Chinese herbal medicine and cognitive and emotional functions during 60-day head-down bed rest

Introduction: This study aimed to test the efficacy of an oral-intake Chinese herbal medicine in enhancing the cognitive and emotional functions of individuals in a simulated microgravity condition. The herbal medicine consisted of ingredients that may enhance cognitive and emotional functions in an extreme environment. Methods: There were 14 healthy male subjects who were randomly assigned to a Chinese medicine (CMG) or a control (CG) group and underwent a 60-d 6° head-down bed-rest protocol. Testing was conducted before (Day -3), throughout (Days 3, 7, 20, 40, 57), and after (Days +3, +10) the bedrest protocol. The Arrow Test, Balloon Analog Risk Task (BART), Dual Task, and Affect Grid were administered on all testing days. Results: The CMG demonstrated consistently higher scores on the BART (Days 20 to 40; Mean: CMG, 43.0 to 46.2 and CG, 30.2 to 25.5) and lower levels of arousal on the Affect Grid (Days 7 to 40; Mean: CMG, 6.9 to 6.7 and CG, 8.1 to 8.0) than did the CG. The CMG showed significantly higher performance on the Arrow Test (incompatible condition) at the beginning of the bed-rest period (Day 3 to 7; Mean: 799.5 ms and 763.1 ms, respectively) which was not observed in the CG. Discussions: Results suggest that the Chinese herbal medicine may calm subjects' emotions by lowering the arousal level. At the same time, it may have produced positive effects in enhancing advantageous risk-taking and to a lesser extent self-regulatory behaviors (in the early phase).