Objectives: Bacopa Monniera is an ayurvedic herbal medicine used in Indian medicine as a memory tonic. Animal models have shown that it is an antioxidant (1), a memory enhancer (2), and an antidepressant (3). Human trials have had variable results, but spatial memory, attention, and information processing tasks seem to be affected by Bacopa. Given the improvements shown the RVIP task as a result of a 12 week Bacopa intervention, an fMRI methodology was employed to see how Bacopa affects the brain during this task. The improved performance in these tasks suggests Bacopa may modulate task specific brain regions. This investigation looks at the effects of Bacopa on the BOLD signal in the RVIP task over a 90 day intervention.
Method: The study utilized a double blind, placebo controlled, crossover design where all participants completed a 90 day course of both Bacopa (300mg daily) and placebo during the study. The participants were aged between 40 and 65 years and in good health. Interventions were separated by a 120 day washout period. Scans were undertaken on a 3T Siemens TRIO magnet before and after each 90 day intervention where participants would complete two runs of the task per scan visit. The RVIP task is a block design which requires participants to respond when they see three odd or even numbers in a stream of numbers presented at 100/minute. The control block requires a response when a zero is seen in the stream of numbers. Blocks last for 1 minute and are repeated 3 times per condition in each of two experimental runs per scan.
Results: Data collection is ongoing at present. Baseline data show a bilateral increase in BOLD activation in the precentral gyrus and precuneus with activation extending to the left inferior frontal gyrus (n=7, p=.005) when compared with control using a task greater than baseline mask. Behavioural data suggest fewer 'hits' in the active task compared to control task.
Conclusions: The methodology of the study sets a gold standard for clinical trials using nutraceuticals and fMRI. Given the ongoing nature of the study, conclusions are merely speculative at this point. However, the task looks to be a sensitive reşection of sustained attention. We anticipate that the 90 day intervention of Bacopa will affect the BOLD signal in these particular regions of interest.
References:
1. Bhattacharya et al (2000) Antioxidant Activity of Bacopa Monniera in Rat Frontal Cortex, Striatum and Hippocampus. Phytotherapy Research, 14, 174 – 179
2. Hota et al (2009) Bacopa monniera leaf extract ameliorates hypobaric hypoxia induced spatial memory impairment. Neurobiology of Disease, 34 (1) 23-39
3. Sairam et al (2001) Prophylactic and curative effects of Bacopa monniera in gastric ulcer models. Phytomedicine, 8 (6) 423-430 Bulletin of Clinical Psychopharmacology 2011;21(Suppl. 2):S189