LRH was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada. SD was partly supported from the NSERC CREATE program.

All of the experiments were approved by the York Ethics board and all participants signed informed consent forms. The experiments were performed in accordance with the Treaty of Helsinki.
1. Stimuli
<ol>
	<li>Tactile Detection Stimulus
	<ol>
		<li>Use a tactor (1.17&#34; diameter and 0.30&#34; thick) to deliver tactile stimuli of 250 Hz vibration for 100 msec. Using a purpose-built tactor provides a linear relationship between the amount of travel and the voltage applied.</li>
		<li>Control tactile stimulus delivery with a 64 bit sound card.
		<ol>
			<li>To drive the tactor, treat it as a loudspeaker. Connect a stereo audio amplifier to a 64-bit computer stereo sound card. Connect the tactor to one of the outputs of the amplifier (e.g., the &#39;left speaker out&#39;). Connect the second channel (e.g., the &#39;right speaker out&#39;) of the amplifier to a regular loudspeaker to provide auditory signals to the participant.</li>
			<li>In the computer code that is controlling the experiment, generate the waveform that will be used to vibrate the tactor (e.g., a 250 Hz sinewave of duration 100 msec), and another waveform for the auditory signal (e.g., a 3,000 Hz sinewave with a duration of 100 msec). See Example Code 1 in the Supplemental Code File.</li>
			<li>Put each of these two waveforms into a two-dimensional array. For the tactor array put the signal in the first dimension and set the second dimension to all zeros. For the sound array put the signal in the second dimension and set the first to all zeros. Play the appropriate array to the soundcard at the appropriate point in the program. See Example Code 1 in the Supplemental Code File for a demonstration of how this is done.</li>
		</ol>
		</li>
		<li>Attach the tactor to a strap with a mechanical-based fastening product.</li>
	</ol>
	</li>
	<li>Masking Stimulus
	<ol>
		<li>Provide the masking stimulus by an electric, hand-held vibrator (4 cm diameter; 83 Hz when set on &#34;low&#34;).</li>
		<li>Based on the areas where masking is to be tested, select the sites where the masking stimulus is to be applied.</li>
	</ol>
	</li>
</ol>
2. Experimental Setup and Design
<ol>
	<li>Arrange the computer and equipment on a desk, with a chair in front of it, for the experimenter.</li>
	<li>Set up a table on which participants rest their left (test) arm. Place a chair to the right side of the table. Put an armrest stand next to the chair on which the participants rest their right (masking arm) elbow. Add cushioning to the table and armrest for comfort.</li>
	<li>Arrange a loudspeaker on a mechanically isolated surface. Arrange foot pedals (connected to the left and right buttons of a computer mouse) so that the participant&#39;s feet will rest comfortably on them (Figure 1).</li>
	<li>Choose the parameters of the study, including the appropriate number of trials required to obtain a reliable estimate of the threshold (typically, between 40-50 trials) and the number of blocks into which the experiment is to be divided (e.g., two blocks of 20-25 trials per condition).</li>
	<li>Make a list of the order in which the conditions will be run. Use this list to determine where to hold the masking stimulus for each block.</li>
	<li>Enter the number of trials directly into the computer program code (e.g., ntrials = 25; See Supplemental Code File). Ensure that each block is no longer than 10 min to maintain attention.</li>
	<li>Program a two-alternative-forced-choice tactile detection task11in which stimulus intensity is controlled with a Bayesian adaptive psychophysical staircase psychometric procedure12.
	<ol>
		<li>For each trial, present two 1 sec intervals, marked by three beeps (5 kHz, 3 kHz and 5 kHz, duration 100 msec), with the tactile stimulus presented in the middle of one of the intervals. Have the participant indicate in which interval the stimulus was presented by means of foot pedals (left for first, right for second). See Example Code 2, which shows how the intervals are run and scored. 
