What is memory ?

It is the store of things learned and retained from our activity or experience. Our memory is a collection of knowledge, experiences, impressions, skills, habits, and many other things. It give us the ability to learn and adapt from previous experiences as well as to build relationships. It has a lifelong storage capacity, and no computer of the wold can match its performance. Short-term memory is the information that we are currently thinking of and it lasts for only a few seconds. Important things which we have experienced and would not like to forget are transferred from short-term memory into long term memory.

What is a stroke ?

A stroke is a serious medical condition occurring as a result of an interruption in the supply of oxygen to the brain. The most frequent reaso for a stroke is the blockage or bursting of a blood vessel in the brain. In both cases, the blood circulation and, hence, the supply of oxygen to the brain is interrupted. The result is damaged brain tissue. Stroke patients may lose all information that was stored in the damaged area and may have to relearn simple things like awaking, swallowing, or writing. Sometimes, the brain can build new connections between the brain cells and repair the damage.

Why must we sleep ?

We may not know exactly why we need to sleep, but we do know that our body needs sleep to rest and recover. If the sleep is inadequate, performance of the brain and the body goes down. One becomes irritable and cannot concentrate. After several days of inadequate sleep, one may start hallucinating. The duration of sleep needed depends on the person and the age. While most babies sleep fro more than 12 hours a day, some old people need only 5-6 hours of sleep.