Name: investigating motor skill learning processes with a robotic manipulandum
Uploaded: 2017-02-12T15:00:00
Description: Watch this Scientific Journal Video about Investigating Motor Skill Learning Processes with a Robotic Manipulandum at JoVE.com

This research was supported by the Swiss National Science Foundation, the Betty and David Koetser Foundation for Brain Research and the ETH Foundation.

The experiments presented here were approved by the Veterinary Office of the Canton of Zurich, Switzerland and were carried out according to national and institutional regulations.
1. Feeding Conditions
NOTE: All training sessions are performed under a scheduled feeding protocol.
<ol>
	<li>Feed the rats 50 g/kg of standard chow once per day, after training is completed. This amount of food is sufficient to prevent major weight loss (body weight is &#62;90% of free...

<ol>
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C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+robotic+platform+to+assess,+guide+and+perturb+rat+forelimb+movements.">A robotic platform to assess, guide and perturb rat forelimb movements.</a> IEEE Trans. Neural Syst. Rehabil. Eng. 21 (5), 796-805 (2013).</li><li>Klein, A., Sacrey, L. -. A. R., Whishaw, I. Q., Dunnett, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+rodent+skilled+reaching+as+a+translational+model+for+investigating+brain+damage+and+disease.">The use of rodent skilled reaching as a translational model for investigating brain damage and disease.</a> Neurosci Biobehav Rev. 36 (3), 1030-1042 (2012).</li><li>Gharbawie, O. A., 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=Parallel+stages+of+learning+and+recovery+of+skilled+reaching+after+motor+cortex+stroke:+&amp;#34;Oppositions&amp;#34;+organize+normal+and+compensatory+movements.">Parallel stages of learning and recovery of skilled reaching after motor cortex stroke: &amp;#34;Oppositions&amp;#34; organize normal and compensatory movements.</a> Behav Brain Res. 175 (2), 249-262 (2006).</li><li>Palm&#233;r, T., Tamt&#232;, M., Halje, P., Enqvist, O., Petersson, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+system+for+automated+tracking+of+motor+components+in+neurophysiological+research.">A system for automated tracking of motor components in neurophysiological research.</a> J Neurosci Meth. 205 (2), 334-344 (2012).</li><li>Alaverdashvili, 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=A+behavioral+method+for+identifying+recovery+and+compensation:+Hand+use+in+a+preclinical+stroke+model+using+the+single+pellet+reaching+task.">A behavioral method for identifying recovery and compensation: Hand use in a preclinical stroke model using the single pellet reaching task.</a> Neurosci Biobehav Rev. 37 (5), 950-967 (2013).</li><li>Alaverdashvili, 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=Compensation+aids+skilled+reaching+in+aging+and+in+recovery+from+forelimb+motor+cortex+stroke+in+the+rat.">Compensation aids skilled reaching in aging and in recovery from forelimb motor cortex stroke in the rat.</a> Neurosci. 167 (1), 21-30 (2010).</li><li>Molina-Luna, K., 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=Dopamine+in+motor+cortex+is+necessary+for+skill+learning+and+synaptic+plasticity.">Dopamine in motor cortex is necessary for skill learning and synaptic plasticity.</a> PloS one. 4 (9), (2009).</li><li>VandenBerg, P. M., Hogg, T. M., Kleim, J. A., 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=Long-Evans+rats+have+a+larger+cortical+topographic+representation+of+movement+than+Fischer-344+rats:+A+microstimulation+study+of+motor+cortex+in+na&#305;&#776;ve+and+skilled+reaching-trained+rats.">Long-Evans rats have a larger cortical topographic representation of movement than Fischer-344 rats: A microstimulation study of motor cortex in na&#305;&#776;ve and skilled reaching-trained rats.</a> Brain Res Bull. 59 (3), 197-203 (2002).</li><li>Whishaw, I. Q., Gorny, B., Foroud, A., Kleim, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-Evans+and+Sprague-Dawley+rats+have+similar+skilled+reaching+success+and+limb+representations+in+motor+cortex+but+different+movements:+some+cautionary+insights+into+the+selection+of+rat+strains+for+neurobiological+motor+research.">Long-Evans and Sprague-Dawley rats have similar skilled reaching success and limb representations in motor cortex but different movements: some cautionary insights into the selection of rat strains for neurobiological motor research.</a> Behav Brain Res. 145 (1-2), 221-232 (2003).</li><li>Harms, K. J., Rioult-Pedotti, M. S., Carter, D. 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Skilled reaching tasks are commonly used to study motor skill acquisition as well as impairment of motor function under pathological conditions6. Reliable and unambiguous analysis of reaching behavior is essential for the study of cellular mechanisms underlying motor skill acquisition, as well as neurophysiological processes involved in loss and subsequent recovery of function in animal models of neurological disease. The results presented here show how spatial and temporal aspects of the pulling ...

