|
|
||||||||
The Journal of Neurophysiology Vol. 82 No. 1 July 1999, pp. 164-175
Copyright ©1999 by the American Physiological Society
Departments of 1Biomedical Engineering and 2Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, Maryland 21205
Davis, Kevin A.,
Ramnarayan Ramachandran, and
Bradford J. May.
Single-Unit Responses in the Inferior Colliculus of Decerebrate
Cats II. Sensitivity to Interaural Level Differences. J. Neurophysiol. 82: 164-175, 1999.
Single units
in the central nucleus of the inferior colliculus (ICC) of
unanesthetized decerebrate cats can be grouped into three distinct
types (V, I, and O) according to the patterns of excitation and
inhibition revealed in contralateral frequency response maps. This
study extends the description of these response types by assessing
their ipsilateral and binaural response map properties. Here the nature
of ipsilateral inputs is evaluated directly using frequency response
maps and compared with results obtained from methods that rely on
sensitivity to interaural level differences (ILDs). In general, there
is a one-to-one correspondence between observed ipsilateral input
characteristics and those inferred from ILD manipulations. Type V units
receive ipsilateral excitation and show binaural facilitation
(EE properties); type I and type O units receive ipsilateral
inhibition and show binaural excitatory/inhibitory (EI) interactions.
Analyses of binaural frequency response maps show that these ILD
effects extend over the entire receptive field of ICC units. Thus the
range of frequencies that elicits excitation from type V units is
expanded with increasing levels of ipsilateral stimulation, whereas the
excitatory bandwidth of type I and O units decreases under the same
binaural conditions. For the majority of ICC units, application of
bicuculline, an antagonist for GABAA-mediated inhibition,
does not alter the basic effects of binaural stimulation; rather, it
primarily increases spontaneous and maximum discharge rates. These
results support our previous interpretations of the putative dominant
inputs to ICC response types and have important implications for
midbrain processing of competing free-field sounds that reach the
listener with different directional signatures.
This article has been cited by other articles:
![]() |
K. T. Nakamoto, S. J. Jones, and A. R. Palmer Descending Projections From Auditory Cortex Modulate Sensitivity in the Midbrain to Cues for Spatial Position J Neurophysiol, May 1, 2008; 99(5): 2347 - 2356. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Davis, O. Lomakin, and M. J. Pesavento Response Properties of Single Units in the Dorsal Nucleus of the Lateral Lemniscus of Decerebrate Cats J Neurophysiol, September 1, 2007; 98(3): 1475 - 1488. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Xie, J. Meitzen, and G. D. Pollak Differing Roles of Inhibition in Hierarchical Processing of Species-Specific Calls in Auditory Brainstem Nuclei J Neurophysiol, December 1, 2005; 94(6): 4019 - 4037. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. M. Chase and E. D. Young Limited Segregation of Different Types of Sound Localization Information among Classes of Units in the Inferior Colliculus J. Neurosci., August 17, 2005; 25(33): 7575 - 7585. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Suta, E. Kvasnak, J. Popelar, and J. Syka Representation of Species-Specific Vocalizations in the Inferior Colliculus of the Guinea Pig J Neurophysiol, December 1, 2003; 90(6): 3794 - 3808. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Ramachandran and B. J. May Functional Segregation of ITD Sensitivity in the Inferior Colliculus of Decerebrate Cats J Neurophysiol, November 1, 2002; 88(5): 2251 - 2261. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Davis Evidence of a Functionally Segregated Pathway From Dorsal Cochlear Nucleus to Inferior Colliculus J Neurophysiol, April 1, 2002; 87(4): 1824 - 1835. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. L. Snyder and D. G. Sinex Immediate Changes in Tuning of Inferior Colliculus Neurons Following Acute Lesions of Cat Spiral Ganglion J Neurophysiol, January 1, 2002; 87(1): 434 - 452. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Ramachandran, K. A. Davis, and B. J. May Single-Unit Responses in the Inferior Colliculus of Decerebrate Cats I. Classification Based on Frequency Response Maps J Neurophysiol, July 1, 1999; 82(1): 152 - 163. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |