Irina Beloozerova Collaborations:
School of Applied Physiology, Center for Human Movement Studies,
Georgia Institute of Technology,
Research in the laboratory of Dr. Prilutsky focuses on the mechanisms of movement generation and control. This includes control of force by the arm during learning new movements, modeling of the spinal cord neural circuitry that controls locomotion, and studying the role of the motor cortex in different locomotor behaviors.
We collaborate with the laboratory of Dr. Prilutsky in the analysis of biomechanics of complex locomotion behaviors and involvement of motor cortex in the control of them. We conduct experiments together, in which we record whole-body kinematics and dynamics of subjects while they walk along a cluttered pathway, along series of elevated platforms, along a narrow strip, or on other complex surfaces. We also record the activity of muscles and the motor region of the cerebral cortex at the same time. The goal is to describe, analyze, and eventually understand biomechanics of complex locomotion behaviors, and their neural correlates.
Brad Farrell from the Georgia
Institute of Technology has actively participated in these studies since he was
an undergraduate student. In fall of 2006 Brad started his graduate studies in
the PhD program of the
Laboratory of Dr. Maxim Volgushev reseaches neurophysiology of the visual system: signal processing in visual cortical neurons in vivo, generation of action potentials and cell electrophysiology, synaptic transmission in the neocortex, and plasticity of synaptic transmission.
We collaborate with the laboratory of Dr. Volgushev in studies aimed at understanding how demands of locomotion task shape visual input and processing of visual information. We use a unique experimental paradigm of active vision in freely moving cats that enables the study of vision under conditions, in which it is naturally used: in the context of coordinated and coherent operation of all systems, including the required levels of attention, motor activity, sensory feedback, and dynamically changing visual input during natural locomotion. This paradigm builds on the complementary strength of visual and motor physiology. Cats readily walk in environments that impose different demands on vision for locomotion: from simple flat surfaces (low demand) to stepping on elevated objects (high demand). Using this robust and repetitive natural behavior we measure visual input, neuronal activity, and behavioral output. To measure visual input, we take footage from a head-fixed camera and record the eye position, gaze trajectory, and biomechanics of head and body. Using these measurements, we calculate visual input in retinotopic and body-centric coordinates. While the cat is walking, we record activity of neurons in primary visual and multisensory parietal cortical areas. We use reverse correlation to reconstruct receptive fields of neurons in retinotopic and body-centric coordinates. To measure behavioral output, we characterize locomotion using 3-dimensional analysis of biomechanics of head, body and limbs, and the accuracy of steps. Our overarching hypothesis maintains that processing in the visual cortex is task-dependent: higher demands on accuracy of stepping lead to an increasing precision of space representation in the visual system.
The general goal of research in the laboratory of Dr. Deliagina is to understand the organization and operation of the neuronal networks responsible for maintenance of the basic body posture.
We collaborate with the laboratory of Dr. Deliagina in studies aimed at characterizing the commands, which are transmitted from the brain motor centers to the spinal cord during different postural tasks. In our joint experiments, we test subjects during balancing on a platform, which periodically tilts 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 allows us to understand the contribution of supraspinal mechanisms to the control of posture.
A graduate student from Karolinska Institute Anastasia Karayannidou defended her thesis on “Spinal and supraspinal mechanisms of postural control” in summer 2009 with 5 full size peer-reviewed publications, 3 of which resulted from her work in our laboratory. Anastasia did a full academic year rotation (2005-2006) in our laboratory during her second year in PhD program, and then visited for more experiments.