		Note: The computer scores the response as &#34;correct&#34; or &#34;wrong&#34; and the adaptive staircase chooses the next value to be presented accordingly. 
		Note: This method determines a threshold value for detecting the vibration at the test site.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 1" src="/files/ftp_upload/53733/53733fig1.jpg" /> 
Figure 1. Experimental Design. This figure shows the set up of the experiment and the materials used. See text for details.
3. Experimental Procedure
<ol>
	<li>Obtain written informed consent. Seat the participant in the chair with their feet resting comfortably on the response foot pedals and explain the experimental procedure.</li>
	<li>Measure and record the length of the dorsal surface of the left forearm. Apply the strap so the tactor is positioned in the middle of the arm halfway between the inner angle of the elbow and the wrist crease.</li>
	<li>Wrap a tensor bandage loosely around the arm several times to hold the tactor in place.</li>
	<li>Instruct participants to place their left arm on the table and rest their right elbow on the armrest. Blindfold the participant to prevent them looking at the stimulus or masking location and instruct them to look straight ahead throughout the experiment.</li>
	<li>Start with a block of 20 practice trials (without the masking stimulus) in order to familiarize participants with the tactile detection task and to allow them to become familiar with the tactile stimuli.</li>
	<li>Following the practice trials, begin the experiment, running the blocks of conditions in a random, counterbalanced order. Before beginning each block, ensure that the arms and the masking stimulus are in the correct positions.
	<ol>
		<li>For each condition, hold the masking stimulus on the chosen site, referring to the list of conditions made earlier. Cross off each condition as it is run. Hold the masking stimulus throughout each block of data collection trials maintaining approximately constant pressure. The masking stimulus can be applied through thin clothing.</li>
		<li>Run the experimental program which will run through a set number of trials as previously selected. Introduce a 2 min rest period after each short block of trials. After a given block of trials is completed, select the next site for the masking stimulus and run the program again. Repeat until all trials are completed.</li>
	</ol>
	</li>
</ol>
4. Data Analysis
<ol>
	<li>To visualize and confirm the estimate of the threshold value returned by the adaptive staircase program12, fit the participants&#39; data with a cumulative Gaussian The formula for a cumulative Gaussian (sigmoid) that goes from 50% (chance level - equal number of 0s - wrong and 1&#39;s- correct) to 100% (all 1&#39;s, all correct) is: 
	probability of a correct response = 0.5 + 0.5/(1+exp(-(x-x0)/std)) 
	where x is the intensity value tested, x0 is the 75% threshold value, and std is the standard deviation of the estimate. This formula can be fitted to the data using any curve-fitting software and the resulting x0 value compared to the adaptive staircase value.
	<ol>
		<li>Ensure that the curve goes between 50% (chance performance) and 100%. Conduct statistical analyses (e.g., t-tests or ANOVAs) on the 75% threshold values obtained under each condition of the experiment (e.g., between different masking sites) to determine if there are any differences between the conditions tested.</li>
	</ol>
	</li>
	<li>In order to identify outliers, calculate the mean and the standard deviation for a given condition. Compare each participant&#39;s score with the mean and if an individual score is more than 2 standard deviation from that mean then regard this score as an outlier and remove it from the analysis. Alternative criteria may be used if desired.</li>
	<li>To standardize the values of the intensity of the tactors (which are in in arbitrary units), convert them to decibels relative to the control thresholds (measured when the masking stimulus is applied to the control site, e.g., the shoulder). Use this formula: 
	dB = 10 x log10 (threshold value/control threshold value).</li>
</ol>

