Electroencephalographic patterns of the goldfish (Carassius auratus l.)

Abstract

The first recordings of electrical potentials from the teleost brain were made by Adrian and Buytendijk (1931), who used isolated brain stem preparations from Carassius auratus L. Slow potential changes (1-3 eye./sec.) were recorded from the medulla oblongata, corresponding to the rhythm of the goldfish respiratory activity. Patterns of higher frequency and low amplitude were also recorded from the optic lobes. Enger (1957) has used the codfish (Gadus callarias) for implanted-electrode recordings, which were somewhat obscured by artifacts due to breathing movements and to the pressure of the electrodes on the brain surface. He obtained, however, records of the spontaneous electrical activity in the brain of an unanaesthetized fish, as well as mesencephalic responses to stimulation by light flashes. Waves of a frequency of 8-13 cyc./sec. dominated the electrical pattern of the midbrain; these were compared by Enger to the mammalian alpha rhythm. He found evidence for an arousal reaction in the mesencephalon^ following sudden photic stimulation, but none following auditory stimulation.