Dance & the Brain

INTRODUCTION

Dance is an art form that requires the coordination of the entire body. More specifically, as described by two authors for the Scientific American Magazine, it is “a confluence of movement, rhythm, and gestural representations” that require complex mental coordination (Brown et al. 2008). Many people enjoy dance for its aesthetic appeal, but studies have implicated significant findings not just for passive observors of dance, such as audience members who don't hold any intention to learn what is being performed, or active observors who are being shown the example of movememnt so that they can later mimic it, but for the actual dancer themself. Whether amateur or professional, there is a lot occurring on the neurological level which explains how the integration of clues from the environment are translated into actual executed movements.

Neuroscientists had paid little to no consideration to dance, until relatively recently when they realized how significant the connection betweem the two were. Thus they began to conduct some of the first brain-imaging studies looking at the neural basis of dance.

Positron Emission Tomography (PET)
PET_scan_2.gif
Figure 1 (Brown et al. 2005)

Through this scanner, neuroscientists were able to further investigate what specific brain structures are involved in different aspects.

While there are localized areas of the brain that are activated when performing sensorimotor activities, there is also an overlap in neural activity, which demonstrates the integration of the individual aspects of dance such as spatial pattern, rhythm, synchronization to external stimuli, and ultimately whole-body coordination. This can be read in further detail in the section below: the integration of brain areas to allow for dance.

The figure to the left is an illustration of a subject demonstrating the dance task whilelying suping in the PET scanner. Prior to the scan, subjects were trained to perform simple bipedal dance movements. This was to limit the occurrence of any motor learning during the time that scans were taken.


ANATOMY AND FUNCTION OF BRAIN STRUCTURES INVOLVED IN DANCE

The scans revealed activations in many regions of the brain contributing to dance learning and performance. Knowing the location and function of these specific brain structures and regions will provide helpful in understanding the unique role that they play both individually, and as a system.

  • Motor cortex, specifically the primary motor cortex (M1), the premotor cortex (PMA), and the supplementary cortex (SMA)
  • Somatosensory cortex
  • Basal ganglia
  • Cerebellum, with a focus on the vermis, lobules IV and VIII, and lobule III
  • Parietal lobule
  • Right frontal operculum – involved in motor sequencing
  • Cingulate motor area (right) – processes aspects of movement intention, and allocation of motor resources

Motor Cortex
The motor cortex is a part of o
motor_cortex.jpg
Figure 2 - Motor Cortex
f the cerebral cortex that is invovled in many different aspects of voluntary motor functions including the planning, control, and execution of voluntary movement. It is composed of four different parts. The primary motor cortex (M1) is located in the posterior aspect of the frontal lobe. Its role is to control the simple features of movement, which it does with the help of Betz cells, large neurons located in grey matter of M1. These neurons descend to the spinal cord and ultimately have direct synapses with their target muscles. The premotor cortex (PMA) rests in the frontal lobe, and received inputs from motor nuclei in the ventro -anterior and -lateral thalamus, the primary somatosensory cortex, along with the prefrontal association cortex. Neurons located in the PMA, which include mirror neurons, are activated during the preparation of movement. In addition, the premotor cortex has roles in the control of both proximal muscles and trunk muscles. The posterior parietal cortex is located has a role in the production of planned movements, as it produces motor commands from the visual, auditory, and somatosensory input that it receives from those systems. The last section of the motor cortex is the supplementary motor area (SMA), which is located in front of the primary motor cortex. Its responsibilities are in motor action planning and coordination for complex movements, including movement arising from interal sources, such as memory.
sensory_homunculus.jpg
Figure 3 - Somatosensory Cortex


Somatosensory Cortex
The somatosensory cortex is located in the postcentral gyrus of the parietal lobe. As this region is the primary sensory receptive area for touch, it is responsible for motor control, and eye-hand coordination related to tactile information from touch and experience through memory. Also located in this area is the sensory homunculus.

Basal Ganglia
The basal ganglia are composed of a group of four nuclei which all play a role in voluntary movement. While they don
basal_ganglia.jpg
Figure 4: Basal ganglia with its 4 components highlighted (from The Dana Foundation)
't have direct inputs or projections with the spinal cord, they receive their input from the cerebral cortex and send their output through the thalamus to the brainstem, as well as to the prefrontal, premotor and motor cortices. The group of nuclei include the striatum, the globus pallidus (which is located medial to the putamen, consists of both an internal and external segment), the substantia nigra (which consists of the pars compacta), and the subthalamic nucleus (which rests above portios of the substantia nigra). The straitum is composed of the caudate and putamen, which are responsible for learning and memory, and regulating movements, respectively. These two nuclei are responsible for the most projections to the basal ganglia.