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The authors declare that they have no competing financial interests.

Here, a detailed protocol for contralateral tactile masking is described and previously published results using the technique to test tactile detection thresholds are shown. The advantage of this method is that thresholds are measured using a psychophysically rigorous technique. The two-alternative forced choice (2AFC) procedure is relatively insensitive to response bias and therefore from attentional effects. The adaptive staircase procedure for honing in on the actual threshold value is very efficient as most of the da...

Tactile masking is where a tactile stimulus at one location on the body alters the perception of a touch at another location. This is a technique pioneered by von Bekesy1to reveal location interactions, especially lateral inhibition, between areas of skin that are adjacent on the body surface. While tactile masking has been studied extensively over the years, research has mainly investigated ipsilateral tactile masking using electrical stimulation2,3, pressure4, and vibrotactile stimulation5,6. In contrast, few studies have looked at contralateral tactile masking in which the masking and probe sites may be far removed. Long-range tactile masking effects have been shown between mirror-symmetric points on the hand and arm5,7-9but these studies have been largely restricted to looking at the hands and fingers7,10, with more extensive parts of the whole body being largely ignored. A goal of such long-range masking experiments is to indicate how components of the body&#39;s representation in the brain may be functionally linked. Here, the phenomenon of long-range tactile masking is explored by investigating how vibration applied to one forearm might affect tactile sensitivity thresholds on the opposite forearm. Threshold refers to the minimum stimulus that is needed to detect a stimulus. We define this as the intensity at which the stimulus is detected 75% of the time. We used a tactile masking technique in which tactile sensitivity (the reciprocal of threshold) on one forearm is measured in the presence of a vibrating stimulus (the mask) on another part of the body. Effective masking is revealed by an increase in the detection threshold i.e., a reduction in sensitivity. The technique can be used in conjunction with other manipulations such as varying limb position or movement to explore their effects on the effectiveness of masking.
Here we used vibrotactile stimuli as the masking stimulus. The advantage of this is that the frequency, and hence the receptor type that it stimulates can be controlled. The technique could be extended to look at pain using electrical stimuli as the probe or mask or both. Also, any site can be used as the masking site allowing the investigation of acupuncture sites for example.

<table border="0" cellpadding="0" cellspacing="0" width="673">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">C-2 tactor</td>
			<td style="width:127px;">ATAC Technology; Engineering Acoustics, Inc.</td>
			<td style="width:164px;"></td>
			<td style="width:167px;">http://www.atactech.com/PR_tactors.html</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Magic Wand</td>
			<td style="width:127px;">Hitachi</td>
			<td style="width:164px;"></td>
			<td style="width:167px;">http://magicwandoriginal.com/magic-wand-original/</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">FC5 Foot Pedals</td>
			<td style="width:127px;">Yamaha Corporation</td>
			<td style="width:164px;"></td>
			<td style="width:167px;">http://ca.yamaha.com/en/products/music-production/accessories/footpedals/fc5/?mode=model</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">MATLAB</td>
			<td style="width:127px;">The Mathworks, Inc.</td>
			<td style="width:164px;"></td>
			<td style="width:167px;">http://www.mathworks.com/products/matlab/</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Velcro</td>
			<td style="width:127px;">Velcro Industries B.V.</td>
			<td style="width:164px;"></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.

Analyses of the data was reported in13. Tactile sensitivity (expressed relative to the thresholds measured in the control condition) on the forearm was significantly reduced (thresholds were significantly increased) when vibrotactile masking stimulation was applied to the opposite arm (Figure 2A), demonstrating a contralateral masking effect between forearms. The effect depended on the position of the masking stimulus on the masking arm, with the largest effect...

Watch this Scientific Journal Video about Testing Tactile Masking between the Forearms at JoVE.com

Testing Tactile Masking between the Forearms

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

Universidad de Cartagena UDEC

Research

JoVE Journal

Behavior

6.3K Views.  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. 

Video: Testing Tactile Masking between the Forearms

Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess children&#39;s cortical processing of light touch, speech sounds and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing children discomfort. To accomplish this we developed a dual channel, time and strength calibrated air puff stimulator that allows both tactile stimulation and sham control. We combined this with the use of event-related potential methodology to allow for high temporal resolution of signals from the primary and secondary somatosensory cortices as well as higher order processing. This methodology also allowed us to measure a multisensory response to auditory-tactile stimulation.

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess infants and children&#39;s cortical processing of light touch, speech sounds, and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing discomfort in vulnerable patients.

Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology ...

Simple and Computer-assisted Olfactory Testing for Mice

Olfaction is highly conserved among species and is required for reproduction and survival.
In humans, olfaction is also one of the senses that is affected with aging and is a strong predictor of neurodegenerative diseases. Thus, olfaction testing is used as a non-invasive diagnostic method to detect neurological deficits early on. In order to understand the mechanisms underlying olfactory network susceptibility, olfactory research in rodents has gained momentum in the past decade.
Here, we present a very simple, time efficient and reproducible olfactory testing method of innate odor perception and sensitivity in mice without the need of any prior food or water restriction. The tests are performed in a familiar environment to the mice, require only the scents and a 2 min session of odorant exposure. The analysis is performed, post-hoc, using computer-assisted commands on ImageJ and can be, therefore, carried out from start to end by one researcher.
This protocol does not require any special hardware or setup and is indicated for any laboratory interested in testing olfactory perception and sensitivity.

