Responses of pre-optic area to intracerebroventricular thyroxine and thyrotropin in dog brain

Electroencephalographic activity (EEG) of pre-optic area (POA) was recorded after intracerebroventricular (ICV) microinjection of thyroxine (T4) and thyrotropin (TSH) in conscious male dogs. Recordings were made for two hours following microinjections. Biphasic responses with increased amplitude were observed in both the treatments, but chronologically the responses obtained with T4 & TSH were opposite to each other.