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

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.

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 degree 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.

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.

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).