The authors would like to thank Alexis M. Wilson and Marisa E. Bertoli for their assistance with filming and preparing the video for this manuscript. This research was supported by the Natural Sciences and Engineering Research Council of Canada (JMK, JRK, IQW), Alberta Innovates-Health Solutions (JMK), and the Canadian Institutes of Health Research (IQW).

<ol>
	<li>Karl, J. M., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+evolutionary+origins+for+the+Reach+and+the+Grasp:+an+explanation+for+dual+visuomotor+channels+in+primate+parietofrontal+cortex.">Different evolutionary origins for the Reach and the Grasp: an explanation for dual visuomotor channels in primate parietofrontal cortex.</a> Front Neurol. 4 (208), (2013).</li><li>Whishaw, I. Q., Karl, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+contribution+of+the+reach+and+the+grasp+to+shaping+brain+and+behaviour.">The contribution of the reach and the grasp to shaping brain and behaviour.</a> Can J Exp Psychol. 68 (4), 223-235 (2014).</li><li>Jeannerod, M., Long, J., Badeley, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intersegmental+coordination+during+reaching+at+natural+visual+objects.">Intersegmental coordination during reaching at natural visual objects.</a> Attention and Performance IX. , 153-169 (1981).</li><li>Arbib, M. A., Brooks, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perceptual+structures+and+distributed+motor+control.">Perceptual structures and distributed motor control.</a> Handbook of Physiology. 2, 1449-1480 (1981).</li><li>De Bruin, N., Sacrey, L. A., Brown, L. A., Doan, J., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+guidance+for+hand+advance+but+not+hand+withdrawal+in+a+reach-to-eat+task+in+adult+humans:+reaching+is+a+composite+movement.">Visual guidance for hand advance but not hand withdrawal in a reach-to-eat task in adult humans: reaching is a composite movement.</a> J Mot Behav. 40 (4), 337-346 (2008).</li><li>Karl, J. M., Sacrey, L. A., Doan, J. B., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hand+shaping+using+hapsis+resembles+visually+guided+hand+shaping.">Hand shaping using hapsis resembles visually guided hand shaping.</a> Exp Brain Res. 219 (1), 59-74 (2012).</li><li>Domell&#246;ff, E., Hopkins, B., Francis, B., R&#246;nnqvist, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+finger+markers+on+the+kinematics+of+reaching+movements+in+young+children+and+adults.">Effects of finger markers on the kinematics of reaching movements in young children and adults.</a> J Appl Biomech. 23 (4), 315-321 (2007).</li><li>Karl, J. M., Sacrey, L. A., Doan, J. B., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+hapsis+guides+accurate+hand+preshaping+for+grasping+food+targets+in+the+mouth.">Oral hapsis guides accurate hand preshaping for grasping food targets in the mouth.</a> Exp Brain Res. 221 (2), 223-240 (2012).</li><li>Karl, J. M., Schneider, L. R., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonvisual+learning+of+intrinsic+object+properties+in+a+reaching+task+dissociates+grasp+from+reach.">Nonvisual learning of intrinsic object properties in a reaching task dissociates grasp from reach.</a> Exp Brain Res. 225 (4), 465-477 (2013).</li><li>Hall, L. A., Karl, J. M., Thomas, B. L., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reach+and+Grasp+reconfigurations+reveal+that+proprioception+assists+reaching+and+hapsis+assists+grasping+in+peripheral+vision.">Reach and Grasp reconfigurations reveal that proprioception assists reaching and hapsis assists grasping in peripheral vision.</a> Exp Brain Res. 232 (9), 2807-2819 (2014).</li><li>Karl, J. M., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Haptic+grasping+configurations+in+early+infancy+reveal+different+developmental+profiles+for+visual+guidance+of+the+Reach+versus+the+Grasp.">Haptic grasping configurations in early infancy reveal different developmental profiles for visual guidance of the Reach versus the Grasp.</a> Exp Brain Res. 232 (9), 3301-3316 (2014).</li><li>Whishaw, I. Q., Karl, J. M., Humphrey, N. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+of+the+Reach+and+the+Grasp+in+the+destriate+(V1)+monkey+Helen:+a+new+anatomy+for+the+dual+visuomotor+channel+theory+of+reaching.">Dissociation of the Reach and the Grasp in the destriate (V1) monkey Helen: a new anatomy for the dual visuomotor channel theory of reaching.</a> Exp Brain Res. 234 (8), 2351-2362 (2016).</li><li>Timmann, D., Stelmach, G. E., Bloedel, 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=Grasping+component+alterations+and+limb+transport.">Grasping component alterations and limb transport.</a> Exp Brain Res. 108 (3), 486-492 (1996).</li><li>Saling, M., Mescheriakov, S., Molokanova, E., Stelmach, G. E., Berger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grip+reorganization+during+wrist+transport:+the+influence+of+an+altered+aperture.">Grip reorganization during wrist transport: the influence of an altered aperture.</a> Exp Brain Res. 108 (3), 493-500 (1996).</li><li>Whishaw, I. Q., Faraji, J., Kuntz, J., Mirza Ahga, B., Patel, M., Metz, G. A. S., 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=Organization+of+the+reach+and+grasp+in+head-fixed+vs+freely-moving+mice+provides+support+for+multiple+motor+channel+theory+of+neocortical+organization.">Organization of the reach and grasp in head-fixed vs freely-moving mice provides support for multiple motor channel theory of neocortical organization.</a> Exp Brain Res. 235 (6), 1919-1932 (2017).</li></ol>

