Research Activities

Maintenance of the basic body posture - upright in humans and dorsal-side-up in quadrupeds - is a vital motor function. Our knowledge about neuronal mechanisms of postural control is relatively scarce. The general goal of our Lab is to understand the organization and operation of the neuronal networks responsible for maintenance of the basic body posture. Our experimental strategy is to investigate postural mechanisms in the animal “models” of different complexity – a lower vertebrate (lamprey), and two mammalian species, rabbit and cat, to reveal common basic principles of postural control.

For the lamprey model, we have developed techniques to study the orientation-dependent activity of individual neurons in vivo and in vitro. By using these techniques, we revealed organization and operation of postural networks stabilizing body orientation in the transverse and sagittal planes, and modifications in their activity underlying changes in the stabilized orientation.

In different species, damage to a vestibular organ causes dramatic postural disturbances. In the lamprey, we investigated impairment of postural networks caused by unilateral labyrinthectomy. On the basis of this knowledge we developed a few methods for compensation of vestibular deficits. Some of these methods have later been successfully applied to mammals (rats).

At present, we study: (i) nervous mechanisms stabilizing body orientation in the horizontal plane, and (ii) spinal mechanisms of decoding the supraspinal commands for postural corrections and for other forms of motor behavior.

For the rabbit and cat models, we study postural corrections caused by tilts of the supporting platform. Our methods allow monitoring the kinematics, forces, EMGs, as well as the activity of individual neurons in freely behaving animals. We characterized functional organization of postural mechanisms stabilizing trunk orientation in the transverse plane.
At present, we study the contribution of spinal and supraspinal mechanisms to the trunk stabilization. This is important for understanding postural dysfunction caused by spinal cord injury. We address the questions: (i) Can the spinal postural mechanisms operate when the supraspinal commands are reduced or abolished by spinal cord injury? (ii) Can the supraspinal commands be substituted by a tonic excitatory drive, e.g., by stimulation of the spinal cord below the lesion?

In collaboration with Dr. Beloozerova (Barrow Neurological Inst., Phoenix , USA ), we are studying the contribution of motor cortex to postural control. By recording the activity of different classes of cortical neurons during postural corrections, we have found that pyramidal tract neurons and inhibitory interneurons are involved in postural control. In current experiments, we study the contribution of individual pyramidal tract neurons to postural tasks of different complexity.

 

Financing:

The Swedish Research Council (M and NT)
Christopher Reeve Paralysis Foundation
National Institute of Health
The Royal Swedish Academy of Science
Gösta Fraenckels Foundation

                                       

SELECTED PUBLICATIONS
Orlovsky G.N., Deliagina T.G., Wallen P. Vestibular control of swimming in lamprey. 1. Responses of reticulospinal neurons to roll and pitch. Exp. Brain Res. (1992), 90,479-488.
Deliagina T.G., Orlovsky G.N., Grillner S., Wallen P. Vestibular control of swimming in lamprey. 2. Characteristics of spatial sensitivity of reticulospinal neurons. Exp. Brain Res. (1992), 90, 489-498.
Deliagina T.G., Orlovsky G.N., Grillner S., Wallen P. Vestibular control of swimming in lamprey. 3. Activity of vestibular afferents. Convergence of vestibular inputs on reticulospinal neurons. Exp. Brain Res. (1992), 90, 499-507.
Deliagina T.G., Grillner S., Orlovsky G.N., Ullen F. Visual input affects the response to roll in reticulospinal neurons of the lamprey. Exp. Brain Res. (1993), 95, 421-428.
Deliagina T.G. Vestibular compensation in lampreys: impairment and recovery of equilibrium control during locomotion. J. exp. Biol., (1997), 200, 1459-1471.
Deliagina T.G., Popova L.B. and Grant G. The role of tonic vestibular input for postural control in rats. Arch. Ital. Biol., (1997), 135, 239-261.
Deliagina T.G. Vestibular compensation in lampreys: role of vision at different stages of recovery of equilibrium control. J. exp. Biol., (1997), 200, 2957-2967.
Deliagina T., Fagerstedt P. (2000) Responses of reticulospinal neurons in intact lamprey to vestibular and visual inputs. J. Neurophysiol. 83, 864-878.
Deliagina T. G., Beloozerova I. N., Popova L. B., Sirota M. G., Swadlow H., Grant G., Orlovsky G. N. Role of different sensory inputs for maintenance of body posture in sitting rat and rabbit. Motor Control (2000), 4, 439-452.
Zelenin P. V., Deliagina T. G., Grillner S., Orlovsky G. N. (2000) Postural control in the lamprey – a study with neuro-mechanical model. J. Neurophysiol., 84, 2880-2887.
Zelenin P. V.,Grillner S., Orlovsky G. N., Deliagina T. G. (2001) Heterogeneity of the population of command neurons in the lamprey. J. Neurosci. 21, 7793-7803.
Deliagina T.G., Pavlova E.L. (2002) Modifications of vestibular responses of individual reticulospinal neurons in the lamprey caused by a unilateral labyrinthectomy. J. Neurophysiol. 87, 1-14.
Pavlova E.L., Deliagina T.G. (2002) Responses of reticulospinal neurons in intact lamprey to pitch. J. Neurophysiol. 88, 1136-1146.
Deliagina T. G., Zelenin P. V., Orlovsky G. N. Encoding and decoding of reticulospinal commands. Brain Research Reviev. (2002), 40, 166-177.
Deliagina T. G. and Orlovsky G. N. Comparative neurobiology of postural control. Current Opinion in Neurobiology (2002), 12 652-657.
Pavlova E.L., Deliagina T.G. (2003) Asymmetry in the pitch control system of the lamprey caused by a unilateral labyrinthectomy. J. Neurophysiol. 89, 2370-2379.
Zelenin P.V.,Grillner S., Orlovsky G.N., Deliagina T.G. (2003) The pattern of motor coordination underlying the roll in the lamprey. Exp. Biol. 206,2557-2566.
Beloozerova I.N., Sirota M.G., Swadlow H.A., Orlovsky G.N., Popova L.B., Deliagina T.G. (2003) Activity of different classes of neurons of the motor cortex during postural corrections. J. Neurosci. 23(21), 7844-7853.
Zelenin P.V., Pavlova E.L., Grillner S., Orlovsky G.N. and Deliagina T.G. (2003) Comparison of the motor effects of individual vestibulo- and reticulospinal neurons on dorsal and ventral myotomes in lamprey. J. Neurophys. 90, 3161-67.
Beloozerova I.N., Zelenin P.V., Popova L.B., Orlovsky G.N., Grillner S., and Deliagina T.G. Postural control in the rabbit maintaining balance on the tilting platform. J. Neurophysiol. (2003), 90, 3783-3793.
Pavlova E. L., Popova L. B., Orlovsky G. N., and Deliagina T. G. (2004) Vestibular compensation in lampreys: restoration of symmetry in reticulospinal commands. J. Exp Biol., 207, 4595-4603.
Beloozerova I. N., Sirota M. G., Orlovsky G. N., Deliagina T. G. (2005) Activity of pyramidal tract neurons in the cat during postural corrections. J Neurophysiol. 93,1831-44

---

Last modified: 2009-06-02