Are action potentials necessary for experience?

Question

We know that, for example, during brain surgery, electrical stimulation in certain parts of the cortex is sufficient for experience, and result in reportable experiences in human subjects.

We also know that action potentials are not sufficient to cause experience when they occur in other parts of the body. For example, as far as I know, humans are not aware of action-potential-caused insulin release in the pancreatic cells.

Further we know that mechanical stimulation of the fingers is converted to action potential trains, then relayed via interneurons, and is subsequently reported as touch. The situation is similar with other senses.

But, are there any examples of reportable experience without preceding action potentials? In other words, are there any cases of experience that is not correlated with electrical activity?

I'm interested because my deeper question is "Does all qualia result from action potentials?"

Answer 1

It is generally accepted that all activity having to do with conscious experience is mediated by spiking in the cortex. Sub-threshold activity, such as excitatory postsynaptic potentials (EPSPs) are not carried forward in the nervous system and will 'fade' before having an effect. It all revolves around action potentials.

Quoting from Kandel et al. (2000):

Action potentials constitute the signals by which the brain receives, analyzes and conveys information. These signals are highly stereotyped throughout the nervous system [...]. The information conveyed by the action potentials is determined not by the form of the signal but by the pathway the signal travels. The brain analyzes patterns of incoming electrical signals and in this way creates our everyday sensations of sight, touch, taste, smell, and sound.

^{Reference
Kandel et al. eds. Principles of Neural Science, 4th ed. McGraw-Hill, 2000}

Answer 2

I think it is safe to say that we simply don't understand nearly enough (anything?) about the neural basis of qualia / experience to be able to give a satisfying answer to this question. That said, at least in the case of human experience, most neuroscientists would agree that if there is any centralized locus of experience it is the brain, and although the brain does have some non-action-potential "commerce", a great deal of it is through action potential mediated communication; I would find it hard to believe that it wasn't involved in conscious experience.

More importantly, being able to test whether one could be consciously experiencing while silencing 100% of action potentials seems like a rather tough experiment to do, given that doing that would probably kill the subject (such as with tetrodotoxin poisoning).