Name: assessing forelimb function after unilateral cervical sci using novel tasks: limb step-alternation, postural instability and pasta handling
Uploaded: 2013-09-16T18:10:00
Duration: 8 min 11 s
Description: Watch this Scientific Journal Video about Assessing Forelimb Function after Unilateral Cervical SCI using Novel Tasks: Limb Step-alternation, Postural Instability and Pasta Handling at JoVE.com

We would like to acknowledge funding from the Mission Connect, a project of TIRR Foundation (CES and ZZK), the Craig Neilsen Foundation (CES) and NSF Graduate Research Fellowship (Grant #: 2011112479 to SAG).

All animal procedures were done in accordance with approved protocols with the internal IACUC at the University of Texas at Austin and under National Institutes of Health (NIH) guidelines.
Animals used in this study had a C3/C4 lateral contusion injury using an Infinite Horizon Impactor, or a C3/C4 lateral hemisection model and these methods can be applied more broadly to other models18. We recommend that researchers test animals for 2 weeks prior to injury, 3 days post injury and regularly (e.g. weekly) for the duration of the study. When performing behavioral tests on post surgical animals, especially at three days post surgery, care must be taken that the animals have recovered sufficiently from the surgery and that the behavioral testing procedures do not cause additional pain or stress to the animals. 
In general, 2-3 weeks of handling and pre-testing may be needed prior to surgery. This involves getting the animal comfortable to the testing environment by handling them in a similar way to how they will be handled during testing as well as allowing the animal to move around freely on the testing surface. It is also important to get the animal used to being held, this can be done by moving the animal on and near the testing surface in non-direct motions to acclimate the animal to handling. It is also important to relax the animals at the beginning and in between test sessions. To relax the animals, hold the animal on a tabletop in a forelimb-only bearing stance, in a "wheelbarrow" position and bounce the animal gently on the tabletop allowing the forelimbs to touch the surface. This teaches the animals to sense below them for a stable surface and is an important and necessary step in the procedure because it ensures that the animals are relaxed before testing begins. 
1. Forelimb Step-alternation Test
<ol>
 <li>Test Summary: Place the animals with both forelimbs touching the tabletop to determine whether they alternate the use of their forelimbs. Move the rat forward, shifting their center of gravity, forcing them to try to step. This test is repeated four times with each animal and if an animal shows ability to alternate at, or higher than, 75%, it is considered to be an alternator. This is a forced motion task, so animals that are considered non-alternators will repeatedly step with the same forelimb.</li>
 <li>Hold an animal on a tabletop in a forelimb-only weight-bearing stance, in a "wheelbarrow" position with their body at nearly 90&deg; from the table.</li>
 <li>Once the animal appears relaxed, push the animal forward to move along the surface of the tabletop.</li>
 <li>Determine and record whether the rat alternates use of the forelimbs while moving across the surface.</li>
 <li>Note and record the forelimb that initiated the movement and whether the animal can alternate or not on the Forelimb Step-Alternation Test Score Sheet (provided).</li>
 <li>Repeat this test at least twice while holding the animal with one hand (right or left hand). Repeat at least twice again while holding the animal in the other hand. </li>
 <li>If rats showed this ability, step-alternation can be tested again by introducing a 5 sec wait after the first step to determine if the pattern of alternation remains after a delay. Note the results and record in the score sheet.</li>
 <li>This test can be used daily, and it is recommended that the animals be tested at least weekly for a repeated measures experiment.</li>
</ol>
