Neurons transmit signals via action potentials. https://en.wikipedia.org/wiki/Action_potential

The "hard problem of consciousness" is complex with many theories. https://en.wikipedia.org/wiki/Hard_problem_of_consciousness

As for experiencing stimuli and sensation. Sometimes called "the easy problem of consciousness". That's explainable by modern research. It's a product of biological systems that are designed to be stimulated by specific stimuli. All of them are complex.

Cognitive functions are a product of neural architecture (neural pathways and regional hubs) in the brain but also from the constantly changing state of neuron potentials (how likely a neuron will or won't fire at a very specific point in time) that are influenced by internal and external stimuli.

Brain oscillations, (brain waves that vary in frequency through the day and tasks, and regions) also heavily influenced this state. So does sleep or how long someone is awake. How much attention they give some things or if they are mind wandering and a whole host of other influences that directly impact priming effects (an effect where once a pathway in the brain has an action potential go through it, it's more likely to fire again --this is time dependent). And subsequently that changing state I referred to.

At present it is incredibly difficult to predict brain activity at a macro scale. Because it does not follow predictable patterns. Because the state is constantly changing. Too many interacting factors that can't be accounted for in a single model.

Humans also do not use real math in our cognitive functions. We use heuristics. I don't know the exact distance or speed that a baseball is traveling towards me. Yet I can predict when I need to swing a bat. (Not me personally but some humans can do this).

Even expert baseball players are not computing the actual real speed (in any unit) when observing the ball moving towards them. They use heuristics which are much faster though less accurate. Experts get better at their estimates though compared to non experts.

We aren't calculators and we don't use numbers like computers do.

A.i. systems are statistical probability formulas. They do use numbers. They are in many ways a fancy search engine. That's not what organic systems are. We don't even use mathematical probability.