dimensions. However, in daily life, our hands move freely in 3D to follow our intentions. In this situation, it is difficult and inadequate to measure a participant&#39;s behavior with questionnaires, which severely limits movement and positions of the hands. Thus, considering the potential applications for sense of ownership and agency in engineering and rehabilitation, a measurement that includes multiple directions and allows free hand movement is needed to evaluate the spatial relationship between visual and proprioceptive feedback in daily life situations. If such measurement were possible, the measured distance between real and observed hands could be utilized as a guideline for the sense of self-body. This could not only become an indicator for the progress of rehabilitation but also a criterion for the spatial offset between the manipulated target in the display and the operating hand. The question remains as to how this measurement can be implemented reliably and effectively.
To address this question, we introduce a novel method to estimate proprioceptive drift, which corresponds to the shift from the position of the participant&#39;s unseen real hand to that of a visible hand-like object, on a 2D plane using the mirror illusion by combining a psychophysical procedure and an analysis using machine learning. Compared to a rubber hand, the hand image in a mirror strongly captures the participant&#39;s perceived position of the unseen real hand. Moreover, a mirrored image immediately reflects voluntary hand movements for hand placement. Thus, a mirror image was selected as the visual feedback of the participant&#39;s hand. In addition, to measure proprioceptive drift similar to daily life situations, the participants positioned their hidden hand trial-by-trial at their will, and the number of trials was increased. Although any combination of directions could have been used, the combination of height and depth was chosen due to the ease of placing the mirror vertically. To check consistency between our method and previous research13, two visual conditions were implemented: with and without visual feedback. In the condition with visual feedback, the mirror was positioned along the midsagittal plane to create a reflected image of the left hand, as if it were seen as the right hand. In the condition without visual feedback, a matte blackboard was used in order to hide the participant&#39;s real right hand. We assessed the effectiveness of this novel method by comparing the results to those obtained with a questionnaire on the sense of ownership and agency.

<table border="0" cellpadding="0" cellspacing="0" width="1020">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:224px;">Acric mirror</td>
			<td style="width:99px;"></td>
			<td style="width:275px;"></td>
			<td style="width:423px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Matte blackboard</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">custom-made stand</td>
			<td></td>
			<td></td>
			<td>e.g. wood pole or PVC(poly vinyl chloride) pipe&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Chair</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Foot pedal</td>
			<td>P.I. Engineering</td>
			<td>Classic X-keys USB, and PS/2 Foot Pedals</td>
			<td>Other response device can be avaliable.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Position sensor</td>
			<td>CyVerse</td>
			<td>SLC-C02</td>
			<td>Other position sensor can be avaliable.</td>
		</tr>
		<tr height="20">
			<td colspan="2" height="20" style="height:20px;">Custom-made retroreflectivemarker</td>
			<td></td>
			<td>The marker provided by the motion capture vendor can be available.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Noise canselling head phone</td>
			<td>bose</td>
			<td>Quiet Comfort 3</td>
			<td>Other head phone can be avaliable.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">PC</td>
			<td>Mouse computer</td>
			<td>NG-N-i300GA</td>
			<td>Other PC can be available.</td>
		</tr>
	</tbody>
</table>

visualization method for proprioceptive drift on a 2d plane using support vector machine

Proprioceptive drift, which is a perceptual shift in body-part position from the unseen real body to a visible body-like image, has been measured as the behavioral correlate for the sense of ownership. Previously, the estimation of proprioceptive drift was limited to one spatial dimension, such as height, width, or depth. As the hand can move freely in 3D, measuring proprioceptive drift in only one dimension is not sufficient for the estimation of the drift in real life situations. In this article, we provide a novel method to estimate proprioceptive drift on a 2D plane using the mirror illusion by combining an objective behavioral measurement (hand position tracking) and subjective, phenomenological assessment (subjective assessment of hand position and questionnaire) with a sophisticated machine learning approach. This technique permits not only an investigation of the underlying mechanisms of the sense of ownership and agency but also assists in the rehabilitation of a missing or paralyzed limb and in the design rules of real-time control systems with a self-body-like usability, in which the operator controls the system as if it were part of his/her own body.

