Introduction
Dance in any form requires high levels of motor control and skill, which are feverishly pursued by aspiring dancers around the world. They attend classes and rehearsals, and watch elite dancers perform choreography they hope to dance themselves one day. When dancers improve it is not only due to their hours of practice as would be expected, but the time they spend watching their teachers, peers and elite dancers also contributes to their skill development. A variety of studies have shown that observation can aid in motor learning, and this is achieved through the action-observation network (AON) [1].

AON Structures and Circuitry
The general areas of the AON include the parietal and premotor areas, as well as subcortical areas. Specific regions within these areas that have primary roles in the AON include the supplementary motor area (SMA), the ventral premotor cortex (PMv), and the inferior parietal lobule (IPL) [2, 3][5]. The general organization is as follows:
Parietal Lobe
Located posterior to the central sulcus, the parietal lobe is responsible for receiving and processing somatosensory information [10]. It receives input from somatosensory, primary motor, premotor, visual, auditory, vestibular, temporal and proprioceptive areas, and has outputs to the primary motor cortex, supplementary motor cortex, and premotor regions. There are also input/output circuits within the subdivisions of the parietal lobe itself [6].
Premotor Area
The premotor area is located anterior and slightly inferior to the primary motor cortex, which is located directly anterior to the central sulcus. The premotor area receives input from the parietal lobe, and has outputs to the primary motor cortex and the spinal cord [6,7].
Supplementary Motor Area
The supplementary motor area is located anterior to the primary motor cortex and superior to the premotor cortex. It has inputs from the prefrontal association areas, and projects to the primary motor cortex, basal ganglia, thalamus, brainstem, and contralateral supplementary motor area [8,9].


The AON is involved in both observational and experiential motor learning, and there appears to be areas of overlap between the two learning types [4][5]. The following paragraphs describe the differences in AON activation in dancers’ brains during observational and experiential learning scenarios.


Figure 1. Figure 2.

Figure 1..png Figure 2..jpg

http://neuroscience.uth.tmc.edu/s3/chapter03.html http://mybrainnotes.com/brain-diagram-1.jpg


Observational Learning
Studies have shown that there is a direct relationship between observation and motor execution, indicating that observation is a viable means of learning new movements such as those involved in dance [3]. Neuroimaging studies of dancers’ brains have shown that when the dancers who were involved in the studies viewed movement patterns that they had previously watched but not danced, there was a significant increase in activity in the ventral premotor areas (PMv), inferior parietal lobule (IPL), and the basal ganglia [5]. Other studies have also shown activation of the superior temporal sulcus (STS), the primary motor cortex (M1), and the cerebellum in similar scenarios [2, 4]. It is interesting to note that other similar studies produced the same imaging results even though the dancers were not asked to learn the movement they were shown, only to watch it [4]. This suggests that the AOR is involved in learning processes that begin when a movement is viewed, even before the dancer is aware of their intention to learn. Of the structures involved, the IPL is of particular interest. Research has shown that the IPL is activated during action observation and/or preparation, and it is associated with the processing of visuomotor information in order to replicate a learned movement. As will be described later, the IPL is also involved with experiential learning, but the PMv is one structure that has been shown to be more active during observation than during physical completion of movement [2].
While this section is devoted to the observational aspect of motor learning and the AON, it is worth noting that having prior experience with a particular style of dance facilitates observational learning, even if no knowledge of the specific movement patterns to be learned is present. This was shown through studies using neuroimaging, the results of which showed significantly more AON activity in dancers’ brains when they watched a new movement in a familiar style of dance vs. a new movement pattern in an unfamiliar style. This suggests that the observational area of the AON can draw upon previously stored experiential information [2].

Experiential Learning
Experiential learning activates certain areas of the AON more-so than purely observational experience. Studies have shown some of these areas to be the STS, the left posterior cingulate cortex, the IPL, the premotor cortex and the right fusiform gyrus. These areas showed greater activation when the dancers in the studies watched simulations of movements that they had performed themselves than when they watched simulations of movements that they had only observed [2-4]. As noted above, the IPL is one main structure that is implicated in both observational and experiential motor learning (See Figure 3.). The second structure that appears to have the most overlap is the premotor cortex. One study found that the improvement in the dancers’ performance over the course of the study was significantly correlated with the amount of premotor activation that occurred; in other words, the premotor cortex reflects both motor learning and competency, while the IPL is only involved in motor learning. Of the dancers in the study, some began the trial at a low level of proficiency and improved greatly, yet they did not reach even the beginning level of the more skilled dancers (who improved only slightly). The premotor activity in the less skilled dancers increased the most over the trial, but even though the skilled dancers didn’t improve as much their premotor activity was still greater than that of the less skilled dancers. This correlation appears to be applicable only when experiential learning vs. observational learning has occurred [4].


Figure 3. Neuroimaging results showing areas of the brain activated only by experiential learning (blue), only by observational learning (red), and by both (yellow).

Figure 3..gif
http://cercor.oxfordjournals.org/content/19/2/315/F5.medium.gif


Conclusion
The studies described above show that the AON allows one to learn not only through first-hand experience but also through observation. The processes involved in experiential and observational learning overlap to some extent, indicating that experience and observation results in mutual enhancement of each motor learning process [2][5]. Each process can also occur independent of the other, and there are important implications of the fact that dancers can learn and begin to develop skill via observation without stepping foot on the dance floor. First, dancers who are attempting to learn potentially dangerous choreography can obtain some level of competency in the movements by first watching other dancers who have already mastered the movements. This poses less risk of injury compared to a hasty attempt without prior observation and mental rehearsal. In addition, dancers who have been injured are not completely exempt from learning. This is especially important for dancers in professional companies who rely on their ability to dance as a source of income. Injured dancers can watch rehearsals and mentally rehearse their parts, which will keep them from needing to start from scratch once their injuries heal. Lastly, dance (especially at the professional level) results in much wear and tear on the body, so strategic incorporation of observation and mental rehearsal could potentially result in less physical damage and a longer, healthier career for professional dancers. Further study of the mechanisms involved in observational and experiential learning could lead to additional improvements in teaching and learning methods.