Note: It is important to alternate the experimenter's hand position since it may affect the alternation behavior of the test animals. The Step-alternation score sheet provided can be used to note paw position and use during stepping. Although we have not incorporated those data into our scoring system currently (we have only used alternation status to group the lesioned animals in the current study), users can readily include paw position data as part of the analysis depending on the specific project.
2.	Postural Instability Test
<ol>
 <li>Test Summary: For this behavioral test, hold rats in a similar position as for the forelimb alternation test, however, each forelimb should be tested individually. The tabletop should be covered with sandpaper (No. 220) to prevent slipping, bracing, or dragging of the forelimbs during the test.
	 <ol>
		 <li>In this test, the distance it takes for the animal to take a step with the forelimb being examined to regain its balance will be recorded.</li>
 <li>Animals within a study group should be approximately the same weight, size and age as large differences in body weight can result in variation in the baseline distance needed for maintaining center of gravity for a given animal 19. A sham group should be included while using PIT to verify that changes in behavior are due to regeneration or recovery rather than age and weight gain.</li>
		 </ol>
	 </li>
	 <li>Hold an animal on a tabletop in a comfortable stance and allow both forelimbs to reach the surface, the animal should comfortably be in a "wheelbarrow" position with their body at nearly 90&deg; from the table. Note that it is important to hold the animal in a more vertical position. This will allow a more consistent distance needed to trigger a step to regain center of gravity.</li>
 <li>Lightly restrain one forelimb against the animal's torso and align the rat's nose with the zero line as viewed from above.</li>
 <li>Move the rat forward. This will shift the animal's center of gravity forward stimulating the animal to step to regain its balance.</li>
 <li>Record the new position of the nose after the rat steps twice and use the average of these two steps as the distance needed to trigger a step.</li>
 <li>Test each forelimb independently 5x, bringing the animal back to the 0 position and verifying that the animal continues to be relaxed in the experimenter's hands before continuing to ensure consistent results.</li>
 <li>Record on the Postural Instability Test (PIT) Score Sheet, provided. This test can be performed daily, and it is recommended that the animals are tested at least weekly for the duration of the experiment.</li>
</ol>
3.	Pasta Handling Test
<ol>
 <li>Test Summary: Use this test to determine the time it takes to eat a piece of pasta and the paw preference during a pasta-eating session. In this test, use 4.0 cm strands of dry pasta (thin spaghetti; diameter ~1.6 mm). The test should be administered at approximately the same time each testing day. Rodents generally eat dry pasta readily; however, 4-6 hours of food withdrawal is recommended before testing if this does not occur.</li>
 <li>Baseline measurements should be acquired 1-2 weeks prior to injury. Prior to baseline recordings, rats should be given the same type of pasta in their home cage to prepare them for testing. Then, allow the rats to eat pasta in a testing chamber and record the time to eat pasta. Pasta pieces should be placed near the front of the testing chamber where the use of forelimbs can be observed readily. Each pasta-eating session should include eating at least three pieces of pasta. Rats are considered proficient in eating pasta if their pasta-eating time is consistent for at least 3 days.</li>
 <li>After training the rats to eating pasta consistently in the testing chamber, place rats in recording chambers.</li>
 <li>Place pasta pieces onto the floor near the front of the testing chamber and record time to eat a piece of pasta, forelimbs used, and the positions of the forelimbs, as seen on the Pasta Handling Score sheet.</li>
 <li>This test can be performed daily, but it is recommended to perform it weekly while observing the animals' weight as to not over-feed the animals.</li>
</ol>
Note: The Pasta Handling Score sheet provides space to record time to eat pasta and paw use, similar to the data included in this study. We have also included areas to record additional details of paw use during a pasta eating session, such as paw position.

