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
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
Lackner JR, Rabin E, DiZio P.  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.  Gravitoinertial force magnitude and direction
influence head-centric auditory localization. J. Neurophysiol., 85: 2455-2460. [abstract]
DiZio, Paul and James R. Lackner.  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.  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.  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.  Analysis
of human postural responses to recoverable falls. Exp
Brain Res.151(3):387-404. [abstract]
Pigeon P, Bortolami SB, DiZio P, Lackner JR.  Coordinated
turn-and-reach movements. II. Planning in an external frame
of reference. J Neurophysiol. 89:290-303.
Pigeon P, Bortolami SB, DiZio P, Lackner JR.  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.  Balance in a rotating
artificial gravity environment. Exp Brain Res. 148:266-71.
Lackner JR, DiZio P.  Cyber Adaptation Syndrome.
In: Encyclopedia of Neuroscience, 3rd edition, CD-ROM
version, G. Adelman, B. Smith (eds). Amsterdam: Elsevier
Lackner JR, DiZio P.  Adaptation to rotating artificial
gravity environments. J Vest. Res., 13 (4/6):
Lackner JR, DiZio P.  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.  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.  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.  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.  Vertical linear
self-motion perception during visual and inertial motion:
more than weighted summation of sensory inputs. J Vestib
Rabin E, Dizio P, Lackner JR.  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. 
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. 
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.  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
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.
Last review: August 18, 2008