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Figure 5 - Cerebellum with 3 functional regions



Cerebellum
The cerebellum integrates inputs coming from the brain and spinal cord to play roles in movement-related functions, specifically fine-tuning motor activity (ie: coordination, precision). It consists of three distinct regions. The vestibulocerebellum, which is composed of the floculonodular lobe, is responsible for the control of balance and eye movements. The spinocerebellum, consisting of the intermediate hemispheres and the vermis, is responsibile for the control of proximal muscles and limbs, and of distal limbs and digits, respectively. The cerebrocerebellum is made up of the lateral hemispheres. Its projectins to motor, premotor, and prefrontal cortices help to explain its functions, which include its involvement in the planning of complex motor actions, and the evaluation of sensory information from errors for movement.


RESEARCH


The localized brain regions involved in three core aspects of dance (including entratinment, meter, and patterned movement) as outlined by the study The Neural Basis of Human Dance have been localized and suggested as the following.

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Figure 6 (Brown et al. 2005)
Entrainment

This entrainment is specific to that of movement to external timekeepers, such as music.
The regions of the brain that are activated include the anterior vermis of the anterior cerebellar lobule III, along with the right medial geniculate nucleus. Figure 2 to the right is an image that reflects activation in the aforementioned brain regions when a study participant performed learned dance step movements to music being played while they were lying in the PET scanner.

Patterned movement
This aspect of dance refers to the spatial navigation of lower-limb (leg) movement, causing the activation of several brain structures, including the primary motor and somatosensory cortices, the premotor cortex, the supplementary motor area, and the somatotopic leg areas of the cerebellum (lobules IV and VIII). Specifically relating to the movement of limbs is activation in the inferior parietal lobule (IPL) during the observation, preparation or simulation of actions. The activity in this region is the most when dancers simulate actions that they have had prior experience to.
Also, specific to physical learning, activity in the premotor cortex is related to both the competency and learning aspsects of dance, as the right premotor cortex is specifically involved in being able to embody an action after it is rehearsed. In addition, activation which has also been seen in the cingulate motor area has been suggested to reflect that this region contains a somatotopic map.
activation_during_movement_2.gif
Figure 7 (Brown et al. 2005)


Meter
This aspect of dance is used to refer to the movement to rhythm that is regular and metric (as opposed to that which is irregular and non-metric). When metered movements are are carried out, the basal ganglia is seen to be activated. More specifically, a strong bilateral signal in the putamen is seen.



NEURONAL CONNECTIONS

Action Observation Network (AON)

Most likely linked to mirror neurons, which may help explain why and how we can copy an action that we see, is the AON. This is a network, which suggests an overall relationship between action and observation. The network itself includes neural connections shared by both physical rehearsal (action) and observational learning (observation) which is evidenced by similarities in neural activity. This activity is seen in premotor and inferior parietal regions, however specifically in regards to training (whether or not through passive observation or physical rehearsal). An interesting thing to note is that the AON is sensitive to these different types of training. In addition, although there are siginificant increases in learning when a dancer is told to study the movement for a time later on, such as a performance, even if the focus isn't of learning from observing, observational learning can still take place.

The integration of brain areas to allow for dance

Despite different regions of the brain being activated for different aspects of dance, in order for dance to be performed, there is a coordination among these various areas that allow for the “bipedal, cyclically repeated dance steps entrained to a musical rhythm” (Brown et al. 2005).

The following findings come directly from Brown et al. study, although other studies that have been performed appear to have similar results.
The melodic and harmonic aspects of the music that is listented to is represented by both the superior temporal gyrus and the superior temporal pole. Regarding the beat of the music, the medial geniculate nucleus seems to send inputs, via brainstem nuclei, to the anterior cerebellar vermis and lobules V and VI in order to support the entrainment of movement to the beat of the music. The basal ganglia, especially the putamen within it, is involved in the metric aspects of movement, whereas the thalamus plays a role to connect the somatosensory to the motor parameters, especially in regards to rhythms which are not-metric. Motion that is bipedal and repeated cyclically, requires coordination between the two limbs, which is supported by the supplementary motor area (SMA), the cingulated motor area, and the cerebellum. Lastly, the spatial guidance of leg movement is provided by the medial aspects of the superior parietal lobule.