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No conflicts of interest declared.

Cervical spinal cord injury (cSCI) can result in devastating and life altering injuries in patients. There are a number of cervical spinal cord injury models developed in rodents that are used to study plasticity of the neural substrates and therapeutic agents. Developing sensitive, effective, reproducible and easy to use behavioral tests to assess functional deficits and recovery after cSCI is an important goal. Here, we describe in detail the use of three such behavioral tests: limb alternation, postural instability and pasta handling.
Spinal cord injury in rodents, as in the human population, is a heterogeneous injury. A very similar injury can induce a variety of behavioral deficits. Therefore, it is important to determine the severity of the lesions in injured animals. We found that the limb alternation task is a very effective way of determining if the contralesional side is damaged after a unilateral injury (hemisection or contusion type injury) to the cervical spinal cord 19. Data from our group showed that the use of this limb alternation task can determine the severity of the injury within the first week after injury. In addition, the more severely injured animals (non-alternators) had a significantly different recovery profile compared to alternators (using the forelimb locomotor scale). Therefore, the limb alternation task is extremely useful in grouping the injured rats into alternators and non-alternators, particularly if the study includes chronic treatment to ensure there is an equal distribution of lesion severity in each treatment group.
It is recommended that the forelimb-alternation test be used in combination with other tasks that can examine the use of animals' forelimbs (such as the forelimb locomotor scale or the cylinder paw preference test). While administering this test it is imperative that the experimenter perform the test the same number of times with each hand (e.g. twice with the left hand and twice with the right) to minimize the effect of experimenter hand position on the rats' behavior. This test is only effective if the animal is relaxed in the experimenter's hands; the 2-3 weeks of handling suggested should afford relaxation. Further, once the animal is relaxed, the experimenter should hold the animal at nearly 90&deg; in a wheelbarrow position to prevent within-animal variation.
The forelimb-alternation test can also provide insight to cross-spinal neural connections when animals are unable to step individually with a paw but are able to perform an alternation task. For normal quadrupedal locomotion in animals such as rats, many brain regions as well as local central pattern generators (CPGs) along the length of the spinal cord are involved. Specifically for forelimb rhythmic movement, the cervical spinal segments, C3-C6 are thought to be important22. Previously, we described anatomical differences between alternators and non-alternators in lesioned animals (a lateral hemisection at C3/C4 was performed) and found more damage to the contralesional dorsal column and corticospinal tract in non-alternating animals18. It is thought that for forelimb movement, rhythmic pattern generator is present at each level of the cervical hemi-segment and that the cross-cord inhibitor connections are responsible for alternation23. Our previous anatomical findings also implies that damage to the contralesional side of the spinal cord may cause disruption to the rhythmic motor output (such as alternation), whereas if the contralesional of the spinal cord is more intact, the rhythmic motor outputs are more likely to function normally. We did not observe significant damage to any contralesional medial ventral portions of the cords and hence that analysis was not performed.
The postural instability test described here is a very useful test because it can detect changes in both forelimb (ipsi- and contralesional) caused by a unilateral lesion. It is important to note that this test should be administered only when the animal is relaxed in the experimenter's hands. In our experience, this can take daily handling of the animals for 2-3 weeks. Once the experimenter and the animal are comfortable, this test is very sensitive and can be used to obtain highly consistent displacement data for each forelimb. If the animal is tense, the experimenter can gently hold the animal and move them up off of and down onto the table until the animal is comfortable and understands that the table is a safe location. Once the animal is relaxed, it is important to hold the animals in a wheelbarrow position at nearly 90&deg; for consistent results. This test is easy to administer and provides insight beyond other behavioral tests by providing information about compensation and deficit with one simple task.
Rats readily eat dry pasta after training in front of the camera. Therefore, pasta handling is a relatively easy test to administer. In this study, we were recording and using data for limb use (left, right or both) and time to eat pasta only. A more detailed analysis including paw adjustments during pasta eating has been described previously in animals with injuries such as unilateral ischemic lesions and unilateral striatal dopamine depletion 20,21,24 . Therefore, it is possible to develop and use a more sensitive analysis from the pasta eating test after cSCI. We included paw position on the scoring sheet, as this may reveal handedness or ability with each hand. Further, we are noting the grip of each paw; some animals rest their paw on one side of the pasta, using it possibly as a support, rather than grip the pasta during eating. If animals are hesitant to eat pasta, a food deprivation step can be introduced to the protocol prior to testing.

