Spatial Alignment of Rotational and Static Tilt Responses of Vestibulospinal Neurons in the Cat

• Published in: Journal of neurophysiology Vol. 82; no. 2; pp. 855 - 862
• Main Authors: Perlmutter, S. I, Iwamoto, Y, Baker, J. F, Peterson, B. W
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-08-1999
• Subjects: Afferent Pathways - physiology; Analysis of Variance; Animals; Cats; Decerebrate State; Head Movements - physiology; Neurons - physiology; Orientation - physiology; Rotation; Space life sciences; Spatial Behavior - physiology; Spinal Cord - cytology; Spinal Cord - physiology; Tilt-Table Test; Vestibule, Labyrinth - cytology; Vestibule, Labyrinth - physiology; vestibulospinal tract; Non-programmatic
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1999.82.2.855

Department of Physiology, Northwestern University School of
Medicine, Chicago, Illinois 60611
Perlmutter, S. I.,
Y. Iwamoto,
J. F. Baker, and
B. W. Peterson.
Spatial Alignment of Rotational and Static Tilt Responses of
Vestibulospinal Neurons in the Cat. J. Neurophysiol. 82: 855-862, 1999. The responses of
vestibulospinal neurons to 0.5-Hz, whole-body rotations in
three-dimensional space and static tilts of whole-body position were
studied in decerebrate and alert cats. The neurons' spatial properties
for earth-vertical rotations were characterized by maximum and minimum
sensitivity vectors ( R max and
R min ) in the cat's horizontal plane. The
orientation of a neuron's R max was not
consistently related to the orientation of its maximum sensitivity
vector for static tilts ( T max ). The angular
difference between R max and
T max was widely distributed between 0° and
150°, and R max and
T max were aligned (i.e., within 45° of
each other) for only 44% (14/32) of the neurons. The alignment of
R max and T max was
not correlated with the neuron's sensitivity to earth-horizontal rotations, or to the orientation of R max in
the horizontal plane. In addition, the extent to which a neuron
exhibited spatiotemporal convergent (STC) behavior in response to
vertical rotations was independent of the angular difference between
R max and T max .
This suggests that the high incidence of STC responses in our sample (56%) reflects not only canal-otolith convergence, but also the presence of static and dynamic otolith inputs with misaligned directionality. The responses of vestibulospinal neurons reflect a
complex combination of static and dynamic vestibular inputs that may be
required by postural reflexes that vary depending on head, trunk, and
limb orientation, or on the frequency of stimulation.