Sentence:  On the other hand , the temporary reduction in hypothalamic excitability through the injection of a barbiturate into the <WSD>posterior</WSD> hypothalamus causes a lessening in frequency and amplitude of cortical strychnine spikes until the hypothalamic excitability is restored . 
Meaning of the word marked with <WSD> tags:  located at or near or behind a part or near the end of a structure