Motor tasks are widely used to assess behavioral and neural changes related to motor learning or to alterations in motor function in neurological or pharmacological animal models. Fine motor function can be difficult to quantify in rodents, however. Tasks requiring manual dexterity, such as manipulation of cereal1, pasta2, or sunflower seeds3 are sensitive and do not require extensive training of the animal. Their main drawback is that these tasks yield mostly qualitative results and can be difficult to score unambiguously.
Skilled reaching tasks, such as variations of the single pellet reaching task are more straightforward to quantify4,5. However, kinematic factors that underlie successful execution of these tasks can only be inferred to a limited extent and require labor-intensive frame-by-frame video analysis.
Robotic devices have gained popularity as means of quantifying aspects of forelimb function and motor skill. Several automated reaching tasks are available. The majority focus on a single aspect of a forelimb movement, such as pulling of a handle along a linear guide6,7, simple distal limb movements8, or pronation and supination of the paw9. While these devices show promise for the analysis of motor function in, they only reflect the complex motor actions executed during single pellet reaching to a limited extend.
Here, we demonstrate the use of a three-degree-of-freedom robotic device, ETH Pattus, developed for training and assessment of various motor tasks in rats10,11. It records planar and rotational movement of rat forelimb movements in reach, grasp, and pulling tasks carried out in the horizontal plane. Rats interact with the robot via a 6 mm-diameter spherical handle that can be reached through a window in the testing cage (width: 15 cm, length: 40 cm, height: 45 cm) and moved in the horizontal plane (pushing and pulling movements) and rotated (pronation-supination movements). Thus, it enables the rat to carry out movements that approximate those executed during conventional single pellet reaching tasks. The window is 10 mm wide and located 50 mm above the cage floor. The handle is located 55 mm above the floor. A sliding door blocks access to the handle between reaching trials and opens when the robot reaches its start position and closes after a trial is completed. After a correctly executed movement, rats receive a food reward on the opposite side of the testing cage.
The robot is controlled via software and records output from 3 rotary encoders at 1000 Hz, resulting in information about the position of the handle in the horizontal plane, as well as its rotation angle (for details, see reference11). The conditions required for successful task execution are defined in the software prior to each training session (e.g. minimum required pulling distance and maximum deviation from midline in a reach-and-pull task). An initial standardized reference position of the handle is recorded with a fixed holder at the start of each training session. This reference is used for all trials within a session, assuring a constant start position of the handle for each trial. Constant positioning of the handle relative to the cage window is assured by alignment of marks on the cage and robot (Figure 1).
Video recordings of the reaching movements are recorded using a small high speed camera (120 frames/s, 640 x 480 resolution). A small display in the camera&#39;s view shows the rat&#39;s identification number, training session, trial number and trial result (success or failed). These videos are used to verify recorded results and to assess the effects of reaching movements that precede the touching, pulling or rotation of the handle.
Here, we demonstrate the use of this robotic platform in variations of a reach-and-pull task. This task can be trained within a period of time that is comparable to other skilled reaching paradigms and yields reproducible results. We describe a typical training protocol, as well as some of the main output parameters. Moreover, we show how minor changes in the used training protocol can result in altered time courses of behavioral outcomes that may represent independent subprocesses within the motor skill learning process.

