Kaj_Sotala comments on Brain-Brain communication - Less Wrong

10 Post author: Jordan 09 December 2011 05:05PM

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Comment author: Kaj_Sotala 10 December 2011 10:37:13AM 1 point [-]

That's what we argued in our brain-to-brain communication paper:

3.2.1. A general cortical algorithm. An adult human brain consists of several areas which are to varying degrees specialized to process different types of information. The functional specialization is correlated with the anatomical differences of different cortical areas. Although there are obvious differences between areas, most cortical areas share many functional and anatomical traits. There has been considerable debate on whether cortical microcircuits are diverse or canonical [Buxhoeveden & Casanova, 2002; Nelson, 2002] but we argue that these differences should be considered as variations of the same underlying cortical algorithm rather than different algorithms. This is because most cortical areas seem to have the capability of processing any type of information. The differences seem to be a matter of optimization to a specific type of information, rather than a different underlying principle.

The cortical areas do lose much of their plasticity during maturation. For instance, it is possible to lose one’s ability to see colors if a specific visual cortical area responsible for color vision is damaged. However, this reflects learning and specialization during the lifespan of the brain rather than innate algorithmic differences between different cortical areas. Plenty of evidence supports the idea that the different cortical areas can process any spatio-temporal patterns.

For instance, the cortical area which normally receives auditory information and develops into the auditory cortex will develop visual representations if the axons carrying auditory information are surgically replaced by axons carrying visual information from the eyes [Newton & Sur, 2004]. The experiments were carried out with young kittens, but a somewhat similar sensory substitution is seen even in adult humans: relaying visual information through a tactile display mounted on the tongue will result in visual perception [Vuillerme & Cuisiner, 2008]. What first feels like tickling in the tongue will start feeling like seeing. In other words, the experience of seeing is not in the visual cortex but in the structure of the incoming information.

Another example of the mammalian brain’s ability to process any type of information is the development of trichromatic vision in mice that, like mammalian ancestors, normally have a dichromatic vision [Jacobs et al., 2007]. All it takes for a mouse to develop primate-like color vision is the addition of a gene encoding the photopigment which evolved in primates. The cortex is able to adapt to this new source information from the retina and can make sense of it. Finally, even the adult cortical areas can be surprisingly adaptive as long as the changes happen slowly enough [Feuillet et al., 2007].