This study was not funded.

The following protocol follows the guidelines of human research ethics committee of the university. See Table of Materials for reference to the commercial products.
NOTE: After receiving approval of the university ethics committee, 20 healthy individuals (7 males and 13 females, mean and standard deviation [SD] of age 30.2 &#177; 16.3 years) were recruited. Each subject read and signed an informed consent form pretrial. Inclusion criteria were right-handed individuals aged 18 or above. Exclusion criteria were any neurological or orthopaedic impairment affecting the upper extremities or uncorrected sight impairment. The subjects were na&#239;ve to the occurrences of incongruent visual-tactile feedback.
1. Pre-trial preparation
<ol>
	<li>Use the wooden box from the box and blocks test10. The dimensions of the box are 53.7 cm x 26.9 cm x 8.5 cm and in the middle of it, is a 15.2 cm high partition. Place a soft sponge layer on both sides of the partition. Place six passive reflective markers on the aspect opposite to the screen, at the four corners and on both ends of the partition (Figure 1a).</li>
	<li>Use a 3D-printer to manufacture a cube with the dimensions of 2.5 cm x 2.5 cm x 2.5 cm, attached to a base with the dimensions of 4.5 cm x 4.5 cm x 1 cm. Before printing, cut each corner of the base to create a square of size 1 cm x 1 cm at each corner (Figure 1a). Attach passive reflective markers on the four corners of the base.</li>
	<li>Place a large screen approximately 1.5 m in front of a table, so that a subject, standing behind the table, is approximately 2 m from the screen. Place the box on the table, 10 cm from the edge opposite to the screen.</li>
	<li>Use a 6-camera motion capture system, activated at 100 Hz, with a plug-in to visualize the partition and the movement of the block in real-time (Figure 1). Calibrate the motion capture system, according to the guidelines of the manufacturer, so that the block and partition of the box are recognized as rigid bodies. 
	NOTE: Proper calibration of the motion capture system and usage of small markers that are firmly attached to the block and partition are required to maintain the illusion.</li>
</ol>
2. Placing the vibrotactile feedback system on the subject
NOTE: The VTF system described herein was previously published11,12,13,14.
<ol>
	<li>Instruct the subject to remove wristwatch, bracelets and rings. Attach the VTF system controller to the forearm of the subject (Figure 2, left image).</li>
	<li>Attach two thin and flexible force sensors to the palmar aspect of the thumb and index fingers over a thin spongy layer (Figure 2, right image).</li>
	<li>Place a cuff on the skin of the upper arm of the subject (Figure 2, left image) and use the fastener to close the cuff comfortably. The cuff will contain three vibrotactile actuators activated via an open-source electronic prototyping platform at a frequency of 233 Hz in a linear relation to the force perceived by the force sensors. The force sensors and vibrotactile actuators are connected to the open-source electronic prototyping platform via shielded electric wires.</li>
</ol>
3. VTF activation
<ol>
	<li>Press the button to activate the battery attached to the controller (Figure 2, left image).</li>
	<li>Ask the subject to press the force sensor&#8217;s instrumented fingers (i.e., the thumb and index fingers) together lightly. Note that the subject will report a sense of vibration at the area under the cuff.</li>
	<li>Instruct the subject to train for 10 min in grasping the block as lightly as possible, using only the two instrumented fingers. Ask the subject to lift the block, move it, and place it back on the table several times, attempting to apply a minimal amount of force on the block. Encourage the subject to attempt to reduce the applied force, even if the block is dropped during grasping.</li>
</ol>
4. Positioning and preparing the subject
<ol>
	<li>Instruct the subject to stand close to the table (up to 10 cm from it), where the box and partition are placed.</li>
	<li>Place a divider at the edge of the table near the subject and above the box, so that the subject is unable to see the box but can easily see the screen in front of him or her (Figure 1a). For the divider, use a hard non-reflective material, preferably wood, fixed on a four legs, which permit the adjustment of their height, to accommodate subjects of different heights.</li>
	<li>Instruct the subject to place the earphones on his or her head.</li>
	<li>Place the block in the middle of the right compartment of the box and guide the hand of the subject to it.</li>
</ol>
5. Commencing trial
NOTE: The described trial is repeated twice, with and without the VTF (a cross-over design is recommended to verify a no learning effect). To perform the trial without the VTF, turn off the battery attached to the controller (Figure 2).
<ol>
	<li>Activate the software controlling the cameras of the motion capture system.</li>
	<li>In the control panel of the visual feedback software (Figure 1b), select with/without VTF, type the code of the subject, click Run, Connect, Open and Start.</li>
	<li>Instruct the subject to perform 16 repetitions of transferring the block with the force sensor&#8217;s instrumented hand while viewing the movement of the virtual block on the screen (Figure 1b). After each transfer, move the block back across the partition to its starting location.</li>
	<li>After the subject completed 16 repetitions, click Stop.</li>
	<li>Ask the subject to rate the difficulty level of performing the task of transferring the block 16 times twice, with and without the VTF, according to the following scale: &#8216;0&#8217; (not difficult at all), &#39;1&#39; (slightly difficult), &#39;2&#39; (moderately difficult), &#39;3&#39; (very difficult), and &#8216;4&#8217; (extremely difficult).</li>
</ol>
6. Post analysis
<ol>
	<li>Use the 3D coordinate data of the block the compute the path of the block and its transfer time. Mark the onset and offset time of each transfer manually as when the block is at the height of the rims of the right (onset) and then left (offset) sides of the box. Calculate the path length of each transfer according to the following equation: 
	(1) <img alt="Equation 1" src="/files/ftp_upload/59493/59493eq1.jpg" /> 
	where <img alt="Equation 2" src="/files/ftp_upload/59493/59493eq2.jpg" /> and <img alt="Equation 3" src="/files/ftp_upload/59493/59493eq3.jpg" /> are the 3D coordinate of the block in two subsequent time points.</li>
	<li>For both conditions, with and without VTF, average the path length and transfer time once for the two transfers with incongruent visual-tactile signals and once for the 14 transfers with the congruent visual-tactile signals.</li>
	<li>Normalized the path and time during block transfer in the presence of incongruent visual-tactile signals by the path and time during block transfer with the presence of congruent visual-tactile signals. Perform the normalization separately for the two conditions (with and without VTF).</li>
	<li>Perform a within-subject repeated-measures ANOVA with two factors: VTF (with and without) and incongruent visual-tactile feedback (with and without).</li>
	<li>If there are no statistical differences when analyzing the results following the instructions in subsection 6.4, use Bayesian repeated measures ANOVAs with two factors15.</li>
	<li>Use the Spearman&#8217;s correlation test with the perceived difficulty level of performing the task with the VTF activated and with the normalized path and duration of the motion</li>
	<li>Set the statistical significance to p &#60; .05.</li>
</ol>