Cervical spinal cord injury (cSCI) is the most prevalent form of SCI in patients, representing about 62% of all SCIs (<a href="http://www.spinalcord.uab.edu" target="_blank">http://www.spinalcord.uab.edu</a>). Injuries to the cervical spinal cord can result in impairments in the upper extremities as well as breathing. A recent study in patients with cSCI suggests that partial or full function of the arm and/or hand is considered to be a major priority 1. Therefore, developing cSCI models and associated behavioral assays that are easy, sensitive and reliable to use is an important goal. There are several useful behavioral tests to assess forelimb function after cSCI in rodents 1-17, however, many of these tests are difficult to use and require specialized equipment. Pasta handling tests have been developed by other groups18,19, but these tests require that the animals be filmed in specific pasta eating cages, which requires a long training period, while the method we propose can be performed in the animals&#39; home cage. Previously described pasta tests require significant analysis time and often expensive software, unlike the test described here. The goal of our method is to develop and use behavioral tests that are easy to use, reliable, and do not require expensive equipment. Specifically, the forelimb step-alternation test described here allows researchers to estimate lesion volume early after injury, providing a means to create equivalent treatment groups before a chronic treatment is administered. In this study, we describe in detail three novel behavioral tests: (1) forelimb step-alternation, (2) postural instability, and (3) pasta handling.
Determining the right behavioral tests to use can be difficult. Indeed, we feel that no one behavioral test can assess the functioning of the forelimbs adequately. Therefore, we suggest using a combination of a few behavioral tests to assess forelimb function after SCI. Categorically speaking, one should use an open-field locomotor type task (e.g. forelimb locomotor scale, cylinder) where animals are assessed on the use of their forelimb during normal locomotion, and a task specific test, where animals are asked to perform a specific task involving the use of their forelimb (eg., pasta eating, postural instability, grip strength, etc.). The behavioral tests described here in detail are useful for determining lesion severity at ~ one week post lesion (forelimb step-alternation, postural instability, pasta handling), the effects of a unilateral lesion on the contralesional forelimb (forelimb step-alternation, postural instability) and fine motor movement of the forelimbs (pasta handling). Knowing the severity and effects of the lesion used can also dictate the appropriate behavioral tests. If fine motor movements of the wrist are not possible after lesion, using a test that measures and quantifies the use of forelimb paws is inappropriate. For example, many of the previously described pasta handling tests look more in depth at the individual movements of digits, however, we found with the severity and location of our injury, this was irrelevant and instead observed differences in the overall placement of the limb.
Researchers may be tempted to conduct many behavioral tests and use a sample of them for demonstration based on the results, however, it is recommended that for each experimental model being used a pilot study is performed to determine appropriate behavioral tests for the lesion. Therefore, it is important to note that the user should have at least some prior knowledge of the type of deficit and extent of a particular lesion type before deciding on behavioral tests to be employed. Assessing lesion severity based on behavioral performance also allows treatment groups to be created with an equal distribution of lesion severity before treatment is administered.

<table border="1">
 <tbody>
 <tr>
 <td>Name of Material/ Equipment</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments/Description</td>
 </tr>
 <tr>
 <td>Sand paper</td>
 <td>3M</td>
 <td>5097</td>
 <td>3M Gold Fre-Cut Sandpaper was used. 
 Any 220-grit sandpaper would work well </td>
 </tr>
 <tr>
 <td>Dry Pasta</td>
 <td>Skinner</td>
 <td></td>
 <td>Skinner Thin Spaghetti was used. It is available at Walmart</td>
 </tr>
 </tbody>
</table>

assessing forelimb function after unilateral cervical sci using novel tasks: limb step-alternation, postural instability and pasta handling

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority of the spinal cord injuries in humans occur at the cervical levels. Therefore, developing cervical injury models and developing relevant and sensitive behavioral tests is of great importance. Here we describe the use of a newly developed forelimb step-alternation test after cervical spinal cord injury in rats. In addition, we describe two behavioral tests that have not been used after spinal cord injury: a postural instability test (PIT), and a pasta-handling test. All three behavioral tests are highly sensitive to injury and are easy to use. Therefore, we feel that these behavioral tests can be instrumental in investigating therapeutic strategies after cSCI.

