Biology 202
2000 Second Web Report
On Serendip

"How long have we been practicing this number?" she yells, " It should be ingrained in your heads by now. The arm reaches up on six, not five! Christina, you should be in this spot after the jete (technical ballet term for a leap) and Danielle, split center with Erica. A five, six, a five , six, seven eight!"

The music blasts and I could feel the harsh bass pounding in my stomach. We try to incorporate her corrections- the arm lifts up on six, not five. I must jete in this direction so that I land up in this spot as indicated by the duct tape in the "down-stage" area of the dance room. X marks the spot. Here comes the dreaded phase.

"Stop the music!" Ms. Dance teacher interrupts. I'm not surprised- my arm went up on seven and I'm no where close to my spot. I'm tired. I'm hot. I want a bucket of ice to dump over my head.

"Okay, it's obvious we need to work on this more. Why don't you all take a fifteen minute break, go get some air, water and go over the phrase. I'll watch the tap number in the meantime. Come back in 20 minutes."

So there we are in the room next door. Girls are reviewing and rigorously kicking over and over and over again. I stand a little off of the center of the room. My limbs do not dare to move. I am looking down at the ground. Whoops, Julia just kicked me because she's rehearsing the jete- turn portion. "Sorry, I'm in your way," I apologize. I walk off to the side, still looking down at the floor. I start the combination in my mind. Okay, the left foot goes here and I step on three so that I can be in my spot my eight. I see this image of myself in my head perfectly executing the dance. I repeat it in my mind once again, never moving any part of my body that would slightly reveal I'm thinking of the combination.

After some fresh air and a few minutes to ourselves, we're ready to rehearse with Ms. Dance teacher again. " A five, six, a five, six , seven eight." She looks amazingly pleased. " Christina, that transition worked after the jete. Your spacing was good, whatever you did to get your spot was good, remember that correction."

So, why did my method of rehearsing work just as well as the traditional method of repeatedly dancing the phrase? Of course, there are many ways to rehearse any style of dance, but according to many dance teachers, the only way to "ingrain the combinations in your heads" is to physically repeat the phrase until you are comfortable. Only then would the dance be well executed.

I never inquired my method of rehearsal because I never actually thought about why I choose to prepare for performances in this way. This process of visualizing motor executions is known as motor imagery. We visualize or think about ourselves moving around in certain ways. The concept of motor imagery has raised such questions such as is performing the actual movement and thinking about the motion almost the same concept? Or are motor receptors activated during the imagery and why are we able to perform even if we've never moved physically in the way we think about it (2).

Motor imagery is a form of visual imagery, however, one distinction that must be made is that motor imagery involves the reconfiguration of the object in relation to its space (4). As part of the motor imagery, we visualize events that occur in represented planes. One more distinction is that motor imagery involves the internal versus external factors. Motor imagery is considered an example of internal imagery because we envision ourselves in motion, not another external figure. When I have a mental rehearsal, I picture what my body would look like when moving and interacting with the external world.

Motor control data has shown that consistent movement results from the endured repetition and practice of these movements. From this hypothesis, it would seem logical that mental practice could only help the consistency in movement, but if mental practice and physical practice were independent of one another, would there still be a correspondence in motor performance and which method would produce better results? (3). One study hypothesized that motor imagery is directly related to motor physiology (3). Since motor imagery involves the perception of what we see, then vision and its effects on motor performance must be addressed. Let's consider just the concept of imagery. If we compare our brains to a visual map, this study says that we can connect objects spatially and realistically the way we would when we actually see two physical, tangible objects. For example, the distance between the red chair and blue couch in my living room would appear in a setting that would be equivalently accurate and proportional to the true distance at which they really exist. From this example, it appears that the representation we have in our heads is a direct result of the actual events rather than a linguistic description (4). This study implies that the images we see in our brains is mostly a compilation of what we have seen, not mostly what we've heard about them. Indeed, both the linguistic and visual aspects play a role in the formed image, but this study strongly asserts that the power of sight is more responsible for regenerating corporeal objects and movements in our heads. This indicates that we create images in our brains based on real figures, occurrences and or objects. The broader topic of visual imagery pertains directly and must be considered when dealing with the more specific sub-category of visual imagery, motor imagery. One point of clarification I would like to make is that I when I compare the physical practice with the mental practice, I am trying to relate this back to my personal experience in dance. I want to compare the preparation of each process in relation to the final results, ultimately the dance performance itself.

Since the images are created, what happens to the output based on the input of these images? (4). The output in this case would result in the actual motor performance of the visualized or physically practiced event. Some studies propose that regardless of the input, whether it be triggered by the tangible object or a vision of the object, the output should be very similar between the actual motor practice and the motor vision. So, if the results could produce negligible differences and resembling results throughout the mental images and the physical practice, the link between the physical practice and the performance or the mental image and the performance might activate comparable parts of the brain to produce similar results.

