Question

Vestibular sense. This lab involves physical activity – you are responsible for determining if you are capable of doing the actions yourself or asking someone to do them in your place and then observing/discussing the results to answer the questions below. Make sure you take a break between each question so you can return to a neutral position / level of activity.

3. Stand on one leg with your eyes closed for at least 15 seconds. Describe if/how this experience differs from having your eyes open. What has changed in terms of the role of the senses in the activity? What is your body doing to remain upright?

Answer 1

• Its different from standing normally because one is trying to focus in order to get the balance right on one leg. When I try to balance on one leg I try to focus on a point in front right between my eyes. The focal point is decided and you try to concentrate on one point.Trying to make a comfortable position,of the leg which you feel comfortable folding and also how would you keep your arms,either on the side or folded in front.
• Visual cues from our eyes give us information about where we are in space. This is why it can be difficult to keep your balance with your eyes closed. Your eyes also send signals to your brain, telling your joints and muscles where and how to move. For example, if you see an obstacle in your path, this visual cue will be sent to your brain which will then signal your muscles to walk around or over the object.
• Your inner ear is also involved in the balancing process. Among its tiny, delicate mechanisms is the semi-circular canal. This fluid-filled tube alerts your central nervous system as to the position of your head.
• You also have a built-in mechanism that tells your nervous system where your arms and legs are in space. It’s called internal spatial orientation, and it’s the automatic sense that lets you know your leg is folded to the side or or pointing forward to strike a balance.
• All three of those methods work together to coordinate your brain’s understanding of your orientation, or at least the orientation of your head in relation to the surface that you’re standing/walking on.
• Standing on one foot with eyes closed is alot harder than standing on one foot with eyes open as it causes disorientation.The disorientation is caused by one or two of those senses telling you that you’re oriented in a different position than the other senses. The disconnect between those senses results in dizziness which in turn leads to nausea and if not corrected, vomiting or even falling.
• If you’re standing on one foot with your eyes open, your body sense can feel any movement that you make off the vertical and your brain will send nerve impulses to your legs to correct the motion before it becomes too extreme. Your ears and especially your eyes concur with what your body awareness is telling you and you can react almost instantaneously to any movement.
• But if you close your eyes then you lose one of those three ways of orienting your head in space relative to the ground. The cochlear canals, because they rely on the movement of the fluid and particles inside, have a very slight delay between the movement of your head and your brain sensing that movement, while with the eyes the knowledge that you’re moving is instantaneous.
• That means that without your eyes, your brain becomes slightly behind any changes in balance you have with your one standing leg. The muscle impulses then become a bit out of phase with the shifts in balance. The brain/muscles then have to overcompensate but by then because of the lag you’ve already started to go too far, or too fast to fix the problem.
• This magnifies the motion and compensation in a sort of feedback loop that very quickly builds to the point where you can no longer compensate fast enough to keep up with the changes and you end up losing your balance and falling.
• If you opened your eyes sometimes you can regain your balance before you fall because the signal from your eyes to your brain is closer to real time than the signal from your ears.
• Eyes open provide the brain with visual feedback that tells us our position, and helps to stay upright.You can see your posture and try to adjust it by focusing at one point in front of you or even balancing your arms in a comfortable position.Also using the leg which you are more comfortable on standing and folding.