Week 6. What is your best candidate(s) of NCC?
Time to make C map?
, collecting the convergent point from starting with the multiple concept of NCC
Hunjae Lee (VCC Lab)
Since the beginning of scientific studying about physiological foundations of human sensation and consciousness, it is well known that a firing of neurons and their interaction are crucial for our daily subjective experiences even in public. They have been vigorously investigated, the relationship between the firing of single neuron and our perception, as we can see a kind of ‘neuron doctrine for perceptual psychology’ already in 1970s (Barlow, 1972). But when it comes to be more detailed information about consciousness, things are getting more difficult.
Neural Correlate of Consciousness (NCC) is defined as a neural state that directly correlates with a conscious state. Such a broad and ambiguous word invokes multi-dimensional finding of NCC by each researchers. For example, prefrontal cortex has been commonly mentioned as NCC, that many references are online in our VC map. And there are still some arguments whether we are aware of neural activity in primary visual cortex or not (Crick et al, 1995; Lee et al, 2007). Beside those NCC only about visual awareness, consciousness can include all of sensational modality (auditory, emotional, imaginary and so on), all of background states such as being awake or asleep (Chalmers, 2000). Thus, finding all-inclusive NCC is a hard problem and challenging.
Instead of suggesting NCC as localized properties, there are some broad proposals that NCC is temporally extended neural firing (Libet , 1994) or involves particular sort of cell, throughout the cortex (Crick et al, 1998). It is tempting to accept these umbrella theories that we can account various conscious experiences. However, we need to minimize size of an NCC to study consciousness, concerning about less explanatory and predictive power (Chalmers, 2000). At first we would better suppose a NCC with narrow system. It is also helpful to investigate our processing of perception.
My suggestion to find best NCC is, accepting multiple NCC at first even they look really dissociated and trying to find converging data about diverse consciousness. In my case I choose prefrontal cortex about VC and thalamus about background state as a candidate of NCC, but temporally. So now it is time to make C map rather than VC map to find critical convergence point. Then, we might find the organizations or interaction of the multiple NCCs.
References
Barlow H. B. (1972). Single units and sensation: a neuron doctrine for perceptual psychology? Perception, 1, 371-394.
Crick, F., & Koch, C. (1995). Are we aware of neural activity in primary visual cortex? Nature, 375, 121-123.
Chalmers, D. (2000). What is a Neural Correlate of Consciousness? In Neural Correlates of Consciousness: Empirical and Conceptual Questions (T. Metzinger, ed), MIT Press. http://consc.net/papers/ncc2.html
Chong, S. C., et al. (in updating). VC Map in the Vision and Consciousness, 2009
Lee, S. H., R. Blake, et al. (2007). Hierarchy of cortical responses underlying binocular rivalry. Nature Neuroscience 10(8): 1048-1054.