Brain Effects of Acupuncture 2 : Laser acupuncture vs Laser EMLA

INTERVENTION: 1. Each subject was asked to apply the EMLA patch (local anaesthetic patch: 5% eutectic emulsion of lidocaine (25mg/g of emulsion) and prilocaine (25 mg/g) with amount of EMLA per patch 1g) at least one hour, max 2 hours before attending the MRI (3 Tesla Philips) scanning room to either the left or right wrist at HT7 acupoint. 2.Removal of EMLA patch 3.Temperature recorded of both HT7 areas: EMLA patched site and control site opposite site. 4. Testing and recording of residual sensation to touch at EMLA site and control site with : Brushing ( a soft bristle paintbrush gently stroked on the skin where EMLA patch had been applied) Prick ( using a toothpick on the same area) Cold ( using a metal rod which has not been exposed to warmth, so it has a cold feel) Heat ( using metal rod warmed to 50 celsius in baby bottle warmer) 5 Laser acupuncture intervention to both HT7 acupoints in each subject at the same session. EMLA HT7 and Control HT7 in each subject are lasered in random order (toss of gold coin) Fibreoptic Continuous Beam Laser wavelength 804nm, 20mW in eight 16 second Active laser blocks, alternating with Rest blocks of same duration 16 seconds. In total 9 Rests and 8 Active Laser blocks. Total laser time for both HT7 was 256 seconds. Total time in scanner 15mins . including preparation time. 6. This was a single session study. Each subject received laser acupuncture in random order (of left or right HT7 first ) followed immediately by laser acupuncture to the opposite HT7. CONDITION: Investigation of the afferent nerve fibres involved in laser acupuncture PRIMARY OUTCOME: Brain activation patterns with laser acupuncture to control HT7 acupoint, using MatLab and Statistical Parametric Mapping analysis (SPM). Brain activation patterns with laser acupuncture to EMLA local anaesthetic patched HT7 acupoint, using MatLab and Statistical Parametric Mapping analysis (SPM). SECONDARY OUTCOME: Not applicable INCLUSION CRITERIA: Healthy subject Able to participate in MRI experiment Able to give informed consent Right handedness