<table border="0" cellpadding="0" cellspacing="0" width="679">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">ETH Pattus</td>
			<td style="width:105px;"></td>
			<td style="width:136px;"></td>
			<td style="width:191px;">ETH Pattus was made by the Rehabilitation Engineering Laboratory of Prof. Gassert at ETH Zurich.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Training cage&#160;</td>
			<td style="width:105px;"></td>
			<td style="width:136px;"></td>
			<td>The plexiglass training cage was made in-house.&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Pellet dispenser</td>
			<td style="width:105px;">Campden Instruments</td>
			<td align="right" style="width:136px;">80209</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">45-mg dustless precision pellets</td>
			<td style="width:105px;">Bio-Serv</td>
			<td style="width:136px;">F0021-J</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">GoPro Hero 3+ Silver Edition&#160;</td>
			<td style="width:105px;">digitec.ch</td>
			<td align="right">284528</td>
			<td>Small highspeed camera&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Small display</td>
			<td style="width:105px;">Adafruit Industries</td>
			<td style="width:136px;">#50, #661</td>
			<td>128x32 SPI Oled display controlled via an Arduino Uno microcontroller and Labview software</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Labview 2012</td>
			<td style="width:105px;">National Instruments</td>
			<td style="width:136px;">776678-3513</td>
			<td>ETH Pattus is compatible with more recent Labview versions.&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Matlab 2014b</td>
			<td style="width:105px;">The Mathworks</td>
			<td style="width:136px;">MLALL</td>
			<td></td>
		</tr>
	</tbody>
</table>

investigating motor skill learning processes with a robotic manipulandum

Skilled reaching tasks are commonly used in studies of motor skill learning and motor function under healthy and pathological conditions, but can be time-intensive and ambiguous to quantify beyond simple success rates. Here, we describe the training procedure for reach-and-pull tasks with ETH Pattus, a robotic platform for automated forelimb reaching training that records pulling and hand rotation movements in rats. Kinematic quantification of the performed pulling attempts reveals the presence of distinct temporal profiles of movement parameters such as pulling velocity, spatial variability of the pulling trajectory, deviation from midline, as well as pulling success. We show how minor adjustments in the training paradigm result in alterations in these parameters, revealing their relation to task difficulty, general motor function or skilled task execution. Combined with electrophysiological, pharmacological and optogenetic techniques, this paradigm can be used to explore the mechanisms underlying motor learning and memory formation, as well as loss and recovery of function (e.g. after stroke).

Here, we show 3 variations of a reach-and pull task using male Long-Evans rats (10-12 weeks old). In the free-pull (FP) group (N = 6), rats were trained to pull the robot&#39;s handle for a 22 day period without lateral restrictions. Animals in the straight-pull 1 (SP1) group (N = 12) were trained to pull the handle without deviating more than 2 mm from midline. These animals transitioned directly from reward-touch (step 2.3) to straight-pull training (step 2.5). For both FP and SP1 anima...

Watch this Scientific Journal Video about Investigating Motor Skill Learning Processes with a Robotic Manipulandum at JoVE.com

Investigating Motor Skill Learning Processes with a Robotic Manipulandum

A paradigm is presented for training and analysis of an automated skilled reaching task in rats. Analysis of pulling attempts reveals distinct subprocesses of motor learning.

Skilled reaching tasks are commonly used in studies of motor skill learning and motor function under healthy and pathological conditions, but can be ...

