The organization of the oculomotor and electromotor systems was examined in the stargazer, a teleost. The electromotor system in these animals is a derivative of the oculomotor system. The extraocular motor nuclei and nerves consist of approximately equal numbers of motoneurons and axons (about 100 per muscle). In contrast, electromotor axons appear to branch several times within the intracranial portion of the IIIrd nerve. The topographical organization of the motoneurons was examined using retrograde transport of horseradish peroxidase injected into the electric organ or eye muscles. Electromotor and oculomotor neurons form distinct populations. Each electric organ receives a strong ipsilateral and a weak contralateral innervation. Individual eye muscles receive unilateral innervations with the expected laterality. Within the oculomotor nucleus there is some topographical separation of motoneurons innervating each muscle. Antidromic field potentials confirm the identity of the electromotor nucleus.
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http://dx.doi.org/10.1002/cne.901830211 | DOI Listing |
Curr Biol
August 2023
Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA. Electronic address:
Steroid hormones remodel neural networks to induce seasonal or developmental changes in behavior. Hormonal changes in behavior likely require coordinated changes in sensorimotor integration. Here, we investigate hormonal effects on a predictive motor signal, termed corollary discharge, that modulates sensory processing in weakly electric mormyrid fish.
View Article and Find Full Text PDFFront Neuroinform
June 2022
Grupo de Neurocomputación Biológica, Departamento de Ingeniería Informática, Escuela Politécnica Superior, Universidad Autónoma de Madrid, Madrid, Spain.
Mormyridae, a family of weakly electric fish, use electric pulses for communication and for extracting information from the environment (active electroreception). The electromotor system controls the timing of pulse generation. Ethological studies have described several sequences of pulse intervals (SPIs) related to distinct behaviors (e.
View Article and Find Full Text PDFCurr Biol
July 2021
Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA. Electronic address:
During interactive communication, animals occasionally cease producing communication signals. The behavioral significance of resumed communication signals following a cessation, or silent pause, has been described in human speech: word recognition by listeners is enhanced after silent pauses, and speakers tend to place such pauses prior to words that are contextually unpredictable and that therefore have high information content. How central nervous systems process signals following pauses differently from signals during continuous communication has not been studied at a cellular level.
View Article and Find Full Text PDFJ Neurophysiol
June 2021
Laboratorio de Neurofisiología Celular y Sináptica, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
The activity of central pattern-generating networks (CPGs) may change under the control exerted by various neurotransmitters and modulators to adapt its behavioral outputs to different environmental demands. Although the mechanisms underlying this control have been well established in invertebrates, most of their synaptic and cellular bases are not yet well understood in vertebrates. , a pulse-type gymnotiform electric fish, provides a well-suited vertebrate model to investigate these mechanisms.
View Article and Find Full Text PDFDev Neurobiol
January 2020
Unidad Bases Neurales de la Conducta, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
Like stomatogastric activity in crustaceans, vocalization in teleosts and frogs, and locomotion in mammals, the electric organ discharge (EOD) of weakly electric fish is a rhythmic and stereotyped electromotor pattern. The EOD, which functions in both perception and communication, is controlled by a two-layered central pattern generator (CPG), the electromotor CPG, which modifies its basal output in response to environmental and social challenges. Despite major anatomo-functional commonalities in the electromotor CPG across electric fish species, we show that Gymnotus omarorum and Brachyhypopomus gauderio have evolved divergent neural processes to transiently modify the CPG outputs through descending fast neurotransmitter inputs to generate communication signals.
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