I’ve heard of the experiments with the brain you’ve mentioned. It is something that could allow dreams to be recorded and watched simply on TV. That would be fascinating. Though, I don’t know why you say that the brain experience is NOT based on physical information. The subject saw the apple (a physical thing), the brain memorized it’s shape, and could recreate it later on (memorized shape). A person, who has never seen an apple, would not be able to recreate it. The brain needs a physical shape to memorize. In the same way our dreams are created. We base our dreams by the objects we know IRL. We can even merge the abilities of two objects in a dream, thus creating things like flying cows or singing elephants etc. But all the information is based on something that physically exists in the real world, or something we simply saw on TV, read in some books or imagined using our creative mind. A painter needs canvas and colors, a dreamer needs a healthy brain with information to base the dream on.
You’re right about time. We defined the seconds, the hours. It might have been as well something different. The same goes for other dimensions (we measure length, area, volume). But the fact that we defined seconds and minutes does not mean that we defined time itself (or length, area or volume). Time has always existed since the Big Bang and will exist until the end of the Universe (if such end ever comes). Time, as well as other dimensions are not controlled by us, we can only measure them, watch them and use them pasivelly. We cannot manipulate them. It seems that you agree with this as long as we are talking about the real life. But what about dreams then? Do you think that other dimensions exist in a dream, or do we have abilities to control these 4 dimensions in a dream? I really doubt that. While it is true that “You can do everything in a dream” there is a border for what our minds can do. We cannot imagine more than 4 dimensions (some people hardly even imagine the 4th itself). Our brains are the same in our dreams as in WL. We do not get some “special” mental abilities in a dream. All of our dreams are based on the 4 dimensions we know. They will be similar to real life and unchangable. We will only be able to use them pasivelly, just like IRL. We cannot control dimensions, since they are not supposed to be controlled. We can only measure and use them, as I said, passively. Many physical laws do not apply to dreams - that is true, since we can remove gravity, we can go through walls etc. However, dimensions are not controlled by physical laws either. They just exist as they do. We have no specific physical laws, which tell us, why length is length, or why time is time as we know it. Since dimensions are “untouchable”, no human being, no force or law of nature could modify it. Therefore, dimensions exist in dreams, but we cannot add more dimensions or modify the existing ones, since we aren’t capable of perceiving such things. Thus, time is unchangable and stationary both in dreams and in waking life. If you measure time in seconds and minutes, these “seconds” and “minutes” will be the same in a dream as in waking life. And that is the point of the thread, answer to the question OP asked (and proven by S. LaBerge scientifically).

If you want to discuss the nature of dimensions, our methods of measuring the dimensions and whether these methods are valid, it would require a new thread, since it is a topic outside of lucid dreaming.