The authors have no competing financial interests to disclose.

The present paper describes how to use frame-by-frame video analysis to quantify the temporal organization, kinematic structure, and a subset of topographical features of human reach-to-grasp movements. The technique can be used to study typical visually-guided reach-to-grasp movements, but also idiosyncratic reach-to-grasp movements. Such movements are difficult to study using traditional 3D motion tracking systems, but are common in developing infants, participants with altered sensory processing, and patients with sensorimotor disorders such as blindness, Parkinson&#39;s disease, Stroke, or Cerebral Palsy. Thus, the use of frame-by-frame video analysis will allow researchers to expand their area of investigation to include a greater range of prehensile behaviors, guided by a wider variety of sensory modalities, by both healthy and clinical populations. Specific advantages of frame-by-frame video analysis include its relative affordability, ease to implement, lack of sensors or markers that hinder sensory and motor abilities of the hands, compatibility with other motion tracking systems, and the ability to describe subtle changes in the reach-to-grasp movement that are often hard to interpret from the kinematic output provided by most traditional 3D motion tracking systems. Together, these features of frame-by-frame video analysis have made it possible to advance our theoretical understanding of the neurobehavioral control of prehension.
While there are many instances in which frame-by-frame video analysis may be the only reliable option for analyzing idiosyncratic reach-to-grasp movements, it is important to note that the technique does face some limitations. First, the distance measures (e.g., peak aperture) acquired using frame-by-frame video analysis are 2D and less precise compared to traditional 3D motion tracking systems. Nonetheless, if necessary, additional cameras could be focused on the region of interest. This would allow the experimenter to select the camera view that provides the clearest fronto-parallel view of the behavioral event of interest, and thus increase the precision of the distance measure for that particular event. Furthermore, if very high precision is required for the distance measures then frame-by-frame video analysis can easily be combined with traditional 3D motion tracking techniques (see Figure 4, 5, and 10) as it does not impede data collection from the traditional system. Secondly, the ultimate success of the technique is critically dependent on the integrity of the video record. Choosing filming views that adequately capture the behavior, using a shutter speed of 1/1000th of a second with a strong light source, and ensuring that the focus of the camera remains stabilized on the action of interest will all help to ensure that individual frames in the video record are crisp, free of motion artifacts, and easy to analyze. Finally, when first learning to implement the technique, researchers may wish to utilize multiple blind raters to ensure high inter-rater reliability for scoring of the various behavioral events. Once trained, however, scoring is highly reliable and interrater reliability can be easily established using only a small subset of sample data.
Frame-by-frame video analysis, in contrast to traditional 3D motion tracking systems, can provide a more ethologically valid description of natural reaching and grasping behavior as it does not require the placement of markers or sensors onto the participant&#39;s arms or hands. Additionally, many 3D motion tracking systems require a constant and direct line of sight between the camera and sensors/markers placed on the hands. To ensure this, most users of this technology ask participants to begin the reach-to-grasp movement with the hand shaped in an unnatural configuration with the index finger and thumb pinched together. They also instruct the participant to grasp the target object in a pre-defined way (usually a pincer grip) with a pre-defined