Snapshot: What is the balance beam test?

When you think of a balance beam, you might think of gymnastics. For humans, a balance beam is a surface where we perform jumps, flips, and other athletic feats. Whether it’s a child taking their first class, or an Olympic athlete going for gold, the balance beam requires both balance and coordination. When a scientist puts a mouse through the balance beam test, they don’t ask them to do this kind of complicated routine, but they are testing those same abilities.

Little Black Mouse on a White Background
Little Black Mouse on a White Background. Photo used under license by Michiel de Wit/Shutterstock.com.

The equipment setup for the balance beam test is simple: two platforms with a beam running between them plus lots of padding underneath so the mouse doesn’t get hurt if it falls off. Over multiple days, the scientist will train the mouse to run across the beam from one platform to another. Once the mouse has been trained, it will go through multiple official test runs. In these tests, the scientist will measure the time it takes for the mouse to cross the beam. They will also count the number of times one of its paws slips off the beam during the crossing. You can see some videos of mice doing the test here.

Mice that have problems with balance and coordination usually take longer to cross the balance beam and have more paw slips during the crossing. The mice might take longer to cross because they are clinging to the beam to try to stay on. Their paws might slip more because they cannot coordinate their movements properly. The scientist can also compare the measurements from the first day of training with the measures taken during the official runs. This shows how well the mouse learned to stay on the beam. This is useful because learning how to do a task and performing the task are two different things. Some parts of the brain are more important for learning, while others are more important for doing the task. Thus, telling those two aspects apart can be useful.

Mouse cossing a balance beam connecting two platforms

A typical balance beam setup, with two platforms and a beam between them. Image by Amy Smith-Dijak.

The balance beam test has been used to understand balance and coordination in both healthy mice and mouse models of disease. In healthy mice, scientists studying the basic biology of balance and coordination use this assay to test if changing the way particular parts of the brain work changes the mouse’s performance. For diseases in which lack of balance and coordination are major features, such as spinocerebellar ataxias, this test is a simple way to check how fast the disease progresses in mouse models. The assay can further be used to test possible treatments for these diseases: better scores after the treatment indicate that the therapy helped the mice improve their balance and coordination.

To sum it up, the balance beam test is a simple and effective assay to measure a mouse’s balance and coordination. Its use helps scientists to understand the basic biology of balance and coordination, as well as uncover why they are impaired in some diseases. Using the balance beam test on mouse models of disease that underwent different treatments, scientists can further measure if the therapy would improve the mouse’s balance and coordination. Therefore, the balance beam test might even help to find new treatments for motor coordination diseases.

If you would like to learn more about the balance beam test, take a look at these resources by the Maze Engineers and Creative Biolabs.

Snapshot written by Dr. Amy Smith-Dijak and edited by Dr.Larissa Nitschke.

Eliminación de la proteína ataxina-2 agregada como vía terapéutica para SCA2

Escrito por el Dr. Vitaliy Bondar Editado por el Dr. Hayley McLoughlin. Publicado inicialmente en el 5 de febrero de 2021. Traducción al español fueron hechas por FEDAES y Carlos Barba.

Una nueva investigación sugiere que la proteína ataxina-2 mutante abruma a las células en SCA2, lo que lleva a una disminución de la autofagia y la eliminación de las proteínas dañadas.

Se pueden hacer muchas comparaciones entre células y seres humanos. Al igual que los humanos, las células pueden acumular basura y desechos en ciertos momentos y este desorden con el tiempo se vuelve problemático e incluso tóxico. Esto es precisamente lo que Jonathan Henry Wardman y sus colegas de la Universidad de Copenhague decidieron investigar a nivel celular. Preguntaron si la falta de una eliminación adecuada de las proteínas defectuosas de la enfermedad afecta la supervivencia y el bienestar celular.

