9604
The origins of reflected light changes associated with neuronal activity ( optical signals ) were investigated in rat somatosensory cortex with optical imaging , microspectrophotometry , and laser - Doppler flowmetry , and dynamic changes in local hemoglobin concentration and oxygenation were focused on .
 hemoglobin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 hemoglobin