Name: tactile semiautomatic passive-finger angle stimulator (tspas)
Uploaded: 2020-07-30T12:30:00.000+00:00
Duration: 4 min 40 s
Description: Watch this Scientific Journal Video about Tactile Semiautomatic Passive-Finger Angle Stimulator TSPAS at JoVE.com

This work was supported by the Japan Society for the Promotion of Science KAKENHI Grants JP17J40084, JP18K15339, JP18H05009, JP18H01411, JP18K18835, and JP17K18855. We also thank the technician (Yoshihiko Tamura) in our laboratory for helping us craft the raised angle.

Written informed consent was obtained from the subjects in compliance with the policies of the local medical ethics committee of Okayama University. The testing procedures gained review and consent from the local medical ethics committee of Okayama University.
1. Detailed composition and function of equipment
<ol>
	<li>Tactile angle stimuli
	<ol>
		<li>The TSPAS uses two-dimensional (2D) raised angles to slide passively across the skin and form a tactile spatial representation of the angles (Figure 2). The tactile angles consist of plastic lines and square bases, which are both made from a transparent acrylic sheet. Because the lines composing the angles are equal and symmetrical, by symmetrically changing the spatial dimensions of the lines, all types of raised plane angles can be created.</li>
		<li>Using a milling machine, cut the acrylic sheet into the polyline with two equal lines (8.0 mm long, 1.5 mm wide, and 1.0 mm high) symmetrically distributed along an imaginary bisector and the square base (40.0 mm long and wide, 3.0 mm high).</li>
		<li>Glue the polyline to the center of the square base to create a 2D raised tactile angle stimulus.</li>
		<li>Make pieces with angle sizes ranging from 50&#176; to 70&#176; in 2&#176; increments. The end point distances (d, see Figure 2) of these angles are 6.8 mm, 7.0 mm, 7.3 mm, 7.5 mm, 7.8 mm, 8.0 mm (60&#176; angle), 8.2 mm, 8.5 mm, 8.7 mm, 8.9 mm, and 9.2 mm. To reduce the impact of the end point distance on angle discrimination to the minimum, use a 60&#176; angle as the reference angle, and other angles as comparison angles.</li>
		<li>Make up 20 pairs of discriminated angles, including 20 identical reference angles and 10 pairs of identical comparison angles whose measured accuracies are &#177; 0.2&#176;. Ensure that the reference angle is presented first 50% of the time when each pair is tested. The experiment can be easily and conveniently updated with tactile angle stimuli.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/61218/61218fig02.jpg" /> 
Figure 2: Example of tactile angle stimuli. 
(A) An example of the reference angle (60&#176;) and two (50&#176; and 70&#176;) of the ten comparison angles used in the experiment. In particular, detailed parameters of the reference angle were drawn. d represents the end point distance, R represents the radius of curvature in the local apex, and r represents the radius of curvature in the end point. (B) Example of a raised angle seen in 3D. The height of the raised line is 1.0 mm from the 3D view. <a href="https://www.jove.com/files/ftp_upload/61218/61218fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Hand plate
	<ol>
		<li>To stabilize the subject&#39;s hand, craft a hand plate perpendicular to the electronic slide (Figure 3). First, using a milling machine, cut a 5.0 mm thick acrylic sheet into a 14.0 cm x 22.0 cm rectangle plate, and then fasten the rectangle plate to a base (14.0 cm wide, 14.0 cm long, and 8.5 high) with tape and glue. After that, using a milling machine, cut a rectangular opening (2.5 cm wide and 5.0 cm long) in the upper left corner of the plate. This allows only the index finger to contact the angle stimulus. Before the experiment, fix the subject&#39;s right hand wrist with nylon tape, and then instruct the subjects to lightly place their right index fingers at the opening of the plate.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/61218/61218fig03.jpg" /> 
Figure 3: Hand position of the subject and tactile angle stimuli movement direction. 
The right hand of the subject was secured with nylon tape, and the subject was instructed to place his or her right index finger into the opening in the plate. The angle stimuli were clamped on the apparatus and were horizontally moved by the electronic slide to passively slide across the fingerpad. <a href="https://www.jove.com/files/ftp_upload/61218/61218fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="3">
	<li>Motorized linear slide
	<ol>
		<li>The electronic slide with a maximum motion distance of 51.0 cm is moved in a straight direction using an easy linear motion motor with 5.0 cm high, 5.4 cm wide, and 71.0 cm long (see Table of Materials), which is a linear-motion system. Connect the motor to a personal computer and set and edit various data using dedicated data editing software (see Table of Materials). Ensure that these settings can make the electronic slide move a specified distance using a given speed with respect to the reference point. This is necessary when moving the angle stimuli directly from an arbitrary position to a specified position.</li>
	</ol>
	</li>
	<li>Computer control system
	<ol>
		<li>The TSPAS is a semiautomatic, computer-controlled system. The data editing software used to control the movement of the slide is PC-based software for editing the data necessary for the operation of motorized actuators. In the experiment, set the velocity of the slide at 20 mm/s and its moving distance at 80 mm for each trial. Each time a button is clicked, the slide moves as previously set.</li>
	</ol>
	</li>
</ol>
2. Running an experiment
<ol>
	<li>Before the experiment, first set the motion type as &#8216;INC&#8217;, motion distance as &#8216;80 mm&#8217;, motion speed as &#8216;20 mm/s&#8217;, motion function as &#8216;single&#8217;, and axis as &#8216;ID = 0&#8217; in the data editing software (see the operating manual in the Table of Materials for instructions on how to set parameters) to ensure that the electronic slide can move both at a distance of 80 mm and a speed of 20 mm/s forward and backward, and at other distances and speeds.</li>
	<li>Recruit subjects whose fingers are free of injuries and calluses. Try to recruit an equal number of male and female subjects within the age range from 18&#8211;35 years old. Note that there is a difference in tactile spatial acuity between female and male subjects, as well as old and young subjects25,26.</li>
	<li>Blindfold the subject and sit him or her at a table with the apparatus (Figure 1). Fix the right hand of the subject with nylon tape and subsequently instruct the subject to lightly place his or her right index finger at the opening of the hand plate (Figure 3).</li>
	<li>Clamp a pair of angles, including the reference angle and the comparison angle, on the slide. After clicking the button, the pair of angles slide for a total distance of 80 mm. They passively go across the index fingerpad at a speed of 20 mm/s. Because there is a distance of 31.8 &#177; 0.8 mm between the reference angle and comparison angle, their interstimulus time interval is approximately 1.6 s.</li>
	<li>After the subject perceives the sizes of the angles, he or she orally reports which of the two angles is larger. If the subject cannot identify which angle is larger, he or she can indicate that the angles are the same. Register the answer of the subject as the response data. After that, the next pair of angles will be continually replaced, presented, and perceived in the same way.</li>
	<li>There are a total of 10 pairs of angles in the formal experiment. Present each pair 10x in a pseudorandom order in which the reference angle passes first 50% of the time. Thus, the experiment contains 100 trials. To avoid uncomfortable sensations on the index finger, after each series of 20 trials have the subject take a 3 min break. Before the experiment, each subject practices 10 trials with other angles to be familiar with the experimental procedure. The experiment should last ~40 min.</li>
</ol>