<ol>
	<li>Aggelopoulos, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perceptual+inference.">Perceptual inference.</a> Neuroscience and Biobehavioral Reviews. 55, 375-392 (2015).</li><li>van der Groen, O., van der Burg, E., Lunghi, C., Alais, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Touch+influences+visual+perception+with+a+tight+orientation-tuning.">Touch influences visual perception with a tight orientation-tuning.</a> PloS One. 8 (11), e79558 (2013).</li><li>Pei, Y. C., 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=Cross-modal+sensory+integration+of+visual-tactile+motion+information:+instrument+design+and+human+psychophysics.">Cross-modal sensory integration of visual-tactile motion information: instrument design and human psychophysics.</a> Sensors. 13 (6), 7212-7223 (2013).</li><li>Kording, K. P., Wolpert, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bayesian+integration+in+sensorimotor+learning.">Bayesian integration in sensorimotor learning.</a> Nature. 427 (6971), 244-247 (2004).</li><li>Tajadura-Jimenez, A., Banakou, D., Bianchi-Berthouze, N., Slater, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embodiment+in+a+Child-Like+Talking+Virtual+Body+Influences+Object+Size+Perception,+Self-Identification,+and+Subsequent+Real+Speaking.">Embodiment in a Child-Like Talking Virtual Body Influences Object Size Perception, Self-Identification, and Subsequent Real Speaking.</a> Scientific Reports. 7 (1), (2017).</li><li>Campos, J. L., Butler, J. S., Bulthoff, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multisensory+integration+in+the+estimation+of+walked+distances.">Multisensory integration in the estimation of walked distances.</a> Experimental Brain Research. 218 (4), 551-565 (2012).</li><li>Sun, H. J., Campos, J. L., Chan, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multisensory+integration+in+the+estimation+of+relative+path+length.">Multisensory integration in the estimation of relative path length.</a> Experimental Brain Research. 154 (2), 246-254 (2004).</li><li>Parmentier, F. B., Ljungberg, J. K., Elsley, J. V., Lindkvist, 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+behavioral+study+of+distraction+by+vibrotactile+novelty.">A behavioral study of distraction by vibrotactile novelty.</a> Journal of Experimental Psychology, Human Perception, and Performance. 37 (4), 1134-1139 (2011).</li><li>Sigrist, R., Rauter, G., Riener, R., Wolf, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Augmented+visual,+auditory,+haptic,+and+multimodal+feedback+in+motor+learning:+a+review.">Augmented visual, auditory, haptic, and multimodal feedback in motor learning: a review.</a> Psychonomic Bulletin &amp; Review. 20 (1), 21-53 (2013).</li><li>Hebert, J. S., Lewicke, J., Williams, T. R., Vette, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normative+data+for+modified+Box+and+Blocks+test+measuring+upper-limb+function+via+motion+capture.">Normative data for modified Box and Blocks test measuring upper-limb function via motion capture.</a> Journal of Rehabilitation Research and Development. 51 (6), 918-932 (2014).</li><li>Raveh, E., Portnoy, S., Friedman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adding+vibrotactile+feedback+to+a+myoelectric-controlled+hand+improves+performance+when+online+visual+feedback+is+disturbed.">Adding vibrotactile feedback to a myoelectric-controlled hand improves performance when online visual feedback is disturbed.</a> Human Movement Science. 58, 32-40 (2018).</li><li>Raveh, E., Friedman, J., Portnoy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+effects+of+adding+vibrotactile+feedback+to+myoelectric+prosthesis+users+on+performance+and+visual+attention+in+a+dual-task+paradigm.">Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm.</a> Clinical Rehabilitation. 32 (10), 1308-1316 (2018).</li><li>Raveh, E., Portnoy, S., Friedman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myoelectric+Prosthesis+Users+Improve+Performance+Time+and+Accuracy+Using+Vibrotactile+Feedback+When+Visual+Feedback+Is+Disturbed.">Myoelectric Prosthesis Users Improve Performance Time and Accuracy Using Vibrotactile Feedback When Visual Feedback Is Disturbed.</a> Archives of Physical Medicine and Rehabilitation. , (2018).</li><li>Raveh, E., Friedman, J., Portnoy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visuomotor+behaviors+and+performance+in+a+dual-task+paradigm+with+and+without+vibrotactile+feedback+when+using+a+myoelectric+controlled+hand.">Visuomotor behaviors and performance in a dual-task paradigm with and without vibrotactile feedback when using a myoelectric controlled hand.</a> Assistive Technology: The Official Journal of RESNA. , 1-7 (2017).</li><li>Dienes, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+Bayes+to+get+the+most+out+of+non-significant+results.">Using Bayes to get the most out of non-significant results.</a> Frontiers in Psychology. 5, 781 (2014).</li><li>Shams, L., Murray, M. M., Wallace, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+Integration+and+Bayesian+Causal+Inference+in+Multisensory+Perception.">Early Integration and Bayesian Causal Inference in Multisensory Perception.</a> The Neural Bases of Multisensory Processes. , (2012).</li><li>D'Amour, S., Pritchett, L. M., Harris, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bodily+illusions+disrupt+tactile+sensations.">Bodily illusions disrupt tactile sensations.</a> Journal of Experimental Psychology, Human Perception, and Performance. 41 (1), 42-49 (2015).</li><li>Tidoni, E., Fusco, G., Leonardis, D., Frisoli, A., Bergamasco, M., Aglioti, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Illusory+movements+induced+by+tendon+vibration+in+right-+and+left-handed+people.">Illusory movements induced by tendon vibration in right- and left-handed people.</a> Experimental Brain Research. 233 (2), 375-383 (2015).</li><li>Fuentes, C. T., Gomi, H., 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=Temporal+features+of+human+tendon+vibration+illusions.">Temporal features of human tendon vibration illusions.</a> The European Journal of Neuroscience. 36 (12), 3709-3717 (2012).</li><li>de Vignemont, F., Ehrsson, H. H., 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=Bodily+illusions+modulate+tactile+perception.">Bodily illusions modulate tactile perception.</a> Current Biology. 15 (14), 1286-1290 (2005).</li><li>Marotta, A., Tinazzi, M., Cavedini, C., Zampini, M., Fiorio, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+Differences+in+the+Rubber+Hand+Illusion+Are+Related+to+Sensory+Suggestibility.">Individual Differences in the Rubber Hand Illusion Are Related to Sensory Suggestibility.</a> PloS One. 11 (12), e0168489 (2016).</li><li>Stevenson, R. A., Zemtsov, R. K., Wallace, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+differences+in+the+multisensory+temporal+binding+window+predict+susceptibility+to+audiovisual+illusions.">Individual differences in the multisensory temporal binding window predict susceptibility to audiovisual illusions.</a> Journal of Experimental Psychology, Human Perception, and Performance. 38 (6), 1517-1529 (2012).</li><li>Maravita, A., Spence, C., Driver, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multisensory+integration+and+the+body+schema:+close+to+hand+and+within+reach.">Multisensory integration and the body schema: close to hand and within reach.</a> Current Biology. 13 (13), R531-R539 (2003).</li><li>Carey, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multisensory+integration:+attending+to+seen+and+felt+hands.">Multisensory integration: attending to seen and felt hands.</a> Current Biology. 10 (23), R863-R865 (2000).</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> Journal of Experimental Psychology, Human Perception, and Performance. 31 (1), 80-91 (2005).</li></ol>