Experimental data, dating from the mid eighties (4), supports the hypothesis that there are several common features between the physical perception and the mental image (2). This data infers that the activity and presence of a "common neural substrate" (4) exists. The studies showed that t here must have been a point of convergence when asked to recognize or perceive the object and when asked to visualize that same object. The cases resulted in recognizing either the actual object or being able to visualize the object, but not both. This study reports, " Such cases are not against the idea of a commonality of neural structures for perception and imagery if one postulates the existence of a hierarchical organization of the mechanisms for processing visual representations" (4). This statement indicates that the two images, whether perceived or visualized in our brains would produce similar images because the two images converged in the posterior part of the left hemisphere according to this study. Furthermore, because a hierarchy system exists when forming these images, each process of forming either image has a specific generation order but eventually, the processes merge in the same brain structure.

This hierarchical system of forming the proper performance of the movement can also be viewed in terms of a complimentary relationship between the "emulator" and the overt practice (2). The emulator in this text is described as the "egocentric behavioral space." Visual representation of the desired movements result from the emulator. The emulator creates these images of the desired movements and then receives "feedback" from the physical performance.

So what exactly happens in my brain and body when I imagine myself practicing that jete? Motor control and training is an un-conscious event " (4). Only when I dance do I consciously realize my motor training. It is at that point when I can actually match my preparation of the desire movement to my physical performance. Visually, we process images in the occipital region of our brain in the vision receptive area. Impulses from the retina are represented here. The recognition and identification of objects requires the associated function of the adjoining visuopsychic area which has connections to the vision receptive area. The visuopsychic area functions in more complex visual recognition like perception, revisualization, visual association and spatial orientation. Once I imagine the steps in dance class, the motor cortex assists me in these movements by activating my skeletal muscles (5). There are connections that run from the occipital to the frontal cortexes which respond with eye movements.

In addition to what happens when I conduct my mental practices, recent evidence has shown that different parts of the brain were activated during overt practice when compared to mental imagery (4). One study reported that in the early eighties, it was shown that the supplementary motor area, or SMA, was stimulated when the brain planned a certain finger movement. But when the plan was physically executed, a change occurred in the primary motor area alone with the SMA. Similarly, it was found that the SMA was activated during the mental and physical performances while the rolandic region, which separates the parietal lobe from the frontal lobe. On the side of the frontal lobe, the primary motor area is located here as the primary sensation area is located on the side of the parietal lobe (6). This study manifests that different parts of the brain respond to the mental preparation and the actual performance. But this study also concluded that due to many differences in purpose of planning and cortical activation due to mental preparation, the activation of the SMA, rolandic region and premotor cortex constantly varied in activation, and its degree of activity (4), (7).

From the evidence and studies I looked at, it is very difficult to conclude whether or not mental preparation or physical practice will give the ultimate performance. Indeed, each could be viewed in separate identities since the mental and physical preparationeach trigger specific changes within our brain. Perhaps the studies show that execution alone can be observed independently and in turn be an effective way of preparing for such a physical task. However, as we see in our every day lives, there is a correlation between what we envision in our heads and how we physically move our bodies through spatial limitations. The correlation, though, does consider one major process : the process of performing and executing what one has prepared (4). Once paradigms and more specific models are created, with the help of brain imaging techniques, we will eventually learn on the molecular level what the direct pattern changes in certain structures of the brain are. From there we will be able to see the exact inputs that occur when visualizing movement and then performing our visual plan. As an earlier study suggested, (4) there must be a convergence in the brain, but no one is not completely sure if the differences are negligible when preparing for motor performance. Even if comparable parts of the brain are affected, the activity is what needs to be focused on. In other words, we have to delve into the microscopic level to see how much of these activities differ and if there is true evidence to support one method of preparation over the other, or if both are required for the ultimate performance.

WWW Sources

2)Perception, Imagery, and the Sensorimotor Loop, This site was helpful in its emulator theory.

3) On Relations Between Perceiving, Imagining and Performing in the Learning of Cyclical Movement , This site was helpful for the studies performed concerning motor imagery in comparison to physical preparation.

4) The Representing Brain: Neural Correlates of Motor Intention and Imagery , This site was my main reference in that it asked many of the same questions I did.

5) TBI Resource Guide , This site was an overall helpful definition finder.

6)Rolandic Region and BRE , This site helped me define the rolandic region.

7) The Role of Premotor Cortex and the Supplementary Motor Area in the Temporal Control of Movement in Man , This provided me with background information on the premotor cortex.

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