LRH wurde von der Natur- und Ingenieurwissenschaften Research Council (NSERC) von Kanada unterstützt. SD wurde teilweise von der NSERC CREATE Programm unterstützt.

Alle Versuche wurden von der York Ethics Board genehmigt und alle Teilnehmer Einverständniserklärungen unterzeichnet. Die Experimente wurden in Übereinstimmung mit dem Vertrag von Helsinki durchgeführt. 1. Stimuli <ol><li> Taktile Erkennung Stimulus <ol><li> Verwenden Sie ein Schütz (1,17 &quot;Durchmesser und 0,30&quot; dick) für 100 ms taktile Reize von 250 Hz Vibration zu liefern. eine speziell gebaute Schütz Verwendung liefert eine lineare Beziehung zwischen dem Betrag der Bewegung und der angelegten Spannung. </li><li> Kontrollieren Tastreizes Lieferung mit einem 64-Bit-Soundkarte. <ol><li> Um das Schütz, behandeln es als einen Lautsprecher treiben. Schließen Sie einen Stereo-Audio-Verstärker auf eine 64-Bit-Computer-Stereo-Soundkarte. Schließen Sie das Schütz zu einem der Ausgänge des Verstärkers (zB die &quot;linken Lautsprecherausgang). Schließen Sie den zweiten Kanal (zB die &quot;richtige Lautsprecherausgang&quot;) des Verstärkers zu einem regulären Lautsprecher akustische Signale an das Par zu schaffennehmer. </li><li> In der Computercode, der das Experiment steuert, erzeugt die Wellenform, die das Schütz (beispielsweise eine 250 Hz Sinuswelle mit einer Dauer von 100 msec), und eine andere Wellenform für die akustischen Signal (beispielsweise ein 3000 Hz Sinuswelle mit einer verwendet werden soll zum Schwingen Dauer von 100 msec). Siehe Beispiel Code 1 in der Zubehör-Code-Datei. </li><li> Setzen jeder dieser beiden Wellenformen in eine zweidimensionale Anordnung. Für die Schütz Array setzen das Signal in der ersten Dimension und stellen Sie die zweite Dimension auf Null. Für den Ton Array setzen das Signal in der zweiten Dimension und stellen die erste auf Null. Spielen Sie den entsprechenden Array an die Soundkarte an der entsprechenden Stelle im Programm. Siehe Beispiel Code 1 in der Zubehör-Code-Datei für eine Demonstration, wie das gemacht wird. </li></ol></li><li> Bringen Sie das Schütz zu einem Gurt mit einem mechanischen basierte Befestigungs Produkt. </li></ol></li><li> Maskierreiz <ol><li> Geben Sie die Maskierreiz durch ein elektrisches, hand Held Vibrator (4 cm Durchmesser, 83 Hz, wenn setzen auf &quot;low&quot;). </li><li> Basierend auf den Gebieten, in denen Maskierung getestet werden soll, wählen Sie die Websites, auf denen die Maskierreizes aufgebracht werden soll. </li></ol></li></ol> 2. Versuchsaufbau und Gestaltung <ol><li> Ordnen Sie den Computer und Geräte auf einem Schreibtisch, mit einem Stuhl davor, für den Experimentator. </li><li> Stellen Sie einen Tisch, auf dem die Teilnehmer ihre linke (Test) Armlehne. Legen Sie einen Stuhl auf der rechten Seite der Tabelle. Legen Sie eine Armlehne Stand neben dem Stuhl, auf dem die Teilnehmer ihr Recht (Maskierung Arm) Ellenbogen ruhen. In Polsterung an den Tisch und Armlehne für Komfort. </li><li> Vereinbaren Sie einen Lautsprecher auf einem mechanisch isoliert Oberfläche. Vereinbaren