The authors have nothing to disclose.

In this study, a protocol that quantifies the effect of adding VTF on the object transfer kinematics in the presence of incongruent visual-tactile stimuli was presented. To the best of our knowledge, this is the only protocol available to test the effect of VTF on the response to incongruent visual-tactile stimuli. The several critical steps involved in the application of incongruent visual-tactile stimuli during object transfer with VTF include the following: attaching the VTF system to the subject, activating the VTF, preparing the motion capture system and movement task, and activating the visual feedback. It is critical that the subject is not aware of the possibility for misleading feedback during the trial. To ensure this, the bottom of the box is lined with soft sponge layer and the subjects wore earphones to eliminate auditory feedback of the block falling and hitting the wooden box. Also, the two transfers of incongruent feedback are chosen randomly out of the 16 transfers, and are programmed to simulate a fall in the start compartment of the box after reaching 2 cm below the partition&#8217;s height, so that the hand is in midair. The two random misleading visuals signals were programed so they would not occur in either the first or last two block transfers and with at least one non-misleading transfer between them.
One advantage of this protocol is that the misleading visual feedback appears randomly and only for a couple of times during the 16-transfer trial. This prevents the subject from mistrusting the virtual presentation. Since the conflict between the two signals, provided to the subject in this trial, is very high, the subjected protocol aims to increase the reliability of the misleading visual feedback, by presenting a reasonable number of block drops. It was discussed by Shams16 that the interaction between auditory and visual signals is affected by the degree of conflict between the two and prior knowledge regarding the trial setup. This might also be the case in the interaction between tactile and visual signals, designed herein. Another advantage of the system is that in order to present the location of the block in real-time, the motion capture system calculates the 3D coordinates of the block, so that the analysis of the movement time and path of the block in each repetition can be performed efficiently and precisely at the end of the trial.
Using this protocol, our preliminary results suggest that when analyzing visual-tactile incongruent signals, one acquired directly by light touch and the other acquired indirectly by vision (virtual representation), the subject may have ignored the indirect visual feedback, and responded to the direct tactile signal. This was also confirmed in the presence of VTF, thereby rejecting the second hypothesis. We expected that the VTF would distract the attention of the subject from the light direct tactile feedback, thereby compelling the subject to respond with hesitation to incongruent stimuli. The hesitation was expected to be expressed by longer path and duration of the block transfer. The assumption was based on results of previous research that showed that vibrotactile novel stimuli capture attention away from an ongoing visual task8. The path length and duration were chosen as indicators of hesitation, differentiating between two conditions: when the misleading visual feedback occurs, the subject can either trust the tactile feedback or the visual feedback. If the subject trusts the tactile feedback, then we expect that he or she will continue the smooth movement path. Conversely, if the subject trusts the false visual feedback, we expect he or she will move the hand back to grasp the fallen block and retransfer it (increasing the path length and duration). One possible explanation for the lack of effect of VTF on the block moving kinematics is that since the VTF was applied in conjunction with the direct tactile feedback, the VTF did not function as a disturbance but rather as an indirect amplifier to the direct tactile feedback. This allowed the subjects to keep trusting the tactile feedback, both direct and indirect, over the virtual visual feedback. In addition to the potential for distraction by vibrotactile signal, another aspect of applying vibration during motor tasking should be considered: its effect on our perception of tactile and proprioception senses. Studies showed that tendon vibration caused illusions between tactile perception and the sense of body dimension or position17,18,19. For example, vibrations to the biceps or triceps muscle tendons produced a proprioceptive illusion which had an effect on the sense of touch20. However, the effect of VTF (i.e., vibration in conjunction with the tactile stimuli) on the tactile perception itself has not been researched so that one cannot theorize whether the vibrations applied to the upper arm during the trial affected the perception of the proprioceptive or tactile senses of the subject. Finally, a possible explanation for the rejection of the second hypothesis is the individual differences in the ability of the subjects to process the VTF, as discussed below.
In this study, the strong correlation between the perceived difficulty level of performing the task with the VTF and the normalized path of the block with VTF, proves the third hypothesis and suggests that subjects, who felt that the VTF disturbed them, trusted the virtual visual feedback more than their tactile senses. Similar reports of individual differences in perception of sense illusions are documented in the literature. For example, subjects with higher Sensory Suggestibility Scale (SSS) scores rated the sense of ownership of a rubber hand in the rubber hand illusion as higher compared with subjects with lower SSS scores21. Another aspect of individual differences in perception of illusions may arise from differences in the temporal perceptual binding window, which causes alterations when integrating multisensory cues22. It was found that individuals with narrower perceptual binding windows were less likely to perceive an illusion, suggesting that they are more likely to dissociate temporally asynchronous inputs. It should be noted that there was no significant correlation between the perceived difficulty level of performing the task with the VTF and the normalized time of the block with VTF. This might be explained by the hand velocity. Specifically, when the subjects increased their hand path length in the presence of the misleading virtual signal, they might have sped up their hand movement so that the total duration for completing the task remained similar to that performed by them without the misleading feedback.
One limitation of this protocol is that the instructions provided to the subjects to apply a minimal force to the block were probably executed differently by the subjects, so that some applied higher forces than others, thereby perceiving a higher direct tactile signal, which might have affected the results. Unfortunately, the forces detected by the force sensors to affirm this assumption were not recorded. Recording the forces is an optional feature for future studies that might contribute information regarding the tactile information perceived by the subject during the trial. Also, the virtual representation designed herein provided the block movement and the location of the box partition so that there was no virtual representation of the hand of the subject. As previous research showed that visual information regarding apparent hand position may have crossmodal influences on tactile judgments, even when vision conflicts with proprioception23,24,25, the addition of hand representation in this trial may have altered the results of this study. Additionally, the chosen task of block transfer might have been too quick. Future modification to this protocol might include a more complicated task so that the differences in the durations for completion of the task, with and without VTF, would have been more considerable. Also, individual differences might be controlled by using the SSS. Last, only a minimal number of repetitions of the visual-tactile incongruent feedback are possible in this protocol, so as not to alert the subject regarding the misleading visual feedback. The protocol reliability would be compromised if the subjects would suspect that they are being deceived by the visual presentation. Therefore, the proportion of misleading feedback per the total number of trials should be minimal. Unfortunately, the small number of incongruent instances may limit the statistical power.
In summary, a new protocol, which presents misleading virtual visual feedback of movement, was tested with and without VTF. The preliminary results show that we trust direct and indirect tactile signals over an indirect visual signal. Furthermore, differences between subjects influence the response to incongruent signals, so that subjects, who felt more disturbed by the VTF, trusted the misleading visual signal over the tactile signal. This protocol could be further explored in upper limb amputees, who use prosthetics, equipped with VTF.