orientation. These directives are required to ensure that the reach-to-grasp movement unfolds in a predictable and stereotypical manner as traditional recording systems can suffer significant data loss when the trajectory of the arm and configuration of the hand do not follow a predictable course that maintains the line of sight between the camera and sensors/markers. Nonetheless, imposing these constraints severely limits the ethological validity of the task and can even alter the organization of the movement; for example, it is not possible to observe the key behavioral event of &#39;collection&#39; when the initial hand configuration is that of a pinch between the thumb and index finger13,14. These limitations are largely overcome when using frame-by-frame video analysis as variations in reach trajectory and hand configuration are much less likely to result in a complete loss of data in the video record so there is no need to impose these unnatural constraints on the reach-to-grasp movement.
Frame-by-frame video analysis also makes it possible to observe subtle modifications of the reach-to-grasp movement beyond what is generally possible with traditional 3D motion tracking systems, especially when the modification is not a specific prediction of the study. An example will illustrate: Figure 5 (top) shows measures of peak aperture acquired from participants reaching-to-grasp three different sized objects either with vision or without vision. The results suggest that participants preemptively scale peak aperture to match the size of the target in the Vision condition, but not in the No Vision condition. In the No Vision condition participants use a consistent peak aperture despite reaching for targets of varying size. If one were to consider only the type of data available from a traditional 3D motion tracking system, similar to that shown in Figure 5 (top left), there are two possible explanations for this discrepancy. First, it could be that in the No Vision condition participants shape the hand into a grasping posture that matches the &#34;average&#34; or &#34;middle&#34; size of the three possible targets. Alternatively, they may not form a grasping posture at all, but rather, they may form a slightly more open hand during transport towards the target, to increase the chances of making tactile contact with the target, that coincidentally matches the size of the &#34;middle&#34; target. To differentiate between these two possibilities, it is necessary to review the data from the frame-by-frame video analysis, a sample of which is given in Figure 5 (top right), which clearly indicates that the participants are not shaping their hand into a grasping posture that matches the &#34;middle&#34; sized object in the No Vision condition; rather, they are forming an open but neutral hand shape that could serve to either locate the target through tactile feedback and/or to grasp the target. Thus, frame-by-frame video analysis can provide clarification when data from traditional 3D motion capture systems is ambiguous and can enable a more veritable interpretation of the results.
The use of frame-by-frame video analysis to study the reach-to-grasp movements of unsighted adults6,8,9,10, human infants11, non-human primates12, and rodents15 has already greatly amplified our understanding of the neurobehavioral control of prehension. Specifically, the results of these studies have consistently shown that in the early stages of prehensile development and evolution the touch-then-grasp strategy, in which the Reach and Grasp are temporally dissociated to capitalize on tactile cues, is preferred over the preshaping strategy in which the two movements are integrated into a single seamless act under visual guidance. These results provide substantial behavioral support for the Dual Visuomotor Channel theory and further suggest that the theory should be revised to account for the fact that separate reach and grasp movements likely originate under tactile control long before they are integrated together under visual guidance1,2.

