Tag Archives: motor

dancing around the world

Ballet. Tap. Jazz. Hip-hop. Ballroom. Contemporary. The list of dance styles goes on. The uniqueness of this art form unifies people across the world. The mere fact that I have traveled across the world and yet feel at home when I see the dancers perform speaks volumes to how unifying it is.

The fluid and intentional motions in contemporary paired with an intense emotional story characterizes the grace behind this style of dance. During the Fli dance spectacle in Paris, I was really reminded of how the style contemporary covers so many different aspects of dance. The combination of technique from ballet to the street steps of hip-hop in this performance really resonated with me. I remember when I would dance, contemporary was one of my favorites because of the style variation. This style pulls in aspects of almost all styles of dance to create an unique and open array of dance moves. One dance could incorporate numerous hip-hop moves and another could integrate jazz and ballet, but they are both constituted as contemporary. During this spectacle, all I could think about was how much I missed dancing up on a stage in front of numerous people.

 

A few days later we also saw a hip hop dance battle take place in the streets of Paris. I was ecstatic for this because hip-hop is my absolute favorite dance style! I think my favorite part aside from the dancing was that I was able to teach Dr. Frenzel a little about the different styles within hip-hop and how each dancer was incorporating different styles during their respective battle. We talked about how hip-hop has a rich history with high amounts of integrated technique from popping, break dancing, whacking, and more! As I was standing there watching these amazing dancers, I wanted to just scream out to cheer them on, and I would have loved to join them out on the floor, but the highly intoxicated man went ahead and did that for me. He was kind escorted away after his hilarious interruption.

        

The big take away from watching these dancers was their ability to move. I stood there and wondered, “How could I ever do that? Because I surely cannot even think about attempting some of these moves.” Since I have devoted my life to science since college has started, watching the dancers made me think of how their sensorimotor system works in producing dance moves. Their specificity and texture of movement holistically defines how dance is such an intricate art form. These artists really must have some enhanced connectivity that aide their precise, synchronized movement to the rhythm of the music.

One study in 2015 took the idea that musicians improved motor, perceptual, and sensorimotor skills compared to controls and applied it to dancers (Karpati et al., 2015). The dancers and musicians participated in different perceptual and sensorimotor tasks to determine who performed better in these tasks, ultimately measuring increased sensorimotor ability. The results showed that dancers showed better results in a dance imitating task while musicians performed better in a rhythm synchronization task, concluding that each artist has specialized sensorimotor skills (Karpati et al., 2015).

Building off of this study, another study conducted research to investigate if dancers with prolonged training have improved functional connectivity in the cortico-basal ganglia loops. (Li et al., 2015). Series of fMRI scans showed that long-term dancers (10 year or more) have increased functional connectivity densities (FCD) in the primary somatosensory and motor cortices which are involved in motor execution and learning. Additionally, increased FCD were found in the cortico-basal ganglia loops which indicate improved motor coordination and integration. There was also a significant increase of FCD in the putamen, which is implicated in the rhythm of dance involving controlled, metric movements (Li et al., 2015).  This study further implicated that dancers do have enhanced function in brain regions that are involved with sensorimotor function.

Although there is not much extensive research in this field, especially pertaining to dance, I agree with the fact that dancers have enhanced connectivity in sensorimotor brain regions to facilitate the movement that is being learned and executed. Maybe next time I see street dancers I’ll join in! Or maybe I’ll just stick to going to the studio to dance!

References

Karpati, F. J., Giacosa, C., Foster, N. E. V., Penhune, V. B., & Hyde, K. L. (2016). Sensorimotor integration is enhanced in dancers and musicians. Experimental Brain Research, 234(3), 893–903. https://doi.org/10.1007/s00221-015-4524-1

Li, G., He, H., Huang, M., Zhang, X., Lu, J., Lai, Y., … Yao, D. (2015). Identifying enhanced cortico-basal ganglia loops associated with prolonged dance training. Scientific Reports, 5(1). https://doi.org/10.1038/srep10271

All images were taken by me.

 

The Broken Escalator Effect (It’s Real)

Every day we take the Paris Metro and RER to and from class. It’s a relatively painless trip, except when there’s a strike going on (which has been almost every day). One day last week, as our motley crew filed through our favorite station, Châtelet, to transfer trains, we reached our favorite stretch of the station: the moving walkways. I approached the walkway without hesitation, took a step onto the belt, and immediately felt myself jolted awake by a sense of falling. As it turned out, the moving walkway was broken that day, and pedestrians were just using it as a normal path. I followed suit and laughed silently at how funny I must have looked to anybody who saw me nearly fall on my face.

