I’m not certain but think that the theory you referred to is Single-neuron Theory of Consciousness [1]. Anyway, if it is not the one, let’s discuss this theory because it has the concept like the one in your question. The abstract of this theory is as follows:
By most accounts, the mind arises from the integrated activity of large populations of neurons distributed across multiple brain regions. A contrasting model is presented in the present paper that places the mind/brain interface not at the whole brain level but at the level of single neurons. Specifically, it is proposed that each neuron in the nervous system is independently conscious, with conscious content corresponding to the spatial pattern of a portion of that neuron's dendritic electrical activity. For most neurons, such as those in the hypothalamus or posterior sensory cortices, the conscious activity would be assumed to be simple and unable to directly affect the organism's macroscopic conscious behavior. For a subpopulation of layer 5 pyramidal neurons in the lateral prefrontal cortices, however, an arrangement is proposed to be present such that, at any given moment: i) the spatial pattern of electrical activity in a portion of the dendritic tree of each neuron in the subpopulation individually manifests a complexity and diversity sufficient to account for the complexity and diversity of conscious experience; ii) the dendritic trees of the neurons in the subpopulation all contain similar spatial electrical patterns; iii) the spatial electrical pattern in the dendritic tree of each neuron interacts nonlinearly with the remaining ambient dendritic electrical activity to determine the neuron's overall axonal response; iv) the dendritic spatial pattern is reexpressed at the population level by the spatial pattern exhibited by a synchronously firing subgroup of the conscious neurons, thereby providing a mechanism by which conscious activity at the neuronal level can influence overall behavior. The resulting scheme is one in which conscious behavior appears to be the product of a single macroscopic mind, but is actually the integrated output of a chorus of minds, each associated with a different neuron.”
Comment:
Fist, I think it is certain that the signaling activity of each neuron, among other millions of neurons, in the neural circuit that creates consciousness contributes something to the whole consciousness. But I think whether we call this minute contribution “consciousness” is a matter of individual’s opinion. However, if we call it “consciousness”, we should be aware that, whatever this minute consciousness is, it is not and cannot be the complex and highly informative consciousness that we feel in our mind, because a single neuron is too simple to be so.
Now, let’s examine the content of the theory. It appears strange to me that the theory asserts that dendritic electrical activity corresponds to consciousness. Dendritic activities are processing activities of incoming information that arrives at dendrites. They are ongoing, unfinished activities. On the other hand, the completely processed, synthesized information comes out at the axons. Also, a lot of current evidence shows that consciousness corresponds to recurrent neuronal activities among and synchronization of various cortical areas [2-5]. The recurrent neuronal activities and synchronization entails activities in the axons too. Therefore, it seems more evidence-based that the composite of all electrical activities, both dendritic and axonal, not dendritic alone, among various cortical areas that include the consciousness neural circuit should be the one that corresponds to consciousness.
Next, regarding assertion i), it’s hard to believe that the spatial pattern of electrical activity in a portion of the dendritic tree of each neuron individually manifests a complexity and diversity sufficient to account for the complexity and diversity of conscious experience, but it’s more probable that the combination of the spatial patterns of electrical activities of a very large group of neurons can manifest the require complexity and diversity. Assertion ii) is possible but needs objective evidence to confirm. Assertion iii) is not a novel assertion but a current standard model of neuronal processing. Assertion iv) is questionable, but it may just an inaccurate wording. I think the wording shouldn’t be “dendritic spatial pattern is re-expressed at the population level by …” but should be “dendritic spatial pattern is processed, and a new axonal spatial pattern is synthesized and expressed at the population level by …”.
References
Sevush S. Single-neuron Theory of Consciousness. Journal of Theoretical Biology. 2005..
Babiloni C, Marzano N, Soricelli A, Cordone S, Millán-Calenti JC, Percio CD, et al. Cortical neural synchronization underlies primary visual consciousness of qualia: Evidence from event-related potentials. Front Hum Neurosci. 2016;10:310.
Dehaene S, Sergent C, Changeux JP. A neuronal network model linking subjective reports and objective physiological data during conscious perception. Proc Natl Acad Sci U S A. 2003 Jul 8;100(14):8520–8525.
Fisch L, Privman E, Ramot M, Harel M, Nir Y, Kipervasser S, et al. Neural “Ignition”: Enhanced activation linked to perceptual awareness in human ventral stream visual cortex. Neuron. 2009 Nov 25;64(4):562–574.
Pollen DA. On the neural correlates of visual perception. Cereb Cortex. 1999; 9(1):4-19.
