Sounds evoked by brain stimulation in the oyster toadfish Opsanus tau L.

Various regions in the brains of anesthetized oyster toadfish were electrically stimulated. Temporal properties of evoked sounds formed a continuum from simple to complex. One-to-one responses (one sound pulse for each stimulus pulse) and buzzes, elicited by stimulation in the caudal medulla and cervical spinal cord, were simpler than natural sounds. Natural grunts vary from individual pulses to long variable interval series of pulses called growls. Grunts were elicited by stimulation in the diencephalon, midbrain, medulla, and spinal cord. Evoked grunt pulses varied in duration from short to long and series of grunts varied from individual pulses to bursts approaching a boatwhistle, the courtship call of the male. Boatwhistles were elicited in male as well as in one female fish by stimulation in medullary and midbrain areas. Sites evoking sound production appeared to be part of an integrated system so that boatwhistles and grunts could be evoked from a single stimulation in various parts of the brain.