Modulations in cerebral hemodynamics under three response requirements while solving language-based problems: A transcranial Doppler study

This experiment used transcranial Doppler ultrasound to measure blood flow velocity in the middle, anterior or posterior cerebral artery (MCA, ACA and PCA, respectively) while separate groups of college students (each n = 20) solved anagrams and constructed new words using letters of a target word, each while viewing, speaking or writing the responses. The silent viewing requirement affected global velocities only while constructing words: velocities in both the MCA and ACA were faster than in the PCA. Speaking the solutions during both types of problems yielded faster overall velocities in the MCA than in the PCA. Finally, writing the solutions while constructing words led to faster velocities in the MCA compared to both the ACA and PCA. Time-course patterns to velocity changes from the thinking periods showed elevations in MCA velocity at the beginning and end of the periods, while PCA velocity typically slowed below baseline in the middle of the periods. These data show that the kind of language-based problem-solving task and the specific response requirement arranged to accomplish a task selectively affected velocity in three cerebral arteries. (C) 1997 Elsevier Science Ltd.