Waveform generation in the weakly electric fish<i>Gymnotus coropinae</i>(Hoedeman): the electric organ and the electric organ discharge

Castelló, María E.; Rodríguez-Cattáneo, Alejo; Aguilera, Pedro A.; Iribarne, Leticia; Pereira, Ana Carolina; Caputi, Ángel A.

doi:10.1242/jeb.022566

Cited by 16 publications

(23 citation statements)

References 39 publications

(57 reference statements)

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“…(1) At the head and abdominal region of G. javari we found a complex EOD, suggesting the presence of an expansion of the EO behind the cleithrum-opercular aponeuroses, as previously described in G. coropinae (Castelló et al, 2009). (2) In G. obscurus, we noted what we will henceforth describe as a 'facultative monophasic EOD', with a dominant positive component followed by a much lower-amplitude negative component, the amplitude of which is strongly dependent on the external load (Bell et al, 1976;Caputi et al, 1998;Rodríguez-Cattáneo and Caputi, 2009).…”

Section: Additional Electrophysiological Techniquessupporting

confidence: 69%

“…The spatiotemporal pattern of EMF and the anatomy of G. javari are much closer to those documented in G. coropinae (Castelló et al, 2009;Rodríguez-Cattáneo et al, 2008) than to other species (Fig.4A).…”

Section: Gymnotus Javarisupporting

confidence: 64%

“…In the case of V 1 , we found two slow waves: one originated at the head (V 1r ) and another (positive) originated at the limit between the central and caudal region of the body. Finally, we found a particular V 3 associated with the presence of a rostral extension of the EO; this was studied in detail elsewhere and is referred to as V 3r (Castelló et al, 2009).…”

Section: Nomenclature Of Waveform Componentsmentioning

confidence: 64%

“…Together, these data suggest that the cephalic expansion of the EO in G. javari is functionally equivalent to the cephalic expansion of the EO in G. coropinae (Castelló et al, 2009). This expansion may generate a short-range field component, which is particularly strong around the head, where the electroreceptive fovea occurs (Castelló et al, 2000).…”

Section: Waveform Diversity Can Be Explained By a Combination Of Fivementioning

confidence: 70%

“…Comparative studies of other species have allowed us to describe an additional type of EO organization that influences the EOD field and its waveform. In Gymnotus coropinae (Rodríguez-Cattáneo et al, 2008;Castelló et al, 2009) we observed a unique pattern comprising a rostral extension of the hypaxial EO below the cleithrum aponeuroses. In this region of the EO, the electrocytes are large, few in number, and may be distinguished by their characteristic shape and innervation patterns (Castelló et al, 2009).…”

Section: Introductionmentioning

confidence: 76%

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Electric organ discharge diversity in the genusGymnotus: functional groups and electrogenic mechanisms

Rodríguez-Cattáneo

Aguilera

Cilleruelo

et al. 2012

Journal of Experimental Biology

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SUMMARYPrevious studies describe six factors accounting for interspecific diversity of electric organ discharge (EOD) waveforms in Gymnotus. At the cellular level, three factors determine the locally generated waveforms: (1) electrocyte geometry and channel repertoire; (2) the localization of synaptic contacts on electrocyte surfaces; and (3) electric activity of electromotor axons preceding the discharge of electrocytes. At the organismic level, three factors determine the integration of the EOD as a behavioral unit: (4) the distribution of different types of electrocytes and specialized passive tissue forming the electric organ (EO); (5) the neural mechanisms of electrocyte discharge coordination; and (6) post-effector mechanisms. Here, we reconfirm the importance of the first five of these factors based on comparative studies of a wider diversity of Gymnotus than previously investigated. Additionally, we report a hitherto unseen aspect of EOD diversity in Gymnotus. The central region of the EO (which has the largest weight on the conspecific-received field) usually exhibits a negative-positive-negative pattern where the delay between the early negative and positive peaks (determined by neural coordination mechanisms) matches the delay between the positive and late negative peaks (determined by electrocyte responsiveness). Because delays between peaks typically determine the peak power frequency, this matching implies a co-evolution of neural and myogenic coordination mechanisms in determining the spectral specificity of the intraspecific communication channel. Finally, we define four functional species groups based on EO/EOD structure. The first three exhibit a heterogeneous EO in which doubly innervated electrocytes are responsible for a main triphasic complex. Group I species exhibit a characteristic cephalic extension of the EO. Group II species exhibit an early positive component of putative neural origin, and strong EO auto-excitability. Group III species exhibit an early, slow, negative wave of abdominal origin, and variation in EO auto-excitability. Representatives of Group IV generate a unique waveform comprising a main positive peak followed by a small, load-dependent negative component.

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Section: Additional Electrophysiological Techniquessupporting

confidence: 69%

Section: Gymnotus Javarisupporting

confidence: 64%

Section: Nomenclature Of Waveform Componentsmentioning

confidence: 64%

Section: Waveform Diversity Can Be Explained By a Combination Of Fivementioning

confidence: 70%