The grouped retina of Gnathonemus petersii [Elektronische Ressource] : a behavioural and electrophysiological study / vorgelegt von Dorothee Haverkate

Doro

Sujets

• Biologie

Informations

• Publié par: friedrich-alexander-universitat_erlangen-nurnberg
• Publié le: 01 janvier 2009
• Nombre de lectures: 40
• Langue: Deutsch
• Poids de l'ouvrage: 3 Mo

Extrait

The grouped retina of Gnathonemus petersii – a behavioural and
electrophysiological study





Der Naturwissenschaftlichen Fakultät
der Friedrich-Alexander-Universität Erlangen-Nürnberg
zur
Erlangung des Doktorgrades






vorgelegt von
Dorothee Haverkate
aus Köln

Als Dissertation genehmigt von der Naturwissenschaftlichen Fakultät der
Universität Erlangen-Nürnberg














Tag der mündlichen Prüfung: 06.08.2009

Vorsitzender der Promotionskommission: Prof. Dr. Eberhard Bänsch
Erstberichterstatter: PD Dr. Stefan Schuster
Zweitberichterstatter: Prof. Dr. J. Helmut BrandstätterTable of contents
TABLE OF CONTENTS
TABLES………………………………………………………………………………………V
TABLE OF FIGURES............................................................................................................ V
SUMMARY………………………………………………………………………………..VIII
ZUSAMMENFASSUNG ........................................................................................................ X
PART I: GENERAL INTRODUCTION ....................................................................... 1
1. The grouped retina of Gnathonemus petersii .......................................................................... 2
2. The experimental animal Gnathonemus petersii..................................................................... 5
3. Aims of the study....................................................................................................................... 7
PART II: ERG-RECORDINGS IN GNATHONEMUS PETERSII .............................. 8
1. Introduction............................................................................................................................... 8
2. Methods ..................................................................................................................................... 9
2.1 Experimental animals.................................................................................................................. 9
2.1.1 Gnathonemus petersii ................................................................................................................. 9
2.1.2 Carassius auratus ....................................................................................................................... 9
2.2 Experimental procedures and setup ............................................................................................ 9
2.2.1 Anaesthesia of the test animals .................................................................................................10
2.2.2 Initial anaesthesia at the beginning of the experiment .............................................................. 10
2.2.3 Immobilization of the animals .................................................................................................. 10
2.2.4 Breathing water and artificial ventilation.................................................................................. 10
2.2.5 Experimental setup.................................................................................................................... 11
2.2.5.1 Setup 1..................................................................................................................................... 11
2.2.5.2 Setup 2...................................................................................................................................... 12
2.2.6 Characterisation of ERG-curves ............................................................................................... 13
3. Modification of the experimental setup and basic characterisation of the ERG-waveform
in Gnathonemus petersii.......................................................................................................... 14
3.1 Establishing the experimental setup for ERG-recordings in Gnathonemus petersii ................. 14
3.2 ERG-recordings from the vitreous body and description of the ERG-waveform of
Gnathonemus petersii ............................................................................................................... 16
3.3 Responses of light adapted fish to ON-and OFF-pulses ........................................................... 17
3.3.1 Response to ON-pulses... 17
3.3.2 to OFF- ........................................................................................................... 20
3.4 Presentation of different ramp-shaped stimuli .......................................................................... 23
3.4.1 Responses of dark-adapted fish................................................................................................. 24
3.4.2 of light-adah ................................................................................................ 25
4. Intensity-response-functions in the dark- and light-adapted state ..................................... 26
5. Critical flicker-fusion-frequency of Gnathonemus petersii.................................................. 29
5.1 The ERG follows modulations up to 50 Hz.............................................................................. 29
6. Spectral sensitivity .................................................................................................................. 32
7. Discussion ................................................................................................................................ 34
i Table of contents
7.1 General properties of the ERG-waveform ................................................................................ 34
7.2 Discussion of the intensity-response-curves and comparison to that of dark-adapted
goldfish ..................................................................................................................................... 35
7.3 Flicker-fusion-frequency (CFF)................................................................................................ 37
7.3.1 The higher the temporal frequency of the stimulus, the less ERG-components
can be identified ....................................................................................................................... 37
7.3.2 Rapidly moving diurnal animals have higher CFFs than slowly moving nocturnal ones......... 37
7.3.3 The present findings showed quite the opposite ....................................................................... 38
7.3.4 Ecological aspects of temporal resolution................................................................................. 38
7.4 Interpretation of spectral sensitivity curves, gained using ERG-recordings ............................. 39
7.4.1 Is Gnathonemus able to detect infrared?................................................................................... 42
7.4.2 Is Gnathonemus UV-sensitive?................................................................................................. 43
7.4.3 Comparison of the ERG-results with earlier behavioural work ................................................ 43
7.4.4 Comparison of the spectral sensitivity in Gnathonemus and goldfish ...................................... 45
PART III: INTRODUCTION OF BEHAVIOURAL METHODS USED TO EXA-
MINE THE VISUAL SYSTEM OF GNATHONEMUS PETERSII: THE
OPTOMOTOR RESPONSE (OMR), THE STARTLE BEHAVIOUR
AND ORIENTATION IN REFERENCE TO THE E-VECTOR .............. 47
1. The optomotor response (OMR)............................................................................................ 48
1.1 Experimental setup.................................................................................................................... 48
1.1.1 Presenting dynamic visual stimuli 49
1.1.2 Video-editing ............................................................................................................................ 52
1.1.3 Video-evaluation....................................................................................................................... 52
1.1.4 Determining the optomotor gain using Fourier-Analysis.......................................................... 53
1.2 Pre-testing the optomotor response........................................................................................... 55
1.2.1 Gnathonemus petersii responded best to low temporal frequencies ......................................... 55
1.2.1.1 The OMR was easily evoked in Gnathonemus petersii at low temporal frequencies............... 55
1.2.1.2 Fish motion had a component that was independent from the pattern frequency presented..... 56
1.2.1.3 In goldfish, comparable OMR required three-fold temporal frequency.................................... 56
1.2.2 The OMR of Gnathonemus was relatively independent from stripe widths ............................. 57
1.2.3 Gnathonemus was not affected by low light conditions...................................... 57
1.3. Faster screening method for OMR-analyses ............................................................................. 59
1.3.1 Comparison of FFT and faster screening method reveals the reliability of both methods........ 59
1.3.2 The OMR does not adapt during a 3.6 min presentation time .................................................. 60
1.3.3 Conditions for examining the OMR in goldfish............................