| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
The Journal of Neurophysiology Vol. 83 No. 3 March 2000, pp. 1224-1242
Copyright ©2000 by the American Physiological Society
Departments of 1Surgery (Otolaryngology-Head and Neck Surgery) and 2Neurobiology, Pharmacology and Physiology, University of Chicago, Chicago, Illinois 60637
Brichta, Alan M. and
Jay M. Goldberg.
Responses to Efferent Activation and Excitatory
Response-Intensity Relations of Turtle Posterior-Crista
Afferents. J. Neurophysiol. 83: 1224-1242, 2000. Multivariate
statistical formulas were used to infer the morphological type and
longitudinal position of extracellularly recorded afferents. Efferent
fibers were stimulated electrically in the nerve branch interconnecting
the anterior and posterior VIIIth nerves. Responses of bouton (B) units
depended on their inferred position: BP units (near the planum
semilunatum) showed small excitatory responses; BT units (near the
torus) were inhibited; BM units (in an intermediate position) had a
mixed response, including an initial inhibition and a delayed
excitation. Calyx-bearing (CD-high) units with an appreciable
background discharge showed large per-train excitatory responses
followed by smaller post-train responses that could outlast the shock
train by 100 s. Excitatory responses were smaller in calyx-bearing
(CD-low) units having little or no background activity than in CD-high
units. Excitatory response-intensity functions, derived from the
discharge during 2-s angular-velocity ramps varying in intensity, were
fit by empirical functions that gave estimates of the maximal response
(rMAX), a threshold velocity
(vT), and the velocity producing a
half-maximal response (v1/2). Linear gain is
equal to rMAX/vS,
vS = v1/2 
vT.
vS provides a measure of the velocity range
over which the response is nearly linear. For B units,
rMAX declines by as much as twofold over the
2-s ramp, whereas for CD units, rMAX
increases by 15% during the same time period. At the end of the ramp,
rMAX is on average twice as high in CD as in
B units. Thresholds are negligible in most spontaneously active units,
including almost all B and CD-high units. Silent CD-low units typically
have thresholds of 10-100 deg/s. BT units have very high linear gains
and vS < 10 deg/s. Linear gains are
considerably lower in BP units and vS > 150 deg/s. CD-high units have intermediate gains and near 100 deg/s
vS values. CD-low units have low gains and
vS values ranging from 150 to more than 300 deg/s. The results suggest that BT units are designed to measure the
small head movements involved in postural control, whereas BP and CD
units are more appropriate for monitoring large volitional head
movements. The former units are silenced by efferent activation,
whereas the latter units are excited. This suggests that the efferent
system switches the turtle posterior crista from a "postural" to a
"volitional" mode.
This article has been cited by other articles:
|
|
 |
|
  J. C. Holt, S. Chatlani, A. Lysakowski, and J. M. Goldberg Quantal and Nonquantal Transmission in Calyx-Bearing Fibers of the Turtle Posterior Crista J Neurophysiol, September 1, 2007; 98(3): 1083 - 1101. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. Holt, A. Lysakowski, and J. M. Goldberg Mechanisms of Efferent-Mediated Responses in the Turtle Posterior Crista J. Neurosci., December 20, 2006; 26(51): 13180 - 13193. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Haque, D. Huss, and J. D. Dickman Afferent Innervation Patterns of the Pigeon Horizontal Crista Ampullaris J Neurophysiol, December 1, 2006; 96(6): 3293 - 3304. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Bonsacquet, A. Brugeaud, V. Compan, G. Desmadryl, and C. Chabbert AMPA type glutamate receptor mediates neurotransmission at turtle vestibular calyx synapse J. Physiol., October 1, 2006; 576(1): 63 - 71. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Holt, J.-T. Xue, A. M. Brichta, and J. M. Goldberg Transmission Between Type II Hair Cells and Bouton Afferents in the Turtle Posterior Crista J Neurophysiol, January 1, 2006; 95(1): 428 - 452. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Xue and E. H. Peterson Hair Bundle Heights in the Utricle: Differences Between Macular Locations and Hair Cell Types J Neurophysiol, January 1, 2006; 95(1): 171 - 186. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. V. Derbenev, C. L. Linn, and P. S. Guth Muscarinic ACh Receptor Activation Causes Transmitter Release From Isolated Frog Vestibular Hair Cells J Neurophysiol, November 1, 2005; 94(5): 3134 - 3142. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Holt, M. Lioudyno, and P. S. Guth A Pharmacologically Distinct Nicotinic ACh Receptor Is Found in a Subset of Frog Semicircular Canal Hair Cells J Neurophysiol, September 1, 2003; 90(3): 1526 - 1536. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Brichta, A. Aubert, R. A. Eatock, and J. M. Goldberg Regional Analysis of Whole Cell Currents From Hair Cells of the Turtle Posterior Crista J Neurophysiol, December 1, 2002; 88(6): 3259 - 3278. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Plotnik, V. Marlinski, and J. M. Goldberg Reflections of Efferent Activity in Rotational Responses of Chinchilla Vestibular Afferents J Neurophysiol, September 1, 2002; 88(3): 1234 - 1244. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. E. Cullen and L. B. Minor Semicircular Canal Afferents Similarly Encode Active and Passive Head-On-Body Rotations: Implications for the Role of Vestibular Efference J. Neurosci., May 30, 2002; (2002) 20026418. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Brichta and J. M. Goldberg Morphological Identification of Physiologically Characterized Afferents Innervating the Turtle Posterior Crista J Neurophysiol, March 1, 2000; 83(3): 1202 - 1223. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
