Sentence:  Important as these differences are , they should not obscure the basic <WSD>fact</WSD> that by shifting the hypothalamic balance sufficiently to the parasympathetic side , we produce depressions , whereas a shift in the opposite direction causes excitatory effects and , eventually , maniclike changes . 
Meaning of the word marked with <WSD> tags:  a piece of information about circumstances that exist or events that have occurred