We present a simple and unbiased olfactory test in mice. With this protocol olfactory discrimination, preference, avoidance and sensitivity to a novel odor as compared to water can be assessed in single behavioral sessions. This method is indicated for a single experimenter and analysis is based on computer-assisted video processing.

Olfaction is highly conserved among species and is required for reproduction and survival.
In humans, olfaction is also one of the senses that is affected ...

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 ...

A Mouse Model of Subchronic and Mild Social Defeat Stress for Understanding Stress-induced Behavioral and Physiological Deficits

Stressful life events often increase the incidence of depression in humans. To study the mechanisms of depression, the development of animal models of depression is essential. Because there are several types of depression, various animal models are needed for a deeper understanding of the disorder. Previously, a mouse model of subchronic and mild social defeat stress (sCSDS) using a modified chronic social defeat stress (CSDS) paradigm was established. In the paradigm, to reduce physical injuries from aggressors, the duration of physical contact between the aggressor and a subordinate was reduced compared to in the original CSDS paradigm. sCSDS mice showed increased body weight gain, food intake, and water intake during the stress period, and their social behaviors were suppressed after the stress period. In terms of the face validity of the stress-induced overeating and overdrinking following the increased body weight gain, the sCSDS mice may show some features related to atypical depression in humans. Thus, a mouse model of sCSDS may be useful for studying the pathogenic mechanisms underlying depression. This protocol will help establish the sCSDS mouse model, especially for studying the mechanisms underlying stress-induced weight gain and polydipsia- and hyperphagia-like symptoms.

Here, methods for developing a mouse model of subchronic and mild social defeat stress are described and used to investigate the pathogenic features of depression including hyperphagia- and polydipsia-like symptoms following increased body weight.

Stressful life events often increase the incidence of depression in humans. To study the mechanisms of depression, the development of animal models of ...

Comparing the Frequency Effect Between the Lexical Decision and Naming Tasks in Chinese

In psycholinguistic research, the frequency effect can be one of the indicators for eligible experimental tasks that examine the nature of lexical access. Usually, only one of those tasks is chosen to examine lexical access in a study. Using two exemplar experiments, this paper introduces an approach to include both the lexical decision task and the naming task in a study. In the first experiment, the stimuli were Chinese characters with frequency and regularity manipulated. In the second experiment, the stimuli were switched to Chinese two-character words, in which the word frequency and the regularity of the leading character were manipulated. The logic of these two exemplar experiments was to explore some important issues such as the role of phonology on recognition by comparing the frequency effect between both the tasks. The results revealed different patterns of lexical access from those reported in the alphabetic systems. The results of Experiment 1 manifested a larger frequency effect in the naming task as compared to the LDT, when the stimuli were Chinese characters. And it is noteworthy that, in Experiment 1, when the stimuli were regular Chinese characters, the frequency effect observed in the naming task was roughly equivalent to that in the LDT. However, a smaller frequency effect was shown in the naming task as compared to the LDT, when the stimuli were switched to Chinese two-character words in Experiment 2. Taking advantage of the respective demands and characteristics in both tasks, researchers can obtain a more complete and precise picture of character/word recognition.

Researchers adopt both the lexical decision task and the naming task to investigate some important topics such as character/word recognition by comparing the frequency effect between these two tasks. This article introduces this approach through two exemplar experiments and elaborates on the underlying logic.

In psycholinguistic research, the frequency effect can be one of the indicators for eligible experimental tasks that examine the nature of lexical access. ...

Neurodevelopmental Reflex Testing in Neonatal Rat Pups

Neurodevelopmental reflex testing is commonly used in clinical practice to assess the maturation of the nervous system. Neurodevelopmental reflexes are also referred to as primitive reflexes. They are sensitive and consistent with later outcomes. Abnormal reflexes are described as an absence, persistence, reappearance, or latency of reflexes, which are predictive indices of infants that are at high risk for neurodevelopmental disorders. Animal models of neurodevelopmental disabilities, such as cerebral palsy, often display aberrant developmental reflexes, as would be observed in human infants. The techniques described assess a variety of neurodevelopmental reflexes in neonatal rats. Neurodevelopmental reflex testing offers the investigator a testing method that is not otherwise available in such young animals. The methodology presented here aims to assist investigators in examining developmental milestones in neonatal rats as a method of detecting early-onset brain injury and/or determining the effectiveness of therapeutic interventions. The methodology presented here aims to provide a general guideline for investigators.