We recommend that animals be tested regularly throughout the experiment in a repeated measures-type experiment for improved analysis and to analyze improvement over time.
Forelimb Step-alternation Test
This test is designed to determine an animal's ability to alternate the use of its forelimbs. Using the forelimb step-alternation test, only 50% of the animals were able to alternate the use of their forelimbs after cSCI 19 at 12-16 weeks post injury (Figure 1A). Next we introduced a delay (5 sec) by holding the animal stationary after the first step before moving the animal forward for the second step. Only 50% of the animals that were alternating the use of their limbs (25% of the total lesioned group) were able to alternate after a 5-sec delay (Figure 1B). We correlated these findings with anatomical studies and the analysis revealed that alternators have significantly larger area of spared corticospinal tract [F(1,1) = 5.56, p &#60; 0.05] and dorsal column [F(1,1) = 19.2, p &#60; 0.003] on the contralesional side 19. These data indicate that the forelimb step alternation test can predict the severity of the lesion as well as unilaterality of the lesions. This test can result in nominal categorical data that should be analyzed with a repeated measures analysis. In this example, it was not a repeated measure, we used one time-point to illustrate the difference between groups. Each animal will be categorized as an &#34;alternator&#34; or a &#34;non-alternator&#34;, separating the animals into two groups of injuries (moderate vs. severe, respectively).
Postural Instability Test
Unilateral lesions of the spinal cord can cause changes not only to the impaired and/or affected limb, but also to the non-impaired limb. The postural instability test (PIT) was previously described and used in animals with a rodent model of Parkinson&#39;s disease 18 and in a rodent model of cSCI 19. We used PIT after cSCI and found that there was a significant effect of lesion status [F(1,1) = 8.17, p &#60; 0.01]. In addition, forelimb displacement (distance to regain center of gravity) was significantly larger in the ipsilesional side (right forelimb) of injured animals compared to animals with sham surgery (6.00 &#177; 0.24 cm versus 8.00 &#177; 0.10 cm, p &#60; 0.0001; Figure 2). The displacement distance on the contralesional forelimb was significantly smaller in lesioned animals compared to sham-operated animals (6.00 &#177; 0.25 cm for sham versus 4.00 &#177; 0.10 cm for cSCI, p &#60; 0.0001; Figure 2). This result indicates that contralesional forelimb also resulted in changes due to lesion to the opposite side (i.e. changes in postural adjustment by the contralesional forelimb to regain center of gravity). The data from this test will be quantitative and should be analyzed using a repeated measures ANOVA to examine changes in groups throughout an experiment.
Pasta Handling Test
Pasta handling was designed to test the skilled use of the forelimbs while eating a piece of dry pasta. A similar test has been used previously to detect deficits in skilled use of forelimbs in animal models of unilateral stroke and Parkinson&#39;s disease 20,21 and after cSCI 19. At chronic time points after injury (12 weeks post-injury), all sham animals ate pasta using both paws during the test period. In the lesioned group, we found that overall time to eat a piece of pasta is similar to the control group (Figure 3). However, more alternators (milder injury; 10 out of 15) were able to use their ipsilesional forelimb compared to non-alternators (severely injured group; 1 out of 7; Figure 3). The pasta handling test provides data that is both continuous and quantitative (time to eat pasta), and categorical (paw use) and should be analyzed appropriately.
<img alt="Figure 1" src="/files/ftp_upload/50955/50955fig1.jpg" /> 
Figure 1. Chronic assessment of forelimb function using the forelimb step-alternation test revealed two different groups of animals with different lesion severity. Animals showed a difference in behavior during forward stepping using both paws. Only 50% of the lesioned animals alternated paws while stepping (alternators; 5 out of 10 lesioned rats), whereas the others showed a lack of step-alternation by taking two contralesional steps in a row (non-alternators; 5 out of 10 lesioned rats). More animals displayed this tendency to take multiple contralesional steps if a 5-sec delay was introduced between steps (8 out of 10 lesioned rats).
<img alt="Figure 2" src="/files/ftp_upload/50955/50955fig2.jpg" /> 
Figure 2. Chronic forelimb behavioral assessment using the postural instability test (PIT). As expected, the ipsilesional forelimb in animals with cervical spinal cord injury (cSCI) had significantly larger displacement distance than animals with sham surgery (6 cm versus 8 cm; *p&#60;0.0001). In addition, the displacement distance on the contralesional forelimb was significantly smaller in lesioned animals compared to sham operated animals (6 cm versus 4 cm; *p&#60;0.0001). This may suggest enhanced function of the contralesional limb during PIT in lesioned animals.
<img alt="Figure 3" src="/files/ftp_upload/50955/50955fig3.jpg" /> 
Figure 3. Forelimb assessment using the pasta handling and eating test showed significant impairments in lesioned non-alternators. The animals were given a standard piece of pasta. Paw use and time to eat pasta were recorded. The results indicated that a low number of alternators (33%) exclusively used their contralesional forelimb (indicating more severe impairment) compared to non-alternators (86%). In addition, animals in all three groups (sham, lesioned alternators, and lesioned non-alternators) took a similar length of time to eat the pasta (p&#60;0.05). <a href="https://www.jove.com/files/ftp_upload/50955/50955fig3large.jpg" target="_blank"> Click here to view larger figure</a>.

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Assessing Forelimb Function after Unilateral Cervical SCI using Novel Tasks: Limb Step-alternation, Postural Instability and Pasta Handling

Three new behavioral tests (forelimb step-alternation, postural instability test, pasta handling test) for evaluating forelimb function after cervical spinal cord injury in rodents are described.

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority ...

assessing-forelimb-function-after-unilateral-cervical-sci-using-novel

Research

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Behavior

Automated Visual Cognitive Tasks for Recording Neural Activity Using a Floor Projection Maze

Neuropsychological tasks used in primates to investigate mechanisms of learning and memory are typically visually guided cognitive tasks. We have developed visual cognitive tasks for rats using the Floor Projection Maze1,2&#160;that are optimized for visual abilities of rats permitting stronger comparisons of experimental findings with other species.
In order to investigate neural correlates of learning and memory, we have integrated electrophysiological recordings into fully automated cognitive tasks on the Floor Projection Maze1,2. Behavioral software interfaced with an animal tracking system allows monitoring of the animal's behavior with precise control of image presentation and reward contingencies for better trained animals. Integration with an in vivo electrophysiological recording system enables examination of behavioral correlates of neural activity at selected epochs of a given cognitive task.
We describe protocols for a model system that combines automated visual presentation of information to rodents and intracranial reward with electrophysiological approaches. Our model system offers a sophisticated set of tools as a framework for other cognitive tasks to better isolate and identify specific mechanisms contributing to particular cognitive processes.

We describe protocols for training rats for chronic electrophysiological recordings in fully automated cognitive tasks on a Floor Projection Maze.

Neuropsychological tasks used in primates to investigate mechanisms of learning and memory are typically visually guided cognitive tasks. We have ...

Uncovering Beat Deafness: Detecting Rhythm Disorders with Synchronized Finger Tapping and Perceptual Timing Tasks

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson&#8217;s disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder).

Behavioral tasks that allow for the assessment of perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) are presented. Synchronization of finger tapping to the beat of an auditory stimuli and detecting rhythmic irregularities provides a means of uncovering rhythm disorders.

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here ...

Performing Behavioral Tasks in Subjects with Intracranial Electrodes

Patients having stereo-electroencephalography (SEEG) electrode, subdural grid or depth electrode implants have a multitude of electrodes implanted in different areas of their brain for the localization of their seizure focus and eloquent areas. After implantation, the patient must remain in the hospital until the pathological area of brain is found and possibly resected. During this time, these patients offer a unique opportunity to the research community because any number of behavioral paradigms can be performed to uncover the neural correlates that guide behavior. Here we present a method for recording brain activity from intracranial implants as subjects perform a behavioral task designed to assess decision-making and reward encoding. All electrophysiological data from the intracranial electrodes are recorded during the behavioral task, allowing for the examination of the many brain areas involved in a single function at time scales relevant to behavior. Moreover, and unlike animal studies, human patients can learn a wide variety of behavioral tasks quickly, allowing for the ability to perform more than one task in the same subject or for performing controls. Despite the many advantages of this technique for understanding human brain function, there are also methodological limitations that we discuss, including environmental factors, analgesic effects, time constraints and recordings from diseased tissue. This method may be easily implemented by any institution that performs intracranial assessments; providing the opportunity to directly examine human brain function during behavior.

