ISSN:0006-8977    

DOI:10.1159/000113264

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

This paper is an overview of some of the major points to arise in the accompanying contributions of this special symposium issue. The symposium papers arose out of discussions among investigators interested in the inner ear and Mauthner cell, with the focus on hydrodynamic components that activate the Mauthner cell through the octavolateralis system. The intention of the symposium was to investigate the possibility of using our knowledge of the Mauthner system to help understand acoustic processing by the ear, and of using our knowledge of fish hearing to better understand Mauthner cell function. This is the first attempt to take a broad look at both systems to see how they might function together. As such, these proceedings can serve as a mini-tutorial for investigators interested in one system or the other. In this summary paper we also identify some of the major uncertainties in our understanding of the ear-Mauthner connection. These include questions about: (1) the identity of the acoustic stimuli that are neuroethologically relevant to the Mauthner system; (2) the relative importance of the various octavolateralis inputs (acoustic, vestibular, or lateral line); (3) the contribution of the different various acoustic endorgans to the Mauthner system; (4) whether the Mauthner system can distinguish sound source location, and (5) whether Mauthner neurobiology is compatible with the prevailing model (the phase model) for determining sound source location by fishes. We believe these issues provide potentially useful avenues of future investigation that should give important insights into both acoustic processing by fish and the function of the Mauthner system.

ISSN:0006-8977    

DOI:10.1159/000113265

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A body of literature suggests that the Mauthner cell startle response can be elicited by stimulation of the ear. While we know that there are projections to the M-cell from the ear, the specific endorgan(s) of the ear projecting to the M-cell are not known. Moreover, there are many reasons to question whether there is one pattern of inner ear to M-cell connection or whether the endorgan(s) projection to the M-cell varies in species that have different hearing capabilities of hearing structures. In this paper, we briefly review the structure of fish ears, with an emphasis on structural regionalization within the ear. We also review the central projections of the ear, along with a discussion of the limited data on projections to the M-cell.

ISSN:0006-8977    

DOI:10.1159/000113266

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Mauthner cells receive neurally coded information from the otolith organs in fishes, and it is most likely that initiation and directional characteristics of the C-start response depend on this input. In the goldfish, saccular afferents are sensitive to sound pressure (< –30 dB re: 1 dyne cm-2) in the most sensitive frequency range (200 to 800 Hz). This input arises from volume fluctuations of the swimbladder in response to the sound pressure waveform and is thus nondirectional. Primary afferents of the saccule, lagena, and utricle of the goldfish also respond with great sensitivity to acoustic particle motion (< 1 nanometer between 100 and 200 Hz). This input arises from the acceleration of the fish in a sound field and is inherently directional. Saccular afferents can be divided into two groups based on their tuning: one group is tuned at about 250 Hz, and the other tuned between 400 Hz and 1 kHz. All otolithic primary afferents phase-lock to sinusoids throughout the frequency range of hearing (up to about 2 kHz). Based on physiological and behavioral studies on Mauthner cells, it appears that highly correlated binaural input to the M-cell, from the sacculi responding to sound pressure, may be required for a decision to respond but that the direction of the response is extracted from small deviations from a perfect interaural correlation arising from the directional response of otolith organs to acoustic particle motio

ISSN:0006-8977    

DOI:10.1159/000113267

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Most physiological and behavioral studies of the Mauthner cells have used the goldfish and a few other fish from the superorder Ostariophysi, series Otophysi (=otophysans). We first provide some background and recent findings on the Mauthner cells of otophysan fish and then compare this information to that known about the Mauthner cells in certain non-otophysan fish. These comparisons are meant to provide the impetus for a comparative approach to understanding the role of the Mauthner cells in behavior.

ISSN:0006-8977    

DOI:10.1159/000113268

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

We present a neural model for how the Mauthner system could compute the direction of a transient sound stimulus originating on either the left or right side of a fish. This computation results in an initial orientation of an escape response away from the side of the stimulus. Our idea is based on the phase model of underwater sound localization by fishes. If the phase model is applicable to the Mauthner system, then the problem of sound localization can be reduced to a logical operator, the EXCLUSIVE-NOR (or XNOR). We show how this can be solved by the Mauthner system using afferents that convey separate inputs of sound pressure transduced by the swimbladder (rarefaction and compression) and particle displacement (left and right) from the inner ear. In our model, both pressure components are responsible for bringing the Mauthner cell to threshold. Mauthner firing is gated by the inhibitory PHP neurons receiving specific combinations of pressure and displacement that implement the XNOR logic. We refer to this as the XNOR model. This model is experimentally verifiable and makes specific predictions about the expected acoustic response characteristics of the Mauthner and PHP neurons. Our model places a component of PHP function into a new neuroethological context and may provide insights into the central neurophysiological mechanisms of directional hearing in fishes. In particular, we show how the XNOR model can be applied to predict the activity of diverse neural elements involved in acoustic localization by fishes.

ISSN:0006-8977    

DOI:10.1159/000113269

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000113270

出版商:S. Karger AG    

年代:1995

数据来源: Karger