Representative results from a previous study are presented to illustrate the method16. Figure 3A shows that the area shapes where the participant could not detect the spatial offset between left and right hand position differed between the conditions with (mirror) and without (blackboard) visual feedback. Figure 3B shows that area sizes in the condition with visual feedback are significantly larger than in the condition without visual feedback ...

Watch this Scientific Journal Video about Visualization Method for Proprioceptive Drift on a 2D Plane Using Support Vector Machine at JoVE.com

Visualization Method for Proprioceptive Drift on a 2D Plane Using Support Vector Machine

This article describes a novel method to estimate proprioceptive drift on a 2D plane using the mirror illusion and combining a psychophysical procedure with an analysis using machine learning.

Proprioceptive drift, which is a perceptual shift in body-part position from the unseen real body to a visible body-like image, has been measured as the ...

The overall goal of this procedure is to estimate and visualize proprioceptive drift in 2D with free selection of the participant's hand position. This method can help answer key questions in psychophysics, engineering, and rehabilitation health, by exploring the method to operate a sense of self body. The main advantage of this technique is to estimate and visualize proprioceptive drift in 2D under the situation where the participant can select their hand locations.Sense of self is originally discussed in the body rehabilitation research field. But now it's expanded to the engineering in the context of embodiment, such as virtual avatar and the artificial bodies. Begin by instructing the participant to perform a tapping movement by keeping the heel of their hand in contact with the mirror.Then start the metronome at a tempo of 60 beats per minute. Instruct the participant to move both hands synchronously according to the sound of the metronome. Ensure that the timing of the participant's hand movements are close to one cycle per second by comparing it to the sound of the metronome several minutes after the tapping begins.Begin by mounting a mirror or blackboard on the stand based on the condition. Use a mirror for the visual feedback condition and a blackboard for a counterbalanced condition without visual feedback. Sit the participant close to the mirror that is positioned along their mid-sagittal plane.Ensure that the participant can only see the mirror image of their left hand and cannot see their real right hand. Next, instruct the participant to pay attention to the image of their left hand in the mirror during the experiment. Put retroreflective markers on the participant's right index fingertip and wrist.Confirm with the participant that the haptic sensation of their right hand is not substantially altered by the markers compared to the left. Next, place noise canceling headphones over the participant's ears so that they will not hear the metronome. Instruct the participant to move their left hand 30 centimeters vertically and 30 centimeters horizontally from the lower right corner of the mirror, and to maintain this left hand position during the experiment.Set this position as the origin of the surface of the 2D plane. Finally, instruct the participant to place their right hand on the other side of the mirror at any position and maintain its position until the end of the trial. At the beginning of a trial, instruct the participant to push the middle button of the foot pedal, which causes a beep through the headphone as feedback of the pedal press.After the beep, instruct the participant to start tapping with both hands synchronously at one hertz on the mirror. After the participant completes six hand movements, instruct them to stop and answer a question about whether they feel the right and left hand are in the same position. Use the right foot pedal for yes, and the left foot pedal for no.Then instruct the participant to move their right hand to another position of their choice. Then start the trial again as practiced. Ensure the participant understands the task, then begin the experiment.Throughout the experiment, check that the timing of the participant's tapping stays at approximately one hertz by viewing the movements compared to the metronome. Allow a break after 100 trials and complete the experiment for the other condition on a separate day. Begin by defining 13 right hand positions for response collection on a questionnaire about sense of ownership and agency.Inform the participant that they will complete the same procedure as before. After synchronously tapping the right and left hands six times, instruct them to orally answer questions about sense of ownership and agency using a seven-point Likert scale. Fill out the questionnaire's scores based on their responses.Show ratings from negative three, meaning totally disagree, to positive three, meaning totally agree, with zero indicating neither agreement nor disagreement or uncertain. Ensure that the participant understands the task. Finally, move the participant's right hand to the next position and have them complete the trial again.The area shapes where the participant could not detect the spacial offset between left and right hand position differ between the conditions. Furthermore, the area sizes and the condition with visual feedback are significantly larger than in the condition without visual feedback, suggesting that the required offset between visual and proprioceptive feedback to maintain proprioceptive drift is approximately 10 centimeters. Here the comparison between visualization of proprioceptive drift and questionnaire results for sense of ownership and agency shows that the offset areas to maintain these phenomena are concentric and almost overlap.This technique can be completed in one hour if it is performed properly. Why attempting this procedure it is important to remember to check whether the participant's performed the task correctly. After it's development this technique pave the way for researchers in the field of psychophysics, engineering, and rehabilitation to explore this dimension method for sense of ownership and agency in multiple dimensions.After watching this video you should have a good idea of how to estimate and human behavior during this experiment of the participant's right hand movement.