Prehension, the act of reaching to grasp an object, is used for many daily functions including acquiring food items for eating, grooming, manipulating objects, wielding tools, and communicating through gesture and written word. The most prominent theory concerning the neurobehavioral control of prehension, the Dual Visuomotor Channel theory1,2,3,4, proposes that prehension consists of two movements - a reach that transports the hand to the location of the target and a grasp that opens, shapes, and closes the hand to the size and shape of the target. The two movements are mediated by dissociable but interacting neural pathways from visual to motor cortex via the parietal lobe1,2,3,4. Behavioral support for the Dual Visuomotor Channel theory has been ambiguous, largely due to the fact that the reach-to-grasp movement appears as a single seamless act and unfolds with little conscious effort. Nonetheless, prehension is almost always studied in the context of visually-guided prehension in which a healthy participant reaches to grasp a visible target object. Under these circumstances the action does appear as a single movement that unfolds in a predictable and stereotypical fashion. Prior to reach onset the eyes fixate on the target. As the arm extends the digits open, preshape to the size of the object, and subsequently start to close. The eyes disengage from the target just prior to target contact and final grasp of the target follows almost immediately afterwards5. When vision is removed, however, the structure of the movement is fundamentally different. The movement dissociates into its constituent components such that an open-handed reach is first used to locate the target by touching it and then haptic cues associated with target contact guide shaping and closure of the hand to grasp6.
Quantification of the reach-to-grasp movement is most often achieved using a 3 dimensional (3D) motion tracking system. These can include infrared tracking systems, electromagnetic tracking systems, or video based tracking systems. While such systems are effective for acquiring kinematic measures of prehension in healthy adult participants performing stereotypical reach-to-grasp movements towards visible target objects, they do have a number of drawbacks. In addition to being very expensive, these systems require the attachment of sensors or markers onto the arm, hand, and digits of the participant. These are usually attached using medical tape, which can impede tactile feedback from the hand, alter natural motor behavior, and distract participants7. As these systems generally produce numerical output related to different kinematic variables such as acceleration, deceleration, and velocity they are also not ideal for investigating how the hand contacts the target. When using these systems, additional sensors or equipment are required to determine what part of the hand makes contact with the target, where on the target contact occurs, and how the configuration of the hand might change in order to manipulate the target. In addition, infrared tracking systems, which are the most commonly employed, require the use of a specialized camera to track the location of the markers on the hand in 3D space6. This requires a direct line of sight between the camera and the sensors on the hand. As such, any idiosyncrasies in the movement are likely to obscure this line of sight and result in the loss of critical kinematic data. There are, however, a large number of instances in which idiosyncrasies in the reach-to-grasp movement are actually the norm. These include during early development when infants are just learning to reach and grasp for objects; when the target object is not visible and tactile cues must be used to guide the reach and the grasp; when the target object is an odd shape or texture; and when the participant presents with any one of a variety of sensorimotor disorders such as a stroke, Huntington&#39;s disease, Parkinson&#39;s disease, Cerebral Palsy, etc. In all of these cases, the reach-to-grasp movement is neither predictable nor stereotypical, nor is it necessarily guided by vision. Consequently, the capability of 3D motion tracking systems to reliably quantify the temporal and kinematic structure of these movements can be severely limited due to disruptions in sensory feedback from the hand, changes in natural motor behavior, loss of data, and/or difficulties interpreting the idiosyncratic kinematic output from these devices.
The present paper describes a novel technique for quantifying idiosyncratic reach-to-grasp movements in various human populations that is affordable, does not impede sensory feedback from the hand or natural motor behavior, and is reliable but can be flexibly modified to suit a variety of experimental paradigms. The technique involves using multiple high-speed video cameras to record the reach-to-grasp movement from multiple angles. The video is then analyzed offline by progressing through the video frames one at a time and using visual inspection to document key behavioral events that, together, provide a quantified description of the temporal and kinematic organization of the reach-to-grasp movement. The present paper describes a comparative analysis of visually- versus nonvisually-guided reach-to-grasp movements in healthy human adults6,8,9,10 in order to demonstrate the efficacy of the technique; however, modified versions of the technique have also been used to quantify the reach-to-grasp actions of human infants11 and non-human primates12. The comprehensive results of the frame-by-frame video analysis from these studies are among the first to provide behavioral evidence in support of the Dual Visuomotor Channel theory of prehension.

