230
higher thresholds at low frequencies (<1000 Hz), but lower thresholds at high
frequencies (>1000 Hz) compared to behavioral thresholds. This suggests there
may be a frequency-dependent effect between different assessment methods.
There are even fewer examples in which different electrophysiological-based
recording methods have been determined in a single species. The goldfi sh ( C. auratus ),
and batrachoidid oyster toadfi sh ( O. tau ) and midshipman fi sh ( Porichthys notatus ),
are some of the most extensively studied species in terms of auditory capabilities.
In addition to several behaviorally generated audiograms (Popper 1971 ; Enger
1966 ; Jacobs and Tavolga 1968 ; Offutt 1968 ), the goldfi sh has been examined physiologically by AEP (Kenyon et al. 1998 ; Smith et al. 2006 ; Cordova and Braun
2007 ; Ladich and Wysocki 2009 ), saccular potentials (Fay 1974 ; Fay and Popper
1975 ), single neuron recordings from saccular and lagenar primary afferents (Fay
1978a , b ; Fay and Ream 1986 ) and recordings from various central auditory nuclei
(Lu and Fay 1993 , 1995 ; Kirsch et al. 2002 ; Ma and Fay 2002 ). The oyster toadfi sh
has an AEP-generated audiogram (Yan et al. 2000 ), single neuron recordings from
saccular primary afferents (Fine 1981 ; Edds-Walton and Fay 1995 ; Fay and EddsWalton 1997 ), and recordings from central auditory nuclei (Edds-Walton and Fay
1998 , 2003 , 2005 ; Fay and Edds-Walton 1999 ; Edds-Walton et al. 2013 ) using both
speaker and shaker table stimulus delivery methods. The Lusitanian toadfi sh
( Halobatrachus didactylus ) also has AEP (Vasconcelos et al. 2007 ; Vasconcelos
and Ladich 2008 ) and saccular potential recordings (Vasconcelos et al. 2011 ). In
addition to behavioral measures (Alderks and Sisneros 2013 ), the midshipman fi sh
has saccular potential recordings (Sisneros 2007 , 2009 ; Alderks and Sisneros 2011 )
single neuron recordings from saccular primary afferents (McKibben and Bass
1999 ; Sisneros and Bass 2003 , 2005 ; Sisneros et al. 2004 ), and central auditory
recordings (Bodnar and Bass 2001a ; Bodnar et al. 2001 ). Primary afferent and central auditory recordings have also been done in the sound-producing mormyrid fi sh
Pollimyrus adspersus (Crawford 1993 , 1997 ; Kozloski and Crawford 2000 ; Suzuki
et al. 2002 ). These limited examples become even further reduced for comparative
purposes, however, because (1) many of these studies were not focused on generating audiograms or determining thresholds, but rather, were testing for other specifi c
temporal or spectral processing mechanisms (i.e., used iso-intensity stimuli), and
(2) recording methods performed in different laboratories with different experimental setups, including stimulus delivery (e.g., underwater speaker vs. shaker table)
and experimental analyses with different threshold criteria, can be variable and
diffi cult to compare. Thus, our current understanding of the relative usefulness of
different electrophysiological-based techniques for determining spectral range and
auditory thresholds for a given species is still in its infancy. Further, the only species
examined thus far with multiple methods are those with either specialized accessory
hearing structures like the Weberian ossicles in goldfi sh, or those endowed with
sonic muscles on their swim bladder that use acoustic signaling as a primary mode
of communication like toadfi sh and midshipman. In contrast, nothing is known
about the majority of fi sh species that do not possess these hearing or sonic
adaptations. What is needed, therefore, is a comparison of different electrophysiological methods to generate audiograms under similar experimental conditions
K.P. Maruska and J.A. Sisneros
higher thresholds at low frequencies (<1000 Hz), but lower thresholds at high
frequencies (>1000 Hz) compared to behavioral thresholds. This suggests there
may be a frequency-dependent effect between different assessment methods.
There are even fewer examples in which different electrophysiological-based
recording methods have been determined in a single species. The goldfi sh ( C. auratus ),
and batrachoidid oyster toadfi sh ( O. tau ) and midshipman fi sh ( Porichthys notatus ),
are some of the most extensively studied species in terms of auditory capabilities.
In addition to several behaviorally generated audiograms (Popper 1971 ; Enger
1966 ; Jacobs and Tavolga 1968 ; Offutt 1968 ), the goldfi sh has been examined physiologically by AEP (Kenyon et al. 1998 ; Smith et al. 2006 ; Cordova and Braun
2007 ; Ladich and Wysocki 2009 ), saccular potentials (Fay 1974 ; Fay and Popper
1975 ), single neuron recordings from saccular and lagenar primary afferents (Fay
1978a , b ; Fay and Ream 1986 ) and recordings from various central auditory nuclei
(Lu and Fay 1993 , 1995 ; Kirsch et al. 2002 ; Ma and Fay 2002 ). The oyster toadfi sh
has an AEP-generated audiogram (Yan et al. 2000 ), single neuron recordings from
saccular primary afferents (Fine 1981 ; Edds-Walton and Fay 1995 ; Fay and EddsWalton 1997 ), and recordings from central auditory nuclei (Edds-Walton and Fay
1998 , 2003 , 2005 ; Fay and Edds-Walton 1999 ; Edds-Walton et al. 2013 ) using both
speaker and shaker table stimulus delivery methods. The Lusitanian toadfi sh
( Halobatrachus didactylus ) also has AEP (Vasconcelos et al. 2007 ; Vasconcelos
and Ladich 2008 ) and saccular potential recordings (Vasconcelos et al. 2011 ). In
addition to behavioral measures (Alderks and Sisneros 2013 ), the midshipman fi sh
has saccular potential recordings (Sisneros 2007 , 2009 ; Alderks and Sisneros 2011 )
single neuron recordings from saccular primary afferents (McKibben and Bass
1999 ; Sisneros and Bass 2003 , 2005 ; Sisneros et al. 2004 ), and central auditory
recordings (Bodnar and Bass 2001a ; Bodnar et al. 2001 ). Primary afferent and central auditory recordings have also been done in the sound-producing mormyrid fi sh
Pollimyrus adspersus (Crawford 1993 , 1997 ; Kozloski and Crawford 2000 ; Suzuki
et al. 2002 ). These limited examples become even further reduced for comparative
purposes, however, because (1) many of these studies were not focused on generating audiograms or determining thresholds, but rather, were testing for other specifi c
temporal or spectral processing mechanisms (i.e., used iso-intensity stimuli), and
(2) recording methods performed in different laboratories with different experimental setups, including stimulus delivery (e.g., underwater speaker vs. shaker table)
and experimental analyses with different threshold criteria, can be variable and
diffi cult to compare. Thus, our current understanding of the relative usefulness of
different electrophysiological-based techniques for determining spectral range and
auditory thresholds for a given species is still in its infancy. Further, the only species
examined thus far with multiple methods are those with either specialized accessory
hearing structures like the Weberian ossicles in goldfi sh, or those endowed with
sonic muscles on their swim bladder that use acoustic signaling as a primary mode
of communication like toadfi sh and midshipman. In contrast, nothing is known
about the majority of fi sh species that do not possess these hearing or sonic
adaptations. What is needed, therefore, is a comparison of different electrophysiological methods to generate audiograms under similar experimental conditions
K.P. Maruska and J.A. Sisneros