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It is widely acknowledged that the use of general anesthetics can undermine the relevance of electrophysiological or microscopical data obtained from a ...

The Social Dimension of Stress: Experimental Manipulations of Social Support and Social Identity in the Trier Social Stress Test

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations supportive behavior of other people as well as positive social relationships can act as powerful resources to cope with stress. In order to study the interplay between these variables, this protocol describes two effective experimental manipulations of social relationships and supportive behavior in the laboratory. In the present article, these two manipulations are implemented in the Trier Social Stress Test (TSST)&#8212;a standard stress induction paradigm in which participants are subjected to a simulated job interview. More precisely, we propose (a) a manipulation of the relationship between different protagonists in the TSST by making a shared social identity salient and (b) a manipulation of the behavior of the TSST-selection committee, which acts either supportively or unsupportively. These two experimental manipulations are designed in a modular fashion and can be applied independently of each other but can also be combined. Moreover, these two manipulations can also be integrated into other stress protocols and into other standardized social interactions such as trust games, negotiation tasks, or other group tasks.

Previous research on the social dimension of stress has focused on two important variables: social identity and social support. This protocol introduces an effective experimental manipulation of these two social variables and describes their implementation in a standard stress induction paradigm (Trier Social Stress Test).

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations ...

A General Method for Evaluating Deep Brain Stimulation Effects on Intravenous Methamphetamine Self-Administration

Substance use disorders, particularly to methamphetamine, are devastating, relapsing diseases that disproportionally affect young people. There is a need for novel, effective and practical treatment strategies that are validated in animal models. Neuromodulation, including deep brain stimulation (DBS) therapy, refers to the use of electricity to influence pathological neuronal activity and has shown promise for psychiatric disorders, including drug dependence. DBS in clinical practice involves the continuous delivery of stimulation into brain structures using an implantable pacemaker-like system that is programmed externally by a physician to alleviate symptoms. This treatment will be limited in methamphetamine users due to challenging psychosocial situations. Electrical treatments that can be delivered intermittently, non-invasively and remotely from the drug-use setting will be more realistic. This article describes the delivery of intracranial electrical stimulation that is temporally and spatially separate from the drug-use environment for the treatment of IV methamphetamine dependence. Methamphetamine dependence is rapidly developed in rodents using an operant paradigm of intravenous (IV) self-administration that incorporates a period of extended access to drug and demonstrates both escalation of use and high motivation to obtain drug.

This article describes the delivery of intracranial electrical stimulation that is temporally and spatially separate from the drug-use environment for the treatment of IV methamphetamine dependence.

Substance use disorders, particularly to methamphetamine, are devastating, relapsing diseases that disproportionally affect young people.  There is a need ...

A Method for Evaluating the Reinforcing Properties of Ethanol in Rats without Water Deprivation, Saccharin Fading or Extended Access Training

Operant oral self-administration methods are commonly used to study the reinforcing properties of ethanol in animals. However, the standard methods require saccharin/sucrose fading, water deprivation and/or extended training to initiate operant responding in rats. This paper describes a novel and efficient method to quickly initiate operant responding for ethanol that is convenient for experimenters and does not require water deprivation or saccharin/sucrose fading, thus eliminating the potential confound of using sweeteners in ethanol operant self-administration studies. With this method, Wistar rats typically acquire and maintain self-administration of a 20% ethanol solution in less than two weeks of training. Furthermore, blood ethanol concentrations and rewards are positively correlated for a 30 min self-administration session. Moreover, naltrexone, an FDA-approved medication for alcohol dependence that has been shown to suppress ethanol self-administration in rodents, dose-dependently decreases alcohol intake and motivation to consume alcohol for rats self-administering 20% ethanol, thus validating the use of this new method to study the reinforcing properties of alcohol in rats.

