Abstract
Summary Ovulation was delayed in 20 of 63 hens following stimulation of a ventromedially limited region of the preoptic brain. The effect was produced following electrical stimulation with stainless steel or platinum electrodes, or by placement of electrodes without passage of current. In accord with our previous findings in the anterior median eminence, the delays in ovulation are believed to originate in the delay in or blockade of the release of ovulation-inducing hormone.