The overall goal of training rats on this reaching task involving a robotic manipulandum is to investigate the processes underlying motor skill learning and motor function recovery. This method can help answer key questions in the field of behavioral neuroscience, specifically related to the mechanisms underlying motor learning and memory formation as well as loss and recovery of function after brain damage or stroke. The main advantage of this technique are that the rats'training and that analysis is easy to perform and that it is more objective than other conventional single pellet reaching task.Moreover, the robotic manipulandum allows for better analysis of kinematics. In preparation, always allow newly acquired rats to habituate to their new home cages for at least a week before training them. During this time, handle the rats regularly and feed them the reward pellets used for the training protocol.To begin the training process, first spend two or three days habituating the rats to the test cage. The first task is to train the rats to simply touch the spherical handle through the cage window and to then move to the opposite side of the cage and retrieve a food reward. First, adjust the software settings so that the handle is located just outside the testing cage window.Now, put the rat in the training cage and hold a pellet near the handle. Direct the rat's attention by tapping on the cage as needed. Continue prompting the rat to the handle this way until it independently reaches through the cage window and touches the handle or food pellet.Then, run the session until 100 touches have been completed or until 60 minutes have elapsed, whichever comes first. Continue training the rat daily until it completes 100 touches within 30 minutes on two consecutive days. This usually occurs in the first two sessions.Once this proficiency is obtained, proceed directly with the next training paradigm. Rats can perform much more quickly in this task than the defined criteria, but it is important to not overtrain them as this can result in overconsolidation of the behavior and stifle shaping of the behavior to the final goal. The next challenge is for the rats to learn the intermediate step of reaching out and pulling the handle.As with reward touch training, it is important not to overtrain as the final goal is to transition to the next stage of training. First, adjust the software setting so that the robot positions the handle 18 millimeters from the window at the start of each trial. The handle must be pulled at least 10 millimeters without interruption for a successful trial.There are no lateral restrictions on the pulling movement. Then perform the sessions as before with 100 trials or 60 minutes marking their ends. If a rat is not reaching far enough to perform the task, then shape the correct behavior by holding a pellet with forceps near the handle.If a rat seems to lose interest in pulling the handle, then tap on the cage or dispense a pellet. Determine the rat's paw preference from its first 20 attempts to pull the handle. Simply choose the paw that is used more often as the dominant paw.Most rats will show a strong preference and used one paw in at least 80%of the trials. Once a dominant paw is noted, adjust the position of the handle laterally to favor this paw. Align the handle to the edge of the window and keep it in this position for all future sessions with this rat.Continue training the task until the rat reaches a plateau performance or performs the task 100 times within 30 minutes on two consecutive days. Only two sessions are typically needed before proceeding to straight pulling. The final stage of training is to teach the rats to pull the handle straightly for a reward.Change the parameters in the software so that a pulling movement that deviates by more than two millimeters from the midline is considered a failure. As usual, each session should be run until either 100 trials are completed or 60 minutes have passed. Continue training the rats on this task until their skill level reaches a plateau or until the rats exceed a defined criteria.Using 10 to 12 week old male Long-Evans rats, three different training techniques were compared over 22 days of training. Each group was given reward touch training. Then the parameters changed.In one group, FP, rats were trained to pull the robot's handle without any lateral restrictions. In the next group, SP1, rats were trained to pull the handle without deviating more than two millimeters from the midline but were not given any free pull training sessions. In the final group, SP2, rats received exactly two free pull training sessions and then transitioned to straight pull training.Importantly for SP2, the handle was kept aligned near one edge of the window resulting in a more challenging task. This condition could occur by accident if the robot isn't consistently aligned to the cage by the operator. Possibly due to this added challenge, the task success rate for SP1 rats plateaued sooner than it did for SP2 rats.Over the sessions, handle movement improved from the first session to the last. The data shown is of one representative rat from the SP2 group. Similarly, the speed of pulling became more regular from the first to the last session indicating a more stable movement was learned.This data is also from a representative SP2 rat. After watching this video, you should have a good understanding of how to perform an automated skilled reaching task and of the factors that may impact your results. As we have shown, minor alteration in the training pattern will affect the animal performance.So when attempting this procedure, it's important to keep all the conditions consistent for each animal such as the handle location.

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Research

JoVE Journal

Behavior

Study Motor Skill Learning by Single-pellet Reaching Tasks in Mice

Reaching for and retrieving objects require precise and coordinated motor movements in the forelimb. When mice are repeatedly trained to grasp and retrieve food rewards positioned at a specific location, their motor performance (defined as accuracy and speed) improves progressively over time, and plateaus after persistent training. Once such reaching skill is mastered, its further maintenance does not require constant practice. Here we introduce a single-pellet reaching task to study the acquisition and maintenance of skilled forelimb movements in mice. In this video, we first describe the behaviors of mice that are commonly encountered in this learning and memory paradigm, and then discuss how to categorize these behaviors and quantify the observed results. Combined with mouse genetics, this paradigm can be utilized as a behavioral platform to explore the anatomical underpinnings, physiological properties, and molecular mechanisms of learning and memory.

Persistent practice improves the precision of coordinated movements.&#160;Here we introduce a single-pellet reaching task, which is designed to assess the learning and memory of forelimb skill in mice.&#160;

Reaching for and retrieving objects require precise and coordinated motor movements in the forelimb. When mice are repeatedly trained to grasp and ...

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior

Kinesthetic awareness is important to successfully navigate the environment. When we interact with our daily surroundings, some aspects of movement are deliberately planned, while others spontaneously occur below conscious awareness. The deliberate component of this dichotomy has been studied extensively in several contexts, while the spontaneous component remains largely under-explored. Moreover, how perceptual processes modulate these movement classes is still unclear. In particular, a currently debated issue is whether the visuomotor system is governed by the spatial percept produced by a visual illusion or whether it is not affected by the illusion and is governed instead by the veridical percept. Bistable percepts such as 3D depth inversion illusions (DIIs) provide an excellent context to study such interactions and balance, particularly when used in combination with reach-to-grasp movements. In this study, a methodology is developed that uses a DII to clarify the role of top-down processes on motor action, particularly exploring how reaches toward a target on a DII are affected in both deliberate and spontaneous movement domains.

