Significant debate still exists about the biophysical mechanisms at work in otoacoustic emission (OAE) generation and how such may differ between mammals and non-mammals given gross morphological differences (e.g., existence of basilar membrane traveling waves, degree of tectorial membrane coupling). To further elucidate general principles at work, we examined the barn owl for interrelationships between spontaneous emissions (SOAEs) and those evoked using a single tone (SFOAEs). First, most ears exhibited SOAEs as a stable periodic ‘rippling’ whose peak-to-peak spacing was relatively constant (∼0.4 kHz). Some ears showed substantially larger narrowband peaks, although their statistical distributions were highly noisy. Second, significant interactions between a low-level tone and SOAE activity were observed via an interference pattern as the tone frequency was swept. Using a suppression paradigm to extract SFOAEs as the residual, the magnitude exhibited a stable pattern of peaks and valleys unique to each ear. Third, SFOAE phase exhibited significant accumulation as frequency was swept, with a phase-gradient delay of approximately 2 ms that was constant across frequency. The amount of SFOAE phase accumulation between adjacent SOAE peaks tended to cluster about an integral number of cycles, as previously observed for humans. Taken together, our data suggest that the principles underlying how active hair cells work together (e.g., entrainment, phase coherence) are shared between widely different inner ear morphologies, leading to the generation of OAEs with similar properties.

1.
Bergevin
C
,
Fulcher
A
,
Richmond
S
,
Velenovsky
D
,
Lee
J
(
2012
)
Interrelationships between spontaneous and low-level stimulus-frequency otoacoustic emissions in humans
.
Hear Res
285
:
20
28
2.
Bergevin
C
,
Shera
CA
(
2010
)
Coherent reflection without traveling waves: on the origin of long-latency otoacoustic emissions in lizards
.
J Acoust Soc Am
127
:
2398
2409
3.
Bergevin
C
,
Velenovsky
D
,
Bonine
K
(
2010
)
Tectorial membrane morphological variation: effects upon stimulus frequency otoacoustic emissions
.
Biophys J
99
:
1064
1072
4.
van Dijk
P
,
Manley
GA
,
Gallo
L
,
Pavusa
A
,
Taschenberger
G
(
1996
)
Statistical properties of spontaneous otoacoustic emissions in one bird and three lizard species
.
J Acoust Soc Am
100
:
2220
2227
5.
Dyson
ML
,
Klump
GM
,
Gauger
B
(
1998
)
Absolute hearing thresholds and critical masking ratios in the European barn owl: a comparison with other owls
.
J Comp Physiol A
182
:
695
702
6.
Fischer
FP
,
Koppl
C
,
Manley
GA
(
1988
)
The basilar papilla of the barn owl Tyto alba: a quantitative morphological SEM analysis
.
Hear Res
34
:
87
101
7.
Gummer
AW
,
Smolders
JW
,
Klinke
R
(
1987
)
Basilar membrane motion in the pigeon measured with the Mössbauer technique
.
Hear Res
29
:
63
92
8.
Hudspeth
AJ
(
2008
)
Making an effort to listen: mechanical amplification in the ear
.
Neuron
59
:
530
545
9.
Kalluri
R
,
Shera
CA
(
2013
)
Measuring stimulus-frequency otoacoustic emissions using swept tones
.
J Acoust Soc Am
134
:
356
368
10.
Köppl
C
(
1997
)
Frequency tuning and spontaneous activity in the auditory nerve and cochlear nucleus magnocellularis of the barn owl Tyto alba
.
J Neurophysiol
77
:
364
377
11.
Köppl
C
,
Gleich
O
,
Manley
GA
(
1993
)
An auditory fovea in the barn owl cochlea
.
J Comp Physiol A
171
:
695
704
12.
Manley
GA
(
2000
)
Cochlear mechanisms from a phylogenetic viewpoint
.
Proc Nat Acad Sci USA
97
:
11736
11743
13.
Manley
GA
,
Schulze
M
,
Oeckinghaus
H
(
1987
)
Otoacoustic emissions in a song bird
.
Hear Res
26
:
257
266
14.
Shera
CA
(
2003
)
Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves
.
J Acoust Soc Am
114
:
244
262
15.
Shera
CA
,
Guinan
JJ
(
1999
)
Evoked otoacoustic emissions arise by two fundamentally different mechanisms: a taxonomy for mammalian OAEs
.
J Acoust Soc Am
105
:
782
798
16.
Takasaka
T
,
Smith
CA
(
1971
)
The structure and innervation of the pigeon’s basilar papilla
.
J Ultrastruct Res
35
:
20
65
17.
Taschenberger
G
,
Manley
GA
(
1997
)
Spontaneous otoacoustic emissions in the barn owl
.
Hear Res
110
:
61
76
18.
Vilfan
A
,
Duke
T
(
2008
)
Frequency clustering in spontaneous otoacoustic emissions from a lizard’s ear
.
Biophys J
95
:
4622
4630
19.
Wit
HP
,
van Dijk
P
,
Manley
GA
(
2012
)
A model for the relation between stimulus frequency and spontaneous otoacoustic emissions in lizard papillae
.
J Acoust Soc Am
132
:
3273
3279
20.
Zweig
G
,
Shera
CA
(
1995
)
The origin of periodicity in the spectrum of evoked otoacoustic emissions
.
J Acoust Soc Am
98
:
2018
2047
This content is only available via PDF.