The segregation of concurrent vocal signals is an auditory processing task faced by all vocal species. To segregate concurrent signals, the auditory system must encode the spectral and temporal features of the fused waveforms such that at least one signal can be individually detected. In the plainfin midshipman fish (Porichthys notatus), the overlapping mate calls of neighboring males produce acoustic beats with amplitude and phase modulations at the difference frequencies (dF) between spectral components. Prior studies in midshipman have shown that midbrain neurons provide a combinatorial code of the temporal and spectral characteristics of beats via synchronization of spike bursts to dF and changes in spike rate and interspike intervals with changes in spectral composition. In the present study we examine the effects of changes in signal parameters of beats (overall intensity level and depth of modulation) on the spike train outputs of midbrain neurons. The observed changes in spike train parameters further support the hypothesis that midbrain neurons provide a combinatorial code of the spectral and temporal features of concurrent vocal signals.
REFERENCES
1.
Assman
, P. F.
, and Summerfield
, Q.
(1990
). “Modeling the perception of concurrent vowels with different fundamental frequencies
,” J. Acoust. Soc. Am.
88
, 680
–697
.2.
3.
Bass, A. H., and Clark, C. (in press). “The physical acoustics of underwater sound communication,” in The Springer Handbook of Auditory Research, edited by A. M. Simmons, A. Popper, and R. Fay (Springer-Verlag, New York).
4.
Bass, A. H., Bodnar, D. A., and Marchaterre, M. A. (1999). “Complementary explanations for existing phenotypes in an acoustic communication system,” in The Design of Animal Communication, edited by M. Hauser and M. Konishi (MIT Press, Cambridge, MA), pp. 493–514.
5.
Bass
, A. H.
, Bodnar
, D. A.
, and Marchaterre
, M. A.
(2000
). “Midbrain acoustic circuitry in a vocalizing fish
,” J. Comp. Neurol.
419
, 505
–531
.6.
Batschelet, E. (1981). Circular Statstics in Biology (Academic, New York).
7.
Bibikov
, N. G.
, and Nizamov
, S. V.
(1996
). “Temporal coding of low frequency amplitude modulation in the torus semicircularis of the grass frog
,” Hear. Res.
101
, 23
–44
.8.
Bodnar
, D. A.
, and Bass
, A. H.
(1997
). “Temporal coding of concurrent acoustic signals in the auditory midbrain
,” J. Neurosci.
17
, 7553
–7564
.9.
Bodnar
, D. A.
, and Bass
, A. H.
(1999
). “A midbrain combinatorial code for temporal and spectral information in concurrent vocal signals
,” J. Neurophysiol.
81
, 552
–563
.10.
Bodnar, D. A., and Bass, A. H. (2000). Unpublished data.
11.
Brantley
, R. K.
, and Bass
, A. H.
(1994
). “Alternative male spawning tactics and acoustic signals in the plainfin midshipman fish, Porichthys notatus (Teleostei, Batrachoididae)
,” Ethology
96
, 213
–232
.12.
Brokx
, J. P. L.
, and Nooteboom
, S. G.
(1982
). “Intonation and the perception of simultaneous voices
,” J. Phonetics
10
, 23
–26
.13.
Cariani
, P.
, and Delgutte
, B.
(1996a
). “Neural correlates of the pitch of complex tones. I. Pitch and pitch salience
,” J. Neurophysiol.
76
, 1698
–1716
.14.
Cariani
, P.
, and Delgutte
, B.
(1996b
). “Neural correlates of the pitch of complex tones. II. Pitch shift, pitch ambiguity, phase invariance, pitch circularity, rate pitch, and the dominance region for pitch
,” J. Neurophysiol.
76
, 1716
–1734
.15.
Chalikia
, M.
, and Bregman
, A.
(1989
). “The perceptual segregation of simultaneous auditory signals: Pulse train segregation and vowel segregation
,” Percept. Psychophys.
46
, 487
–496
.16.
Culling
, J. F.
, and Darwin
, C. J.
(1994
). “Perceptual and computational separation of simultaneous vowels: Cues arising from low frequency beating
,” J. Acoust. Soc. Am.
95
, 1559
–1569
.17.
Crawford
, J. D.
(1993
). “Central auditory neurophysiology of a sound producing fish: The mesencephalon of Pollimyrus isidori (Mormyridae)
,” J. Comp. Physiol.
172
, 136
–152
.18.
Crawford
, J. D.
(1997
). “Feature-detecting neurons in the brain of a sound producing fish
,” J. Comp. Physiol.
180
, 439
–450
.19.
de Cheveigne
, A.
(1993
). “Separation of concurrent harmonic sounds: Fundamental frequency estimation and a time-domain cancellation model of auditory proecsssing
,” J. Acoust. Soc. Am.
93
, 3271
–3290
.20.
de Cheveigne
, A.
(1997
). “Concurrent vowel identification. III. A neural model of harmonic interference cancellation
,” J. Acoust. Soc. Am.
101
, 2857
–2865
.21.
Fay, R. R. (1993). “Structure and function in sound discrimination among vertebrates,” in The Evolutionary Biology of Hearing, edited by D. B. Webster, R. R. Fay, and A. Popper (Springer, New York), pp. 229–266.
