Signal Changes in Hippocampal Subfields during Controlled Breathing Patterns by Using Functional MRI

Abstract

The purpose of this study was to investigate the functional properties of each hippocampal subfield and determine its association with decreased working memory due to abnormal breathing. Eleven healthy volunteers participated in this study and performed a breathing task in magnetic resonance imaging (MRI). To quantify the effects of various breathing patterns on the hippocampus, we segmented its subfields and then applied them to the functional MRI (fMRI) data to measure the signal change according to the respiration pattern. The results indicated that mouth breathing (mouth inhalation and exhalation) had the biggest effect on signal change. Of all subfields studied, the hippocampal head showed the greatest change. These findings imply that mouth breathing can significantly induce blood oxygenation level-dependent (BOLD) signal change in the hippocampus; especially, the hippocampal head is the most susceptible to breathing alterations, suggesting that it could be strongly associated with poor working memory in habitual mouth-breathers.