Fußpedale (verbunden mit dem linken und rechten Tasten einer Computermaus), so dass die Füße des Teilnehmers wird bequem auf ihnen (Abbildung 1) ruhen. </li><li> Wählen Sie die Parameter der Studie, einschließlich der entsprechenden Anzahl von Studien erforderlicheine verlässliche Schätzung der Schwellenwert (in der Regel zwischen 40-50 Versuche) und die Anzahl der Blöcke, in welche das Experiment (zB zwei Blöcke von 20-25 Versuche pro Bedingung) unterteilt werden soll zu erhalten. </li><li> Machen Sie eine Liste der Reihenfolge, in der die Bedingungen, durchgeführt werden. Verwenden Sie diese Liste zu bestimmen, wo die Maskierung Reiz für jeden Block zu halten. </li><li> Geben Sie die Anzahl der Versuche direkt in den Computerprogrammcode (zB ntrials = 25; siehe Zusatzcode-Datei). Sicherzustellen, dass jeder Block nicht mehr als 10 min Aufmerksamkeit beizubehalten. </li><li> Programmieren Sie eine Zwei-Alternative-Forced-Choice taktile Detektionsaufgabe 11, in der Intensität Reiz ist mit einem Bayesian adaptive psychophysischen Treppe psychometrischen Verfahren 12 gesteuert. <ol><li> Für jeden Versuch, präsentieren zwei 1 Sekunden-Intervallen, gekennzeichnet durch drei Signaltöne (5 kHz, 3 kHz und 5 kHz, Dauer 100 ms), mit dem taktilen Reiz in der Mitte präsentiert von einem der Intervalle. Haben die Teilnehmer indicate in dem Intervall der Reiz durch Fußpedale (links für erste, direkt für die zweite) vorgestellt wurde. Siehe Beispiel-Code 2, die zeigt, wie die Intervalle ausgeführt werden und erzielt. Hinweis: Die Computer-Scores die Antwort als &quot;richtig&quot; oder &quot;falsch&quot; und dem adaptiven Treppe wählt den nächsten Wert entsprechend präsentiert werden. Hinweis: Dieses Verfahren bestimmt einen Schwellenwert für die Schwingung an der Teststelle zu detektieren. </li></ol></li></ol><img alt="Abbildung 1" src="/files/ftp_upload/53733/53733fig1.jpg" /> Abbildung 1. Experimentelles Design. Diese Abbildung zeigt den Aufbau des Experiments und die verwendeten Materialien. Siehe Text für Details. 3. Versuchsdurchführung <ol><li> Erhalten eine schriftliche Einverständniserklärung. Setzen Sie die Teilnehmer auf dem Stuhl mit den Füßen bequem auf den Antwort Fußpedale ruht und erläutern die Versuchsdurchführung. &lt;/ Li&gt; <li> Messen und die Länge der Rückenfläche des linken Unterarms aufzunehmen. Übernehmen Sie den Gurt so das Schütz in der Mitte des Arms auf halbem Weg zwischen der Innenwinkel des Ellenbogens und der Handgelenksfalte positioniert ist. </li><li> Wickeln Sie ein Tensor Verband lose um den Arm mehrmals das Schütz in Position zu halten. </li><li> Weisen Sie die Teilnehmer ihre linken Arm auf den Tisch zu legen und ihren rechten Ellbogen auf die Armlehne ruhen. Augenbinde, die Teilnehmer zu verhindern, dass sie auf den Reiz oder Standort suchen Maskierung und sie anweisen, während des gesamten Versuchs geradeaus zu schauen. </li><li> Beginnen Sie mit einem Block von 20 Praxis Studien (ohne Maskierung Stimulus), um vertraut zu machen Teilnehmer mit dem taktilen Erkennung Aufgabe