22.
Gerhardt
, H. C.
(1981a
). “Mate call recognition in the green treefrog (Hyla cinerea): Importance of two frequency bands as a function of sound pressure level
,” J. Comp. Physiol.
144
, 9
–16
.23.
Gerhardt
, H. C.
(1981b
). “Mating call recognition in the barking treefrog (Hyla gratiosa): Responses to synthetic calls and comparisons with the green treefrog (Hyla cinerea)
,” J. Comp. Physiol.
144
, 17
–25
.24.
Gerhardt
, H. C.
(1987
). “Evolutionary and neurobiological implications of selective phontoaxis in the green treefrog, Hyla cinerea
,” Anim. Behav.
35
, 1479
–1489
.25.
Gooler
, D. M.
, and Feng
, A. S.
(1992
). “Temporal coding in the frog auditory midbrain: The influence of duration and rise time on the processing of complex amplitude-modulated stimuli
,” J. Neurophysiol.
67
, 1
–22
.26.
Keilson
, S. E.
, Richards
, V. M.
, Wyman
, B. T.
, and Young
, E. D.
(1997
). “The representation of concurrent vowels in the cat anesthetized ventral cochlear nucleus: Evidence for a periodicity-tagged spectral representation
,” J. Acoust. Soc. Am.
102
, 1056
–1071
.27.
Kozloski
, J.
, and Crawford
, J. D.
(2000
). “Transformations of an auditory temporal code in the medulla of a sound producing fish
,” J. Neurosci.
20
, 2400
–2408
.28.
Langner
, G.
(1983
). “Evidence for neuronal periodicity dertection in the auditory system of the guinea fowl—Implications for pitch analysis in the time domain
,” Exp. Brain Res.
52
, 333
–345
.29.
Langner
, G.
, and Schreiner
, C. E.
(1988
). “Periodicity coding in the inferior colliculus of the cat. I. Neuronal mechanisms
,” J. Neurophysiol.
60
, 1799
–1822
.30.
Lu
, Z.
, and Fay
, R. R.
(1993
). “Acoustic response properties of single units in the torus semicircularis of the goldfish, Carassius auratus
,” J. Comp. Physiol.
173
, 33
–48
.31.
McKibben, J. (1998). “A neuroethological analysis of acoustic communication in the plainfin midshipman fish, Porichthys notatus,” Ph.D. thesis, Cornell University.
32.
McKibben
, J. R.
, and Bass
, A. H.
(1998
). “Behavioral assessment of acoustic parameters relevant to signal recognition and preference in a vocal fish
,” J. Acoust. Soc. Am.
104
, 3520
–3535
33.
McKibben, J. R., and Bass, A. H. (2000). Unpublished results.
34.
Meddis
, R.
, and Hewitt
, M. J.
(1992
). “Modelling the identification of concurrent vowels with different fundamental frequencies
,” J. Acoust. Soc. Am.
91
, 233
–245
.35.
Merzenich
, M. M.
, and Reid
, M. D.
(1974
). “Representation of the cochlea within the inferior colliculus of the cat
,” Brain Res.
77
, 397
–415
.36.
Palmer
, A. R.
(1990
). “The representation of the spectra and fundamental frequency of steady-state single- and double-vowel sounds in the temporal discharge patterns of guinea pig cochlear nerve fibers
,” J. Acoust. Soc. Am.
88
, 1412
–1426
.37.
Rees
, A.
, and Palmer
, A. R.
(1989
). “Neuronal responses to amplitude-modulated and pure tone stimuli in the guinea pug inferior colliculus, and their modifcation by broadband noise
,” J. Acoust. Soc. Am.
85
, 1978
–1994
.38.
Rees
, A.
, Sarbaz
, A.
, Malmierca
, M. S.
, and Le Beau
, F. E. N.
(1997
). “Regularity of firing of neurons in the inferior colliculus
,” J. Neurophysiol.
77
, 2945
–2965
.39.
Rose
, G. J.
, and Capranica
, R. R.
(1985
). “Sensitivity to amplitude modulated sounds in an anuran auditory nervous system
,” J. Neurophysiol.
53
, 446
–465
.40.
Sarbaz, A., and Rees, A. (1996). “Amplitude modulation encoding and regularly firing neurons in the inferior colliculus,” Association for Research in Otolaryngology Midwinter Meeting 19, 155.
41.
Schreiner
, C. E.
, and Langner
, G.
(1988
). “Periodicity coding in the inferior colliculus of the cat. II. Topographical organization
,” J. Neurophysiol.
60
, 1823
–1840
.42.
Schreiner
, C. E.
, and Langner
, G.
(1994
). “Laminar fine structure of frequency organization in auditory midbrain
,” Nature (London)
388
, 383
–386
.43.
Semple
, M. N.
, and Aitkin
, L. M.
(1979
). “Representation of sound frequency and laterality by units in the central nucleus of cat inferior colliculus
,” J. Neurophysiol.
42
, 1626
–1639
.
This content is only available via PDF.
© 2001 Acoustical Society of America.
2001
Acoustical Society of America
You do not currently have access to this content.