<ol>
	<li>Smith, A. M., Chapman, C. E., Donati, F., Fortier-Poisson, P., Hayward, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perception+of+simulated+local+shapes+using+active+and+passive+touch.">Perception of simulated local shapes using active and passive touch.</a> Journal of Neurophysiology. 102 (6), 3519-3529 (2009).</li><li>Reuter, E. M., Voelcker-Rehage, C., Vieluf, S., Godde, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Touch+perception+throughout+working+life:+Effects+of+age+and+expertise.">Touch perception throughout working life: Effects of age and expertise.</a> Experimental Brain Research. 216 (2), 287-297 (2012).</li><li>Craig, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grating+orientation+as+a+measure+of+tactile+spatial+acuity.">Grating orientation as a measure of tactile spatial acuity.</a> Somatosensory and Motor Research. 16 (3), 197-206 (1999).</li><li>Craig, J. C., Johnson, K. 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+two-point+threshold:+Not+a+measure+of+tactile+spatial+resolution.">The two-point threshold: Not a measure of tactile spatial resolution.</a> Current Directions in Psychological Science. 9 (1), 29-32 (2000).</li><li>Tong, J., Mao, O., Goldreich, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-point+orientation+discrimination+versus+the+traditional+two-point+test+for+tactile+spatial+acuity+assessment.">Two-point orientation discrimination versus the traditional two-point test for tactile spatial acuity assessment.</a> Frontiers in Human Neuroscience. 7, 1-11 (2013).</li><li>Goldreich, D., Wong, M., Peters, R. M., Kanics, I. 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+tactile+automated+passive-finger+stimulator+(TAPS).">A tactile automated passive-finger stimulator (TAPS).</a> Journal of Visualized Experiments. (28), e1374 (2009).</li><li>Johnson, K. O., Phillips, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+spatial+resolution.+I.+Two-point+discrimination,+gap+detection,+grating+resolution,+and+letter+recognition.">Tactile spatial resolution. I. Two-point discrimination, gap detection, grating resolution, and letter recognition.</a> Journal of Neurophysiology. 46 (6), 1177-1191 (1981).</li><li>Legge, G. E., Madison, C., Vaughn, B. N., Cheong, A. M. Y., Miller, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retention+of+high+tactile+acuity+throughout+the+life+span+in+blindness.">Retention of high tactile acuity throughout the life span in blindness.</a> Perception and Psychophysics. 70 (8), 1471-1488 (2008).</li><li>Yang, J., Ogasa, T., Ohta, Y., Abe, K., Wu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decline+of+human+tactile+angle+discrimination+in+patients+with+mild+cognitive+impairment+and+Alzheimer's+disease.">Decline of human tactile angle discrimination in patients with mild cognitive impairment and Alzheimer's disease.</a> Journal of Alzheimer's Disease. 22 (1), 225-234 (2010).</li><li>Wu, J., Yang, J., Ogasa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Raised-angle+discrimination+under+passive+finger+movement.">Raised-angle discrimination under passive finger movement.</a> Perception. 39 (7), 993-1006 (2010).</li><li>Sathian, K., Zangaladze, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+learning+is+task+specific+but+transfers+between+fingers.">Tactile learning is task specific but transfers between fingers.</a> Perception and Psychophysics. 59 (1), 119-128 (1997).</li><li>Wong, M., Peters, R. M., Goldreich, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+physical+constraint+on+perceptual+learning:+tactile+spatial+acuity+improves+with+training+to+a+limit+set+by+finger+size.">A physical constraint on perceptual learning: tactile spatial acuity improves with training to a limit set by finger size.</a> Journal of Neuroscience. 33 (22), 9345-9352 (2013).</li><li>Trzcinski, N. K., Gomez-Ramirez, M., Hsiao, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+consequences+of+experience-dependent+plasticity+on+tactile+perception+following+perceptual+learning.">Functional consequences of experience-dependent plasticity on tactile perception following perceptual learning.</a> European Journal of Neuroscience. 44 (6), 2375-2386 (2016).</li><li>Essock, E. A., Krebs, W. K., Prather, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superior+Sensitivity+for+Tactile+Stimuli+Oriented+Proximally-Distally+on+the+Finger:+Implications+for+Mixed+Class+1+and+Class+2+Anisotropies.">Superior Sensitivity for Tactile Stimuli Oriented Proximally-Distally on the Finger: Implications for Mixed Class 1 and Class 2 Anisotropies.</a> Journal of Experimental Psychology: Human Perception and Performance. 23 (2), 515-527 (1997).</li><li>Gurtubay-Antolin, A., Leon-Cabrera, P., Rodriguez-Fornells, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+evidence+of+hierarchical+cognitive+control+during+Haptic+processing:+An+fMRI+study.">Neural evidence of hierarchical cognitive control during Haptic processing: An fMRI study.