Support for this research was provided by the University of Maryland Kinesiology Graduate Research Initiative Fund to Yue Du.

The protocol was performed in accordance with the guidelines approved by the Institutional Review Board at the University of Maryland, College Park.
1. Experimental Set-up
<ol>
	<li>Set up a motion capture system as shown in Figure 1a. Place eight cameras in a circle with a radius of 4 m. 
	NOTE: The number and positions of cameras can be varied, provided all cameras are appropriately positioned to obtain a clear vision of all reflective markers attached to a participant&#39;s body.</li>
	<li>Set up a stepping station in the center of the circle. Position a &#34;home position&#34; covered by dark blue felt mats in the center of the stepping station and place six stepping targets covered by light blue felt mats surrounding the home position as its front, back, and side (Figure 1b). Determine the distance between the targets and home position, according to an individual&#39;s stepping distance (see step 3 in the foot-stepping SRT task procedure).</li>
	<li>To control the task pacing condition, place two electric rubber sensors, which generate analog signals when touched, under the home position to detect the time when the feet return.</li>
	<li>Position a 23&#39;&#39; monitor 2 m in front of the home position. The six visual stimuli are spatially matched with those six stepping targets on the floor.</li>
	<li>Control the appearance order of the visual stimuli using a computer program installed in a laptop.</li>
	<li>Synchronize the laptop and the motion capture system using a data output and acquisition device.</li>
	<li>Turn on the motion capture cameras, and aim them so that each camera can view the volume surrounding the stepping station.</li>
	<li>Identify whether there are unwanted reflective objects from the capture volume (e.g., reflection from light, floor, or any reflective materials). Cover these identified reflective objects with fabric material, so that they are not mistakenly collected as data during experimental trials.</li>
	<li>Using the instructions and equipment supplied with the motion capture system, calibrate the motion capture system to ensure accurate collection of 3-D data from reflective markers18.</li>
	<li>For dynamic calibration, wave the calibration wand supplied with the motion capture system through the space where all reflective markers would move when participants perform the SRT task. Collect 2,000 frames of imaging data for dynamic calibration.</li>
	<li>For static calibration, place the calibration wand on the floor with a position and orientation which can be used as the origin of the coordination system of the motion capture system. Run the motion capture system to set the origin.</li>
	<li>Design a marker set depending on the purpose of study. 
	NOTE: One example is shown in Figure 1b where a 38-marker set-up is used.</li>
	<li>Follow the vendor-supplied instructions to create a labeling skeleton template that can be used for reconstruction and auto-labelling in later data acquisition and processing18. Specifically, ask a participant to stand on the home position of the stepping station with all markers attached. Instruct the participant to stand as still as possible and make sure all markers are visible through the motion capture system. Capture a trial (lasting about 10 s). In the motion capture system, assign each marker a name and create segments by connecting markers together. Link all segments to finalize the skeleton template (shown in Figure 1c).</li>
</ol>
2. Participant Preparation
<ol>
	<li>Inform participants to wear appropriate attire (e.g., shorts and a t-shirt) before visiting the lab.</li>
	<li>Upon arrival, ask participants to carefully read and sign the consent form. Screen for study eligibility. 
	NOTE: The screening questionnaires could be different based on the purpose of each individual study. These questionnaires may include, but are not limited to, the hand dominance questionnaire19, global physical activity level questionnaire20, neurological health questionnaire, and the Movement Assessment Battery for Children21.</li>
