what is the role of the brain in a reflex action?
The purpose of reflex action is to provide quick response in situations where the organism does not have enough time to think. Reflex arcs are formed in the spinal cord, although the information inputs also reach the brain. This helps the brain to record this event and remember it for future use.
(The information about the reflex action is sent to the brain after 1 or 2 seconds. This is so that we should be aware of what has happened. The brain on its own cannot react as fast as the reflex action. So the part of the reaction process is carried out by the spinal cord, but the information is also sent to the brain so that the person can be aware of the stimulus and prevent himself from that situation again.
For example you remove your hand when touching a hot object. This is a reflex action. But sending the information to the brain makes the person aware that the object is hot and hence not to touch it again.)