und ihnen zu ermöglichen, mit den taktilen Reizen vertraut zu machen. </li><li> Im Anschluss an die Praxis Studien beginnen, das Experiment, die Blöcke von Bedingungen in einer zufälligen, ausgeglichen fahrbereitem Zustand. Vor jeder Block beginnen, stellen Sie sicher, dass die Arme und die Maskierung stimulus sind in den richtigen Positionen. <ol><li> Für jede Bedingung, halten Sie die Maskierreiz von der gewählten Standort, die sich auf der Liste der Bedingungen früher gemacht. Kreuz aus jedem Zustand, wie es laufen wird. Halten Sie die Maskierreiz während jeder Datenblock Sammlung Studien annähernd konstanten Druck aufrechterhalten. Die Maskierreiz können durch dünne Kleidung aufgetragen werden. </li><li> Führen Sie das Versuchsprogramm, das durch eine festgelegte Anzahl von Versuchen ausgeführt wird, wie zuvor ausgewählt. Einführung einer 2 min Ruhezeit nach jedem kurzen Block von Studien. Nach einer gegebenen Block von Studien abgeschlossen ist, wählen Sie die nächste Seite für die Maskierung Reiz und das Programm erneut aus. Wiederholen, bis alle Prüfungen abgeschlossen sind. </li></ol></li></ol> 4. Datenanalyse <ol><li> Durch das adaptive Treppe Programm 12, passen die Teilnehmerdaten mit einem kumulierten Gauß&#39;schen Die Formel für einen kumulierten Gauß&#39;schen zurückgekehrt zu visualisieren und die Schätzung des Schwellenwerts bestätigen(Sigmoid), die von 50% geht (Zufallsniveau - gleiche Anzahl von 0s - falsch und 1&#39;S- korrekt) bis 100% (alle 1, alle korrekt) ist: Wahrscheinlichkeit einer korrekten Antwort = 0,5 + 0,5 / (1 + exp (- (x-x0) / std)) wobei x der Intensitätswert getestet ist, x0 ist die Schwelle von 75% Wert, und std ist die Standardabweichung der Schätzung. Diese Formel kann an die Daten angepasst werden unter Verwendung eines beliebigen Kurvenanpassungssoftware und der damit x0 Wert im Vergleich zu dem adaptiven Treppe Wert. <ol><li> Stellen Sie sicher, dass die Kurve zwischen 50% (Zufall Leistung) und 100% geht. Statistische Analysen durchzuführen (beispielsweise t-Tests oder ANOVA) auf den 75% Schwellenwerten unter jeder Bedingung des Experiments erhalten (beispielsweise zwischen verschiedenen Maskierungs sites) zu bestimmen, ob es irgendwelche Unterschiede zwischen den Bedingungen getestet. </li></ol></li><li> Um Ausreißer zu identifizieren, den Mittelwert und die Standardabweichung für einen bestimmten Zustand zu berechnen. Vergleichen einzelnen Teilnehmer Punktzahl mit der mittleren undwenn ein Einzelergebnis ist mehr als zwei Standardabweichungen von das bedeutet dann betrachten diese Punktzahl als Ausreißer und entfernen Sie sie aus der Analyse. Alternative Kriterien können verwendet werden, falls gewünscht. </li><li> Um die Werte der Intensität der Schütze standardisieren (die in sind in willkürlichen Einheiten), wandeln sie in Bezug auf die Regelschwellen zu Dezibel (gemessen, wenn die Maskierungs Stimulus an die Steuerstelle aufgetragen wird, beispielsweise der Schulter). Verwenden Sie diese Formel: dB = 10 x log 10 (Schwellenwert / Steuer Schwellenwert). </li></ol>