Los investigadores optaron por estudiar células derivadas de un paciente que tiene ataxia espinocerebelosa tipo 2 (SCA2). La causa de SCA2 es la expansión de la repetición CAG en el gen ATAXIN-2 , que codifica la cadena de aminoácidos de poliglutamina en una proteína de unión al ARN , ataxina-2. Se encuentra que la proteína ATXN2 expandida poliQ defectuosa se agrega dentro de la célula y las horas extraordinarias pueden afectar su supervivencia. La acumulación de productos proteicos agregados derivados de genes mutados es un sello distintivo de muchos tipos de ataxias espinocerebelosas, así como de otras formas de trastornos neurodegenerativos como la enfermedad de Parkinson.

No está claro cómo la agregación de proteínas afecta la supervivencia celular. Sin embargo, se han correlacionado múltiples defectos celulares con la agregación de ataxina-2. Por ejemplo, se ha informado que las mitocondrias que generan energía para una célula funcionan de manera anormal en modelos celulares SCA2. Además, un mecanismo de depuración celular, llamado autofagia , que es responsable de limpiar los compartimentos celulares defectuosos y ciertas proteínas rotas, se muestra menos eficaz en varios modelos de SCA2. Estos mecanismos los autores decidieron investigar en su artículo de investigación recientemente publicado.

scientist using microscope
Una nueva investigación que utiliza células SCA2 arroja luz sobre las causas de los síntomas de la enfermedad. Foto de Chokniti Khongchum en Pexels.com

Los científicos identificaron por primera vez la evidencia de disfunción celular SCA2 mediante la detección de una elevación significativa de los niveles de caspasa-9 y caspasa-8. Son proteínas que indican estrés celular y muerte. Los autores plantearon la hipótesis de que dicha disfunción celular puede deberse a la acumulación de ataxina-2 defectuosa. Para probar esta hipótesis, decidieron bloquear sistemáticamente dos vías celulares que procesan proteínas defectuosas: proteostasis y autofagia.

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Spotlight: The Movement Analysis and Robotics Laboratory (MARlab)

MAR lab logo

Principal Investigator: Dr. Maurizio Petrarca

Location: Bambino Gesù Children Hospital, Rome, Italy

Year Founded: 2000

What models and techniques do you use?

  • Wearable Technologies
  • Movement analysis
  • Robotics
  • Clinical standardized assessment tools
Seven researchers stand infrom of a presentation screen
This is group picture taken during a conference. From left to right: Silvia Minosse, Alberto Romano, Martina Favetta, Maurizio Petrarca (PI), Gessica Vasco, Susanna Summa and Riccardo Carbonetti. Image courtesy of Susanna Summa.

Research Focus

What is your research about?

MARlab has a lot of experience in the rehabilitation of children with motor disorders including cerebellar diseases. We specialize in the use of motion analysis systems and robotics. Using advanced tools, we customize assessments and rehabilitative settings matching children needs in an ecological context.

We are involved in research to define specific digital biomarker and we are exploring different technological solutions, including wearable technology, to monitor the patient at home.

Rehabilitative competencies assure clinical opportunity in developing technological tools for training and assessment of the postural control, upper-limb coordination, gait, speech and cognition in pathological conditions.

Why do you do this research?

Ataxias are rare and chronic diseases usually without cure. The progression of the disease needs to be monitored periodically, so patients visit the hospital to control their condition by performing several clinical protocols. Developing more accurate and precise technology, to measure symptoms remotely, will help us better measure the impact of different treatments and rehabilitation in ecological contexts, decreasing the patient’s stress. This will help researchers and doctors knowing what works best for the patient. 

Bambino Gesù Children Hospital Logo

The Movement Analysis and Robotics Laboratory (MARlab) is located in the Bambino Gesù Children Hospital in Rome, Italy.

Fun Fact

We are a pediatric hospital very close to sea and our walls are painted with underwater landscapes.

A hospital walkway with the walls painted with sea creatures and submarines

For More Information, check out the Bambino Gesù Children Hospital website!


