Behavioral, physiological and anatomical studies will be carried out on Pteronotus p. parnellii. These bats lend themselves well to the study of mechanisms controlling auditory input and they provide a model system for studies on acoustic-laryngeal interactions and morphological specializations of the cochlea for sharp tuning. Behavioral and physiological experiments will utilize simulated (pendulum) flight with animals actively involved in the echolocation of fixed, moving or fluttering targets. The responses of the cochlea, VIIIth nerve and CNS auditory centers to emitted pulses and echoes, and to CF and FM tone bursts will be monitored continuously during flight and a video system will record the animal's attentiveness to specific targets. Single unit studies will focus on the properties of auditory nerve fibers and on factors which affect sharp tuning. Special attention will be given to the labeling of cell populations with known frequency responses and the subsequent establishment of more precise cochlear frequency maps. Frequency maps will be superimposed on three-dimensional, computer reconstructions of the cochlea, VIIIth nerve and specific parts of the organ of Corti. The density, arrangement and physiological influence of a newly discovered layer of cells containing contractile proteins will be studied by immunocytochemical and electronmicroscopic techniques. The hypothesis that these cells contact and apply radial tension to the basilar membrane-spiral ligament complex and affect the mechanical properties of the cochlea will be tested. The physiological effects of the uptake and transport of latex microspheres by the VIIIth nerve will be analyzed and selective photothermolytic destruction of spiral ganglion cells and efferent cell bodies will be attempted. These studies have wide applications in the study of basic auditory mechanisms, in the development of more sophisticated active sonar systems for the blind, and in the potential application of photothermolytic techniques to the treatment of tinnitus or any disorder where selected groups of neurons might be advantageously destroyed.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS012445-12
Application #
3394871
Study Section
Hearing Research Study Section (HAR)
Project Start
1978-07-01
Project End
1989-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
12
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Henson Jr, O W; Xie, D H; Keating, A W et al. (1995) The effect of contralateral stimulation on cochlear resonance and damping in the mustached bat: the role of the medial efferent system. Hear Res 86:111-24
Henson, O W; Koplas, P A; Keating, A W et al. (1990) Cochlear resonance in the mustached bat: behavioral adaptations. Hear Res 50:259-73
Henson Jr, O W; Keating, A W; Henson, M M (1989) Evoked potential correlates of echolocation in the mustached bat, Pteronotus p. parnellii. Hear Res 38:213-9
Henson, M M; Henson Jr, O W (1988) Tension fibroblasts and the connective tissue matrix of the spiral ligament. Hear Res 35:237-58
Campbell, J P; Henson, M M (1988) Olivocochlear neurons in the brainstem of the mouse. Hear Res 35:271-4
Bishop, A L; Henson Jr, O W (1987) The efferent cochlear projections of the superior olivary complex in the mustached bat. Hear Res 31:175-82
Henson, M M; Burridge, K; Fitzpatrick, D et al. (1985) Immunocytochemical localization of contractile and contraction associated proteins in the spiral ligament of the cochlea. Hear Res 20:207-14
Henson Jr, O W; Schuller, G; Vater, M (1985) A comparative study of the physiological properties of the inner ear in Doppler shift compensating bats (Rhinolophus rouxi and Pteronotus parnellii). J Comp Physiol A 157:587-97
Kobler, J B; Wilson, B S; Henson Jr, O W et al. (1985) Echo intensity compensation by echolocating bats. Hear Res 20:99-108