Patients implanted with intracranial electrodes provide a unique opportunity to record neurological data from multiple areas of the brain while the patient performs behavioral tasks. Here, we present a method of recording from implanted patients that can be reproducible at other institutions with access to this patient population.

Patients having stereo-electroencephalography (SEEG) electrode, subdural grid or depth electrode implants have a multitude of electrodes implanted in ...

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 ...

Using Fiberless, Wearable fNIRS to Monitor Brain Activity in Real-world Cognitive Tasks

Functional Near Infrared Spectroscopy (fNIRS) is a neuroimaging technique that uses near-infrared light to monitor brain activity. Based on neurovascular coupling, fNIRS is able to measure the haemoglobin concentration changes secondary to neuronal activity. Compared to other neuroimaging techniques, fNIRS represents a good compromise in terms of spatial and temporal resolution. Moreover, it is portable, lightweight, less sensitive to motion artifacts and does not impose significant physical restraints. It is therefore appropriate to monitor a wide range of cognitive tasks (e.g., auditory, gait analysis, social interaction) and different age populations (e.g., new-borns, adults, elderly people). The recent development of fiberless fNIRS devices has opened the way to new applications in neuroscience research. This represents a unique opportunity to study functional activity during real-world tests, which can be more sensitive and accurate in assessing cognitive function and dysfunction than lab-based tests. This study explored the use of fiberless fNIRS to monitor brain activity during a real-world prospective memory task. This protocol is performed outside the lab and brain haemoglobin concentration changes are continuously measured over the prefrontal cortex while the subject walks around in order to accomplish several different tasks.

Monitoring brain activity outside the lab without physical constraints presents methodological challenges. A fiberless, wearable functional Near Infrared Spectroscopy (fNIRS) system was used to measure brain activity during an ecological prospective memory task. It was demonstrated that this system could be used to monitor brain activity during non-lab based experiments.

Functional Near Infrared Spectroscopy (fNIRS) is a neuroimaging technique that uses near-infrared light to monitor brain activity. Based on neurovascular ...

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 ...

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: STW). Thus, in clinical rehabilitation separation of sit-to-stand and gait initiation - termed sit-to-stand-and-walk (STSW) - is usual. However, a standardized STSW protocol with a clearly defined analytical approach suitable for pathological assessment has yet to be defined.
Hence, a goal-orientated protocol is defined that is suitable for healthy and compromised individuals by requiring the rising phase to be initiated from 120% knee height with a wide base of support independent of lead limb. Optical capture of three-dimensional (3D) segmental movement trajectories, and force platforms to yield two-dimensional (2D) center-of-pressure (COP) trajectories permit tracking of the horizontal distance between COP and whole-body-center-of-mass (BCOM), the decrease of which increases positional stability but is proposed to represent poor dynamic postural control.
BCOM-COP distance is expressed with and without normalization to subjects&#39; leg length. Whilst COP-BCOM distances vary through STSW, normalized data at the key movement events of seat-off and initial toe-off (TO1) during steps 1 and 2 have low intra and inter subject variability in 5 repeated trials performed by 10 young healthy individuals. Thus, comparing COP-BCOM distance at key events during performance of an STSW paradigm between patients with upper motor neuron injury, or other compromised patient groups, and normative data in young healthy individuals is a novel methodology for evaluation of dynamic postural stability.

Here, we present a novel protocol to measure positional stability at key events during the sit-to-stand-to-walk using the center-of-pressure to the whole-body-center-of-mass distance. This was derived from the force platform and three-dimensional motion-capture technology. The paradigm is reliable and can be utilized for the assessment of neurologically compromised individuals.

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: ...