</a> eNeuro. 5 (6), (2018).</li><li>Yang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+priming+modulates+the+activation+of+the+fronto-parietal+circuit+during+tactile+angle+match+and+non-match+processing:+an+fMRI+study.">Tactile priming modulates the activation of the fronto-parietal circuit during tactile angle match and non-match processing: an fMRI study.</a> Frontiers in Human Neuroscience. 8, 926 (2014).</li><li>Yu, Y., Yang, J., Ejima, Y., Fukuyama, H., Wu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+Functional+Connectivity+of+the+Contra-+and+Ipsilateral+Secondary+Somatosensory+Cortex+during+Tactile+Object+Recognition.">Asymmetric Functional Connectivity of the Contra- and Ipsilateral Secondary Somatosensory Cortex during Tactile Object Recognition.</a> Frontiers in Human Neuroscience. 11, (2018).</li><li>Olczak, D., Sukumar, V., Pruszynski, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Edge+orientation+perception+during+active+touch.">Edge orientation perception during active touch.</a> Journal of Neurophysiology. 120 (5), 2423-2429 (2018).</li><li>Lederman, S. J., Taylor, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perception+of+interpolated+position+and+orientation+by+vision+and+active+touch.">Perception of interpolated position and orientation by vision and active touch.</a> Perception and Psychophysics. 6 (3), 153-159 (1969).</li><li>Peters, R. M., Staibano, P., Goldreich, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+orientation+perception:+An+ideal+observer+analysis+of+human+psychophysical+performance+in+relation+to+macaque+area+3b+receptive+fields.">Tactile orientation perception: An ideal observer analysis of human psychophysical performance in relation to macaque area 3b receptive fields.</a> Journal of Neurophysiology. 114 (6), 3076-3096 (2015).</li><li>Bensmaia, S. J., Hsiao, S. S., Denchev, P. V., Killebrew, J. H., Craig, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+tactile+perception+of+stimulus+orientation.">The tactile perception of stimulus orientation.</a> Somatosensory and Motor Research. 25 (1), 49-59 (2008).</li><li>Morash, V., Pensky, A. E. C., Alfaro, A. U., McKerracher, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+haptic+spatial+abilities+in+the+blind.">A review of haptic spatial abilities in the blind.</a> Spatial Cognition and Computation. 12 (2-3), 83-95 (2012).</li><li>Wang, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+angle+discriminability+improvement:+roles+of+training+time+intervals+and+different+types+of+training+tasks.">Tactile angle discriminability improvement: roles of training time intervals and different types of training tasks.</a> Journal of Neurophysiology. 122 (5), 1918-1927 (2019).</li><li>Yang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+priming+modulates+the+activation+of+the+fronto-parietal+circuit+during+tactile+angle+match+and+non-match+processing:+an+fMRI+study.">Tactile priming modulates the activation of the fronto-parietal circuit during tactile angle match and non-match processing: an fMRI study.</a> Frontiers in Human Neuroscience. 8, 926 (2014).</li><li>Peters, R. M., Hackeman, E., Goldreich, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diminutive+Digits+Discern+Delicate+Details:+Fingertip+Size+and+the+Sex+Difference+in+Tactile+Spatial+Acuity.">Diminutive Digits Discern Delicate Details: Fingertip Size and the Sex Difference in Tactile Spatial Acuity.</a> Journal of Neuroscience. 29 (50), 15756-15761 (2009).</li><li>Sathian, K., Zangaladze, A., Green, J., Vitek, J. L., DeLong, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tactile+spatial+acuity+and+roughness+discrimination:+Impairments+due+to+aging+and+Parkinson's+disease.">Tactile spatial acuity and roughness discrimination: Impairments due to aging and Parkinson's disease.</a> Neurology. 49 (1), 168-177 (1997).</li><li>Hoehler, F. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Logistic+equations+in+the+analysis+of+S-shaped+curves.">Logistic equations in the analysis of S-shaped curves.</a> Computers in Biology and Medicine. 5 (3), 367-371 (1995).</li><li>Kuehn, E., Doehler, J., Pleger, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+vision+on+tactile+Hebbian+learning.">The influence of vision on tactile Hebbian learning.</a> Scientific Reports. 7 (1), 1-11 (2017).</li><li>Weder, B., Nienhusmeier, M., Keel, A., Leenders, K. L., Ludin, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Somatosensory+discrimination+of+shape:+Prediction+of+success+in+normal+volunteers+and+parkinsonian+patients.">Somatosensory discrimination of shape: Prediction of success in normal volunteers and parkinsonian patients.</a> Experimental Brain Research. 120 (1), 104-108 (1998).</li></ol>

