Hi Alam, Brain rhythms refer to clearly different arrangment of massed neuronal activity associated with specific behaviors. Distinct: something that is clearly different from others so that it is very noticible. Pattern: arrangment of different things in a group. This arrangment can be based on their shape, size, etc. For example, imagine that you put five BLUE pens in a row (this is a pattern), and you put another five RED pens next to it (this is another pattern that is different from the previous one). I hope I explained it well.