Telencephalic lesions and behavior in the teleost, Macropodus opercularis: reproduction, startle reaction, and operant behavior in the male.

Bilateral ablation of the telecephalon at the level of the anterior commissure blocked reproduction in male paradise fish. Lesioned males performed species typical displays at the start of the spawning trial but thereafter avoided the female, and they did not build nests. All the sham-operated males spawned and built nests. The reaction of the male to a startle stimulus and the rate of operant responding for visual reinforcement were used as additional, independent measures of the behavioral effects of the ablation. Removal of the teleneephalon greatly increased startle reactivity and decreased the rate of operant responding. Hyperreaefivity could account for long response latencies, reduced mobility, and other reported effects of telencephalic ablation in teleosts which have previously been attributed to impaired nonspecific arousal.