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</ol>

Die Autoren erklären, dass sie keine finanziellen Interessen haben.

Hier wird ein detailliertes Protokoll für Gegen taktile Maskierung wird beschrieben und bisher veröffentlichten Ergebnisse mit Hilfe der Technik taktile Erkennungsschwellen zu testen, werden angezeigt. Der Vorteil dieser Methode ist, dass Schwellen gemessen werden eine psychophysikalisch strengen Technik. Die zwei Alternative gezwungen Wahl (2AFC) Verfahren ist relativ unempfindlich gegenüber Antworttendenz und somit von Aufmerksamkeitseffekten. Die adaptive Treppe Verfahren auf dem tatsächlichen Schwellenwert Honen...

Taktile Maskierung ist, wo ein taktiler Reiz an einer Stelle auf dem Körper, um die Wahrnehmung einer Berührung an einer anderen Stelle verändert. Dies ist eine Technik Pionierarbeit von von Bekesy ein Standort-Wechselwirkungen zu offenbaren, insbesondere laterale Hemmung, zwischen den Bereichen der Haut, die auf der Körperoberfläche benachbart sind. Während taktile Maskierungs ausgiebig über die Jahre untersucht wurde, hat sich die Forschung überwiegend ipsilateral taktile Maskierung unter Verwendung elektrischer Stimulation 2, 3, 4 und taktile Stimulation Druck 5, 6 untersucht. Im Gegensatz dazu haben nur wenige Studien bei Gegen taktile Maskierung sah in dem die Maskierung und Sondenorte entfernt werden weit kann. 9, aber diese Studien wurden weitgehend eingeschränkt Blick auf die Hände und Finger 7 - Langstrecken-taktile Maskierungseffekte wurden zwischen spiegelsymmetrisch Punkte auf der Hand und Arm 5, 7 gezeigt, 10, mit umfangreicheren Teilen des ganzen Körpers weitgehend ignoriert. Ein Ziel dieser Langstrecken-Maskierung Experimente ist zu zeigen, wie die Komponenten der Vertretung der Körper im Gehirn funktionell verknüpft werden. Hier wird das Phänomen der Langstrecken-taktilen Maskierung durch Untersuchung untersucht, wie Vibrationen zu einem Unterarm könnte Tastempfinden Schwellen auf der gegenüberliegenden Unterarm beeinflussen. Schwellenwert bezieht sich auf die minimale Stimulus, der erforderlich ist, einen Stimulus zu detektieren. Wir definieren dies als die Intensität, bei der der Stimulus 75% der Zeit erfasst wird. Wir verwendeten eine taktile Maskierungstechnik, bei der taktile Empfindlichkeit (der reziproke Wert threshold) auf einen Unterarm in Gegenwart eines schwingenden Stimulus (die Maske) auf einem anderen Teil des Körpers gemessen. Wirksame Maskierung wird durch eine Erhöhung der Nachweisgrenze, dh einer Verringerung der Empfindlichkeit ergab. Die Technik kann verwendet werden in Verbindung mit weiteren Manipulationen, wie unterschiedlichen Gliedmaßen Position or Bewegung ihre Auswirkungen auf die Wirksamkeit der Maskierung zu erkunden. Hier haben wir vibrotaktilen Reize als Maskierungs Reiz. Der Vorteil davon ist, dass die Frequenz und damit der Rezeptor-Typ, die es stimuliert gesteuert werden kann. Die Technik könnte erweitert werden, um Schmerzen zu suchen mit Hilfe elektrischer Impulse als Sonde oder Maske oder beides. Außerdem kann jede Website als Maskierungs Website verwendet werden, um die Untersuchung der Akupunktur-Sites zum Beispiel ermöglichen.

<table><tbody><tr><td>C-2 tactor</td><td>ATAC Technology; Engineering Acoustics, Inc.</td><td></td><td>http://www.atactech.com/PR_tactors.html</td></tr><tr><td>Magic Wand</td><td>Hitachi</td><td></td><td>http://magicwandoriginal.com/magic-wand-original/</td></tr><tr><td>FC5 Foot Pedals</td><td>Yamaha Corporation</td><td></td><td>http://ca.yamaha.com/en/products/music-production/accessories/footpedals/fc5/?mode=model</td></tr><tr><td>MATLAB</td><td>The Mathworks, Inc.</td><td></td><td>http://www.mathworks.com/products/matlab/</td></tr><tr><td>Velcro</td><td>Velcro Industries B.V.</td><td></td><td>http://www.velcro.com/</td></tr></tbody></table>

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.