Our favorite Metro stop

Later that afternoon, on the return journey, I’d had ample time to wake up during the day. As we approached the same collection of moving walkways, I made sure to take note of the functionality of the machines. They were all still broken, but I decided to follow the crowd and walk along one of the belts anyway. This time, I approached, took a step, and felt jolted again! I was shocked at my brain’s miscalculation despite my conscious awareness that the walkway was stationary. I presumed that it had to be some sort of perceptual memory that I had for moving walkways. Perhaps because reality wasn’t matching up with what my brain had learned to be true of “people-movers” countless times before, my mind was having trouble adjusting. I decided it was worth a search in the literature when I got home.

No "broken escalator effect" here

What I found was not only reassuring for my vestibular system, but also immensely interesting. There is an extensive collection of scientific research on what has been called the “broken escalator phenomenon,” (Reynolds and Bronstein, 2003). Evidently, the effect is more evident on moving walkways, but because nobody knows what to call them, the original authors of the phrase decided to go with escalator instead. Once the phenomenon became well known as a common occurrence in city-dwellers, researchers sought to describe what was actually happening to cause this “feeling of uneasiness” despite absolute consciousness of the fact that the conveyor was not moving

First, experimenters had subjects walk on a short, stationary moving walkway a few times while measuring walking speed, postural sway, and muscle contraction (Reynolds and Bronstein, 2003). Afterwards, the experimenters turned on the walkway and had the same subjects board the machine. Not surprisingly, subjects made several physical changes as they got used to the moving version, but the most significant change observed was in the actual velocity of movement just prior to boarding. Naturally, the subjects increased their pace by .3 m/s in order to minimize being jerked by the belt. This is similar to what happens to us in everyday life. We encounter a majority of moving walkways in their “on” position, and we become accustomed to increasing pace, leaning forward, and flexing our leg muscles as we approach them. Next, the researchers informed the subjects that the walkway would be turned off, and in fact, they could see so for themselves. When they approached the walkway this time, all subjects stumbled, and many were shocked or laughed at the occurrence. Analysis of the physiological data showed that approach velocity, trunk lean, and muscle contraction took place at levels in between normal walking values and the values seen when subjects were accustomed to the moving walkway. It seemed that the brain was confused by seeing a normally moving pathway in a motionless state, and addressed the situation by “hedging its bets” so to speak. Interestingly, repeating a second trial with the “off” walkway shows no signs of distress. The brain learns quickly to adopt normal walking motor programs for the motionless walkway. Further studies have shown that skin conductance also increases just prior to experiencing the “broken escalator phenomenon,” implying that subconscious, fear-based mechanisms are at play (Green et al., 2010). This may explain why the hiccup occurs even when one consciously recognizes that normal walking will suffice.

Primary motor cortex, where the researchers stimulated.

Given that this phenomenon is strikingly similar to the lack of balance that many neurological disease patients experience, further studies aimed to find ways to modulate to the occurrence (Kaski et al., 2012). Recently, researchers tried this using a technique called transcranial direct current stimulation (tDCS), which is a lot like connecting a battery to your skull, except it’s scientific. Subjects went through the same experimental procedure as in the first study, but just before had a small anodal current passed through their brain for 15 minutes before the moving platform phase of testing. The researchers targeted the primary motor cortex, an area of the brain responsible for executing movement and storing motor memories, or the actual plans that the body uses to coordinate movement. The researchers believed that the broken escalator effect occurred due to an inability to suppress the brain’s default “moving walkway motor plan,” so activating primary motor cortex would cause the phenomenon to become even more extreme. Indeed, the subjects who received the electrical stimulation showed a larger broken escalator effect and took more trials to adjust to the stationary pathway than control subjects who received no stimulation. Though the nature of the experiment did not necessarily prove that the broken escalator effect is due to overactive motor memory, the results are significant in that they show it is possible to manipulate gait and motor problems with relatively simple technology. tDCS is fairly cheap and straightforward compared to other similar technologies, and its lack of precision actually lends itself nicely to working with the distributed neural systems of locomotion. Though this study used tDCS to worsen a locomotor problem, this same system may soon become a useful tool in neurological diseases that show locomotor symptoms such as stroke, Parkinson’s multiple sclerosis, and Alzheimer’s disease.

 

-Max Farina

 

References:

Reynolds RF, Bronstein AM (2003) The broken escalator phenomenon. Experimental Brain Research.

Green DA, Bunday KL, Bowen J, Carter T, Bronstein AM (2010) What does autonomic arousal tell us about locomotor learning? Neuroscience 170: 42-53.

Kaski D, Quadir S, Patel M, Yousif N, Bronstein AM (2012) Enhanced locomotor adaptation aftereffect in the “broken escalator” phenomenon using anodal tDCS. Journal of Neurophysiology 107: 2493-2505.