The authors declare that they have no competing conflicts of interest, financial or otherwise.

A new measure for tactile spatial acuity, tactile AD, is presented. In this system a pair of angles passively slides across the immobilized index fingerpad of a subject. AD combines the advantages of GO and TPD, reducing the impact of intensive cues and the neural peak impulse rate of a single point. This study shows that there is a gradual change in perceptual discrimination as the angle difference changes between the reference angle and the comparison angle4. In addition to the age effect, train...

Touch perception is a fundamental form of the sensations processed by the somatosensory system, including haptic perception and tactile perception. Passive tactile perception, as opposed to active exploration, means that the object is moved to make contact with static skin1,2. As in other senses, spatial resolution in tactile perception, also termed tactile spatial acuity, is usually represented by the tactile threshold, detection threshold, or discrimination threshold2,3. In the past 100 years, the two-point threshold has commonly been used as a measure of tactile spatial acuity4. However, many studies have indicated that the two-point threshold is an invalid index of tactile spatial ability because two-point discrimination (TPD) cannot exclude nonspatial cues (e.g., if two points are too close, they may locate a single afferent receptive field, which readily evokes increased neural activity) and maintain a stable criterion for responses3,4,5. Owing to the number of drawbacks of TPD, several new and promising methods have been developed as replacements, such as tactile grating orientation (GO)3,6, two-point orientation discrimination5, raised letter recognition, gap detection7, dot patterns, Landolt C rings8, and angle discrimination (AD)9,10. At present, because of the advantages in operating GO, as well as the spatial structure and complexity of the stimulus used, GO is increasingly used to measure tactile spatial acuity11,12,13.
Although tactile GO is thought to rely on underlying spatial mechanisms, thereby yielding a reliable measure of tactile spatial acuity, it is still debated whether GO performance is partly affected by nonspatial cues14 (e.g., intensive signs that may provide a cue to identify the difference between orientation stimuli). Additionally, GO only consists of simple spatial orientation (i.e., horizontal and vertical) tasks and primarily involves sensory processing, which limits its use when exploring the hierarchical interplay between tactile primary processing in the primary somatosensory cortex and tactile advanced possessing involving the posterior parietal cortex (PPC) and supramarginal gyrus (SMG)15,16,17. To compensate for these drawbacks, tactile AD was developed to measure tactile spatial acuity9,10. In AD, a pair of angles passively slide across the fingertip. The angles vary in size, and the subject needs to determine which of the angles is larger. To consistently accomplish this task, spatial features of tactile angles must be represented and stored in the working memory and then compared and discerned. Therefore, tactile AD involves not only primary processing but also advanced cognition of tactile perception, such as working memory and attention.
As in a variety of line orientation perception tests, in tactile AD the subject is presented successively with one reference angle and one comparison angle and is asked to indicate which is the larger angle18,19,20,21. The lines composing the angles are equal in length and symmetrically distributed along an imaginary bisector. By symmetrically changing the spatial dimensions of the lines, all types of raised plane angles can be created. Therefore, a critical advantage of this method is that the angles being differentiated have similar spatial structures. In addition, the spatial representation gained in the AD is more sequential than that gained in GO. However, the AD threshold provides evidence that tactile spatial acuity is sufficient to allow spatial discrimination between objects22. Furthermore, the tactile spatial perception of the angle may be experienced from point to line and finally form a two-dimensional plane angle in which nonspatial cues may play only a small role.
