Alternative neural pathways initiate fast-start responses following lesions of the mauthner neuron in goldfish
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Previous studies in adult fish show a one-to-one, time-locked, correlation between the presence of an initial action potential in the Mauthner (M-) cell and the onset of C-type fast-start responses in which the initial turn is away from the side of the active M-cell. In the present study we ask whether the M-cell is necessary for such behavioral acts.
Single M-cells in goldfish were electrolytically lesioned by passing current (7.2 μA for 20 s) from a stainless steel microelectrode situated at the M-cell initial segment. Behavioral responses were elicited by dropping a ball into the aquarium holding the fish. The behavior was filmed at 500 frames/s and responses with an initial turn opposite the side of the lesioned cell (non-Mauthner responses) were compared with responses opposite the intact cell (M-initiated responses).
Control experiments on acute preparations showed that such lesions prevent the M-cell from participating in behavioral responses because orthodromic synaptic activation of the M-axon is blocked, even though after the lesion the axon maintained resting potential and could conduct impulses to antidromic stimulation (Fig. 1). Chronic recordings from lesioned fish showed that in no case was the damaged M-cell observed to fire during any behavioral trials.
The main finding was that non-Mauthner responses were no different in mechanical performance (angular velocity, displacement speed, etc.) or response probability than M-initiated responses (Figs. 4, 10, 11). The only difference was that the non-Mauthner responses were significantly longer in response latency than the M-initiated responses (Fig. 7). Such non-Mauthner responses have not yet been observed in intact goldfish.
It is concluded that firing of the M-cell is causally related to the onset of C-type fast-start responses. But, when the M-cell is inactivated, alternative neural pathways that coexist with the M-cell can initiate the C-type fast-start behavior pattern.
KeywordsBehavioral Response Initial Segment Synaptic Activation Response Probability Adult Fish
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- Davis WJ (1978) On the trail of the command neuron. Behav Brain Sci 1:17–19Google Scholar
- Diamond J (1971) The Mauthner cell. In: Hoar WS, Randall DJ (eds) Fish physiology, vol 5. Academic Press, New York, pp 265–346Google Scholar
- Eaton R, Farley RD (1975) Mauthner neuron field potential in newly hatched larvae of the zebra fish. J Neurophysiol 38:502–512Google Scholar
- Eaton RC, Bombardieri RA (1978) Behavioral functions of the Mauthner neuron. In: Faber DS, Korn H (eds) Neurobiology of the Mauthner cell. Raven Press, New York, pp 221–244Google Scholar
- Eaton RC, Bombardieri RA, Meyer DL (1977a) The Mauthner-initiated startle response in teleost fish. J Exp Biol 66:65–81Google Scholar
- Eaton RC, Farley RD, Kimmel CB, Schabtach E (1977b) Functional development in the Mauthner cell system of embryos and larvae of the zebra fish. J Neurobiol 8:151–172Google Scholar
- Eaton RC, Lavender WA, Wieland CM (1981a) Identification of Mauthner-initiated response patterns in goldfish: Evidence from simultaneous cinematography and electrophysiology. J Comp Physiol 144:521–531Google Scholar
- Eaton RC, Lavender WA, Wieland CM (1981b) The Mauthner cell is not the only neuron that can initiate C-type fast-starts in adult goldfish. Neurosci Abstr 7:843Google Scholar
- Faber DS, Funch PG (1980) Differential properties of orthodromic and antidromic impulse propagation across the Mauthner cell initial segment. Brain Res 190:255–260Google Scholar
- Faber DS, Korn H (1978) Electrophysiology of the Mauthner cell: Basic properties, synaptic mechanisms, and associated networks. In: Faber DS, Korn H (eds), Neurobiology of the Mauthner cell. Raven Press, New York, pp 47–131Google Scholar
- Furshpan E, Furukawa T (1962) Intracellular and extracellular responses of the several regions of the Mauthner cell of the goldfish. J Neurophysiol 25:732–771Google Scholar
- Hackett JT, Faber DS (1981) What is the role of the goldfish Mauthner cell impulse in the “tail flip” reflex? Neurosci Abstr 7:362Google Scholar
- Kalt MR, Tandler B (1971) A study of fixation of early amphibian embryos for electron microscopy. J Ultrastruct Res 36:633–645Google Scholar
- Kimmel CB (1982) Reticulospinal and vestibulospinal neurons in the young larva of a teleost fish,Brachydanio rerio. Prog Brain Res (in press)Google Scholar
- Kimmel CB, Eaton RC, Powell SL (1980) Decreased fast-start performance of zebrafish larvae lacking Mauthner neurons. J Comp Physiol 140:343–350Google Scholar
- Kimmel CB, Powell SL, Metcalfe WK (1982) Brain neurons which project to the spinal cord in young larvae of the zebrafish. J Comp Neurol (in press)Google Scholar
- Lashley K (1950) In search of the engram. Symp Soc Exp Biol 4:454–482Google Scholar
- Rock MK (1980) Functional properties of the Mauthner cell in the tadpoleRana catesbeiana. J Neurophysiol 44:135–150Google Scholar
- Rock MK, Hackett JT, Brown DL (1981) Does the Mauthner cell conform to the criteria of the command neuron concept? Brain Res 204:21–27Google Scholar
- Zottoli SJ (1977) Correlation of the startle reflex and Mauthner cell auditory responses in unrestrained goldfish. J Exp Biol 66:243–154Google Scholar
- Zottoli SJ (1978) Comparative morphology of the Mauthner cell in fish and amphibians. In: Faber DS, Korn H (eds) Neurobiology of the Mauthner cell. Raven Press, New York, pp 13–45Google Scholar