The Knob Supination Task: A Semi-automated Method for Assessing Forelimb Function in Rats

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity largely use video analysis of reaching or food manipulation. While these tasks are easy to implement and are robust across disease models, they are subjective and laborious for the experimenter. Automating traditional tasks or creating new automated tasks can make the tasks more efficient, objective, and quantitative. Since rats are less dexterous than primates, central nervous system (CNS) injury produces more subtle deficits in dexterity, however, supination is highly affected in rodents and crucial to hand function in primates. Therefore, we designed a semi-automated task that measures forelimb supination in rats. Rats are trained to reach and grasp a knob-shaped manipulandum and turn the manipulandum in supination to receive a reward. Rats can acquire the skill within 20 &plusmn; 5 days. While the early part of training is highly supervised, much of the training is done without direct supervision. The task reliably and reproducibly captures subtle deficits after injury and shows functional recovery that accurately reflects clinical recovery curves. Analysis of data is performed by specialized software through a graphical user interface that is designed to be intuitive. We also give solutions to common problems encountered during training, and show that minor corrections to behavior early in training produce reliable acquisition of supination. Thus, the knob supination task provides efficient and quantitative evaluation of a critical movement for dexterity in rats.

This manuscript describes a semi-automated task that quantifies supination in rats. Rats reach, grasp, and supinate a spherical manipulandum. The rat is rewarded with a pellet if the turn angle exceeds a criterion set by the user. This task increases throughput, sensitivity to injury, and objectivity compared to traditional tasks.

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity ...

A Novel Single Animal Motor Function Tracking System Using Simple, Readily Available Software

We have recently demonstrated that implanting intracortical microelectrodes in the motor corteces of rats&#160;results in immediate and lasting motor deficits. Motor impairments were manually quantified through an open field grid test to measure the gross motor function and through a ladder test to measure the fine motor function. Here, we discuss a technique for the automated quantification of the video-recorded tests using our custom Capadona Behavioral Video Analysis System: Grid and Ladder Test, or BVAS. Leveraging simple and readily available coding software (see the Table of Materials), this program allows for the tracking of a single animal on both the open field grid and the ladder tests. In open field grid tracking, the code thresholds the video for intensity, tracks the position of the rat over the 3 min duration of the grid test, and analyzes the path. It then computes and returns measurements for the total distance traveled, the maximum velocity achieved, the number of left- and right-handed turns, and the total number of grid lines crossed by the rat. In ladder tracking, the code again thresholds the video for intensity, tracks the movement of the rat across the ladder, and returns calculated measurements including the time it took the rat to cross the ladder, the number of paw slips occurring below the plane of the ladder rungs, and the incidence of failures due to stagnation or reversals. We envision that the BVAS developed here can be employed for the analysis of motor function in a variety of applications, including many injury or disease models.

The current study aimed to automate the quantification of motor deficits in rats. The initial evaluation model assesses motor loss resulting from an intracortical microelectrode implantation in the motor cortex. We report on the development and use of a tracking algorithm using easily adaptable, simple, and readily available coding software.

We have recently demonstrated that implanting intracortical microelectrodes in the motor corteces of rats&#160;results in immediate and lasting motor ...

An Instrumented Pull Test to Characterize Postural Responses

Impairment of postural reflexes, termed postural instability, is a common and disabling deficit in Parkinson's disease. To assess postural reflexes, clinicians typically employ the pull test to grade corrective responses to a backward perturbation at the shoulders. However, the pull test is prone to issues with reliability and scaling (score/4). Here, we present an instrumented version of the pull test to more precisely quantify postural responses. Akin to the clinical test, pulls are manually administered except pull force is also recorded. Displacements of the trunk and feet are captured by a semi-portable motion tracking system. Raw data represent distance traveled (in millimeter units), making subsequent interpretation and analysis intuitive. The instrumented pull test also detects variabilities influencing pull test administration, such as pull force, thereby identifying and quantifying potential confounds that can be accounted for by statistical techniques. The instrumented pull test could have application in studies seeking to capture early abnormalities in postural responses, track postural instability over time, and detect responses to therapy.

Impairment of postural reflexes, termed postural instability, is difficult to quantify. Clinical assessments such as the pull test suffer issues with reliability and scaling. Here, we present an instrumented version of the pull test to objectively characterize postural responses.

Impairment of postural reflexes, termed postural instability, is a common and disabling deficit in Parkinson's disease. To assess postural reflexes, ...