	<li>Ask participants to take off their shoes and socks, then attach 38 spherical reflective markers, each 50 mm in diameter, to the skin at pre-determined significant bony landmarks using double sided, hypo-allergenic adhesive tape and pre-wrapping tape. This marker set-up is the same as the customized skeleton template shown in Figure 1b.</li>
	<li>Clear all unwanted reflections other than those 38 markers from the participant&#39;s body (see step 1.8).</li>
	<li>Instruct participants to stand quietly on the home position in a T-pose. Run the motion capture system to capture all markers for 10 s (i.e., the calibration trial).</li>
</ol>
3. The Foot-stepping SRT Task Procedure
<ol>
	<li>Before each participant starts the task, set up the parameters, including, but not limited to: participant ID, group ID, number of learning block, the time length of stimulus presentation, and the time interval between stimuli (ISI) or response-stimulus interval (RSI) that controls the time interval between the completion of movement and the onset of the next stimulus (in this case, electric rubber sensors are needed under the home position; see protocol section 1 for details). 
	NOTE: The ISI could be varied (e.g., 1,300 ms or 1,000 ms) according to the purpose of the study.</li>
	<li>Instruct participants to stand on the home position and adjust the distance of the home position so that participants can comfortably step onto all six targets on the floor.</li>
	<li>Instruct participants to quickly step on each target several times, and mark the distance from the home position to each target at the most comfortable stepping length for each participant.</li>
	<li>Provide the task instructions to participants.
	<ol>
		<li>Instruct participants that once a stimulus appears at one of six locations shown on the monitor, they need to step as quickly and accurately as possible to the corresponding target on the floor and then return to the home position.</li>
		<li>Ask participants to step with the right foot to the three targets located on the right side (i.e., targets 1, 2, and 6; Figure 1a), and the left foot to the other three targets (i.e., targets 3, 4, and 5; Figure 1a). 
		NOTE: The numbers are invisible to participants during the entire task.</li>
		<li>Inform participants that there is a 3 min break after each run (i.e., learning block) of the task. Modify the length of the break based on experimental needs. Set a time alarm to remind participants of the end of the break.</li>
		<li>Instruct participants to keep their elbows by their side and bent at a ninety-degree angle when they perform the task so that the cameras can see the markers placed on the hip.</li>
	</ol>
	</li>
	<li>Run a practice block that consists of 36 steps (i.e., stimuli appear 36 times with a ISI of 1,300&#160;ms; see the foot-stepping SRT task procedure for details) so that participants are familiar with the task. Instruct participants that stimuli will continuously appear at one of six locations and they need to respond to stimuli as fast and accurately as they can. Stimuli in this block appear in a random order. 
	NOTE: The ISI could be replaced by an RSI (see the foot-stepping SRT task procedure for details). If a very short ISI is used, participants may not be able to respond to some stimuli. These steps are considered errors.</li>
	<li>After the practice block, start the experimental blocks. In this protocol, there are six blocks and each experimental block is comprised of 100 steps/stimuli. Give participants a mandatory 3 min break after each block. 
	NOTE: Under the 1,300 ms ISI condition, each block typically takes about 2.5 min. If a RSI is used, the length of each block may vary depending on how fast participants respond to stimuli.
	<ol>
		<li>Instruct participants to complete six experimental blocks. Set the specific order of visual stimuli according to experimental purposes. Stimuli follow either a specified or random sequence. The presentation of stimulus order is unknown to participants. 