This protocol describes a novel and efficient method to quickly initiate operant responding for ethanol in rats that, contrary to standard methods, does not require water deprivation or saccharin/sucrose fading to initiate responding.

Operant oral self-administration methods are commonly used to study the reinforcing properties of ethanol in animals. However, the standard methods ...

A Novel Experimental and Analytical Approach to the Multimodal Neural Decoding of Intent During Social Interaction in Freely-behaving Human Infants

Understanding typical and atypical development remains one of the fundamental questions in developmental human neuroscience. Traditionally, experimental paradigms and analysis tools have been limited to constrained laboratory tasks and contexts due to technical limitations imposed by the available set of measuring and analysis techniques and the age of the subjects. These limitations severely limit the study of developmental neural dynamics and associated neural networks engaged in cognition, perception and action in infants performing &#8220;in action and in context&#8221;. This protocol presents a novel approach to study infants and young children as they freely organize their own behavior, and its consequences in a complex, partly unpredictable and highly dynamic environment. The proposed methodology integrates synchronized high-density active scalp electroencephalography (EEG), inertial measurement units (IMUs), video recording and behavioral analysis to capture brain activity and movement non-invasively in freely-behaving infants. This setup allows for the study of neural network dynamics in the developing brain, in action and context, as these networks are recruited during goal-oriented, exploration and social interaction tasks.

This protocol presents a novel methodology for the neural decoding of intent from freely-behaving infants during unscripted social interaction with an actor. Neural activity is acquired using non-invasive high-density active scalp electroencephalography (EEG). Kinematic data is collected with inertial measurement units and supplemented with synchronized video recording.

Understanding typical and atypical development remains one of the fundamental questions in developmental human neuroscience. Traditionally, experimental ...

Feeding Experimentation Device (FED): Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents

Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in mice: the Feeding Experimentation Device (FED). FED is an open-source system that was designed to facilitate flexibility in food intake studies. Due to its compact and battery powered design, FED can be placed within standard home cages or other experimental equipment. Food intake measurements can also be synchronized with other equipment in real-time via FED's transistor-transistor logic (TTL) digital output, or in post-acquisition processing as FED timestamps every event with a real-time clock. When in use, a food pellet sits within FED's food well where it is monitored via an infrared beam. When the pellet is removed by the mouse, FED logs the timestamp onto its internal secure digital (SD) card and dispenses another pellet. FED can run for up to 5 days before it is necessary to charge the battery and refill the pellet hopper, minimizing human interference in data collection. Assembly of FED requires minimal engineering background, and off-the-shelf materials and electronics were prioritized in its construction. We also provide scripts for analysis of food intake and meal patterns. Finally, FED is open-source and all design and construction files are online, to facilitate modifications and improvements by other researchers.

Feeding Experimentation Device FED: Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents

Feeding Experimentation Device (FED) is an open-source device for measuring food intake in mice. FED can also synchronize food intake measurements with other techniques via a real-time digital output. Here, we provide a step-by-step tutorial for the construction, validation, and usage of FED.

Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in ...

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 ...

Reducing State Anxiety Using Working Memory Maintenance

The purpose of this protocol is to explain how to examine the relationship between working memory processes and anxiety by combining the Sternberg Working Memory (WM) and the threat of shock paradigms. In the Sternberg WM paradigm, subjects are required to maintain a series of letters in the WM for a brief interval and respond by identifying whether the position of a given letter in the series matches a numerical prompt. In the threat of shock paradigm, subjects are exposed to alternating blocks where they are either at risk of receiving unpredictable presentations of a mild electric shock or are safe from the shock. Anxiety is probed throughout the safe and threat blocks using the acoustic startle reflex, which is potentiated under threat (Anxiety-Potentiated Startle (APS)). By conducting the Sternberg WM paradigm during the threat of shock and probing the startle response during either the WM maintenance interval or the intertrial interval, it is possible to determine the effect of WM maintenance on APS.