Illusions are exploitations of the limitations of our senses, as we mistakenly perceive information that deviates from objective reality. Our perceptual inference is based on our experience in interpreting sensory data and on the calculation of our brain of the most reliable estimate of reality in the presence of ambiguous sensory input1.
A sub-category in the research of illusions is one that combines incongruent sensory signals. The illusion that results from incongruent sensory signals originates from the constant multisensory integration performed by our brain. While there are numerous studies concerning incongruence in visual-auditory signals, incongruence in other sensory pairs is less reported. This difference in the number of reports might be attributed to the higher simplicity in designing a setup that incorporates visual-auditory incongruence. However, studies that report results relating to other sensory pairs modalities, are interesting. For example, the effect of incongruent visual-haptic signals on visual sensitivity2 was studied using a system where the visual and haptic stimuli were matched in spatial frequency; however, the haptic and visual orientation was identical (congruent) or orthogonal (incongruent). In another study, the effect of incongruent visual-tactile motion stimuli on the perceived visual direction of motion was investigated using a visual-tactile cross-modal integration stimulator with a lighted panel that presents visual stimuli and a tactile stimulator that presents tactile motion stimuli with arbitrary motion direction, speed, and indentation depth in the skin3. It was suggested that we internally represent both the statistical distribution of the task and our sensory uncertainty, combining them in a manner consistent with a performance-optimizing Bayesian process4.
Virtual reality has made the ability to deceive the visual feedback to the subject an easy task. Several studies used multisensory virtual reality to misalign visual and somatosensory information. For example, virtual reality was recently used to induce embodiment in a child&#8217;s body, with or without activation of a child-like voice distortion5. In another example, the visual presentation of the walking distance during self-motion was extended and was therefore incongruent with the travel distance felt by body-based cues6. A similar virtual reality setup was designed for a cycling activity7. All of the aforementioned literature, however, did not combine an interference to one of the senses, in addition to the incongruent signal. We chose the tactile sense to receive such a disturbance.
Our tactile sensory system provides direct evidence as to whether an object is being grasped. We therefore expect that when direct visual feedback is distorted or unavailable, the role of the tactile sensory system in object manipulation tasks will be prominent. However, what would happen if the tactile sensory channel was also disturbed? This is a possible outcome of using vibrotactile feedback (VTF) for sensory augmentation, as it captures the attention of the individual8. Today, augmented feedback of different modalities is used as an external tool, meant to enhance our internal sensory feedback and improve performance during motor learning, in sport and in rehabilitation settings9.
The study of incongruent visual-tactile stimuli may enhance our understanding regarding perception of the sensory input. Particularly, quantification of the additive or reductive value of VTF during motor function that involves incongruent visual-tactile stimuli, can assist in future prosthetics design, smart sport-wear, or any other garments that incorporate VTF. Since amputees are deprived of tactile stimuli at the distal aspect of their residuum, their daily usage of the VTF, embedded in the prosthetic to convey knowledge of grasping, for example, might influence how they perceive visual feedback. Understanding of the mechanism of perception under these conditions, will allow engineers to perfect VTF modalities to reduce the negative effect on VTF users.
We aimed to test the effect of VTF on the response to incongruent visual-tactile stimuli. In the presented setup, the tactile feedback is acquired by grasping a block and moving it across a partition; the visual feedback is a real-time virtual presentation of the moving block and the partition (acquired using a motion capture system). Since the subject is prevented from seeing the actual hand movement, the only visual feedback is the virtual one. The congruent feedback is the reliable presentation of the movement of the block, so that the subject feels that the block is grasped and sees it move along with the path of the hand. The incongruent feedback appears as the movement of the block diverts from the actual movement path, so that it seems to drop from the hand when it is actually still held by the subject, thereby contradicting the tactile feedback. Three hypotheses were tested: when moving an object from one place to another using virtual visual feedback, (i) the path and duration of the object&#8217;s transfer motion will increase when incongruent visual-tactile stimuli is presented, (ii) this change will increase when incongruent visual-tactile stimuli is presented and VTF is activated on the moving arm, and (iii) a positive correlation will be found between the perceived difficulty level of performing the task with the VTF activated and the path and duration of the object&#8217;s transfer motion. The first hypothesis originates from aforementioned literature that report that various modalities of incongruent feedback affect our responses. The second hypothesis relates to the previous findings that VTF captures the attention of the individual. For the third hypothesis, we assumed that subjects who were more disturbed by the VTF, will trust the virtual visual feedback more than their tactile sense.