<table>
	<tbody>
		<tr>
			<td>High Speed Video Cameras</td>
			<td>Casio</td>
			<td>http://www.casio-intl.com/asia-mea/en/dc/ex_f1/ or http://www.casio-intl.com/asia-mea/en/dc/ex_100/</td>
			<td>Casio EX-F1 High Speed Camera or Casio EX-100 High Speed Camera used to collect high speed video records</td>
		</tr>
		<tr>
			<td>Adobe Photoshop</td>
			<td>Adobe</td>
			<td>http://www.adobe.com/ca/products/photoshop.html</td>
			<td>Software used to calibrate and measure distances on individual video frames</td>
		</tr>
		<tr>
			<td>Adobe Premiere Pro</td>
			<td>Adobe</td>
			<td>http://www.adobe.com/ca/products/premiere.html?sdid=KKQOM&#38;mv=search&#38;s_kwcid=AL!3085!3!193588412847!e!!g!!adobe%20premiere%20pro&#38;ef_id=WDd17AAABAeTD6-D:20170606160204:s</td>
			<td>Software used to perform Frame-by-Frame Video Analysis</td>
		</tr>
		<tr>
			<td>Height-Adjustable Pedestal</td>
			<td>Sanus</td>
			<td>http://www.sanus.com/en_US/products/speaker-stands/htb3/</td>
			<td>A height adjustable speaker stand with a custom made 9 cm x 9 cm x 9 cm triangular top plate attached to the top with a screw is used as a reaching pedestal</td>
		</tr>
		<tr>
			<td>1 cm Calibration Cube</td>
			<td>Learning Resources (Walmart)</td>
			<td>https://www.walmart.com/ip/Learning-Resources-Centimeter-Cubes-Set-500/24886372</td>
			<td>A 1 cm plastic cube is used to transform distance measures from pixels to centimeters</td>
		</tr>
		<tr>
			<td>Studio Light</td>
			<td>Dot Line</td>
			<td>https://www.bhphotovideo.com/c/product/1035910-REG/dot_line_rs_5620_1600w_led_light.html</td>
			<td>Strong lamp with cool LED light used to illumate the participant and testing area</td>
		</tr>
		<tr>
			<td>3 Dimensional (3D) Sleep Mask</td>
			<td>Kfine</td>
			<td>https://www.amazon.com/Kfine-Sleeping-Contoured-lightweight-Comfortable/dp/B06W5CDY78?th=1</td>
			<td>Used as a blindfold to occlude vision in the No Vision condition</td>
		</tr>
		<tr>
			<td>Orange Slices</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Orange slices served as the large sized reaching targets</td>
		</tr>
		<tr>
			<td>Donut Balls</td>
			<td>Tim Hortons</td>
			<td>http://www.timhortons.com/ca/en/menu/timbits.php</td>
			<td>Old fashion plain timbits from Tim Hortons served as the medium sized reaching targets</td>
		</tr>
		<tr>
			<td>Blueberries</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Blueberries served as the small sized reaching targets</td>
		</tr>
	</tbody>
</table>

frame-by-frame video analysis of idiosyncratic reach-to-grasp movements in humans

Prehension, the act of reaching to grasp an object, is central to the human experience. We use it to feed ourselves, groom ourselves, and manipulate objects and tools in our environment. Such behaviors are impaired by many sensorimotor disorders, yet our current understanding of their neural control is far from complete. Current technologies for investigating human reach-to-grasp movements often utilize motion tracking systems that can be expensive, require the attachment of markers or sensors to the hands, impede natural movement and sensory feedback, and provide kinematic output that can be difficult to interpret. While generally effective for studying the stereotypical reach-to-grasp movements of healthy sighted adults, many of these technologies face additional limitations when attempting to study the unpredictable and idiosyncratic reach-to-grasp movements of young infants, unsighted adults, and patients with neurological disorders. Thus, we present a novel, inexpensive, and highly reliable yet flexible protocol for quantifying the temporal and kinematic structure of idiosyncratic reach-to-grasp movements in humans. High speed video cameras capture multiple views of the reach-to-grasp movement. Frame-by-frame video analysis is then used to document the timing and magnitude of pre-defined behavioral events such as movement start, collection, maximum height, peak aperture, first contact, and final grasp. The temporal structure of the movement is reconstructed by documenting the relative frame number of each event while the kinematic structure of the hand is quantified using the ruler or measure function in photo editing software to calibrate 2 dimensional linear distances between two body parts or between a body part and the target. Frame-by-frame video analysis can provide a quantitative and comprehensive description of idiosyncratic reach-to-grasp movements and will enable researchers to expand their area of investigation to include a greater range of naturalistic prehensile behaviors, guided by a wider variety of sensory modalities, in both healthy and clinical populations.

