273
and Davisson 2011 ), but less amenable for actively swimming fi sh that can quickly
entangle themselves in the wire. The development of chronically implanted microwire electrodes and telemetry tag (Mensinger and Deffenbaugh 1998 , 2000 ) or tether
provided the ability for stable, long-term recording (up to a week) in freely moving
fi sh. This chapter summarizes the use of this system for exploring the sensory physiology of the inner ear and lateral line. The eventual goal is to determine the relative
contribution and the possible integration of each system during multimodal stimulation. For example, fi sh swimming will stimulate both otoliths and the lateral line,
and it is unclear how these organs will process auditory input during movement.
1.1 The Toadfi sh
Batrachoid fi sh ( Opsanus sp. and Porichthys sp.) have been developed into important biological models for investigating muscle physiology (Elemans et al. 2014 ;
Harwood et al. 2011 ), excretory function (Walsh et al. 2008 ), and vestibular physiology (Rabbitt et al. 1995 ). However, as sound generation and reception is an integral part of their natural history, they also have become subjects for neuroethology
and bioacoustic studies. The Fay laboratory has detailed the neuroanatomy and the
auditory physiology of the saccular endorgan of the toadfi sh, Opsanus tau (EddsWalton et al. 1999 , 2013 ; Edds-Walton and Fay 2003 , 2005a , b , 2008 , 2009 ) demonstrating its ability to encode pure tones in the range of fi sh vocalizations. Both
male and female fi sh produce broadband grunts by means of rapid contraction of
sonic muscles surrounding the swim bladder. However, only sexually mature male
toadfi sh produce a bimodal vocalization, termed a boatwhistle, which is used to
acoustically attract females to nesting sites (Fine et al. 1977 ; Gray and Winn 1961 ).
The boatwhistle consists of a brief, irregular initial grunt (broadband) followed by
an extended period of regular pulsing (fundamental frequency < 200 Hz) (EddsWalton et al. 2002 ). Although the production and reception of the sound has resulted
in many investigations on sonic muscle and auditory physiology (Harwood et al.
2011 ; Mensinger 2014 ; Walsh et al. 2008 ), the mechanism by which female fi sh
locate the males, and which characteristics (i.e., amplitude, frequency, duration) of
the call infl uence mate choice remain largely unknown.
2 Materials and Methods
2.1 Telemetry Tag
An inductive telemetry system was developed for recording neural activity from
free swimming fi sh. The system consisted of three channel microwire electrodes, a
cylindrical (38 × 15 mm dia) transmitting telemetry tag and receiver coils. The
Multimodal Sensory Input in the Utricle and Lateral Line of the Toadfi sh, Opsanus…
and Davisson 2011 ), but less amenable for actively swimming fi sh that can quickly
entangle themselves in the wire. The development of chronically implanted microwire electrodes and telemetry tag (Mensinger and Deffenbaugh 1998 , 2000 ) or tether
provided the ability for stable, long-term recording (up to a week) in freely moving
fi sh. This chapter summarizes the use of this system for exploring the sensory physiology of the inner ear and lateral line. The eventual goal is to determine the relative
contribution and the possible integration of each system during multimodal stimulation. For example, fi sh swimming will stimulate both otoliths and the lateral line,
and it is unclear how these organs will process auditory input during movement.
1.1 The Toadfi sh
Batrachoid fi sh ( Opsanus sp. and Porichthys sp.) have been developed into important biological models for investigating muscle physiology (Elemans et al. 2014 ;
Harwood et al. 2011 ), excretory function (Walsh et al. 2008 ), and vestibular physiology (Rabbitt et al. 1995 ). However, as sound generation and reception is an integral part of their natural history, they also have become subjects for neuroethology
and bioacoustic studies. The Fay laboratory has detailed the neuroanatomy and the
auditory physiology of the saccular endorgan of the toadfi sh, Opsanus tau (EddsWalton et al. 1999 , 2013 ; Edds-Walton and Fay 2003 , 2005a , b , 2008 , 2009 ) demonstrating its ability to encode pure tones in the range of fi sh vocalizations. Both
male and female fi sh produce broadband grunts by means of rapid contraction of
sonic muscles surrounding the swim bladder. However, only sexually mature male
toadfi sh produce a bimodal vocalization, termed a boatwhistle, which is used to
acoustically attract females to nesting sites (Fine et al. 1977 ; Gray and Winn 1961 ).
The boatwhistle consists of a brief, irregular initial grunt (broadband) followed by
an extended period of regular pulsing (fundamental frequency < 200 Hz) (EddsWalton et al. 2002 ). Although the production and reception of the sound has resulted
in many investigations on sonic muscle and auditory physiology (Harwood et al.
2011 ; Mensinger 2014 ; Walsh et al. 2008 ), the mechanism by which female fi sh
locate the males, and which characteristics (i.e., amplitude, frequency, duration) of
the call infl uence mate choice remain largely unknown.
2 Materials and Methods
2.1 Telemetry Tag
An inductive telemetry system was developed for recording neural activity from
free swimming fi sh. The system consisted of three channel microwire electrodes, a
cylindrical (38 × 15 mm dia) transmitting telemetry tag and receiver coils. The
Multimodal Sensory Input in the Utricle and Lateral Line of the Toadfi sh, Opsanus…