Unilateral kainic acid lesions reveal dominance of right archistriatum in avian fear behavior.

Unilateral injections of 1 microgram of kainic acid in the archistriatum of 5-day-old domestic chicks reduced fear, as expressed by distress calls (peeps), significantly more than did identical injections in the same structure on the left side. This result adds affective behavior to the growing list of functions that have been shown to be differentially controlled by the right and left hemispheres in birds. The directions of the specializations are intriguingly similar to those for verbal and affective functions in human beings.