Watch this Scientific Journal Video about Frame-by-Frame Video Analysis of Idiosyncratic Reach-to-Grasp Movements in Humans at JoVE.com

Frame-by-Frame Video Analysis of Idiosyncratic Reach-to-Grasp Movements in Humans

This protocol describes how to use frame-by-frame video analysis to quantify idiosyncratic reach-to-grasp movements in humans. A comparative analysis of reaching in sighted versus unsighted healthy adults is used to demonstrate the technique, but the method can also be applied to the study of developmental and clinical populations.

Prehension, the act of reaching to grasp an object, is central to the human experience. We use it to feed ourselves, groom ourselves, and manipulate ...

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8.2K Views.  Thompson Rivers University. This protocol describes how to use frame-by-frame video analysis to quantify idiosyncratic reach-to-grasp movements in humans. A comparative analysis of reaching in sighted versus unsighted healthy adults is used to demonstrate the technique, but the method can also be applied to the study of developmental and clinical populations.

Video: Frame-by-Frame Video Analysis of Idiosyncratic Reach-to-Grasp Movements in Humans

Using Eye Movements to Evaluate the Cognitive Processes Involved in Text Comprehension

The present article describes how to use eye tracking methodologies to study the cognitive processes involved in text comprehension. Measuring eye movements during reading is one of the most precise methods for measuring moment-by-moment (online) processing demands during text comprehension. Cognitive processing demands are reflected by several aspects of eye movement behavior, such as fixation duration, number of fixations, and number of regressions (returning to prior parts of a text). Important properties of eye tracking equipment that researchers need to consider are described, including how frequently the eye position is measured (sampling rate), accuracy of determining eye position, how much head movement is allowed, and ease of use. Also described are properties of stimuli that influence eye movements that need to be controlled in studies of text comprehension, such as the position, frequency, and length of target words. Procedural recommendations related to preparing the participant, setting up and calibrating the equipment, and running a study are given. Representative results are presented to illustrate how data can be evaluated. Although the methodology is described in terms of reading comprehension, much of the information presented can be applied to any study in which participants read verbal stimuli.

The present article describes how to use eye tracking methodologies to study the cognitive processes involved in text comprehension. Descriptions of eye tracking equipment, how to develop experimental stimuli, and procedural recommendations are included. The information presented can be applied to most any study using verbal stimuli.

The present article describes how to use eye  tracking methodologies to study the cognitive processes involved in text  comprehension. Measuring eye ...

Contextual and Cued Fear Conditioning Test Using a Video Analyzing System in Mice

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association between environmental cues and aversive experiences. In this test, mice are placed into a conditioning chamber and are given parings of a conditioned stimulus (an auditory cue) and an aversive unconditioned stimulus (an electric footshock). After a delay time, the mice are exposed to the same conditioning chamber and a differently shaped chamber with presentation of the auditory cue. Freezing behavior during the test is measured as an index of fear memory. To analyze the behavior automatically, we have developed a video analyzing system using the ImageFZ application software program, which is available as a free download at http://www.mouse-phenotype.org/. Here, to show the details of our protocol, we demonstrate our procedure for the contextual and cued fear conditioning test in C57BL/6J mice using the ImageFZ system. In addition, we validated our protocol and the video analyzing system performance by comparing freezing time measured by the ImageFZ system or a photobeam-based computer measurement system with that scored by a human observer. As shown in our representative results, the data obtained by ImageFZ were similar to those analyzed by a human observer, indicating that the behavioral analysis using the ImageFZ system is highly reliable. The present movie article provides detailed information regarding the test procedures and will promote understanding of the experimental situation.

This article presents a protocol for a contextual and cued fear conditioning test using a video analyzing system to assess fear learning and memory in mice.

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association ...

Studying Food Reward and Motivation in Humans

A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as hedonics, motivation, and goal value in more objective ways. This is particularly relevant for the understanding of overeating and obesity as well as their potential treatments. In this paper are described a set of measures of food-related motivation using handgrip force as a motivational measure. These methods can be used to examine changes in food related motivation with metabolic (satiety) and pharmacological manipulations and can be used to evaluate interventions targeted at overeating and obesity. However to understand food-related decision making in the complex food environment it is essential to be able to ascertain the reward goal values that guide the decisions and behavioral choices that people make. These values are hidden but it is possible to ascertain them more objectively using metrics such as the willingness to pay and a method for this is described. Both these sets of methods provide quantitative measures of motivation and goal value that can be compared within and between individuals.