Written by Dr. Susanna Summa, Edited by Celeste Suart

2 Minuti di Scienza: Come si misura clinicamente la gravità dei sintomi in pazienti atassici

Il coordinare facilmente ed efficacemente movimenti  come il parlare e il camminare è essenziale nello svolgimento della vita quotidiana. L’abilità di orchestrare questi movimenti con successo è generalmente chiamata “coordinazione mootoria”. Anche se i pazienti di SCA in genere sono in grado di iniziare movimenti coorporei, la loro abilitá di eseguirli in modo agevole e preciso è alterata. Per esempio, è possibile notare l’incordinazione motoria in pazienti atassici che non riescono a camminare lungo una linea retta, o nella difficoltà che hanno nel deglutire. Questi ed altri problemi motori possono notevolmente inficiare la vita quotidiana. Poter valutare fino a che punto un paziente sia in grado di fare questi movimenti offre un’ indicazione della gravità della patologia in ciascun individuo affetto dalla malattia.

Black pencil lying on top of paper that has scoring chart on it
Immagine ottenuta da Pixabay, Pexels.com

A differenza di ciò che analisi cliniche di routine misurano, come la pressione sanguigna o i livelli di zucchero nel sangue, non esiste una semplice misura per quantificare i movimenti umani. Per sopperire a questa carenza, sono state sviluppate numerose unità di misura con l’intento di assegnare una quantificazione standard as esami di coordinazione motoria.  Una di queste misure è la Scala per la Valutazione e la Classificazione dell’Atassia (SVCA). Un medico esperto (generalmente un neurologo) analizza la capacità del paziente di portare a termine alcuni comandi ( come ad esempio alzarsi in piedi o camminare) e poi, usando la SVCA, assegna  un voto per ogni comando. La procedura dura  circa 15-20 minuti, e in genere include i seguenti esami:

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BDNF can reverse ataxia in SCA1 mice, even after symptom onset

Written by Anna Cook Edited by Dr. David Bushart

Brain-derived neurotrophic factor can prevent ataxia in SCA1 mice. New research shows that the treatment works even if it’s started after mice develop signs of ataxia.

SCA1 is a neurodegenerative disease caused by a mutation in the Ataxin1 gene. People with SCA1 often develop symptoms around 30-40 years old, although this can vary. The most common symptoms include ataxia, or movement problems that make it difficult to move and walk. These symptoms get progressively worse, eventually leading to problems with swallowing or speaking. There is currently no cure for SCA1 so it is important that research is conducted into potential treatments.

The lab of Dr. Marija Cvetanovic at the University of Minnesota has been using a mouse model of SCA1 to try to identify new treatments. In the past, these researchers have shown that a molecule called brain-derived neurotrophic factor (BDNF) could delay the onset of ataxia in a mouse model of SCA1.

A laboratory mouse sitting on a researcher's hand.
Research using SCA1 mice shows that BDNF treatment can have an impact, even after ataxia symptoms begin showing. Photo used under license by unoL/Shutterstock.com.

BDNF is a molecule found in the brain that is very important for healthy brain development. It is needed to keep many processes in the brain working normally. The researchers showed that levels of BDNF were reduced in the brains of SCA1 mice. The researchers injected BDNF into the brains of these mice to try to make up for the lost BDNF. This treatment, before the mice had begun to develop symptoms of ataxia, prevented the onset of motor problems and Purkinje cell death. You can read more about those findings in this past SCASource article.

This previous work was very promising, but there was one problem. In this study, the treatment was only tested before the SCA1 mice developed signs of motor problems or changes in their brains. In the real world, if we want to help SCA1 patients, we need treatments that will work even once the disease has started to progress. It was therefore important for the researchers to find out whether this treatment would work later in disease progression. That is exactly what they did next: In December 2020, the Cvetanovic lab published the results from their study testing BDNF as a treatment after mice had started to develop signs of SCA1.

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