passages.id: split_4_test_130_passage
passages.type: progene_text
passages.text: Optical signal responses at 577 , 586 , and 805 nm showed a monophasic increase in absorbance coincident with the increase in rCBF ; however , the signal responses at 605 and 760 nm were biphasic ( an early increase and late decrease in absorbance ) and microanatomically heterogeneous .