This article describes a set of methods for the measurement of food related motivation and food related goal values in humans.

A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as ...

Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with schizophrenia who are at familial high risk (FHR) may show similar cognitive and emotional changes. However, the neurological changes underlying the emergence of these symptoms remain unclear. This study sought to identify differences in frontal, striatal, and limbic regions in children and adolescents with FHR using functional magnetic resonance imaging. Groups of 21 children and adolescents at FHR and 21 healthy controls completed an emotional oddball task that relied on selective attention and the suppression of task-irrelevant emotional information. The standard oddball task was modified to include aversive and neutral distractors in order to examine potential group differences in both emotional and executive processing. This task was designed specifically to allow for children and adolescents to complete by keeping the difficulty and emotional image content age-appropriate. Furthermore, we demonstrate a technique for suitable fMRI registration for children and adolescent participants. This paradigm may also be applied in future studies to measure changes in neural activity in other populations with hypothesized developmental changes in executive and emotional processing.

This paper describes how to use the emotional oddball task and fMRI to measure brain activation in children and adolescents at familial high risk for schizophrenia (FHR).&#160;FMRI was used to measure differences in fronto-striato-limbic regions during an emotional oddball task. Children with FHR exhibited abnormal functional activation during adolescence.

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with ...

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic &#946;-Blocker

The basic design used in our human fear-conditioning studies on disrupting reconsolidation includes testing over different phases across three consecutive days. On day 1 - the fear acquisition phase, healthy participants are exposed to a series of picture presentations. One picture stimulus (CS1+) is repeatedly paired with an aversive electric stimulus (US), resulting in the acquisition of a fear association, whereas another picture stimulus (CS2-) is never followed by an US. On day 2 - the memory reactivation phase, the participants are re-exposed to the conditioned stimulus without the US (CS1-), which typically triggers a conditioned fear response. After the memory reactivation we administer an oral dose of 40 mg of propranolol HCl, a &#946;-adrenergic receptor antagonist that indirectly targets the protein synthesis required for reconsolidation by inhibiting the noradrenaline-stimulated CREB phosphorylation. On day 3 - the test phase, the participants are again exposed to the unreinforced conditioned stimuli (CS1- and CS2-) in order to measure the fear-reducing effect of the manipulation. This retention test is followed by an extinction procedure and the presentation of situational triggers to test for the return of fear. Potentiation of the eye blink startle reflex is measured as an index for conditioned fear responding. Declarative knowledge of the fear association is measured through online US expectancy ratings during each CS presentation. In contrast to extinction learning, disrupting reconsolidation targets the original fear memory thereby preventing the return of fear. Although the clinical applications are still in their infancy, disrupting reconsolidation of fear memory seems to be a promising new technique with the prospect to persistently dampen the expression of fear memory in patients suffering from anxiety disorders and other psychiatric disorders.

Disrupting reconsolidation is a promising approach to dampen the behavioral expression of fear memory in patients with anxiety disorders or posttraumatic stress disorder. In a series of human fear conditioning studies we showed that disrupting reconsolidation by the noradrenergic &#946;-blocker propranolol is very effective in erasing conditioned fear responding.

The basic design used in our human fear-conditioning studies on disrupting reconsolidation includes testing over different phases across three consecutive ...

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 ...

Measuring Delay Discounting in Humans Using an Adjusting Amount Task

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. Delay discounting tasks are used to identify indifference points, which reflect equal preference for two dichotomous reward alternatives differing in both delay and magnitude. Indifference points are key to assessing the shape of a delay-discounting gradient because they allow us to isolate the effect of delay on value. For example, if at a 1 week delay and a maximum of $1,000, the indifference point is at $700 we know that, for that participant, a 1-week delay corresponds to a 30% reduction in value. This video outlines an adjusting amount delay-discounting task that identifies indifference points relatively quickly and is inexpensive and easy to administer. Once data have been collected, non-linear regression techniques are typically used to generate discounting curves. The steepness of the discounting curve reflects the degree of impulsive choice of a group or individual. These techniques have been used with a wide range of commodities and have identified populations that are relatively impulsive. For example, people with substance abuse problems discount delayed rewards more steeply than control participants. Although degree of discounting varies as a function of the commodity examined, discounting of one commodity correlates with discounting of other commodities, which suggests that discounting may be a persistent pattern of behavior1.