The AD threshold was found to increase with increasing age, which might result from the need for high cognitive load in the tactile AD task. Thus, it may provide a monitoring mechanism in cognitive impairment diagnosis9,10. Although AD performance is affected by age-related decline, it can be significantly improved in young people by continuous training or similar tactile task training23. Furthermore, fMRI studies showed that a delayed match-to-sample tactile angle task activated certain cortical regions responsible for working memory, such as the posterior parietal cortex17,24. These findings suggest that tactile angle discrimination is a promising measure for tactile spatial acuity involving advanced cognition. Here, the tactile AD equipment and its use is described in detail. Other tactile researchers can reproduce the AD equipment and use it in their research.
The tactile AD equipment, or tactile semiautomatic passive-finger angle stimulator (TSPAS), uses an electronic slide to convey a pair of angle stimuli to slide passively across the skin (Figure 1). The subjects&#39; arms lie comfortably, prostrate on a tabletop. The right hand sits on a hand plate in the table, and an index fingerpad is situated slightly below the opening of the plate. Computer software can control the slide, move it at a fixed speed, and move it forward and backward. As the slide moves forward, the angle stimuli slide passively across the skin at a fixed speed starting at the fingertip. When the slide moves backward to its starting position and changes to another pair of angle stimuli, the subject needs to lift the index finger up and wait for an order to lightly place it again at the opening. Thus, the equipment presents tactile angle stimuli at a controlled speed, stable contact duration, and constant interstimulus interval. The subject orally reports a sequence number, and the experimenter registers it as a response and proceeds to conduct the next trial.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/61218/61218fig01.jpg" /> 
Figure 1: Overview of the TSPAS. 
The equipment consists of four parts: 1) tactile angle stimuli (i.e., the reference angle and ten comparison angles); 2) the hand plate that fixes the hand of the subject in place and keeps only the index finger in contact with the stimuli; 3) the electronic slider that carries the tactile stimuli; and 4) the personal computer (PC) control system that controls the speed and the movement distance of the electronic slide. <a href="https://www.jove.com/files/ftp_upload/61218/61218fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table><tbody><tr><td>Acrylic sheet (3 mm)</td><td>MonotaRO Co.,Ltd.</td><td>33159874</td><td>Good Material</td></tr><tr><td>Acrylic sheet (1 mm)</td><td>MonotaRO Co.,Ltd.</td><td>45547101</td><td>Good Material</td></tr><tr><td>EZ limo (easy linear motion motor)</td><td>ORIENTAL MOTOR CO., LTD. Made in Japan</td><td>EZS3</td><td>Good Motorized Linear Slides</td></tr><tr><td>Data Editing Software</td><td>ORIENTAL MOTOR CO., LTD. Made in Japan</td><td>EZED2</td><td>easy to use</td></tr><tr><td>Operating Manual (Orientalmotor)</td><td>ORIENTAL MOTOR CO., LTD. Made in Japan</td><td>HL-17151-2</td><td>Good Guidebook</td></tr></tbody></table>

tactile semiautomatic passive-finger angle stimulator (tspas)

Passive tactile perception is the ability to passively and statically perceive stimulus information coming from the skin; for example, the ability to sense spatial information is the strongest in the skin on the hands. This ability is termed tactile spatial acuity, and is measured by the tactile threshold or discrimination threshold. At present, the two-point threshold is extensively used as a measure of tactile spatial acuity, although many studies have indicated that critical deficits exist in two-point discrimination. Therefore, a computer-controlled tactile stimulus system was developed, the tactile semiautomated passive-finger angle stimulator (TSPAS), using the tactile angle discrimination threshold as a new measure for tactile spatial acuity. The TSPAS is a simple, easily operated system that applies raised angle stimuli to a subject&#39;s passive fingerpad, while controlling movement speed, distance, and contact duration. The components of the TSPAS are described in detail as well as the procedure to calculate the tactile angle discrimination threshold.