It is unclear how top-down signals from the ventral visual stream affect movement. We developed a paradigm to test motor behavior towards a target on a 3D depth inversion illusion. Significant differences are reported in both deliberate, goal-directed movements and automatic actions under illusory and veridical viewing conditions.

Kinesthetic awareness is important to successfully navigate the environment. When we interact with our daily surroundings, some aspects of movement are ...

Compensatory Limb Use and Behavioral Assessment of Motor Skill Learning Following Sensorimotor Cortex Injury in a Mouse Model of Ischemic Stroke

Mouse models have become increasingly popular in the field of behavioral neuroscience, and specifically in studies of experimental stroke. As models advance, it is important to develop sensitive behavioral measures specific to the mouse. The present protocol describes a skilled motor task for use in mouse models of stroke. The Pasta Matrix Reaching Task functions as a versatile and sensitive behavioral assay that permits experimenters to collect accurate outcome data and manipulate limb use to mimic human clinical phenomena including compensatory strategies (i.e., learned non-use) and focused rehabilitative training. When combined with neuroanatomical tools, this task also permits researchers to explore the mechanisms that support behavioral recovery of function (or lack thereof) following stroke. The task is both simple and affordable to set up and conduct, offering a variety of training and testing options for numerous research questions concerning functional outcome following injury. Though the task has been applied to mouse models of stroke, it may also be beneficial in studies of functional outcome in other upper extremity injury models.

Mouse models have become increasingly popular in studies of behavioral neuroscience. As models advance, it is important to develop sensitive behavioral measures specific to the mouse. This protocol describes the Pasta Matrix Reaching Task, which is a skilled motor task for use in mouse models of stroke.

Mouse models have become increasingly popular in the field of behavioral neuroscience, and specifically in studies of experimental stroke. As models ...

Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception. Researchers have used single-pulse and repetitive TMS to stimulate the lip representation in the motor cortex. The excitability of the lip motor representation can be investigated by applying single TMS pulses over this cortical area and recording TMS-induced motor evoked potentials (MEPs) via electrodes attached to the lip muscles (electromyography; EMG). Larger MEPs reflect increased cortical excitability. Studies have shown that excitability increases during listening to speech as well as during&#160;viewing speech-related movements. TMS can be used also to disrupt the lip motor representation. A 15-min train of low-frequency sub-threshold repetitive stimulation has been shown to suppress motor excitability for a further 15-20 min. This TMS-induced disruption of the motor lip representation impairs subsequent performance in demanding speech perception tasks and modulates auditory-cortex responses to speech sounds. These findings are consistent with the suggestion that the motor cortex contributes to speech perception. This article describes how to localize the lip representation in the motor cortex and how to define the appropriate stimulation intensity for carrying out both single-pulse and repetitive TMS experiments.

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception.&#160; This article describes how to record motor evoked potentials (MEPs) from the lip muscles and how to disrupt the motor lip representation using repetitive TMS.

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception. ...

Functional Near Infrared Spectroscopy of the Sensory and Motor Brain Regions with Simultaneous Kinematic and EMG Monitoring During Motor Tasks

There are several advantages that functional near-infrared spectroscopy (fNIRS) presents in the study of the neural control of human movement. It is relatively flexible with respect to participant positioning and allows for some head movements during tasks. Additionally, it is inexpensive, light weight, and portable, with very few contraindications to its use. This presents a unique opportunity to study functional brain activity during motor tasks in individuals who are typically developing, as well as those with movement disorders, such as cerebral palsy. An additional consideration when studying movement disorders, however, is the quality of actual movements performed and the potential for additional, unintended movements. Therefore, concurrent monitoring of both blood flow changes in the brain and actual movements of the body during testing is required for appropriate interpretation of fNIRS results. Here, we show a protocol for the combination of fNIRS with muscle and kinematic monitoring during motor tasks. We explore gait, a unilateral multi-joint movement (cycling), and two unilateral single-joint movements (isolated ankle dorsiflexion, and isolated hand squeezing). The techniques presented can be useful in studying both typical and atypical motor control, and can be modified to investigate a broad range of tasks and scientific questions.

