Effects of lesions in the medial preoptic region on precocial copulation in the male chick

Chicks showing androgen-induced precocial copulation to a prone hand were given bilateral electrolytic lesions in the medial preoptic region. Symmetrical lesions in the medial preoptic area disrupted copulatory behavior over the 10-day postoperative test period. Asymmetrical or sham lesions did not differentially affect copulatory activity. Postoperative records indicated that all animals showed similar increases in weight gain and comb size.