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. We outline a computer-based delay discounting task that is easy to implement and allows for the quantification of the degree of delay discounting in human participants.

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. Delay discounting tasks ...

A Protocol of Manual Tests to Measure Sensation and Pain in Humans

Numerous qualitative and quantitative techniques can be used to test sensory nerves and pain in both research and clinical settings. The current study demonstrates a quantitative sensory testing protocol using techniques to measure tactile sensation and pain threshold for pressure and heat using portable and easily accessed equipment. These techniques and equipment are ideal for new laboratories and clinics where cost is a concern or a limiting factor. We demonstrate measurement techniques for the following: cutaneous mechanical sensitivity on the arms and legs (von-Frey filaments), radiant and contact heat sensitivity (with both threshold and qualitative assessments using the Visual Analog Scale (VAS)), and mechanical pressure sensitivity (algometer, with both threshold and the VAS). The techniques and equipment described and demonstrated here can be easily purchased, stored, and transported by most clinics and research laboratories around the world. A limitation of this approach is a lack of automation or computer control. Thus, these processes can be more labor intensive in terms of personnel training and data recording than the more sophisticated equipment. We provide a set of reliability data for the demonstrated techniques. From our description, a new laboratory should be able to set up and run these tests and to develop their own internal reliability data.

The goal of this procedure is to demonstrate a battery of quantitative techniques for sensory and pain measurement in humans. The equipment and techniques described are commonly found in pain clinics or are easy to obtain.

Numerous qualitative and quantitative techniques can be used to test sensory nerves and pain in both research and clinical settings. The current study ...

Measuring the Kinematics of Daily Living Movements with Motion Capture Systems in Virtual Reality

The inability to complete instrumental activities of daily living (IADL) is a precursor to various neuropsychological diseases. Questionnaire-based assessments of IADL are easy to use but prone to subjective bias. Here, we describe a novel virtual reality (VR) test to assess two complex IADL tasks: handling financial transactions and using public transportation. While a participant performs the tasks in a VR setting, a motion capture system traces the position and orientation of the dominant hand and head in a three-dimensional Cartesian coordinate system. Kinematic raw data are collected and converted into &#39;kinematic performance measures,&#39; i.e., motion trajectory, moving distance, and time to completion. Motion trajectory is the path of a particular body part (e.g., dominant hand or head) in space. Moving distance refers to the total distance of the trajectory, and time to completion is how long it took to complete an IADL task. These kinematic measures could discriminate patients with cognitive impairment from healthy controls. The development of this kinematic measuring protocol allows detection of early IADL-related cognitive impairments.

We designed a virtual reality test to assess instrumental activities of daily living (IADL) with a motion capture system. We propose a detailed kinematic analysis to interpret the participant&#39;s various movements, including trajectory, moving distance, and time to completion to evaluate IADL capabilities.

The inability to complete instrumental activities of daily living (IADL) is a precursor to various neuropsychological diseases. Questionnaire-based ...

Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded via an eye tracker as the participant produces or comprehends a spoken language describing the concurrent visual world. This paradigm has high versatility, as it can be used in a wide range of populations, including those who cannot read and/or who cannot overtly give their behavioral responses, such as preliterate children, elderly adults, and patients. More importantly, the paradigm is extremely sensitive to fine grained manipulations of the speech signal, and it can be used to study the online processing of most topics in language comprehension at multiple levels, such as the fine grained acoustic phonetic features, the properties of words, and the linguistic structures. The protocol described in this article illustrates how a typical visual world eye tracking study is conducted, with an example showing how the online processing of some semantically complex statements can be explored with the visual world paradigm.

The visual world paradigm monitors participants' eye movements in the visual workspace as they are listening to or speaking a spoken language. This paradigm can be used to investigate the online processing of a wide range of psycholinguistic questions, including semantically complex statements, such as disjunctive statements.

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded ...