Now how can a brain handle so many frequencies and accesses at once? If a person walks and eats ice cream, and also says Hi to her friend all at the same time, wouldn'tthe brain be confused?

A single satellite in space can handle ten thousand phone calls at once and won't be jammed. See picture.
 a single satellite can handle a lot of phone calls

Why can a single satellite handle so many frequencies and won't be confused? The answer is that every single frequency has a different level. For example, if a frequency has a level value 3, it travels from one phone (value 3) to another phone (value 3). A phone rated value 4 will not receive the frequency from value 3. That's why you always can speak to the right party by dialing the correct number. One single phone line can also transmit thousands of frequencies and distribute them to correct parties all at once. As long as each frequency is different, the system won't be confused.
frequencies traveling through single line

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