<table>
	<tbody>
		<tr>
			<td>3D printer</td>
			<td>Makerbot</td>
			<td></td>
			<td>https://www.makerbot.com/</td>
		</tr>
		<tr>
			<td>Box and Blocks test</td>
			<td>Sammons Preston</td>
			<td></td>
			<td>https://www.performancehealth.com/box-and-blocks-test</td>
		</tr>
		<tr>
			<td>Flexiforce sensors (1lb)</td>
			<td>Tekscan Inc.</td>
			<td></td>
			<td>https://www.tekscan.com/force-sensors</td>
		</tr>
		<tr>
			<td>JASP</td>
			<td>JASP Team</td>
			<td></td>
			<td>https://jasp-stats.org/</td>
		</tr>
		<tr>
			<td>Labview</td>
			<td>National Instruments</td>
			<td></td>
			<td>http://www.ni.com/en-us/shop/labview/labview-details.html</td>
		</tr>
		<tr>
			<td>Micro Arduino</td>
			<td>Arduino LLC</td>
			<td></td>
			<td>https://store.arduino.cc/arduino-micro</td>
		</tr>
		<tr>
			<td>Motion capture system</td>
			<td>Qualisys</td>
			<td></td>
			<td>https://www.qualisys.com</td>
		</tr>
		<tr>
			<td>Shaftless vibration motor</td>
			<td>Pololu</td>
			<td></td>
			<td>https://www.pololu.com/product/1638</td>
		</tr>
		<tr>
			<td>SPSS</td>
			<td>IBM</td>
			<td></td>
			<td>https://www.ibm.com/analytics/spss-statistics-software</td>
		</tr>
	</tbody>
</table>

applying incongruent visual-tactile stimuli during object transfer with vibro-tactile feedback

The application of incongruent sensory signals that involves disrupted tactile feedback is rarely explored, specifically with the presence of vibrotactile feedback (VTF). This protocol aims to test the effect of VTF on the response to incongruent visual-tactile stimuli. The tactile feedback is acquired by grasping a block and moving it across a partition. The visual feedback is a real-time virtual presentation of the moving block, acquired using a motion capture system. The congruent feedback is the reliable presentation of the movement of the block, so that the subject feels that the block is grasped and see it move along with the path of the hand. The incongruent feedback appears as the movement of the block diverts from the actual movement path, so that it seems to drop from the hand when it is actually still held by the subject, thereby contradicting the tactile feedback. Twenty subjects (age 30.2 &#177; 16.3) repeated 16 block transfers, while their hand was hidden. These were repeated with VTF and without VTF (total of 32 block transfers). Incongruent stimuli were presented randomly twice within the 16 repetitions in each condition (with and without VTF). Each subject was asked to rate the difficulty level of performing the task with and without the VTF. There were no statistically significant differences in the length of the hand paths and durations between transfers recorded with congruent and incongruent visual-tactile signals &#8211; with and without the VTF. The perceived difficulty level of performing the task with the VTF significantly correlated with the normalized path length of the block with VTF (r = 0.675, p = 0.002). This setup is used to quantify the additive or reductive value of VTF during motor function that involves incongruent visual-tactile stimuli. Possible applications are prosthetics design, smart sport-wear, or any other garments that incorporate VTF.

We used the described technique to test the three hypotheses that when moving an object from one place to another using virtual visual feedback: (i) the path and duration of the object&#8217;s transfer motion will increase when incongruent visual-tactile stimuli is presented; (ii) this change will increase when incongruent visual-tactile stimuli is presented and VTF is activated on the moving arm; and (iii) a positive correlation will be found between the perceived difficulty level of performing the task with the VTF activated and the path and duration of the object&#8217;s transfer motion.
The results support the third hypothesis. The reported difficulty levels of performing the task with and without the VTF are presented in Figure 3. According to Spearman&#8217;s correlation test, the perceived difficulty level (from &#8216;0&#8217; = not difficult at all, to &#8216;4&#8217; = extremely difficult) of performing the task with the VTF significantly correlated with the normalized path length of the block with VTF (r = 0.675, p = 0.002; Figure 4). In other words, the normalized path length in the presence of incongruent visual-tactile signals was longer for subjects who perceived the task as more difficult when using the VTF. There was no significant correlation between the perceived difficulty level of performing the task with the VTF and the normalized path length of the block without VTF (r = 0.132, p = 0.589). Also, there were no significant correlations between the perceived difficulty level of performing the task with the VTF and the normalized block transfer time, with and without the VTF (r = -0.056, p = 0.825 and r = -0.066, p = 0.788, respectively).
We suggest normalizing the path length and time, since the absolute time and path of each subject depended on the movement speed and strategy of each subject, so that a non-normalized value would not have reflected the individual&#8217;s change in movement pattern due to the appearance of the incongruent visual-tactile signals. Since, after each transfer, we repositioned the block back to the exact starting position, the path length of the block was not affected by the starting position. For the within-subject repeated-measures ANOVA with two factors, VTF (with and without) and incongruent visual-tactile feedback (with and without), no statistically significant main effects were found in the length of the hand paths during a block transfer for trials with VTF compared to trials without VTF (F(1,15) = 0.029, p = 0.866) and for trials with congruent visual-tactile feedback compared with trials with incongruent visual-tactile feedback (F(1,15) = 0.031, p = 0.863). Also, no statistically significant main effects were found in the times to transfer a block for trials with VTF compared to trials without VTF (F(1,15) = 0.354, p = 0.561) and for trials with congruent visual-tactile feedback compared with trials with incongruent visual-tactile feedback (F(1,15) = 1.169, p = 0.297).
During the trials without VTF, there were no statistically significant differences in the length of the hand paths during a block transfer between transfers recorded with incongruent and congruent visual-tactile signals (27.3 &#177; 13.1 cm and 25.9 &#177; 12.2 cm, respectively) and between the times to transfer a block recorded with incongruent and congruent visual-tactile signals (1.18 &#177; 0.56 s and 1.20 &#177; 0.57 s, respectively). Similarly, when adding VTF, there were no statistically significant differences in the lengths of the hand paths during a block transfer, recorded with incongruent and congruent visual-tactile signals (24.7 &#177; 7.4 cm and 26.1 &#177; 11.1 cm, respectively) and between the time to transfer a block recorded with incongruent and congruent visual-tactile signals (1.21 &#177; 0.38 s and 1.06 &#177; 0.41 s, respectively). According to Bayesian statistics, the absence of difference involving the group factors can only be taken as anecdotal evidence given that none of the fitted models are substantially better than the null model (2.769 &#60; all BF01 &#60; 33.573) with a maximal error of 2.72%.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59493/59493fig1.jpg" /> 
Figure 1: The trial setup. (a) Markers placed on the box (6 markers in red, 2 of which were placed on the partition) and the block (4 markers in blue), hidden from the subject&#8217;s eyes. The markers were tracked in real time by the motion capture system and the 3D coordinates of all markers were recorded in real-time. (b) The partition and movement of the block were presented on a screen, situated in front of the subject. The software activation steps are described in the research protocol<s>.</s> <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59493/59493fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59493/59493fig2.jpg" /> 
Figure 2: The vibrotactile feedback system. The system controller is attached to the forearm of the subject and the cuff is wrapped around the upper arm (left image). The force sensors are placed on the palmar aspect of the thumb and index fingers (right image). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59493/59493fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/59493/59493fig3.jpg" /> 
Figure 3: The reported difficulty levels (0 = not difficult at all, 1 = slightly difficult, 2 = moderately difficult, 4 = extremely difficult) of performing the task with and without the vibrotactile feedback (VTF). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59493/59493fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/59493/59493fig4.jpg" /> 
Figure 4: A scatter plot of the perceived difficulty level (0 = not difficult at all, 1 = slightly difficult, 2 = moderately difficult, 4 = extremely difficult) of performing the task with VTF in relation to the normalized path length of the block when transferred with VTF. The normalized path length (the path length in the presence of incongruent visual-tactile signals divided by the path length in the presence of congruent visual-tactile signals) was significantly longer for subjects who perceived the task as more difficult when using the VTF. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59493/59493fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Applying Incongruent Visual-Tactile Stimuli during Object Transfer with Vibro-Tactile Feedback at JoVE.com

