Ajahn Brahm's talk given at Chui Huay Lim in Singapore on 14th June 2016, about "Unlocking the Secrets of Your Mind". The talk about the topic begins properly around 13 minutes into the recording.
Ajahn starts by talking about the nature of mind (which is not in the heart or brain, but that the brain and heart are in the mind). When we realise how big the mind is, we can then begin to unlock it, for our benefit for example, for our health. Ajahn also shares a story about a Thai monk who carries metal tool-kits into plane cabins relying solely on his prior meditation & chanting to prevent getting caught!
Teaching retrieved from https://www.youtube.com/watch?v=X60Py9IhCKE (YouTube Channel: Buddhist Fellowship)