		NOTE: The number of experimental blocks could vary. Here, a 6-block design is introduced where a specified sequence A is given in blocks 1 - 4 and 6 and a novel sequence B is presented in block 5. The specific and random sequence could also be varied. In this protocol, sequence A follows the order of 1423564215 (i.e., 1 - right side, 2 - right front, 3 - left front, 4 - left side, 5 - left back, and 6 - right back) and sequence B follows the order of 3615425214.</li>
		<li>Before each learning block, instruct participants to response to stimuli as quickly and accurately as they can.</li>
	</ol>
	</li>
	<li>Upon the completion of all learning blocks, ask participants to complete a posttest that consists of widely used recall and recognition tests described in the literature13,14,22.</li>
</ol>
4. Data Processing and Statistical Analysis
<ol>
	<li>For each participant, open collected data trials in the motion capture system software. Review each trial and fill in any gaps in the trial data according to the vendor-supplied instructions18.</li>
	<li>Export each data trial as an ASCII file that contains three coordinates for all 38 markers.</li>
	<li>Derive variables (i.e., reaction time (RT), movement time (MT), response time, and trajectory of the COM) from the ASCII files following steps below:
	<ol>
		<li>Input the ASCII data files into data analysis software. Use an eighth-order Butterworth filter with a cutoff frequency of 10 Hz to filter the data3. 
		NOTE: The way to derive the COM movement trajectory depends on the marker set-up. In the 38-marker set-up shown in Figure 1b, methods and anthropometric parameters described by De Leva23 may be employed. One can also track the movement of the approximate COM measured by a marker set at the level of the fifth lumbar vertebra24.</li>
		<li>Derive response time, RT, and MT following the descriptions below:
		<ol>
			<li>Use the markers attached on the heels, big toes, and the 5th metatarsals to characterize the trajectories of foot movements in data analysis software.</li>
			<li>Plot the trajectory of these three markers along the vertical direction (perpendicular to the floor). Plot the trajectory of the toe marker within the horizontal plane (parallel to the floor) to identify whether each step is correctly performed to the right target. Steps to a wrong target are excluded for later statistical analyses.</li>
			<li>Mark the baseline of each marker&#39;s height before and after each step.</li>
			<li>Identify the movement onset of each marker as the first sample when the marker reaches 10% of the maximum height.</li>
			<li>Since each subject may use different strategies to touch the target (using the toes or the 5th metatarsal), define the movement onset using the marker that reaches its peak the earliest.</li>
			<li>Identifies the end-point of stepping as the time point when the used marker drops to the same height as the onset.</li>
			<li>Continuously run the data analysis program until 100 steps are processed.</li>
			<li>For all steps, calculate and output the response time as the temporal difference between the stimulus onset and the end of movement, RT as the temporal difference between the stimulus and movement onsets, and MT as the temporal difference between the movement onset and its end point. Save the output files in the .xls format.</li>
			<li>Using these .xls files, calculate means of these variables for each block and across participants, data which will subsequently be used for statistical analyses.</li>
			<li>Since there is typically a within-subject factor (i.e., learning block) in the experimental design, use mixed-effect ANOVAs to analyze data (repeated measures ANOVA could be used with caution regarding the sphericity assumption). Determine the co-variance matrix used in the mixed-effect ANOVA by the Akaike&#39;s Information Criterion (AIC). Decompose the significant results from the ANOVA using post hoc tests with specific multiple comparison correction procedures (depending on the experimental design). Set the statistical significance level at p = 0.05.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

