Kage Baker was subject to overloads. Sensory, mostly: too much colour or noise or scent or humidity. Often, too much emotion; brought on by over-indulgence in strongly-flavoured movies, music and waters.
It was why she was not very social. She avoided crowds for the simple reason that she didn’t want her head to blow up. Which is what she said it felt like, when the input got to be too much. Noises that happen in your head are technically “phantom” – in that they bypass the ordinary nervous channels – but they are real enough to the temporal cortex, which has to process them. When Kage was stressed by crowds, especially, she would develop migraines and synesthesia: overload.
A curious facet of the dedicated sensory portions of the brain is that the sight, hearing, etc. centers have no choice but to interpret input by their specific rulebooks. If nerves feed activity to your vision centers, you’re gonna see something; if to your hearing centers, you’re gonna hear it. You can demonstrate this easily right now – press a finger to your (Closed! Closed!) eye: you will see patterns in the dark. The optic nerve interprets pressure as visual stimulation, and passes it on as such. Under ordinary circumstances, it has no choice.
But blending can occur. Wrong numbers. Crossed circuits. Maybe this is one of the sources of synesthesia, that fascinating phenomenon wherein people taste colours and see music and so forth. Everybody’s got a little of that. Some people have a lot. Some people cannot cope with it; others learn to enjoy always perceiving the letter E as male, green and smelling of stone dust … it’s probably just part of the normal sensory interpretation spectrum, and some are more subject to it than others. As long as these customized perceptions don’t interfere with daily life, it’s basically a who-cares situation – like hearing an extra octave higher, or seeing a little in UV light (which some rare humans do. They have 4 kinds of cones, not just 3, in their eyes.)
A friend of mine and Kage’s sees a faint blue light a few seconds before an Aurora display begins: he has never been able to duplicate it in any medium, because no one makes paint or ink or glass or chalk that colour. And if he did duplicate it somehow, the rest of us wouldn’t see it. We don’t have those cones. But he does, and he vastly enjoys it.
There are cases of people who did not realize they had kinesthesia until told – no one ever thought to inform them that not everyone “tastes” the colours of Crayons they pick up. Just like no one thought to tell the blind Helen Keller that the ocean was salt water – when she first encountered it, with the sensory array that was “normal” for her, she got a considerable shock. I think most kinesthetics have that kind of problem.
When it works smoothly, all is normal and there is nothing to remark upon. You smell roses and see a pale orange light behind your eyes: that’s normal. It’s only when our senses get disarranged – and as Charles Dickens point out, so many things can do that to them – that the sensory input gets jarring or excessive. The wise person then retreats to some venue with less input – and if they don’t, the brain wallops them with a migraine and enforces some down time.
That happened to Kage a lot. It doesn’t happen as much to me – Kage always said I was better wired than she was – but from time to time we all get it. Maybe that’s one of the reasons I am sleeping so much these days; I am wading through Kage’s mind when I am awake, and that is deep and active water … no wonder my brain is shorting out from time to time.
Time for some chemical amelioration, I think. Caffeine, fresh nectarines, aged cheese. Walnut pound cake, and the warm breathing velvet of the cat sitting here on the desk. And chocolate. Lots and lots of chocolate.
Not even Kage ever overloaded on that.