Monitoring brain activity during upright motor tasks is of great value when investigating the neural source of movement disorders. Here, we demonstrate a protocol that combines functional near infrared spectroscopy with continuous monitoring of muscle and kinematic activity during 4 types of motor tasks.

There are several advantages that functional near-infrared spectroscopy (fNIRS) presents in the study of the neural control of human movement. It is ...

Quantifying Learning in Young Infants: Tracking Leg Actions During a Discovery-learning Task

Task-specific actions emerge from spontaneous movement during infancy. It has been proposed that task-specific actions emerge through a discovery-learning process. Here a method is described in which 3-4 month old infants learn a task by discovery and their leg movements are captured to quantify the learning process. This discovery-learning task uses an infant activated mobile that rotates and plays music based on specified leg action of infants. Supine infants activate the mobile by moving their feet vertically across a virtual threshold. This paradigm is unique in that as infants independently discover that their leg actions activate the mobile, the infants&#8217; leg movements are tracked using a motion capture system allowing for the quantification of the learning process. Specifically, learning is quantified in terms of the duration of mobile activation, the position variance of the end effectors (feet) that activate the mobile, changes in hip-knee coordination patterns, and changes in hip and knee muscle torque. This information describes infant exploration and exploitation at the interplay of person and environmental constraints that support task-specific action. Subsequent research using this method can investigate how specific impairments of different populations of infants at risk for movement disorders influence the discovery-learning process for task-specific action.

A method is described in which 3-4 month old infants learn a task by discovery and their leg movements are captured to quantify the learning process.

Task-specific actions emerge from spontaneous movement during infancy. It has been proposed that task-specific actions emerge through a discovery-learning ...

Event-related Potentials During Target-response Tasks to Study Cognitive Processes of Upper Limb Use in Children with Unilateral Cerebral Palsy

Unilateral Cerebral Palsy (CP) is a neurodevelopmental disorder that is a very common cause of disability in childhood. It is characterized by unilateral motor impairments that are frequently dominated in the upper limb. In addition to a reduced movement capacity of the affected upper limb, several children with unilateral CP show a reduced awareness of the remaining movement capacity of that limb. This phenomenon of disregarding the preserved capacity of the affected upper limb is regularly referred to as Developmental Disregard (DD). Different theories have been postulated to explain DD, each suggesting slightly different guidelines for therapy. Still, cognitive processes that might additionally contribute to DD in children with unilateral CP have never been directly studied. The current protocol was developed to study cognitive aspects involved in upper limb control in children with unilateral CP with and without DD. This was done by recording event-related potentials (ERPs) extracted from the ongoing EEG during target-response tasks asking for a hand-movement response. ERPs consist of several components, each of them associated with a well-defined cognitive process (e.g., the N1 with early attention processes, the N2 with cognitive control and the P3 with cognitive load and mental effort). Due to its excellent temporal resolution, the ERP technique enables to study several covert cognitive processes preceding overt motor responses and thus allows insight into the cognitive processes that might contribute to the phenomenon of DD. Using this protocol adds a new level of explanation to existing behavioral studies and opens new avenues to the broader implementation of research on cognitive aspects of developmental movement restrictions in children.

Several children with unilateral Cerebral Palsy seem to disregard the preserved capacity of their affected upper limb. This Developmental Disregard is extensively described in the literature but the involved cognitive processes have not been studied. To study underlying cognitive factors of upper limb control, an event-related potential protocol was developed.

Unilateral Cerebral Palsy (CP) is a neurodevelopmental disorder that is a very common cause of disability in childhood. It is characterized by unilateral ...

Using a Split-belt Treadmill to Evaluate Generalization of Human Locomotor Adaptation

Understanding the mechanisms underlying locomotor learning helps researchers and clinicians optimize gait retraining as part of motor rehabilitation. However, studying human locomotor learning can be challenging. During infancy and childhood, the neuromuscular system is quite immature, and it is unlikely that locomotor learning during early stages of development is governed by the same mechanisms as in adulthood. By the time humans reach maturity, they are so proficient at walking that it is difficult to come up with a sufficiently novel task to study de novo locomotor learning. The split-belt treadmill, which has two belts that can drive each leg at a different speed, enables the study of both short- (i.e., immediate) and long-term (i.e., over minutes-days; a form of motor learning) gait modifications in response to a novel change in the walking environment. Individuals can easily be screened for previous exposure to the split-belt treadmill, thus ensuring that all experimental participants have no (or equivalent) prior experience. This paper describes a typical split-belt treadmill adaptation protocol that incorporates testing methods to quantify locomotor learning and generalization of this learning to other walking contexts. A discussion of important considerations for designing split-belt treadmill experiments follows, including factors like treadmill belt speeds, rest breaks, and distractors. Additionally, potential but understudied confounding variables (e.g., arm movements, prior experience) are considered in the discussion.