This protocol describes the experimental set-up and procedures for a modified SRT task. The modified SRT task shares its appealing simplicity with the classic SRT task, although the modified SRT task demands use of a motion capture technique. Like the classic SRT task, many parameters could be manipulated for specific research questions in the foot-stepping SRT task, including but not limited to: the length of interval-stimulus interval or response-stimulus interval27, the type of sequence structu...

Implicit motor sequence learning, generally known as learning a sequence without knowing the sequence, is critical to our daily activities and has been well studied by a paradigmatic task named the serial reaction time (SRT) task designed by Nissen and Bullemer1. In this classic SRT task, participants press keys to respond quickly and accurately to visual stimuli. To examine sequence learning, the appearance of visual stimuli is manipulated to follow either a pre-structured or random sequence, which is unknown to participants. Learning is evidenced by the faster response time to the pre-structured sequence (e.g., the training sequence) than that to the random or another pre-structured sequence1,2. While the classic SRT task typically requires bi-manual finger tapping, a vast majority of implicit motor sequence learning in everyday activities, such as dancing, playing musical instruments, or playing sports, involves whole body actions that present postural and inertial challenges not found in the classic SRT task. Thus, we proposed that sequence learning tasks need to be more multifaceted. In addition, the focus of the previous research has been almost exclusively on the cognitive component of the task (e.g., decision making or action selection), ignoring the motor control issues involved in sequence learning (e.g., movement execution). Thus, to further understand implicit motor sequence learning, it is essential to study sequence learning in a whole-body or gross motor task that better approximates our daily motor activities.
In our recent studies, we extended the classic SRT task to a modified SRT task where finger pressing was replaced by foot stepping to incorporate postural control into sequence learning3,4,5. This modified task presents its own advantages to complement the classic SRT task. First, the gross motor sequence learning task better mimics daily sequential activities where whole-body movement is involved. To date, our understanding of motor sequence learning typically comes from the classic SRT task, but little is known whether the knowledge of motor sequence learning from the classic SRT task remains to be true in learning sequential motor skills in daily activities. Thus, the modified SRT task allows us to examine whether the systematically reported characteristics (e.g., age-independent implicit sequence learning between children and adults) in the finger-pressing SRT task remain when postural control is involved. Additionally, in populations with posture control and gross motor skill learning difficulties, such as children with developmental coordination disorder6,7,8, understanding how posture control interacts with gross motor sequence learning is critical to help improve intervention strategies, and thus optimize the effectiveness of learning sequential motor skills in daily life.
Second, a common notion about implicit sequence learning is that motor planning, and not movement execution, plays an important role in learning a sequence in the classic SRT task9. This is because pressing keys does not involve moving to new locations in space, as the fingers are always on the response keys. However, many daily sequential behaviors involve large spatial movements. Little is known as to whether movement execution is a key player in motor sequence learning when large spatial movements are required. In the classic SRT task, response time, the summation of reaction time (RT) and movement time (MT), serves as an indicator of sequence learning. The foot-stepping SRT task, like other paradigms involving spatial movements10, allows the researcher to disentangle response time in implicit sequence learning into RT, which reflects cognitive processing, and MT, which characterizes the movement itself.
Third, in addition to MT, the combination of the foot-stepping SRT task and motion capture techniques provides rich data on the continuous whole-body movement (e.g., movement of the center of mass, or COM). Measuring the continuous change of movement has the advantage of revealing the dynamics of the cognitive processes underlying the discrete response measured by RT or MT11,12. In particular, learning sequences in the SRT task are typically explained as a mixture of explicit and implicit processes. That is, despite the common use of the SRT task as an implicit learning task, participants often show the capability to verbally recall the learned sequence after the SRT task, suggesting an explicit component involved in implicit sequence learning. Although the explicit component can be assessed by recall tests conducted after the SRT task13,14, these post-task tests lack the ability to examine the temporal evolution of explicit knowledge during learning. We propose that with explicit sequence knowledge, an individual would know the location of the next stimulus, and thus produce anticipatory postural adjustment15,16,17 in a feedforward manner to prepare for the stepping foot to move to the corresponding target. Therefore, examining the movement of the COM before the stimulus appearance (i.e., anticipation) opens a window to studying the progressive development of explicit memory during implicit sequence learning.
The protocol demonstrates the experimental set-up and procedure of the foot-stepping SRT task. We provide representative results of response time, RT, and MT. In addition, we present results regarding the relationship between posture control and the explicit processes underlying implicit motor sequence learning.

<table><tbody><tr><td>Vicon motion capture system</td><td>Vicon</td><td>Vicon T-40, T-160, calibration wand</td><td>Alternative systems may be used</td></tr><tr><td>50 mm reflective markers</td><td>Vicon</td><td>N/A</td><td>Numbers of markers may be varied</td></tr><tr><td>Labview software</td><td>National Instruments</td><td>N/A</td><td>Control visual stimuli. Use together with DAQ board. Alternative software may be used</td></tr><tr><td>DAQ board</td><td>National Instruments</td><td>BNC-2111; DAQCard-6024E</td><td></td></tr><tr><td>MATLAB</td><td>MathWorks</td><td>N/A</td><td>Alternative software may be used</td></tr><tr><td>double sided hypo-allergenic adhesive tape</td><td></td><td>N/A</td><td></td></tr><tr><td>pre-wrapping tape</td><td></td><td>N/A</td><td></td></tr></tbody></table>

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 above paradigm is implemented by Du and colleagues in a series of studies3,4,5. We use a part of data adopted from one of these studies4 to represent the usage of the foot-stepping SRT task. In this study, there are 6 learning blocks and a RSI of 700 ms is used. Visual stimuli followed sequence A (i.e., 1423564215; Figure 1a) in b...

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The "Motor" 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 ...

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8.4K Views.  University of Maryland, College Park. 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.

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

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 ...

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 ...