Applying Incongruent Visual-Tactile Stimuli during Object Transfer with Vibro-Tactile Feedback

We present a protocol to apply incongruent visual-tactile stimuli during an object transfer task. Specifically, during block transfers, performed while the hand is hidden, a virtual presentation of the block shows random occurrences of false block drops. The protocol also describes adding vibrotactile feedback while performing the motor task.

The application of incongruent sensory signals that involves disrupted tactile feedback is rarely explored, specifically with the presence of vibrotactile ...

applying-incongruent-visual-tactile-stimuli-during-object-transfer

Nanyang Technological University

Research

JoVE Journal

Behavior

5.4K Views.  Tel Aviv University. We present a protocol to apply incongruent visual-tactile stimuli during an object transfer task. Specifically, during block transfers, performed while the hand is hidden, a virtual presentation of the block shows random occurrences of false block drops. The protocol also describes adding vibrotactile feedback while performing the motor task.

Video: Applying Incongruent Visual-Tactile Stimuli during Object Transfer with Vibro-Tactile Feedback

Irrelevant Stimuli and Action Control: Analyzing the Influence of Ignored Stimuli via the Distractor-Response Binding Paradigm

Selection tasks in which simple stimuli (e.g. letters) are presented and a target stimulus has to be selected against one or more distractor stimuli are frequently used in the research on human action control. One important question in these settings is how distractor stimuli, competing with the target stimulus for a response, influence actions. The distractor-response binding paradigm can be used to investigate this influence. It is particular useful to separately analyze response retrieval and distractor inhibition effects. Computer-based experiments are used to collect the data (reaction times and error rates). In a number of sequentially presented pairs of stimulus arrays (prime-probe design), participants respond to targets while ignoring distractor stimuli. Importantly, the factors response relation in the arrays of each pair (repetition vs. change) and distractor relation (repetition vs. change) are varied orthogonally. The repetition of the same distractor then has a different effect depending on response relation (repetition vs. change) between arrays. This result pattern can be explained by response retrieval due to distractor repetition. In addition, distractor inhibition effects are indicated by a general advantage due to distractor repetition. The described paradigm has proven useful to determine relevant parameters for response retrieval effects on human action.

The distractor-response binding paradigm is described. It can be used to shed light on the influence irrelevant stimuli, competing with targets for a response, can have on human action. Both response retrieval effects and distractor inhibition effects can be analyzed within the paradigm.

Selection tasks in which simple stimuli (e.g. letters) are presented and a target stimulus has to be selected against one or more distractor stimuli are ...

Applying Stereotactic Injection Technique to Study Genetic Effects on Animal Behaviors

Stereotactic injection is a useful technique to deliver high titer lentiviruses to targeted brain areas in mice. Lentiviruses can either overexpress or knockdown gene expression in a relatively focused region without significant damage to the brain tissue. After recovery, the injected mouse can be tested on various behavioral tasks such as the Open Field Test (OFT) and the Forced Swim Test (FST). The OFT is designed to assess locomotion and the anxious phenotype in mice by measuring the amount of time that a mouse spends in the center of a novel open field. A more anxious mouse will spend significantly less time in the center of the novel field compared to controls. The FST assesses the anti-depressive phenotype by quantifying the amount of time that mice spend immobile when placed into a bucket of water. A mouse with an anti-depressive phenotype will spend significantly less time immobile compared to control animals. The goal of this protocol is to use the stereotactic injection of a lentivirus in conjunction with behavioral tests to assess how genetic factors modulate animal behaviors.

Stereotactic injection of lentiviruses expressing cDNAs or shRNAs can modulate gene expression in specific brain areas of mice. Here, we present a protocol to combine stereotactic injections with behavioral tasks, such as the Open Field Test (OFT) and the Forced Swim Test (FST).

Stereotactic injection is a useful technique to deliver high titer lentiviruses to targeted brain areas in mice. Lentiviruses can either overexpress or ...