This protocol demonstrates how to measure anxiety-potentiated startle during the Sternberg Working Memory paradigm.

The purpose of this protocol is to explain how to examine the relationship between working memory processes and anxiety by combining the Sternberg Working ...

A New Method for Inducing a Depression-Like Behavior in Rats

Contagious depression is a phenomenon that is yet to be fully recognized and this stems from insufficient material on the subject. At the moment, there is no existing format for studying the mechanism of action, prevention, containment, and treatment of contagious depression. The purpose of this study, therefore, was to establish the first animal model of contagious depression.
Healthy rats can contract depressive behaviors if exposed to depressed rats. Depression is induced in rats by subjecting them to several manipulations of chronic unpredictable stress (CUS) over 5 weeks, as described in the protocol. A successful sucrose preference test confirmed the development of depression in the rats. The CUS-exposed rats were then caged with na&#239;ve rats from the contagion group (1 na&#239;ve rat/2 depressed rats in a cage) for an additional 5 weeks. 30 social groups were created from the combination of CUS-exposed rats and na&#239;ve rats.
This proposed depression-contagion protocol in animals consists mainly of cohabiting CUS-exposed and healthy rats for 5 weeks. To ensure that this method works, a series of tests are carried out - first, the sucrose preference test upon inducing depression to rats, then, the sucrose preference test, alongside the open field and forced-swim tests at the end of the cohabitation period. Throughout the experiment, rats are given tags and are always returned to their cages after each test.
A few limitations to this method are the weak differences recorded between the experimental and control groups in the sucrose preference test and the irreversible traumatic outcome of the forced swim test. These may be worth considering for suitability before any future application of the protocol. Nonetheless, following the experiment, na&#239;ve rats developed contagion depression after 5 weeks of sharing the same cage with the CUS-exposed rats.

This protocol describes a new model by which healthy rats could contract depression over a given time periodthrough contagion by exposure to chronic unpredictable stressed (CUS) rats.

Contagious depression is a phenomenon that is yet to be fully recognized and this stems from insufficient material on the subject. At the moment, there is ...

Virtual Reality Experiments with Physiological Measures

Virtual reality (VR) experiments are increasingly employed because of their internal and external validity compared to real-world observation and laboratory experiments, respectively. VR is especially useful for geographic visualizations and investigations of spatial behavior. In spatial behavior research, VR provides a platform for studying the relationship between navigation and physiological measures (e.g., skin conductance, heart rate, blood pressure). Specifically, physiological measures allow researchers to address novel questions and constrain previous theories of spatial abilities, strategies, and performance. For example, individual differences in navigation performance may be explained by the extent to which changes in arousal mediate the effects of task difficulty. However, the complexities in the design and implementation of VR experiments can distract experimenters from their primary research goals and introduce irregularities in data collection and analysis. To address these challenges, the Experiments in Virtual Environments (EVE) framework includes standardized modules such as participant training with the control interface, data collection using questionnaires, the synchronization of physiological measurements, and data storage. EVE also provides the necessary infrastructure for data management, visualization, and evaluation. The present paper describes a protocol that employs the EVE framework to conduct navigation experiments in VR with physiological sensors. The protocol lists the steps necessary for recruiting participants, attaching the physiological sensors, administering the experiment using EVE, and assessing the collected data with EVE evaluation tools. Overall, this protocol will facilitate future research by streamlining the design and implementation of VR experiments with physiological sensors.

Virtual reality (VR) experiments can be difficult to implement and require meticulous planning. This protocol describes a method for the design and implementation of VR experiments that collect physiological data from human participants. The Experiments in Virtual Environments (EVE) framework is employed to accelerate this process.