By Joshua Brumberg
For the first day of class I like to introduce the concept that the brain is an integrative device. I ask my class to stand up with their hands at their sides and I ask them to stay still, something most students do not have a problem doing. I then ask the students to stand on one leg and remain still, this is a slightly harder task. I then ask the students to bend one knee and still keep still, at this point many people have to steady themselves, and some students will put out their hands for balance. Finally I ask the students to close their eyes and try to maintain their balance at this point most students cannot and they put their raised foot down. I then ask the class to sit back in their seats and we discuss the task.
The class easily realizes we are most stable when we have two feet on the ground and as we lift up one leg things get harder; further discussion gets them to realize that sensory inputs arriving via their visual system are being used by their brains to help maintain their balance (via descending inputs to motorneurons which activate muscles in the legs). When their eyes are closed they have to rely on proprioceptive inputs from their ankles which are slower to arrive to their brains’, which makes it harder to quickly correct deviations in balance. The ultimate realization is that different sensory (visual, proprioceptive) and motor systems do not work in isolation but in conjunction, which is a primary focus of the class.
Dr. Joshua Brumberg is the Dean of the Sciences at the Graduate Center and a Professor of Psychology at the Graduate Center and Queens College.