We describe a protocol for investigating human locomotor adaptation using the split-belt treadmill, which has two belts that can drive each leg at a different speed. We specifically focus on a paradigm designed to test the generalization of adapted locomotor patterns to different walking contexts (e.g., gait speeds, walking environments).

Understanding the mechanisms underlying locomotor learning helps researchers and clinicians optimize gait retraining as part of motor rehabilitation. ...

Using Virtual Reality to Transfer Motor Skill Knowledge from One Hand to Another

As far as acquiring motor skills is concerned, training by voluntary physical movement is superior to all other forms of training (e.g. training by observation or passive movement of trainee&#39;s hands by a robotic device). This obviously presents a major challenge in the rehabilitation of a paretic limb since voluntary control of physical movement is limited. Here, we describe a novel training scheme we have developed that has the potential to circumvent this major challenge. We exploited the voluntary control of one hand and provided real-time movement-based manipulated sensory feedback as if the other hand is moving. Visual manipulation through virtual reality (VR) was combined with a device that yokes left-hand fingers to passively follow right-hand voluntary finger movements. In healthy subjects, we demonstrate enhanced within-session performance gains of a limb in the absence of voluntary physical training. Results in healthy subjects suggest that training with the unique VR setup might also be beneficial for patients with upper limb hemiparesis by exploiting the voluntary control of their healthy hand to improve rehabilitation of their affected hand.

We describe a novel virtual-reality based setup which exploits voluntary control of one hand to improve motor-skill performance in the other (non-trained) hand. This is achieved by providing real-time movement-based sensory feedback as if the non-trained hand is moving. This new approach may be used to enhance rehabilitation of patients with unilateral hemiparesis.

As far as acquiring motor skills is concerned, training by voluntary physical movement is superior to all other forms of training (e.g. training by ...

The "Motor" in Implicit Motor Sequence Learning: A Foot-stepping Serial Reaction Time Task

This protocol describes a modified serial reaction time (SRT) task used to study implicit motor sequence learning. Unlike the classic SRT task that involves finger-pressing movements while sitting, the modified SRT task requires participants to step with both feet while maintaining a standing posture. This stepping task necessitates whole body actions that impose postural challenges. The foot-stepping task complements the classic SRT task in several ways. The foot-stepping SRT task is a better proxy for the daily activities that require ongoing postural control, and thus may help us better understand sequence learning in real-life situations. In addition, response time serves as an indicator of sequence learning in the classic SRT task, but it is unclear whether response time, reaction time (RT) representing mental process, or movement time (MT) reflecting the movement itself, is a key player in motor sequence learning. The foot-stepping SRT task allows researchers to disentangle response time into RT and MT, which may clarify how motor planning and movement execution are involved in sequence learning. Lastly, postural control and cognition are interactively related, but little is known about how postural control interacts with learning motor sequences. With a motion capture system, the movement of the whole body (e.g., the center of mass (COM)) can be recorded. Such measures allow us to reveal the dynamic processes underlying discrete responses measured by RT and MT, and may aid in elucidating the relationship between postural control and the explicit and implicit processes involved in sequence learning. Details of the experimental set-up, procedure, and data processing are described. The representative data are adopted from one of our previous studies. Results are related to response time, RT, and MT, as well as the relationship between the anticipatory postural response and the explicit processes involved in implicit motor sequence learning.

The &quot;Motor&quot; in Implicit Motor Sequence Learning: A Foot-stepping Serial Reaction Time Task

We introduce the foot-stepping serial reaction time (SRT) task. This modified SRT task, complementing the classic SRT task that involves only finger-pressing movement, better approximates daily sequenced activities and allows researchers to study the dynamic processes underlying discrete response measures and disentangle the explicit process operating in implicit sequence learning.

This protocol describes a modified serial reaction time (SRT) task used to study implicit motor sequence learning. Unlike the classic SRT task that ...