Asymmetric Walkway: A Novel Behavioral Assay for Studying Asymmetric Locomotion

Behavioral assays are commonly used for the assessment of sensorimotor impairment in the central nervous system (CNS). The most sophisticated methods for quantifying locomotor deficits in rodents is to measure minute disturbances of unconstrained gait overground (e.g., manual BBB score or automated CatWalk). However, cortical inputs are not required for the generation of basic locomotion produced by the spinal central pattern generator (CPG). Thus, unconstrained walking tasks test locomotor deficits due to motor cortical impairment only indirectly. In this study, we propose a novel, precise foot-placement locomotor task that evaluates cortical inputs to the spinal CPG. An instrumented peg-way was used to impose symmetrical and asymmetrical locomotor tasks mimicking lateralized movement deficits. We demonstrate that shifts from equidistant inter-stride lengths of 20% produce changes in the forelimb stance phase characteristics during locomotion with preferred stride length. Furthermore, we propose that the asymmetric walkway allows for measurements of behavioral outcomes produced by cortical control signals. These measures are relevant for the assessment of impairment after cortical damage.

Here, we present a protocol to quantify precise stepping in rodents. Cortical and the spinal central pattern generator signals are required for precise foot-placement during obstructed locomotion. We report here the novel constrained walking task that directly examines precise stepping behavior.

Behavioral assays are commonly used for the assessment of sensorimotor impairment in the central nervous system (CNS). The most sophisticated methods for ...

Acquisition of a High-precision Skilled Forelimb Reaching Task in Rats

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor learning and execution is of critical importance in order to understand the principles and processes that underlie motor function. Here we present a paradigm to study movement acquisition within a daily session of training (within-session) representing the fast learning component and primary acquisition as well as skilled motor learning over several training sessions (between-session) representing the slow learning component and consolidation of the learned task. This behavioral paradigm increases the degree of difficulty and complexity of the motor skill task due to two features: First, the animal realigns its body prior to each pellet retrieval forcing renewed orientation and preventing movement execution from the same angle. Second, pellets are grasped from a vertical post that matches the diameter of the pellet and is placed in front of the cage. This requires a precise grasp for successful pellet retrieval and thus prevents simple pulling of the pellet towards the animal. In combination with novel genetics, imaging and electrophysiological technologies, this behavioral method will aid to understand the morphological, anatomical and molecular underpinnings of motor learning and memory.

A paradigm is presented to analyze the acquisition of a high-precision skilled forelimb reaching task in rats.

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor ...

A Modified Lean and Release Technique to Emphasize Response Inhibition and Action Selection in Reactive Balance

Assessment of reactive balance traditionally imposes some type of perturbation to upright stance or gait followed by measurement of the resultant corrective behavior. These measures include muscle responses, limb movements, ground reaction forces, and even direct neurophysiological measures such as electroencephalography. Using this approach, researchers and clinicians can infer some basic principles regarding how the nervous system controls balance to avoid a fall. One limitation with the way in which these assessments are currently used is that they heavily emphasize reflexive actions without any need to revise automatic postural reactions. Such an exclusive focus on these highly stereotypical reactions would fail to adequately address how we can modify these reactions should the need arise (e.g., avoiding an obstacle with a recovery step). This would appear to be a glaring omission when one considers the enormous complexity of the environments we face daily. Overall, the status quo when evaluating the neural control of balance fails to truly expose how higher brain resources contribute to preventing falls in complex settings. The present protocol offers a way to require suppression of automatic, but inappropriate corrective balance reactions, and force a selection among alternative action choices to successfully recover balance following postural perturbation.

Here we offer a protocol that allows the user to selectively change affordances and/or constraints on movements that are relevant for recovering balance after postural perturbation.

Assessment of reactive balance traditionally imposes some type of perturbation to upright stance or gait followed by measurement of the resultant ...

