Research in the Ashton Graybiel Spatial Orientation Laboratory covers human spation orientation, motor control, and adaptation. Basic mechanisms and their practical implications are both of interest. Unique approaches include 1) emphasis on intersensory and sensory-motor interactions, 2) recognition of the intimate relationship between moment-to-moment control and long-term adaptation, and 3) exploitation of non-terrestrial conditions, such as space flight, artificial gravity and virtual environments and of clinical populations with loss of vision, proprioception, or vestibular function.

Our research on control of reaching movements illustrates these themes. Some stages of making goal directed reaching movements are localizing a target, planning a path, and generating the forces necessary to move. From a mechanical perspective, combinations of muscle length and force produce posture and movement. A traditional experimental approach to inferring the nature of neural control involves unexpectedly perturbing movement trajectories and observing the resulting errors. We have developed a new perturbation paradigm employing a rotating room facility located in our laboratory that simulates an "artificial gravity" environment.

Our paradigm involves comparing movements made in a normal stationary environment to ones made in the rotating room. The centrifugal force field generated during rotation may be similar enough to the terrestrial gravitational field for a rotating space vehicle to be used for generating "artificial gravity". However, rotation also leads to Coriolis forces that are potential source of side effects that could prohibit the use of rotation for artificial gravity. For example reaching movements made in a rotating room generate Coriolis forces that are directly proportional to the cross product of the room's angular velocity and the arm's linear velocity within the room. Our research has investigated the implications of Coriolis force perturbations for astronaut performance and health during long duration space missions in a rotating space vehicle, and we have also made use of the Coriolis force perturbations for basic research.

Coriolis force perturbations in the rotating room are transient (only present when the arm is moving), unexpected and unique because they act without local contact. We have found that reaching movements are deviated, in endpoint and path, in the direction of Coriolis forces in the rotating room, whereas traditional perturbation techniques have not resulted in endpoint errors. Adaption to Coriolis forces occurs within 10-20 movements such that straight, accurate reaches are again possible, and mirror-image aftereffects occur when rotation stops. The pattern of findings has shown that 1) the field of candidate control variables for movement execution does not include muscle stiffness, 2) proprioception is paramount in trajectory monitoring and adaptation, 3) the relevant proprioceptive information includes a strong cutaneous component in addition to muscle spindle, joint and tendon signals, 4) cutaneous inputs from perturbations during movement execution are utilized in different ways from cutaneous signals generated by contact with surfaces at movement termination, 5) posture and movement involve separate control elements, 6) the nervous system represents and utilizes detailed "expectations" about the forces that will be encountered during a reaching movement, and 7) the movement plan is more dynamic than we and others originally assumed.

Other problems being actively investigated include 1) the role of Coriolis and other unusual forces in eye-head coordination and calibration, 2) vestibular, and proprioceptive influences on visual and auditory localization, 3) haptic, visual, auditory and vestibular factors in perceived body orientation, position sense, static posture and locomotion, 4) causes and ways of alleviating motion sickness disorientation and misorientation in space flight, artificial gravity and virtual environments.

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Selected publications

Lackner JR, Rabin E, DiZio P. [2001] Stabilization of posture by precision touch of the index finger with rigid and flexible filaments. Exp Brain Res, 139: 454-464. [abstract]

DiZio P, Lackner JR, Held RM, Shinn-Cunningham B, Durlach NI. [2001] Gravitoinertial force magnitude and direction influence head-centric auditory localization. J. Neurophysiol., 85: 2455-2460. [abstract]

DiZio, Paul and James R. Lackner. [2001] Coriolis-force-induced trajectory and endpoint deviations in the reaching movements of labyrinthine-defective subjects. J. Neurophysiol. 85: 784-789. [abstract]

Lackner JR, DiZio P. [2002] Adaptation to Coriolis force perturbation of movement trajectory; role of proprioceptive and cutaneous somatosensory feedback. Adv Exp Med Biol. 508:69-78. [abstract]

Kurtzer I, DiZio P, Lackner J. [2003] Task-dependent motor learning. Exp Brain Res. 153:128-32. [abstract]

DiZio P, Lackner JR. J [2002-2003] Sensorimotor aspects of high-speed artificial gravity: III. Sensorimotor adaptation. Vestib Res.;12(5-6):291-9. [abstract]

