Active Thermography (AT): For this case, temperature mapping over both carotid arteries will be done with the application of maximum cooling (within comfort limit) for 45-60 seconds either in pulsed or lock-in manner. While pulsed mode is the continuous application of cooling, lock-in cooling will be intermittent. The frequency of application of cooling under lock-in cooling method is yet to be decided. However, for both the methods, maximum cooling time will remain fixed as 45-60 seconds. The final cooling method to be used is yet to be decided. Cooling will be done either through a cooling pad or using a cold air blower. The temperature of the cooling fluid in the cooling pad and air for the blower will be maintained in the range of 0oC to 5oC (provisionally), respectively. Due to application of cooling, the localized skin tissue will cool down and start rewarming to attain equilibrium temperature with the ambient as earlier (before application of cooling). A continuous thermoscanning will be done from the instance of application of cooling to the reaching of a fixed temperature (to be decided) during the rewarming. However, the maximum acquisition time after the removal of cooling will be kept fixed to 180 seconds. This procedure will be done 2 times for each subject on both carotid arteries. The relaxation time between every procedure will be 10 minutes. A warming pad or hot air blower will be used after every run of the test so as to quickly bring the skin temperature to normal. Temperature of the hot fluid in the warming pad or warm air through blower will be kept slightly higher than room temperature but less than body core temperature (provisionally in the range of 25oC to 35 oC). The total time for the complete procedure would be around 60 min.