Know Your Enemy

Wow! There's a lot going on in that Big Homo Sapien Brain of yours.




Some of it you are aware of on a conscious level. But, a lot of it goes on without you even knowing about it.




Take the Ear. That big (or small) layered dish thing stuck on both sides of your head.




We have all heard that in space, no one can hear you scream. That's because sound waves have to have a medium to travel through. Space is a vacuum, so there is nothing to vibrate. The air around us provides such a medium, and most the sounds that you hear are results of vibrations in the air molecules around you. So, if by any chance you are travelling in space, I'd take a torch with you. You never know.




Apparently humans can hear sounds from around 20Hz to 20,000 Hz. 20Hz being the low end vibrations, and 20,000 being the high end. Just like the Eye sees a certain spectrum of colour's, but by no means all of them, the Ear hears a certain range of sounds, but by no means all of them. Who knows why this is. Guess we hear and see all the frequencies necessary for our survival. An expert may tell you something different.




The ability to detect and distinguish sounds varies from person to person. Some people are acutely aware of slight changes in frequencies, and some aren't. In other words, I may pick up the fact that a singer is flat, and you may not. Guess that is down to a lot of different factors. Do you like the music that is playing? Are you listening to it? Have you got perfect pitch? Are you musically trained? Can you actually hear it? Does it bother you? Do you actually care? etc etc etc.




It is also well known that our ability to detect different frequencies will deteriorate as we get older, which is why I get away with "pardon" a lot more now than I use to! Our ability to detect the frequencies at the extreme ends of the normal hearing range disappears. A fact illustrated by the recent invention of deterrents, used to disperse teenagers in public places, that emit a high pitched whistle at the extreme end of the human hearing range. This frequency cant be heard by people above the age of about 20, I think.




In your inner Ear is a thing called a Basilar Membrane. On this membrane are hair cells that are what is called frequency specific (or selective). Each hair cell will only respond to a certain frequency. So, if you hear a Piano play a note of middle C, then only the hairs corresponding to the frequencies generated by that particular piano key will react.



You think that's complicated? That's the simple bit. That piano key has generated a series of different frequencies by making a hammer hit a string. That string, as it vibrates, generates a whole series of different frequencies, and your Basilar Membrane responds to them all.




Ok! Now. I am not a Neuroscientist, so I am not going to pretend to be one. But........



From what I understand, the hair cells on the Basilar Membrane are all connected to the Auditory Cortex, which contains a rather large amount of Neurons (amongst other things). Certain groups of Neurons respond to certain Hair cells on the Basilar Membrane, and if they receive a message from the Hair Cells, they fire up to tell you that you are hearing a certain frequency. So, in essence, the Neurons in the Auditory Cortex are laid out to correspond to the Hair Cells on the Basilar Membrane.



(I don't know how many Neurons are involved. But according to the books, there are around 100,000,000000 (100 Billion) Neurons in the Brain of a healthy person. That is about the same as the estimates of how many stars there are in our Galaxy, and, how many observable Galaxies there are in our Universe! Quite a lot going on in your head then.)



I'm not even going to bother to go into how many different parts of the brain are set into motion when you are listening to a favourite piece of music. I'm not even sure that Neuroscientists have quite got on top of that one yet. And imagine how much more complicated that becomes if you are the one playing it? The fact of the matter is that the ability to perceive sound and process it into something coherent and useful is truly a miracle of evolution. (All you Creationists out there. Don't jump on that one, cos' I'm not going to bite. I'm keeping an open mind thanks.)



Right. As the title says. Know your Enemy. Somewhere in my Auditory Cortex there is a group of Neurons that are fired up all day. They never take a rest. They cant take a rest. They don't seem to want to take a rest. Taking a break does not seem to be a concept that they are aware of. But they are just doing what they are told. It's not their fault. Some of the Hair Cells on my Basilar Membrane are damaged. And, as a result, are constantly putting out a false signal, telling this little bunch of Neurons that they are hearing a sound. A very high pitched frequency. This damage could have been caused by anything, a knock to the head, a sudden loud noise, watching too much Battlestar Galactica. Anything. (How can you watch too much BSG i hear a certain amount of you cry?)


The reason that I'm glad I know this is the following. As much as it hacks me off every day. As much as I sometimes wake up in the morning praying to the Lords of Kobol to take away my hearing for half an hour so that I can have some peace and quiet, or sort me out so that I can hear the TV without having to turn it up too loud, or hear the frequencies that I need to hear to make a decent mix of the music that I have just created on my Computer. I now know that there are still around a 100,000,000,000 or so Neurons in my brain that are working pretty much as they should. I can walk, talk, sit, eat, create, remember, imagine, calculate, and Lord knows how many other amazing things without any noticeable problems. I don't have a serious mental illness, a disability, or any kind of major psychological defects that I know of. I have no twisted desire to go to war, or steal anything, or hurt anybody else. And I live in a time where other people are able to make some sense of what is going on in my head, and not stick me in an asylum cos' they think I am hearing voices from the dark side! I think that I'm pretty lucky in the great scheme of things.