SUGGESTED IMPLICATIONS

The beneficial findings from studies exploring the connection between dance and the brain has led to the incorporation of dance in other aspects. This can be seen through the use of dance as therapy for individuals with Parkinson's Disease, whose benefits are explored through the study.

SUMMARY

Research has revealed a lot about the regions and specific structures of the brain which are activated during dance. Much of these findings speak a lot about how a dancer of any level can transform what they observe into movements of their own, also giving an observor a deeper appreciation and understanding for dancing such as seen here (This video is a representaion of the different aspects of ballet, but to an extreme, such as balance, patterned movement, and coordination in just one performance). In addition, they provide meaningful insights that can be applied to a population of non-dancers, who may benefit.


GLOSSARY OF TERMS

Action Observation Network (AON)
a network including neural connections shared by both physical rehearsal (action) and observational learning (observation), suggesting a relationship between action and observation
Entrainment (specific to movement)
a synchronization of movement to external timekeepers, such as music
Mirror neurons
a neuron that "mirrors" the behavior of the observed action as though it were carrying out that action itself
Positron Emitron Topography (PET)
a nuclear medicine imaging technique which produces a 3-D image of the body's functional processes
Sensory homunculus
an image representation of the parts of the primary somatosensory cortex responsible for the exchange of sensory information

QUIZ

Multiple Choice
1. Which region of the brain integrates inputs coming from the brain and spinal cord to play roles in movement-related function?
a. basal ganglia
b. right supplementary motor area
c. cerebellum
d. posterior parietal cortex

2. Which nuclei of the basal ganglia is the most activated during regular and metric movement?
a. subthalamic nucleus
b. putamen
c. substantia nigra
d. striatum

3. Which structure plays a role to connect the somatosensory to the motor parameters?
a. somatosensory cortex
b. basal ganglia
c. cerebellum
d. thalamus

True/ False
4. The 3 core aspects of dance include entrainments of movement to internal timekeepers, patterned movement, and irregular and non-metric movement.

5. Training cannot occur through both passive observation and physical rehearsal.

6. Mirror neurons are the name of the neurons located in the PMA which are activated during the preparation of movement.

Short Answer/Essay
From what you already know about dance, along with something new that you just learned, provide your own definiton of dance that incorporates its different components.

How specifically can the findings of research translate to being helpful in populations outside of the dance community, such as seen with individuals with Parkinson's Disease?

Answers
1. C
2. B
3. D
4. F
5. F
6. T


FURTHER SUGGESTED READINGS

Badets, A., Y. Blandin, and C. H. Shea. (2006) Intention in motor learning through observation. Quarterly Journal of Experimental Psychology. 59:377-386
This study attempts to answer the question of whether observational learning is enhanced when reproduction of the observed behavior is the intended goal.

Calvo-Merino, B., D. E. Glaser, J. Grezes, R. E. Passingham, and P. Haggard. (2005) Action observation and acquired motor skills: an FMRI study with expert dancers. Cerebral Cortex 15:1243-1249.
Study available here:
For more information on the 'mirror system', through this study performed on dancers, it answers the question of if and how our brain simulate the observed actions of someone else performing.

Ehrsson, H. H., E. Naito, S. Geyer, K. Amunts, K. Zilles, H. Forssberg, and P.E. Roland. (2000) Simultaneous movements of upper and lower limbs are coordinated by motor representations that are shared by both limbs: a PET study. European Journal of Neuroscience 12:3385-3398
Study available here
This study specifically examines how limb movement is coordinated.

http://www.ivarhagendoorn.com/
This is the link to Ivar Hagendoorn's website who as a choreographer, photographer, and researcher has contributed a significant amount to the research that looks at dance and the brain.
References
Brown, S., M. J. Martinez, and L. M. Parsons. (2006) The neural basis of human dance. Cerebral Cortex 16:1157-1167.

Brown, S., and L. Parsons. (2008) So you think you can dance?:PET scans reveal your brain's inner choreography. Scientific American Magazine

Cross, E. S., A. F. de C. Hamilton, and S. T. Grafton. (2006) Building a motor simulation de novo: observation of dance by dancers. Neuroimage 31:1257-1267

Cross, E. S., D. J. M. Kraemer, A. F. de C. Hamilton, W. M. Kelley, and S. T. Grafton. (2009) Sensitivity of the action observation network to physical and observational learning. Cerebral Cortex 19:315-326

NOVA. Mirror Neurons. Available from: http://www.pbs.org/wgbh/nova/body/mirror-neurons.html. Accessed: 16 December 2010.