Recording Single Neurons' Action Potentials from Freely Moving Pigeons Across Three Stages of Learning

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed single-neuron activity while animals are acquiring an operantly conditioned response, or when that response is extinguished. But even in these cases, observation periods usually encompass only a single stage of learning, i.e. acquisition or extinction, but not both (exceptions include protocols employing reversal learning; see Bingman&#160;et al.1 for an example). However, acquisition and extinction entail different learning mechanisms and are therefore expected to be accompanied by different types and/or loci of neural plasticity.
Accordingly, we developed a behavioral paradigm which institutes three stages of learning in a single behavioral session and which is well suited for the simultaneous recording of single neurons&#39; action potentials. Animals are trained on a single-interval forced choice task which requires mapping each of two possible choice responses to the presentation of different novel visual stimuli (acquisition). After having reached a predefined performance criterion, one of the two choice responses is no longer reinforced (extinction). Following a certain decrement in performance level, correct responses are reinforced again (reacquisition). By using a new set of stimuli in every session, animals can undergo the acquisition-extinction-reacquisition process repeatedly. Because all three stages of learning occur in a single behavioral session, the paradigm is ideal for the simultaneous observation of the spiking output of multiple single neurons. We use pigeons as model systems, but the task can easily be adapted to any other species capable of conditioned discrimination learning.

Learning new stimulus-response associations engages a wide range of neural processes which are ultimately reflected in changing spike output of individual neurons. Here we describe a behavioral protocol allowing for the continuous registration of single-neuron activity while animals acquire, extinguish, and reacquire a conditioned response within a single experimental session.

While the subject of learning has attracted immense interest from both behavioral and neural scientists, only relatively few investigators have observed ...

Neuroscience

Assessing Corticospinal Excitability During Goal-Directed Reaching Behavior

Reaching is a widely studied behavior in motor physiology and neuroscience research. While reaching has been examined using a variety of behavioral manipulations, there remain significant gaps in the understanding of the neural processes involved in reach planning, execution, and control. The novel approach described here combines a two-dimensional reaching task with transcranial magnetic stimulation (TMS) and concurrent electromyography (EMG) recording from multiple muscles. This method allows for the noninvasive detection of corticospinal activity at precise time points during the unfolding of reaching movements. The example task code includes a delayed response reaching task with two possible targets displayed &#177; 45&#176; off the midline. Single pulse TMS is delivered on the majority of task trials, either at the onset of the preparatory cue (baseline) or 100 ms prior to the imperative cue (delay). This sample design is suitable for investigating changes in corticospinal excitability during reach preparation. The sample code also includes a visuomotor perturbation (i.e., cursor rotation of &#177; 20&#176;) to investigate the effects of adaptation on corticospinal excitability during reach preparation. The task parameters and TMS delivery can be adjusted to address specific hypotheses about the state of the motor system during reaching behavior. In the initial implementation, motor evoked potentials (MEPs) were successfully elicited on 83% of TMS trials, and reach trajectories were recorded on all trials.

Reaching is a fundamental skill that allows humans to interact with the environment. Several studies have aimed to characterize reaching behavior using a variety of methodologies. This paper offers an open-source application of transcranial magnetic stimulation to assess the state of corticospinal excitability in humans during reaching task performance.

Reaching is a widely studied behavior in motor physiology and neuroscience research. While reaching has been examined using a variety of behavioral ...

Automated Assessment of Fine Motor Performance in Mice Using the Erasmus Ladder

Monitoring Fine and Associative Motor Learning in Mice Using the Erasmus Ladder

Behavior is shaped by actions, and actions necessitate motor skills such as strength, coordination, and learning. None of the behaviors essential for sustaining life would be possible without the ability to transition from one position to another. Unfortunately, motor skills can be compromised in a wide array of diseases. Therefore, investigating the mechanisms of motor functions at the cellular, molecular, and circuit levels, as well as understanding the symptoms, causes, and progression of motor disorders, is crucial for developing effective treatments. Mouse models are frequently employed for this purpose.
This article describes a protocol that allows the monitoring of various aspects of motor performance and learning in mice using an automated tool called the Erasmus Ladder. The assay involves two phases: an initial phase where mice are trained to navigate a horizontal ladder built of irregular rungs (&#34;fine motor learning&#34;), and a second phase where an obstacle is presented in the path of the moving animal. The perturbation can be unexpected (&#34;challenged motor learning&#34;) or preceded by an auditory tone (&#34;associative motor learning&#34;). The task is easy to conduct and is fully supported by automated software.
This report shows how different readouts from the test, when analyzed with sensitive statistical methods, allow fine monitoring of mouse motor skills using a small cohort of mice. We propose that the method will be highly sensitive to evaluate motor adaptations driven by environmental modifications as well as early-stage subtle motor deficits in mutant mice with compromised motor functions.