Bortolami SB, DiZio P, Rabin E, Lackner JR. [2003] Analysis of human postural responses to recoverable falls. Exp Brain Res.151(3):387-404. [abstract]

Pigeon P, Bortolami SB, DiZio P, Lackner JR. [2003] Coordinated turn-and-reach movements. II. Planning in an external frame of reference. J Neurophysiol. 89:290-303. [abstract]

Pigeon P, Bortolami SB, DiZio P, Lackner JR. [2003] Coordinated turn-and-reach movements. I. Anticipatory compensation for self-generated coriolis and interaction torques. J Neurophysiol. 89:276-89. [abstract]

Soeda K, DiZio P, Lackner JR. [2003] Balance in a rotating artificial gravity environment. Exp Brain Res. 148:266-71. [abstract]

Lackner JR, DiZio P. [2003] Cyber Adaptation Syndrome. In: Encyclopedia of Neuroscience, 3rd edition, CD-ROM version, G. Adelman, B. Smith (eds). Amsterdam: Elsevier Science.

Lackner JR, DiZio P. [2004] Adaptation to rotating artificial gravity environments. J Vest. Res., 13 (4/6): 321-330.

Lackner JR, DiZio P. [2004] Multisensory influences on orientation and movement control. In: The Handbook of Multisensory Processes, G Calvert, C Spence, B Stein (eds), MIT Press, pp. 409-423.

Kurtzer I, DiZio PA, Lackner JR. [2005] Adaptation to a novel multi-force environment. Exp Brain Res. 2005 Jul;164:120-32. Epub 2005 Apr 16.

Hudson TE, Lackner JR, DiZio P. [2005] Rapid adaptation of torso pointing movements to perturbations of the base of support. Exp Brain Res. 2005 Sep;165:283-93. Epub 2005 Jun 8.

Lackner JR, DiZio P. [2005] Motor control and learning in altered dynamic environments. Curr Opin Neurobiol. 2005 Dec;15:653-9. Epub 2005 Nov 3.

Wright WG, DiZio P, Lackner JR. [2005] Vertical linear self-motion perception during visual and inertial motion: more than weighted summation of sensory inputs. J Vestib Res. 2005;15:185-95.

Rabin E, Dizio P, Lackner JR. [2006] Time course of haptic stabilization of posture. Exp Brain Res. 2006 Mar;170:122-6. Epub 2006 Feb 25.

Bortolami SB, Rocca S, Daros S, Dizio P, Lackner JR. [2006] Mechanisms of human static spatial orientation. Exp Brain Res. 2006 Aug;173:374-88. Epub 2006 Apr 21.

Bortolami SB, Pierobon A, Dizio P, Lackner JR. [2006] Localization of the subjective vertical during roll, pitch, and recumbent yaw body tilt. Exp Brain Res. 2006 Aug;173:364-73. Epub 2006 Apr 21.

Wright WG, Dizio P, Lackner JR. [2006] Perceived self-motion in two visual contexts: Dissociable mechanisms underlie perception. J Vestib Res. 2006;16:23-8.

Lackner JR, Dizio P. (2006) Space motion sickness. Exp Brain Res. 2006 Nov; 175:377-99. Epub 2006 Oct 5. [abstract]

Bryan AS, Bortolami SB, Ventura J, DiZio P, Lackner JR. Influence of gravitoinertial force level on the subjective vertical during recumbent yaw axis body tilt. Exp Brain Res. 2007 Nov;183:389-97.

Rabin E, DiZio P, Ventura J, Lackner JR. Influences of arm proprioception and degrees of freedom on postural control with light touch feedback. J Neurophysiol. 2008 Feb;99:595-604.

Bortolami SB, Pigeon P, Dizio P, Lackner JR. Dynamics model for analyzing reaching movements during active and passive torso rotation. Exp Brain Res. 2008 Jun;187(4):525-34.

Bortolami SB, Pigeon P, Dizio P, Lackner JR. Kinetic analysis of arm reaching movements during voluntary and passive rotation of the torso. Exp Brain Res. 2008 Jun;187(4):509-23.

 

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Last review: August 18, 2008