Behavioral testing is the gold standard for determining outcomes following brain injury, and can identify the presence of developmental disabilities in infants and children. Neurodevelopmental reflexes are an early indicator of these abnormalities. A host of easily accomplished developmental reflex tests in the neonatal rodent were developed and described here.

Neurodevelopmental reflex testing is commonly used in clinical practice to assess the maturation of the nervous system. Neurodevelopmental reflexes are ...

Using Wavelet Entropy to Demonstrate how Mindfulness Practice Increases Coordination between Irregular Cerebral and Cardiac Activities

In both the East and West, traditional teachings say that the mind and heart are somehow closely correlated, especially during spiritual practice. One difficulty in proving this objectively is that the natures of brain and heart activities are quite different. In this paper, we propose a methodology that uses wavelet entropy to measure the chaotic levels of both electroencephalogram (EEG) and electrocardiogram (ECG) data and show how this may be used to explore the potential coordination between the mind and heart under different experimental conditions. Furthermore, Statistical Parametric Mapping (SPM) was used to identify the brain regions in which the EEG wavelet entropy was the most affected by the experimental conditions. As an illustration, the EEG and ECG were recorded under two different conditions (normal rest and mindful breathing) at the beginning of an 8-week standard Mindfulness-based Stress Reduction (MBSR) training course (pretest) and after the course (posttest). Using the proposed method, the results consistently showed that the wavelet entropy of the brain EEG decreased during the MBSR mindful breathing state as compared to that during the closed-eye resting state. Similarly, a lower wavelet entropy of heartrate was found during MBSR mindful breathing. However, no difference in wavelet entropy during MBSR mindful breathing was found between the pretest and posttest. No correlation was observed between the entropy of brain waves and the entropy of heartrate during normal rest in all participants, whereas a significant correlation was observed during MBSR mindful breathing. Additionally, the most well-correlated brain regions were located in the central areas of the brain. This study provides a methodology for the establishment of evidence that mindfulness practice (i.e., mindful breathing) may increase the coordination between mind and heart activities.

This manuscript describes how to use the wavelet entropy index to analyze high-density electroencephalography (EEG) and electrocardiography (ECG) data. We show that the irregularity of cerebral and cardiac activities became more coordinated during mindfulness-based stress reduction practice.

In both the East and West, traditional teachings say that the mind and heart are somehow closely correlated, especially during spiritual practice. One ...

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 ...

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.

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

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

In our continuously developing &#39;around the clock&#39; society, there is a need to increase our understanding of how changes in biology, physiology and psychology influence our health and performance. Embedded within this challenge, is the increasing need to account for individual differences in sleep and circadian rhythms, as well as to explore the impact of time of day on performance in the real world. There are a number of ways to measure sleep and circadian rhythms from subjective questionnaire-based methods to objective sleep/wake monitoring, actigraphy and analysis of biological samples. This paper proposes a protocol that combines multiple techniques to categorize individuals into Early, Intermediate or Late circadian phenotype groups (ECPs/ICPs/LCPs) and recommends how to conduct diurnal performance testing in the field. Representative results show large differences in rest-activity patterns derived from actigraphy, circadian phase (dim light melatonin onset and peak time of cortisol awakening response) between circadian phenotypes. In addition, significant differences in diurnal performance rhythms between ECPs and LCPs emphasizes the need to account for circadian phenotype. In summary, despite the difficulties in controlling influencing factors, this protocol allows a real-world assessment of the impact of circadian phenotype on performance. This paper presents a simple method to assess circadian phenotype in the field and supports the need to consider time of day when designing performance studies.

Here, we present a method to investigate diurnal rhythms in performance following accurate categorization of participants into circadian phenotype groups based on the Munich ChronoType Questionnaire, gold standard circadian phase biomarkers and actigraphic measures.

In our continuously developing &#39;around the clock&#39; society, there is a need to increase our understanding of how changes in biology, physiology and ...