Hanzhang Lu1, Daren Denniston2, Binu
Thomas1, Jinsoo Uh1, Thomas J. Carmody2,
Richard Auchus3, Ramon Diaz-Arristia4, Carol Tamminga2,
E. Sherwood Brown2
1Advanced Imaging Research
Center, University of Texas Southwestern Medical Center, Dallas, TX, United
States; 2Department of Psychiatry, University of Texas
Southwestern Medical Center, Dallas, TX, United States; 3Internal
Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United
States; 4Department of Neurology, University of Texas Southwestern
Medical Center, Dallas, TX, United States
An important application of fMRI is to provide a marker for medication effect on neural activity. A potential problem is that other consequences of the medication, including global changes in physiology, are often not considered, but could influence the amplitude of fMRI signal independent of neural activity. Here we demonstrated that hydrocortisone, a stress and corticosteroid hormone that are used to treat asthma and other medical illnesses but could cause memory decline, reduces resting venous blood oxygenation and that normalized fMRI signal after accounting for this global change allowed the detection of hippocampal alterations after merely three days of medication.
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