Every activity of our body is controlled by brain. The beating of the heart or the movement of a hand or the mental thinking involved in solving a puzzle are all governed by the brain. Every conceivable activity of our body has certain fixed location in the brain which controls that particular activity. There is a particular part of the brain which keeps the person awake and alert. Any failure of this system leads to loss of consciousness.
The information processing and communication system within the brain involves minute electrical signals generated in one place and transmitted to the desired site through fine neural network very much similar to the telephone cables.
In epilepsy or seizure disorder there is a sudden, excessive and uncontrolled discharge of electrical signals within the brain. These electrical discharges can disturb the smooth and orderly functioning of the body. If the signals are emanating from a location in the brain which control movements of a body part, it can result in sudden and uncontrolled movement of the respective body part. If these abnormal electrical signals propagate to other parts of the brain, there will be similar jerking of the entire body. If these electrical signals travel across the seat of consciousness it may result in loss of consciousness. Similarly abnormal electrical activity arising from parts of the brain monitoring sensations can result in disturbances of sensation. Such transient sensory disturbances are called sensory seizures.