Force and Position Control in Humans - The Role of Augmented Feedback

During motor behaviour, humans interact with the environment by for example manipulating objects and this is only possible because sensory feedback is constantly integrated into the central nervous system and these sensory inputs need to be weighted in order meet the task specific goals. Additional feedback presented as augmented feedback was shown to have an impact on motor control and motor learning. A number of studies investigated whether force or position feedback has an influence on motor control and neural activation. However, as in the previous studies the presentation of the force and position feedback was always identical, a recent study assessed whether not only the content but also the interpretation of the feedback has an influence on the time to fatigue of a sustained submaximal contraction and the (inhibitory) activity of the primary motor cortex using subthreshold transcranial magnetic stimulation. This paper describes one possible way to investigate the influence of the interpretation of feedback on motor behaviour by investigating the time to fatigue of submaximal sustained contractions together with the neuromuscular adaptations that can be investigated using surface EMG. Furthermore, the current protocol also describes how motor cortical (inhibitory) activity can be investigated using subthreshold TMS, a method known to act solely on the cortical level. The results show that when participants interpret the feedback as position feedback, they display a significantly shorter time to fatigue of a submaximal sustained contraction. Furthermore, subjects also displayed an increased inhibitory activity of the primary cortex when they believed to receive position feedback compared when they believed to receive force feedback. Accordingly, the results show that interpretation of feedback results in differences on a behavioural level (time to fatigue) that is also reflected in interpretation-specific differences in the amount of inhibitory M1 activity.

Controlling an identical movement with position or force feedback results in different neural activation and motor behavior. This protocol describes how to investigate behavioral changes by looking at neuromuscular fatigue and how to evaluate motor cortical (inhibitory) activity using subthreshold TMS with respect to the interpretation of augmented feedback.

During motor behaviour, humans interact with the environment by for example manipulating objects and this is only possible because sensory feedback is ...

Novel Object Exploration as a Potential Assay for Higher Order Repetitive Behaviors in Mice

Restricted, repetitive behaviors (RRBs) are a core feature of autism spectrum disorder (ASD) and disrupt the lives of affected individuals. RRBs are commonly split into lower-order and higher-order components, with lower order RRBs consisting of motor stereotypies and higher order RRBs consisting of perseverative and sequencing behaviors. Higher order RRBs are challenging to model in mice. Current assays for RRBs in mice focus primarily on the lower order components, making basic biomedical research into potential treatments or interventions for higher-order RRBs difficult. Here we describe a new assay, novel object exploration. This assay uses a basic open-field arena with four novel objects placed around the perimeter. The test mouse is allowed to freely explore the arena and the order in which the mouse investigates the novel objects is recorded. From these data, patterned sequences of exploration can be identified, as can the most preferred object for each mouse. The representative data shared here and past results using the novel object exploration assay illustrate that inbred mouse strains do demonstrate different behavior in this assay and that strains with elevated lower order RRBs also show elevated patterned behavior. As such, the novel object exploration assay appears to possess good face validity for higher order RRBs in humans and may be a valuable assay for future studies investigating novel therapeutics for ASD.

Higher order restricted, repetitive behaviors (RRBs) disrupt the lives of affected individuals. These behaviors are challenging to model in rodents, making basic biomedical research into potential treatments or interventions for RRBs difficult. Here we describe novel object exploration as a potential assay for higher order RRBs in mice.

Restricted, repetitive behaviors (RRBs) are a core feature of autism spectrum disorder (ASD) and disrupt the lives of affected individuals.  RRBs are ...

Novel Object Recognition Test for the Investigation of Learning and Memory in Mice

The object recognition test (ORT) is a commonly used behavioral assay for the investigation of various aspects of learning and memory in mice. The ORT is fairly simple and can be completed over 3 days: habituation day, training day, and testing day. During training, the mouse is allowed to explore 2 identical objects. On test day, one of the training objects is replaced with a novel object. Because mice have an innate preference for novelty, if the mouse recognizes the familiar object, it will spend most of its time at the novel object. Due to this innate preference, there is no need for positive or negative reinforcement or long training schedules. Additionally, the ORT can also be modified for numerous applications. The retention interval can be shortened to examine short-term memory, or lengthened to probe long-term memory. Pharmacological intervention can be used at various times prior to training, after training, or prior to recall to investigate different phases of learning (i.e., acquisition, early or late consolidation, or recall). Overall, the ORT is a relatively low-stress, efficient test for memory in mice, and is appropriate for the detection of neuropsychological changes following pharmacological, biological, or genetic manipulations.

The object recognition test (ORT) is a simple and efficient assay for evaluating learning and memory in mice. The methodology is described below.

The object recognition test (ORT) is a commonly used behavioral assay for the investigation of various aspects of learning and memory in mice. The ORT is ...

The (Spatial) Memory Game: Testing the Relationship Between Spatial Language, Object Knowledge, and Spatial Cognition

The memory game paradigm is a behavioral procedure to explore the relationship between language, spatial memory, and object knowledge. Using two different versions of the paradigm, spatial language use and memory for object location are tested under different, experimentally manipulated conditions. This allows us to tease apart proposed models explaining the influence of object knowledge on spatial language (e.g., spatial demonstratives), and spatial memory, as well as understanding the parameters that affect demonstrative choice and spatial memory more broadly. Key to the development of the method was the need to collect data on language use (e.g., spatial demonstratives: &#34;this/that&#34;) and spatial memory data under strictly controlled conditions, while retaining a degree of ecological validity. The language version (section 3.1) of the memory game tests how conditions affect language use. Participants refer verbally to objects placed at different locations (e.g., using spatial demonstratives: &#34;this/that red circle&#34;). Different parameters can be experimentally manipulated: the distance from the participant, the position of a conspecific, and for example whether the participant owns, knows, or sees the object while referring to it. The same parameters can be manipulated in the memory version of the memory game (section 3.2). This version tests the effects of the different conditions on object-location memory. Following object placement, participants get 10 seconds to memorize the object&#39;s location. After the object and location cues are removed, participants verbally direct the experimenter to move a stick to indicate where the object was. The difference between the memorized and the actual location shows the direction and strength of the memory error, allowing comparisons between the influences of the respective parameters.

The Spatial Memory Game: Testing the Relationship Between Spatial Language, Object Knowledge, and Spatial Cognition

We present a protocol to explore the relationship between spatial language production, spatial memory, and object knowledge. The procedure allows experimental manipulation of, and control over, conditions of object knowledge, language at instruction, and physical location, thus teasing apart cognitive and linguistic models describing interactions between these variables.