In this study, the 3AFC (3-alternative forced-choice) technique and the logistic curve were used to estimate the tactile AD threshold. Participants were instructed to orally report the larger of the two angles perceived, or if they did not detect the difference, they could indicate the same. The equation of the logistic curve, which has been commonly applied to psychophysical experiments to measure thresholds27,28,29 is:
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Tactile Semiautomatic Passive-Finger Angle Stimulator TSPAS

Presented is the tactile semiautomated passive-finger angle stimulator TSPAS, a new way to assess tactile spatial acuity and tactile angle discrimination using a computer-controlled tactile stimulus system that applies raised angle stimuli to a subject&#39;s passive fingerpad, while controlling for movement speed, distance, and contact duration.

Tactile Semiautomatic Passive-Finger Angle Stimulator (TSPAS)

Passive tactile perception is the ability to passively and statically perceive stimulus information coming from the skin; for example, the ability to ...

tactile-semiautomatic-passive-finger-angle-stimulator-tspas

Research

JoVE Journal

Behavior

2.8K Views.  Okayama University. Gepresenteerd is de tactiele semi-automatische passieve-vinger hoekstimulator TSPAS, een nieuwe manier om tactiele ruimtelijke scherpte en tactiele hoekdiscriminatie te beoordelen met behulp van een computergestuurd tactiel stimulussysteem dat verhoogde hoekprikkels toepast op het passieve vingerpad van een onderwerp, terwijl het wordt gecontroleerd op bewegingssnelheid, afstand en contactduur.

Video: Tactile Semiautomatic Passive-Finger Angle Stimulator TSPAS

Measurement of Vibration Detection Threshold and Tactile Spatial Acuity in Human Subjects

Tests that allow the precise determination of psychophysical thresholds for vibration and grating orientation provide valuable information about mechanosensory function that are relevant for clinical diagnosis as well as for basic research. Here, we describe two psychophysical tests designed to determine the vibration detection threshold (automated system) and tactile spatial acuity (handheld device). Both procedures implement a two-interval forced-choice and a transformed-rule up and down experimental paradigm. These tests have been used to obtain mechanosensory profiles for individuals from distinct human cohorts such as twins or people with sensorineural deafness.

Here, we present protocols to determine vibration detection thresholds and tactile acuity using psychophysical methods in man.

Tests that allow the precise determination of psychophysical thresholds for vibration and grating orientation provide valuable information about ...

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 ...

Testing Tactile Masking between the Forearms

Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, usually using stimuli that are close together to reveal local interactions. Masking effects have also been demonstrated in which a tactile stimulus alters the perception of a touch at a distant location. Such effects can provide insight into how components of the body's representations in the brain may be linked. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at corresponding contralateral locations. To explore the matching of corresponding points across the body, we can measure the spatial tuning and effect of posture on contralateral masking. Careful controls are required to rule out direct effects of the remote stimulus, for example by mechanical transmission, and also attention effects in which thresholds may be altered by the participant's attention being drawn away from the stimulus of interest. The use of this technique is beneficial as a behavioural measure for exploring which parts of the body are functionally connected and whether the two sides of the body interact in a somatotopic representation. This manuscript describes a behavioural protocol that can be used for studying contralateral tactile masking.

Here we explore contralateral tactile masking between the forearms in which tactile detection thresholds are modulated by vibration applied to a remote site. The details of which remote sites have an effect can tell us about how the body is represented in the brain.

Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, ...

Breathing-controlled Electrical Stimulation (BreEStim) for Management of Neuropathic Pain and Spasticity

Electrical stimulation (EStim) refers to the application of electrical current to muscles or nerves in order to achieve functional and therapeutic goals. It has been extensively used in various clinical settings. Based upon recent discoveries related to the systemic effects of voluntary breathing and intrinsic physiological interactions among systems during voluntary breathing, a new EStim protocol, Breathing-controlled Electrical Stimulation (BreEStim), has been developed to augment the effects of electrical stimulation. In BreEStim, a single-pulse electrical stimulus is triggered and delivered to the target area when the airflow rate of an isolated voluntary inspiration reaches the threshold. BreEStim integrates intrinsic physiological interactions that are activated during voluntary breathing and has demonstrated excellent clinical efficacy. Two representative applications of BreEStim are reported with detailed protocols: management of post-stroke finger flexor spasticity and neuropathic pain in spinal cord injury.

Breathing-controlled Electrical Stimulation BreEStim for Management of Neuropathic Pain and Spasticity

The purpose is to present a new method, breathing-control electrical stimulation (BreEStim) for management of neuropathic pain and spasticity.

