Physiological and anatomical studies on large neurons of central nervous system of the sea lamprey (Petromyzon marinus). I. Müller and Mauthner cells.

Abstract

Individual Muller and Mauthner cells and their axons were studied in isolated central nervous systems of both larval and adult sea lampreys. Each of the axons was traced through serial histological sections of the spinal cord to its respective soma in the brain. Recordings with intracellular electrodes showed that the cells received synaptic input on electrical stimulation of the optic, trigeminal, vestibular and posterior line nerves, as well as the spinal cord. Muller and Mauthner axons also exhibited postsynaptic potentials, which were produced by distributed synapses. Stimulation of individual Muller and Mauthner axons in situ through intracellular electrodes led to distinctive movements in larvae and adults. Such movements required stimulation frequencies of about 40/sec. and included flexions of the body and tail, movements of the fins, rotations of the body and propagated undulations.