Die Analyse der Daten wurde in 13 berichtet. Tastgefühl (ausgedrückt relativ zu den Schwellenwerten in der Kontrollbedingung gemessen wird) auf dem Unterarm wurde signifikant verringert (Schwellenwerte wurden signifikant erhöht), wenn vibrotaktile Maskierungs Stimulation zum gegenüberliegenden Arm (2A) angewendet wurde, einen kontralateralen Maskierungseffekt zwischen Unterarme zeigen. Die Wirkung war abhängig von der Position des Maskierungs Stimulus auf...

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Testing Tactile Masking between the Forearms

Testing Tactile Maskierung zwischen den Unterarmen

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, ...

testing-tactile-masking-between-the-forearms

Research

JoVE Journal

Behavior

6.3K Aufrufe.  York University. 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. 

Serie: Testing Tactile Masking between the Forearms

The Crossmodal Congruency Task as a Means to Obtain an Objective Behavioral Measure in the Rubber Hand Illusion Paradigm

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden hand is touched. If the viewed and felt touches are given at the same time then this is sufficient to induce the compelling experience that the rubber hand is one's own hand. The RHI can be used to investigate exactly how the brain constructs distinct body representations for one's own body. Such representations are crucial for successful interactions with the external world. To obtain a subjective measure of the RHI, researchers typically ask participants to rate statements such as "I felt as if the rubber hand were my hand". Here we demonstrate how the crossmodal congruency task can be used to obtain an objective behavioral measure within this paradigm.
The variant of the crossmodal congruency task we employ involves the presentation of tactile targets and visual distractors. Targets and distractors are spatially congruent (i.e. same finger) on some trials and incongruent (i.e. different finger) on others. The difference in performance between incongruent and congruent trials - the crossmodal congruency effect (CCE) - indexes multisensory interactions. Importantly, the CCE is modulated both by viewing a hand as well as the synchrony of viewed and felt touch which are both crucial factors for the RHI.
The use of the crossmodal congruency task within the RHI paradigm has several advantages. It is a simple behavioral measure which can be repeated many times and which can be obtained during the illusion while participants view the artificial hand. Furthermore, this measure is not susceptible to observer and experimenter biases. The combination of the RHI paradigm with the crossmodal congruency task allows in particular for the investigation of multisensory processes which are critical for modulations of body representations as in the RHI.

We demonstrate how an objective measure can be employed in the widely employed rubber hand illusion paradigm. This measure is obtained by modifying the well-established crossmodal congruency task. This task allows the investigation of multisensory processes which are critical for modulations of body representations as in the rubber hand illusion.

Die Kongruenz Crossmodale Aufgabe als ein Mittel zum Ziel Behavioral Messen in der Rubber Hand Illusion Paradigm erhalten

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden ...

Forschung

Verhalten

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

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

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

Virtuelle Hand und Virtual-face Illusions Erstellen zur Untersuchung der Selbstdarstellung

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

Using Facial Electromyography to Assess Facial Muscle Reactions to Experienced and Observed Affective Touch in Humans

"Affective" touch is believed to be processed in a manner distinct from discriminatory touch and to involve activation of C-tactile (CT) afferent fibers. Touch that optimally activates CT fibers is consistently rated as hedonically pleasant. Patient groups with impaired social-emotional functioning also show disordered affective touch ratings. However, relying on self-reported ratings of touch has many limitations, including recall bias and communication barriers. Here, we describe a methodological approach to study affective responses to touch via facial electromyography (EMG) that circumvents the reliance on self-report ratings. Facial EMG is an objective, quantitative, and non-invasive method to measure facial muscle activity indicative of affective responses. Responses can be assessed across healthy and patient populations without the need for verbal communication. Here, we provide two separate datasets demonstrating that CT-optimal and non-optimal touch elicit distinct facial muscle reactions. Moreover, facial EMG responses are consistent across stimulus modalities, e.g. tactile (experienced touch) and visual (observed touch). Finally, the temporal resolution of facial EMG can detect responses on timescales that supersede that of verbal reporting. Together, our data suggest that facial EMG is a suitable methodology for use in affective tactile research that can be used to supplement, or in some cases, supplant, existing measures.

We describe a protocol to assess facial muscle activity in response to experienced and observed tactile stimulation using facial electromyography.

Verwendung von Gesichts Elektromyographie Gesichtsmuskel Reaktionen auf erfahrene und beobachteten affektive Berührung beim Menschen bewerten

"Affective" touch is believed to be processed in a manner distinct from discriminatory touch and to involve activation of C-tactile (CT) afferent fibers. ...

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 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.

Anwendung der indikierten visuellen Stimuli während der Objektübertragung mit Vibro-Taktile Feedback

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

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.

Ein taktiles 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 ...

Biologie

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.

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.

Taktiler halbautomatischer Passiv-Finger-Winkelstimulator (TSPAS)

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

Virtual Hand with Ambiguous Movement between the Self and Other Origin: Sense of Ownership and 'Other-Produced' Agency

The feeling that a body part is one&#8217;s own body (sense of ownership; SoO) and the feeling based on the causal relationship between one&#8217;s will and action (sense of agency; SoA) have been recognized as the basis of our bodily self-consciousness. Previously, the illusory SoO over a fake body part (e.g., rubber hand) was introduced as the rubber hand illusion (RHI). Furthermore, it was determined that one could also evoke a SoA over an object with movements linked to the one&#8217;s prior intention. On the other hand, the postdictivity of our spontaneity implies that it is essentially inseparable whether actions originate from self or others. In other words, our SoA or daily experiences are obtained in such as inseparable scenario. Previous research, however, has maintained the premise that self- and other-origin movements are perceptually distinguishable. Here, we implement a protocol to make these aspects ambiguous for the participants and to estimate whether they can feel SoO and/or SoA and how. To this end, we employ an experiment using virtual reality, under which participants observe virtual fingers moving very slowly (or quickly or not moving) while their own fingers do not move. For evaluation of the illusory SoO, measurements of skin conductance responses against a knife threat are adopted. Additionally, we introduce face-to-face interviews to determine whether the feelings regarding the slow movement match the conventional SoA definition. Our representative results suggest that the SoO is evoked over the hand, and various attitudes to accept its movement as the participant&#8217;s own with awareness that they did not originate it are reported by the majority. As the results show, the novelty of this protocol is discovering that in such a situation, the SoO cooperates with an externally produced SoA to establish one&#8217;s own bodily experience rather than the independence of the SoO and SoA.

While previous research on bodily self-consciousness assumed that self- and other-origin movements were perceptually distinguishable, this protocol allows them to be ambiguous on a virtual hand with unintentional slight movements. This enables us to observe one&#8217;s experience formed by SoO and other-produced SoA, rather than the absence of SoA.

Virtuelle Hand mit mehrdeutigen Bewegungen zwischen dem Selbst und anderen Ursprüngen: Sinn des Eigentums und "Anders produzierter" Agentur

The feeling that a body part is one&#8217;s own body (sense of ownership; SoO) and the feeling based on the causal relationship between one&#8217;s will ...

Estimation of Contact Regions Between Hands and Objects During Human Multi-Digit Grasping

To grasp an object successfully, we must select appropriate contact regions for our hands on the surface of the object. However, identifying such regions is challenging. This paper describes a workflow to estimate the contact regions from marker-based tracking data. Participants grasp real objects, while we track the 3D position of both the objects and the hand, including the fingers' joints. We first determine the joint Euler angles from a selection of tracked markers positioned on the back of the hand. Then, we use state-of-the-art hand mesh reconstruction algorithms to generate a mesh model of the participant's hand in the current pose and the 3D position. 
Using objects that were either 3D printed or 3D scanned-and are, thus, available as both real objects and mesh data-allows the hand and object meshes to be co-registered. In turn, this allows the estimation of approximate contact regions by calculating the intersections between the hand mesh and the co-registered 3D object mesh. The method may be used to estimate where and how humans grasp objects under a variety of conditions. Therefore, the method could be of interest to researchers studying visual and haptic perception, motor control, human-computer interaction in virtual and augmented reality, and robotics.