Glossary of Terms

  • Observational learning – the process of acquiring motor skill via passive watching of a movement or set of movements
  • Experiential learning – the process of acquiring motor skill via first hand action/imitation of a movement or set of movements
  • Mental rehearsal – the act of visualizing the process to be learned and performed
  • Choreography – a sequence of steps and movements
  • Inferior – below
  • Superior – above
  • Anterior – front, in front of
  • Posterior – back, in back of
  • Contralateral - on the other side
  • Central sulcus – groove or fold that runs across the brain along the coronal plane
  • Coronal plane – axis that divides the body into anterior and posterior halves
  • AON – action-observation network
  • SMA – supplementary motor area
  • PMv – ventral premotor cortex
  • IPL – inferior parietal lobule
  • STS – superior temporal sulcus
  • M1 – primary motor cortex

Links to Further Readings

The Dancing Brain
This Dana Foundation article that explores the concept of the neurological basis of what makes dance so captivating, thrilling, engaging, etc.
http://www.dana.org/news/cerebrum/detail.aspx?id=2930
Action Observation and Acquired Motor Skills: An fMRI Study with Expert Dancers
This article explores the function of the AOR in the context of an individual’s specific motor repertoire
http://cercor.oxfordjournals.org/content/15/8/1243.full

Test Your Understanding
  1. T/F The AON includes portions of the parietal lobe.
  2. T/F Motor learning cannot occur simply by observing a movement
  3. T/F The premotor cortex reflects both learning and competency
  4. T/F The supplementary motor area is located posterior to the central gyrus
  5. T/F The parietal lobe only projects to areas involved in motor control
  6. T/F Neuroimaging studies have shown that there is no overlap between the areas of the AOR that are responsible for observational learning and the areas responsible for experiential learning
  7. T/F The IPL is active during preparation for movement
  8. Describe how familiarity with a particular style of dance relates to learning and AON activation
  9. Describe how it was found that the premotor cortex reflects competency
  10. Describe one way that dancers can benefit from observational learning
Answer Key
  1. T
  2. F
  3. T
  4. F
  5. F
  6. F
  7. T
  8. Familiarity enhances observational learning; AON activation increases to a greater extent when dancers watch movements from a style they are familiar with, even if they have never performed the actual movements being viewed.
  9. Neuroimaging studies of dancers’ brains showed that the premotor cortex increases proportionally to the level of competency; the level of activation reflected both the change in the level of skill and the absolute level of skill. Some less skilled dancers showed more improvement but a lower total skill level, while other dancers showed less improvement but a higher total skill level, and the premotor cortex activity reflected this.
  10. Reduced risk of injury, capacity to learn even while injured, or reduced wear-and-tear on the body

References

1. Gatti, R., et al., Action observation versus motor imagery in learning a complex motor task: a short review of literature and a kinematics study. Neurosci Lett, 2013. 540: p. 37-42.
2. Cross, E.S., A.F. Hamilton, and S.T. Grafton, Building a motor simulation de novo: observation of dance by dancers. Neuroimage, 2006. 31(3): p. 1257-67.
3. Calvo-Merino, B., et al., Action observation and acquired motor skills: an FMRI study with expert dancers. Cereb Cortex, 2005. 15(8): p. 1243-9.
4. Cross, E.S., et al., Sensitivity of the action observation network to physical and observational learning. Cereb Cortex, 2009. 19(2): p. 315-26.
5. Grafton S., Cross E. Dance and the Brain [Online]. The Dana Foundation. http://www.dana.org/news/publications/detail.aspx?id=10744 [23 November, 2013].
6. 3/2/2011. The Parietal Lobes [Online]. Carleton. http://http-server.carleton.ca/~btansley/psyc3207/notes/3207Topic6.pdf [23 November, 2013].
7. Knierim J. Chapter 3: Motor Cortex [Online]. University of Texas Medical School. http://neuroscience.uth.tmc.edu/s3/chapter03.html [23 November, 2013].
8. Swenson. Chapter 11 – The Cerebral Cortex [Online]. Dartmouth. http://www.dartmouth.edu/~rswenson/NeuroSci/chapter_11.html#chapter_11_primary+secondary [23 November, 2013].
9. Motor Cortex [Online]. Tutis Vilis. https://blackboard.gordon.edu/bbcswebdav/pid-98396-dt-content-rid-551747_1/courses/KIN4502013FA/KIN4502012FA_ImportedContent_20120828012916%288%29/KIN4502011FA_ImportedContent_20110826042521/KIN4502010FA_ImportedContent_20100819090538/Content%20Areas/Motor%20Cortices/Web%20Resources%20%28Motor%20Cortices%29/Motor%20Cortex%20Tutorial/Motor_Cortex_Tutorial.pdf [23 November, 2013].
10. Young PA., Young PH., Tolbert DL. Basic Clinical Neuroscience. Philadelphia, PA: Lippincott Williams & Wilkins, 2008, p.209-215.