Author Spotlight: Unveiling Neural Mechanisms Through Automated Evaluation of Motor Learning and Myelin Plasticity Studies Using the Erasmus Ladder 

This article presents a protocol that allows a non-invasive and automated assessment of fine motor performance, as well as adaptive and associative motor learning upon challenges, using a device called the Erasmus Ladder. Task difficulty can be titrated to detect motor impairment ranging from major to subtle degrees.

Behavior is shaped by actions, and actions necessitate motor skills such as strength, coordination, and learning. None of the behaviors essential for ...

Motor Maps

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
One principle of brain organization is the topographic mapping of information. Especially in sensory and motor cortices, adjacent regions of the brain tend to represent information from adjacent parts of the body, resulting in maps of the body expressed on the surface of the brain. The primary sensory and motor maps in the brain surround a prominent sulcus known as the central sulcus. The cortex anterior to the central sulcus is known as the precentral gyrus and contains the primary motor cortex, while the cortex posterior to the central sulcus is known as the postcentral gyrus and contains the primary sensory cortex (Figure 1).
<img alt="Figure 1" src="/files/ftp_upload/10175/10175fig1.jpg" /> 
Figure 1: Sensory and motor maps around the central sulcus. The primary motor cortex, which contains a motor map of the body&#39;s effectors, is anterior to the central sulcus, in the precentral gyrus of the frontal lobe. The primary somesthetic (sensory) cortex, which receives touch, pain, and temperature information from the external parts of the body, is located posterior to the central sulcus, in the postcentral gyrus of the parietal lobe.
In this experiment, functional neuroimaging is used to demonstrate the motor map in the precentral gyrus. This map is often called the motor homunculus, which is Latin for &#34;little man,&#34; because it is as if there is a little version of one&#39;s self represented in this part of a person&#39;s brain. One interesting property of this map is that more cortical space is devoted to body parts requiring finer control, such as the hands and mouth, which results in disproportionate representation of those appendages in the cortex. Also, because of the anatomy of the motor system, the neurons that control the right side of the body are in the left primary motor cortex, and vice versa. Therefore, when a participant in the experiment is asked to move their right hand or foot, an increased activation on their left precentral gyrus is expected.
In this experiment, participants are asked to alternately move their hands and feet, on the left and right sides, while their brain activity is measured with fMRI. Since the fMRI signal relies on changes in blood oxygenation, which are slow in comparison to the movements the participants make, the periods of movement are separated with periods of stillness to ensure that the various conditions can be distinguished from each other and from the resting baseline. To achieve precise timing of the movements, participants are instructed on when to begin and end each movement with a visual cue. The methods in this video are similar to those used by several fMRI studies that have demonstrated somatotopy in primary motor cortex.1,2

Studying Brain Activation and Motor Maps Using fMRI

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
One principle of brain organization is the topographic ...

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Staircase Test for Motor Function Assessment in a Hemiparkinsonian Rat

Source: Rattka, M, et al., <a href="https://app.jove.com/v/53951">A Novel Approach to Assess Motor Outcome of Deep Brain Stimulation Effects in the Hemiparkinsonian Rat: Staircase and Cylinder Test.</a> J. Vis. Exp. (2016).
This video demonstrates the staircase test to assess motor function in a hemiparkinsonian rat with a right brain lesion. The lesion disrupts dopamine signaling, impairing left paw control, which results in more pellets remaining on the left stairs, indicating motor dysfunction.

Source: Rattka, M, et al., A Novel Approach to Assess Motor Outcome of Deep Brain Stimulation Effects in the Hemiparkinsonian Rat: Staircase and Cylinder ...