When we grasp an object, multiple regions of the fingers and hand typically make contact with the object's surface. Reconstructing such contact regions is challenging. Here, we present a method for approximately estimating the contact regions by combining marker-based motion capture with existing deep learning-based hand mesh reconstruction.

Abschätzung von Kontaktbereichen zwischen Händen und Objekten beim mehrstelligen Greifen des Menschen

To grasp an object successfully, we must select appropriate contact regions for our hands on the surface of the object. However, identifying such regions ...

Non-Invasive Modulation and Robotic Mapping of Motor Cortex in the Developing Brain

Mapping the motor cortex with transcranial magnetic stimulation (TMS) has potential to interrogate motor cortex physiology and plasticity but carries unique challenges in children. Similarly, transcranial direct current stimulation (tDCS) can improve motor learning in adults but has only recently been applied to children. The use of tDCS and emerging techniques like high&#8211;definition tDCS (HD-tDCS) require special methodological considerations in the developing brain. Robotic TMS motor mapping may confer unique advantages for mapping, particularly in the developing brain. Here, we aim to provide a practical, standardized approach for two integrated methods capable of simultaneously exploring motor cortex modulation and motor maps in children. First, we describe a protocol for robotic TMS motor mapping. Individualized, MRI-navigated 12x12 grids centered on the motor cortex guide a robot to administer single-pulse TMS. Mean motor evoked potential (MEP) amplitudes per grid point are used to generate 3D motor maps of individual hand muscles with outcomes including map area, volume, and center of gravity. Tools to measure safety and tolerability of both methods are also included. Second, we describe the application of both tDCS and HD-tDCS to modulate the motor cortex and motor learning. An experimental training paradigm and sample results are described. These methods will advance the application of non-invasive brain stimulation in children.

We demonstrate protocols for the modulation (tDCS, HD-tDCS) and mapping (robotic TMS) of the motor cortex in children.

Nicht-invasive Modulation und Robotik-Mapping von Motor Cortex im sich entwickelnden Gehirn

Mapping the motor cortex with transcranial magnetic stimulation (TMS) has potential to interrogate motor cortex physiology and plasticity but carries ...

Neurowissenschaften

Capturing Dynamic Finger Gesturing with High-resolution Surface Electromyography and Computer Vision

Finger gestures are a critical element in human communication, and as such, finger gesture recognition is widely studied as a human-computer interface for state-of-the-art prosthetics and optimized rehabilitation. Surface electromyography (sEMG), in conjunction with deep learning methods, is considered a promising method in this domain. However, current methods often rely on cumbersome recording setups and the identification of static hand positions, limiting their effectiveness in real-world applications. The protocol we report here presents an advanced approach combining a wearable surface EMG and finger&#160;tracking system to capture comprehensive data during dynamic hand movements. The method records muscle activity from soft printed electrode arrays (16 electrodes) placed on the forearm as subjects perform gestures in different hand positions and during movement. Visual instructions prompt subjects to perform specific gestures while EMG and finger positions are recorded. The integration of synchronized EMG recordings and finger tracking data enables comprehensive analysis of muscle activity patterns and corresponding gestures. The reported approach demonstrates the potential of combining EMG and visual tracking technologies as an important resource for developing intuitive and responsive gesture recognition systems with applications in prosthetics, rehabilitation, and interactive technologies. This protocol aims to guide researchers and practitioners, fostering further innovation and application of gesture recognition in dynamic and real-world scenarios.

The paper presents a comprehensive protocol for simultaneously recording hand-electromyography (EMG) and visual finger tracking during natural finger gesturing. The visual data is designed to serve as the ground truth for the development of accurate EMG-based computational models for finger gesture recognition.

Erfassung dynamischer Fingergesten mit hochauflösender Oberflächen-Elektromyographie und Computer Vision

Finger gestures are a critical element in human communication, and as such, finger gesture recognition is widely studied as a human-computer interface for ...