Posture

Supraspinal control of posture

During most everyday activities, humans and animals need to maintain a specific body posture. Typically a deviation from a desired posture evokes correcting motor response, which leads to restoration of the posture. In this posture control system commands for postural corrections are generated on the basis of sensory information. This control system is based on the in-born mechanisms and operates automatically. Both spinal networks and supraspinal motor centers participate, but at present their contributions are not clear.

The overall aim of this project of Dr. Beloozerova is to characterize the commands transmitted from the brain motor centers to the spinal cord during postural tasks. This will allow us to understand the relationship between the two levels of postural control: spinal and supraspinal. We hypothesize that the contribution from higher brain centers increases with complication of postural tasks, and strive to understand this contribution.

In our experiments, we test subjects during balancing on a platform, which periodically tilts a little to the right and then to the left. We encourage the subjects to assume different postures (such as leaning to the right or to the left) or to perform stepping movements while still keeping balance on the platform. We record kinematics and dynamic parameters of limbs and body movements, the activity of limb muscles, and the neuronal activity of the motor cortex, motor thalamus, and midbrain. We then compare body mechanics, the activity of muscles, and the activity of brain areas during balancing with different postural configurations and reveal the parameters, which are associated specifically with each of the configurations.

This project is a collaborative effort between our laboratory and the laboratory of Dr. Tatiana Deliagina at Karolinska Institute in Stockholm, Sweden. Every year for the last ten years, one, two or three members of Dr. Deliagina group are visiting Phoenix for several weeks, and we conduct experiments together. Then during the remainder of the year, we extensively exchange the results of data analyses, and also draft and finalize publications.

A graduate student from Karolinska Institute Anastasia Karayannidou did her full academic year rotation (2005-2006) in my laboratory during her second year in graduate school. She came back next year for a month of additional experiments and then successfully defended her Ph.D. in June 2009 with five full size publications, three of which resulted from her work in my laboratory.