Synaesthesia of a sort?

A few days ago a chunk of a lower back tooth fell out, leaving what felt like a huge hole in that part of my mouth. Then waking up this morning, the hole seems much smaller.

A bit later a chunk of wax fell out of my ear, looking far smaller out than it had felt in.

Then I remembered a neighbour, years ago now, commenting on much the same thing, in his case the huge size of the hole left by a tooth extraction, another impression which wore off with time.

And then there are the various occasions on which I have commented on how small something seems in a snap taken by my telephone, compared with its apparent size at the time.

LWS-N, for which there is an entry point at reference 2, talks of maps of the world on small patches of cortex – cerebral or cerebellar – which are organised in a topical way, rather as the visual scene is reproduced on the retina or on a photograph.

Perhaps these maps are very dynamic, shifting quite a lot from frame to frame, with the size of features on the patch directly related to its importance, in some sense or other. Rather as the size of features on the somatosensory part of the brain seems to be a function of the number of nerves serving the feature in question. Bing turns up lots of pictures of this sort of thing, with one such included above.

I associate now to the surprise which Friston talks about in his various papers on the minimisation of free energy in the brain, for example at reference 1. Perhaps both the subjective experience, the sensation, of size and the sensation of surprise are closely related to the total amount of neural activity for the thing in question. Activity which, other things being equal, tends to fall away with familiarity. We know all about the thing in question, there is no surprise, no need to process that surprise away by cerebration.

From where I associate on to the intimidation – fear even – that one feels in the presence of things that are very large and just in front of one. Large enough that they occupy most of the visual field; just enough left around the edges to make you realise, or perhaps sense, how large they are.

I also recall reading, quite recently, although I cannot now put my hand on the paper in question, that our motor and sensory sensations are all mixed up. That in some sense what we experience when we look at something is a prediction of the motor actions needed to reach out and touch, to handle the something.

Which all goes to show that I am a little way off understanding how sensations from the world around us are mapped onto the busy patch of cortex proposed by LWS-N to amount to consciousness.

Reference 1: The free-energy principle: a unified brain theory? - Karl Friston – 2010.

Reference 2: http://psmv3.blogspot.co.uk/2018/05/an-update-on-seeing-red-rectangles.html.

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