Sentence:  On the other hand , the temporary reduction in hypothalamic excitability through the injection of a barbiturate into the posterior <WSD>hypothalamus</WSD> 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:  a basal part of the diencephalon governing autonomic nervous system