The memory game paradigm is a behavioral procedure to explore the relationship between language, spatial memory, and object knowledge. Using two different ...

Control of Eating Behavior Using a Novel Feedback System

Subjects eat food from a plate that sits on a scale connected to a computer that records the weight loss of the plate during the meal and makes up a curve of food intake, meal duration and rate of eating modeled by a quadratic equation. The purpose of the method is to change eating behavior by providing visual feedback on the computer screen that the subject can adapt to because her/his own rate of eating appears on the screen during the meal. The data generated by the method is automatically analyzed and fitted to the quadratic equation using a custom made algorithm. The method has the advantage of recording eating behavior objectively and offers the possibility of changing eating behavior both in experiments and in clinical practice. A limitation may be that experimental subjects are affected by the method. The same limitation may be an advantage in clinical practice, as eating behavior is more easily stabilized by the method. A treatment that uses this method has normalized body weight and restored the health of several hundred patients with anorexia nervosa and other eating disorders and has reduced the weight and improved the health of severely overweight patients.

Subjects eat food from a plate placed on a scale connected to a computer that records the weight loss of the plate during the meal. Feedback on the computer screen allows the subject to adapt her/his eating behavior to reference curves thus normalizing body weight.

Subjects eat food from a plate that sits on a scale connected to a computer that records the weight loss of the plate during the meal and makes up a curve ...

Novel Object Recognition and Object Location Behavioral Testing in Mice on a Budget

Ethologically relevant behavioral testing is a critical component of any study that uses mouse models to study the cognitive effects of various physiological or pathological changes. The object location task (OLT) and the novel object recognition task (NORT) are two effective behavioral tasks commonly used to reveal the function and relative health of specific brain regions involved in memory. While both of these tests exploit the inherent preference of mice for the novelty to reveal memory for previously encountered objects, the OLT primarily evaluates spatial learning, which relies heavily on hippocampal activity. The NORT, in contrast, evaluates non-spatial learning of object identity, which relies on multiple brain regions. Both tasks require an open-field-testing arena, objects with equivalent intrinsic value to mice, appropriate environmental cues, and video recording equipment and the software. Commercially available systems, while convenient, can be costly. This manuscript details a simple, cost-effective method for building the arenas and setting up the equipment necessary to perform the OLT and NORT. Furthermore, the manuscript describes an efficient testing protocol that incorporates both OLT and NORT and provides typical methods for data acquisition and analysis, as well as representative results. Successful completion of these tests can provide valuable insight into the memory function of various mouse model systems and appraise the underlying neural regions that support these functions.

Here we provide a protocol which includes comprehensive instructions for the economical establishment of murine object location and novel object recognition behavioral testing, including the design, cost, and construction of required equipment as well as execution of behavioral testing, data collection, and analysis.

Ethologically relevant behavioral testing is a critical component of any study that uses mouse models to study the cognitive effects of various ...

A Vibrotactile Feedback Device for Seated Balance Assessment and Training

Postural perturbations, motion tracking, and sensory feedback are modern techniques used to challenge, assess, and train upright sitting, respectively. The goal of the developed protocol is to construct and operate a sitting platform that can be passively destabilized while an inertial measurement unit quantifies its motion and vibrating elements deliver tactile feedback to the user. Interchangeable seat attachments alter the stability level of the device to safely challenge sitting balance. A built-in microcontroller allows fine-tuning of the feedback parameters to augment sensory function. Posturographic measures, typical of balance assessment protocols, summarize the motion signals acquired during timed balance trials. No dynamic sitting protocol to date provides variable challenge, quantification, and sensory feedback free of laboratory constraints. Our results demonstrate that non-disabled users of the device exhibit significant changes in posturographic measures when balance difficulty is altered or vibrational feedback provided. The portable, versatile device has potential applications in rehabilitation (following skeletal, muscular, or neurological injury), training (for sports or spatial awareness), entertainment (via virtual or augmented reality), and research (of sitting-related disorders).

A sitting platform has been developed and assembled that passively destabilizes sitting posture in humans. During the user&#39;s stabilizing task, an inertial measurement unit records the device&#39;s motion, and vibrating elements deliver performance-based feedback to the seat. The portable, versatile device may be used in rehabilitation, assessment, and training paradigms.

Postural perturbations, motion tracking, and sensory feedback are modern techniques used to challenge, assess, and train upright sitting, respectively. ...

Multi-Modal Signals for Analyzing Pain Responses to Thermal and Electrical Stimuli

The assessment of pain relies mostly on methods that require a person to communicate. However, for people with cognitive and verbal impairments, existing methods are not sufficient as they lack reliability and validity. To approach this problem, recent research focuses on an objective pain assessment facilitated by parameters of responses derived from physiology, and video and audio signals. To develop reliable automated pain recognition systems, efforts have been made in creating multimodal databases in order to analyze pain and detect valid pain patterns. While the results are promising, they only focus on discriminating pain or pain intensities versus no pain. In order to advance this, research should also consider the quality and duration of pain as they provide additional valuable information for more advanced pain management. To complement existing databases and the analysis of pain regarding quality and length, this paper proposes a psychophysiological experiment to elicit, measure, and collect valid pain reactions. Participants are subjected to painful stimuli that differ in intensity (low, medium, and high), duration (5 s / 1 min), and modality (heat / electric pain) while audio, video (e.g., facial expressions, body gestures, facial skin temperature), and physiological signals (e.g., electrocardiogram [ECG], skin conductance level [SCL], facial electromyography [EMG], and EMG of M. trapezius) are being recorded. The study consists of a calibration phase to determine a subject&#8217;s individual pain range (from low to intolerable pain) and a stimulation phase in which pain stimuli, depending on the calibrated range, are applied. The obtained data may allow refining, improving, and evaluating automated recognition systems in terms of an objective pain assessment. For further development of such systems and to investigate pain reactions in more detail, additional pain modalities such as pressure, chemical, or cold pain should be included in future studies. Recorded data of this study will be released as the &#8220;X-ITE Pain Database&#8221;.

This article focuses on the experimental elicitation of pain through heat (thermal) and electrical stimulation while recording physiological, visual, and paralinguistic responses. It aims at collecting valid multimodal data for analyzing pain based on its intensity, quality, and duration.&#160;

The assessment of pain relies mostly on methods that require a person to communicate. However, for people with cognitive and verbal impairments, existing ...