Human consciousness, awareness or whatever?

zoobyshoe

http://en.wikipedia.org/wiki/Synesthesia

This came out frequently in the links posted in the huge synesthesia thread. There doesn't seem to be any evidence for physical "cross-wiring". Testing shows the experiencer has to cognitively apprehend the stimulus before the second sense kicks in.

Pythagorean

What's the evidence of concurrents? I see the assertion, but wikipedia doesn't divulge the method.

Scholarpedia is generally more thoroughly referenced, and you might interpret some of its references as "evidence":
http://www.scholarpedia.org/article/...ological_basis

but Scholarpedia also tends to be idiosyncratic sometimes since the original authors write the Scholarpedia articles (this one is written by Ramachandran who references his own work, so possible conflict of interests).

Anyway, Ramachandran distinguishes between (at least, didn't read it all) two different synesthetes: "lower synesthetes" and "higher synesthetes". You can probably guess by the names which name refers to which of the theories each of us has introduced in this thread.

Anyway, we're getting off topic.

zoobyshoe

This article goes into more depth:

http://en.wikipedia.org/wiki/Ideasthesia

madness

http://www.nature.com/neuro/journal/...ll/nn1906.html

zoobyshoe

What this tells me is that 'hyperconnectivity' allows for the second sense to kick in after the concept (idea) has been grasped. It allows for the second sensory experience without automatically causing it or triggering it. In the concept of "cross-wiring" the input from one sense is automatically also sent to a second and the mind becomes aware of both reactions after the fact. "Ideathesia" on the other hand is dependent on first grasping the meaning:

http://en.wikipedia.org/wiki/Ideasthesia

madness

http://www.daysyn.com/Bargary_Mitchell2008.pdf

This is an interesting review on the different theories and evidences for connectivity in synaesthesia. It looks like its still an open question, but some theories do involve "higher order" brain areas, either through excitation or disinhibition of the secondary sensory area.

zoobyshoe

From your link:

If someone wants to refer to this, "cross-activation of one cortical area by another" as "cross wiring" I don't have an objection. But the idea that the impulses from the senses are split somewhere in the circuit before reaching the cortex with one part being erroneously wired up to a non-related sense is the one that used to be speculatively suggested. For years Cytowic was under the impression the synaesthetic split somehow took place in the hippocampus. When I hear "cross wiring" that's what I think of.

SimsStuart

The question being explored here is best answered from the affective neuroscience perspective, if one has a serious interest in understanding how the brain actually produces secondary consciousness (the degree of consciousness typically experienced by human beings). The weight of evidence provided by such researchers as Panksepp, Damasio, and Solms strongly supports a bottom-up model of consciousness, where the subcortical primary process (genetically provided) emotional circuitry provides the energy for all secondary and tertiary cognition. These primary process emotional systems have been located and identified, although research into how they interact (and are mediated by) with the neocortical regions of the brain are still ongoing. This new model of consciousness is very new and is still coming into focus, but it is producing wonderful testable hypothesis related to depression and other prevalent psychopathologies. I recommend reading The Archeology of Mind, by Jaak Panksepp for a more thorough exploration of this emerging neuropsychological paradigm.

pumila

Just my thoughts - The underlying mechanisation of reasoning in humans seems to be the use of symbols as abstractions that represent components in the real world. Hence we can think about things that are not currently present, or emotions which have no visible existence that we can point to. These symbols can be visual (road signs, sign language), auditory (a fire alarm), or written or spoken language. By far the most extensive and finely grained symbol representation is language, sign, written and spoken. I find maths easiest with written language, while working out a presentation is easiest spoken internally. I do not know, but I suspect that those deaf from birth might use sign language for internal reasoning?