Abstract

Due to its relative simplicity, the electrosensory system is ideally suited for the integration of behavioral and cellular approaches and, therefore, has led to most detailed explanations of stimulus perception and motor performance at the single-cell level. The electric sense shares basic principles in the coding of sensory information with more advanced sensory modalities, such as vision and audition in birds and mammals, and thus provides a convenient model system for studying neuronal mechanisms of information processing in general. Most significantly, some behavioral responses of electric fish are so robust that they remain intact in physiological preparations, thus allowing simultaneous studies at the behavioral and cellular level. The current project will continue to explore the structural and functional organization of the torus semicircularis, a laminated midbrain structure homologous to the inferior colliculus of mammals, which processes temporal and spatial aspects of electrosensory information. By using quartz glass pipettes (prepared by the new 'laser puller' of the Sutter Company), even very small cells, with soma diameters in the range of 5 micra, can now be penetrated and labelled intracellularly. This offers the opportunity of labelling and recording from neurons that could barely be explored in the past. One of these small-neuron types resides in lamina 6 of the torus and computes temporal disparities in the arrival of two inputs, comparable to the processing of interaural time differences in auditory systems. The temporal resolution of these neurons appears to be in the microsecond range. In addition to studies in largely intact fish, we intend to explore functional and structural properties of the torus in slice preparations. Due to the anatomical organization of projections to the torus, one could stimulate lamina 6 of the torus in a near natural manner and explore the physiological properties of small cells under the enhanced mechanical stability of a slice preparation.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS022244-08A1
Application #
3404429
Study Section
Hearing Research Study Section (HAR)
Project Start
1985-12-01
Project End
1997-06-30
Budget Start
1993-07-01
Budget End
1994-06-30
Support Year
8
Fiscal Year
1993
Total Cost
Indirect Cost

  Institution

Name
University of California San Diego
Department
Type
Schools of Earth Sciences/Natur
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093

  Publications

Wong, C J (2000) Electrical stimulation of the preoptic area in Eigenmannia: evoked interruptions in the electric organ discharge. J Comp Physiol A 186:81-93
Wong, C J (1997) Connections of the basal forebrain of the weakly electric fish, Eigenmannia virescens. J Comp Neurol 389:49-64
Wong, C J (1997) Afferent and efferent connections of the diencephalic prepacemaker nucleus in the weakly electric fish, Eigenmannia virescens: interactions between the electromotor system and the neuroendocrine axis. J Comp Neurol 383:18-41
Zupanc, G K; Horschke, I (1996) Salvage pathway of pyrimidine synthesis: divergence of substrate specificity in two related species of teleostean fish. Comp Biochem Physiol B Biochem Mol Biol 114:269-74
Heiligenberg, W; Metzner, W; Wong, C J et al. (1996) Motor control of the jamming avoidance response of Apteronotus leptorhynchus: evolutionary changes of a behavior and its neuronal substrates. J Comp Physiol A 179:653-74
Wessel, R (1995) In vitro study of phase resetting and phase locking in a time-comparison circuit in the electric fish, Eigenmannia. Biophys J 69:1880-90
Kennedy, G; Heiligenberg, W (1994) Ultrastructural evidence of GABA-ergic inhibition and glutamatergic excitation in the pacemaker nucleus of the gymnotiform electric fish, Hypopomus. J Comp Physiol A 174:267-80
Metzner, W (1993) The jamming avoidance response in Eigenmannia is controlled by two separate motor pathways. J Neurosci 13:1862-78
Heiligenberg, W; Kawasaki, M (1992) An internal current source yields immunity of electrosensory information processing to unusually strong jamming in electric fish. J Comp Physiol A 171:309-16
Zupanc, G K; Airey, J A; Maler, L et al. (1992) Immunohistochemical localization of ryanodine binding proteins in the central nervous system of gymnotiform fish. J Comp Neurol 325:135-51

Showing the most recent 10 out of 30 publications