Electrical stimulation (EStim) refers to the application of electrical current to muscles or nerves in order to achieve functional and therapeutic goals. ...

Medicine

A Simple Non-invasive Method for Temporary Knockdown of Upper Limb Proprioception

Proprioception may be the least well measured of all contributors to the neural control of movement. New precise, reliable measures of proprioception are needed for clinical diagnosis of impairment, and to measure outcomes of proprioceptive training. The purpose of this simple, non-invasive method is to temporarily knockdown upper limb proprioception in healthy adults, to an extent that would be useful in the development and testing of upper limb proprioception measures. Knockdown models have two main advantages over studying humans with impaired proprioception: participant availability and the ability to control the extent of impairment across participants. Current published methods of temporary proprioception knockdown of the upper limb, such as ischemic nerve blocks and cryotherapy, are invasive, impractical, or uncomfortable for the participant. Here, vibration over the ulnar groove was used to reduce upper limb proprioception. High frequency vibration may reduce proprioceptive acuity by inhibiting pacinian corpuscle-induced input. The effect of vibration used in this protocol was confirmed using two quantitative measures. This method was simple to administer, comfortable for participants, and practical.

The goal of this protocol is to demonstrate a practical method to temporarily interfere with proprioception in the upper limb of healthy humans.

Proprioception may be the least well measured of all contributors to the neural control of movement. New precise, reliable measures of proprioception are ...

A Tactile Automated Passive-Finger Stimulator (TAPS)

Although tactile spatial acuity tests are used in both neuroscience research and clinical assessment, few automated devices exist for delivering controlled spatially structured stimuli to the skin. Consequently, investigators often apply tactile stimuli manually. Manual stimulus application is time consuming, requires great care and concentration on the part of the investigator, and leaves many stimulus parameters uncontrolled. We describe here a computer-controlled tactile stimulus system, the Tactile Automated Passive-finger Stimulator (TAPS), that applies spatially structured stimuli to the skin, controlling for onset velocity, contact force, and contact duration. TAPS is a versatile, programmable system, capable of efficiently conducting a variety of psychophysical procedures. We describe the components of TAPS, and show how TAPS is used to administer a two-interval forced-choice tactile grating orientation test.
Corresponding Author: Daniel Goldreich

A Tactile Automated Passive-Finger Stimulator TAPS

We describe a computer-controlled device for investigating the sense of touch: the Tactile Automated Passive-finger Stimulator (TAPS). We describe the components of TAPS, and show how TAPS is used to administer a two-interval forced-choice tactile grating orientation test.

Although tactile spatial acuity tests are used in both neuroscience research and clinical assessment, few automated devices exist for delivering ...

Biology

A Simple Stimulatory Device for Evoking Point-like Tactile Stimuli: A Searchlight for LFP to Spike Transitions

Current neurophysiological research has the aim to develop methodologies to investigate the signal route from neuron to neuron, namely in the transitions from spikes to Local Field Potentials (LFPs) and from LFPs to spikes.
LFPs have a complex dependence on spike activity and their relation is still poorly understood1. The elucidation of these signal relations would be helpful both for clinical diagnostics (e.g. stimulation paradigms for Deep Brain Stimulation) and for a deeper comprehension of neural coding strategies in normal and pathological conditions (e.g. epilepsy, Parkinson disease, chronic pain). To this aim, one has to solve technical issues related to stimulation devices, stimulation paradigms and computational analyses. Therefore, a custom-made stimulation device was developed in order to deliver stimuli well regulated in space and time that does not incur in mechanical resonance. Subsequently, as an exemplification, a set of reliable LFP-spike relationships was extracted.
The performance of the device was investigated by extracellular recordings, jointly spikes and LFP responses to the applied stimuli, from the rat Primary Somatosensory cortex. Then, by means of a multi-objective optimization strategy, a predictive model for spike occurrence based on LFPs was estimated.
The application of this paradigm shows that the device is adequately suited to deliver high frequency tactile stimulation, outperforming common piezoelectric actuators. As a proof of the efficacy of the device, the following results were presented: 1) the timing and reliability of LFP responses well match the spike responses, 2) LFPs are sensitive to the stimulation history and capture not only the average response but also the trial-to-trial fluctuations in the spike activity and, finally, 3) by using the LFP signal it is possible to estimate a range of predictive models that capture different aspects of the spike activity.

To elucidate the complex transition from Local Field Potentials (LFPs) to spikes a suitable stimulator for light mechanical peripheral stimuli was built. As an application, the spiking activities recorded from somatosensory cortex were analyzed by a multi-objective optimization strategy. The results demonstrated that the proposed stimulator was able to deliver tactile stimuli with millisecond and millimeter precisions.

Current neurophysiological research has the aim to develop methodologies to investigate the signal route from neuron to neuron, namely in the transitions ...

