Abstract
Observations were made of the emotional response to electrostimulation at various sites of the hypothalamus via chronically implanted electrodes in unrestrained chickens and of blood pressure responses to similar electrostimulation in chicken under anesthesia, with results which may be summarized as follows:
1) In response to stimulation of the nucleus mammilaris medialis or lateralis the chicken stooped with its feathers ruffled up, making searching action and emitting clucking; noises.
2) Chickens displayed the same responses to electrostimulation of the nucleus hypothalamic inferior, nucleus hypothalamicus lateralis or posterior medialis, the birds showed warning or searching action clucking.
3) In all these cases with stimulation of the nuclei noted, elevation of the bloodd pressure was evident as a reaction to electrostimulation.
4) Neither any appreciable influence on the behavior nor change in the blood pressure was noted to occur in response to stimulation of the optic chiasma or the limbs of the optic nerves.
5) Electrostimulation at sites other than the above described produced no behavioral change or, in some instances, caused attention or warning responses alone.
6) Comparison of these findings with what is known with cats which have been studied in detail as to their emotional reactivity to electrostimulation of the brain, suggest that differences between the two species and innate disposition and degree of domestication of individual animal are intricately involved in the emotional reaction.