Neuroscience

Revolutionizing Stroke Rehabilitation with Enhanced Grasping and Finger Recovery

A Flexible Wearable Supernumerary Robotic Limb for Chronic Stroke Patients

In this study, we present a flexible wearable supernumerary robotic limb that helps chronic stroke patients with finger rehabilitation and grasping movements. The design of this innovative limb draws inspiration from bending pneumatic muscles and the unique characteristics of an elephant's trunk tip. It places a strong emphasis on crucial factors such as lightweight construction, safety, compliance, waterproofing, and achieving a high output-to-weight/pressure ratio. The proposed structure enables the robotic limb to perform both envelope and fingertip grasping. Human-robot interaction is facilitated through a flexible bending sensor, detecting the wearer's finger movements and connecting them to motion control via a threshold segmentation method. Additionally, the system is portable for versatile daily use. To validate the effectiveness of this innovation, real-world experiments involving six chronic stroke patients and three healthy volunteers were conducted. The feedback received through questionnaires indicates that the designed mechanism holds immense promise in assisting chronic stroke patients with their daily grasping activities, potentially improving their quality of life and rehabilitation outcomes.

Author Spotlight: Enhancing Grasping Abilities for Hemiplegic Patients with Flexible Robotic Limbs 

This protocol introduces a flexible wearable supernumerary robotic limb tailored to assist in finger rehabilitation for stroke patients. The design incorporates a bending sensor to facilitate seamless human-robot interaction. Validation through experiments involving both healthy volunteers and stroke patients underscores the efficacy and dependability of the proposed study.

In this study, we present a flexible wearable supernumerary robotic limb that helps chronic stroke patients with finger rehabilitation and grasping ...

Engineering

Ocular Kinematics Measured by In Vitro Stimulation of the Cranial Nerves in the Turtle

After animals are euthanized, their tissues begin to die. Turtles offer an advantage because of a longer survival time of their tissues, especially when compared to warm-blooded vertebrates. Because of this, in vitro experiments in turtles can be performed for extended periods of time to investigate the neural signals and control of their target actions. Using an isolated head preparation, we measured the kinematics of eye movements in turtles, and their modulation by electrical signals carried by cranial nerves. After the brain was removed from the skull, leaving the cranial nerves intact, the dissected head was placed in a gimbal to calibrate eye movements. Glass electrodes were attached to cranial nerves (oculomotor, trochlear, and abducens) and stimulated with currents to evoke eye movements. We monitored eye movements with an infrared video tracking system and quantified rotations of the eyes. Current pulses with a range of amplitudes, frequencies, and train durations were used to observe effects on responses. Because the preparation is separated from the brain, the efferent pathway going to muscle targets can be examined in isolation to investigate neural signaling in the absence of centrally processed sensory information.

Ocular Kinematics Measured by In Vitro Stimulation of the Cranial Nerves in the Turtle

This protocol describes how to use an in vitro isolated turtle head preparation to measure the kinematics of their eye movements. After removal of the brain from the cranium, cranial nerves can be stimulated with currents to quantify rotations of the eye and changes in pupil sizes.

After animals are euthanized, their tissues begin to die. Turtles offer an advantage because of a longer survival time of their tissues, especially when ...

Therapy Interventions for Upper Limb Amputees Undergoing Selective Nerve Transfers

Targeted Muscle Reinnervation (TMR) improves the biological control interface for myoelectric prostheses after above-elbow amputation. Selective activation of muscle units is made possible by surgically re-routing nerves, yielding a high number of independent myoelectric control signals. However, this intervention requires careful patient selection and specific rehabilitation therapy. Here a rehabilitation protocol is presented for high-level upper limb amputees undergoing TMR, based on an expert Delphi study. Interventions before surgery include detailed patient assessment and general measures for pain control, muscle endurance and strength, balance, and range of motion of the remaining joints. After surgery, additional therapeutic interventions focus on edema control and scar treatment and the selective activation of cortical areas responsible for upper limb control. Following successful&#160;reinnervation of target muscles, surface electromyographic (sEMG) biofeedback is used to train the activation of the novel muscular units. Later on, a table-top prosthesis may provide the first experience of prosthetic control. After fitting the actual prosthesis, training includes repetitive drills without objects, object manipulation, and finally, activities of daily living. Ultimately, regular patient appointments and functional assessments allow tracking prosthetic function and enabling early interventions if malfunctioning.

This work presents a protocol to enhance prosthetic function after selective nerve transfer surgery. Rehabilitation interventions include patient information and selection, support of wound healing, cortical re-activation of sensory-motor areas of the upper limb, training of selective muscle activation, prosthetic handling in daily life, and regular follow-up assessments.

Tactile Semiautomatic Passive-Finger Angle Stimulator (TSPAS)

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