The human mind has only the capacity for one thought at a time. We can carry out multiple tasks all at once where automatic processes run in parallel, but we will only ever hold one conscious thought at any given time. Our minds relentlessly produce conscious thoughts one after the other, and they cascade down like the ticking of a clock. Our thoughts regulate the passage of time, and we regulate time by our thoughts, and it gives the appearance that time is real. It creates the illusion that time is constant and invariable and outside ourselves, when it's actually perpetrated by our rate of perception. Our thoughts can often appear so concrete that our ideas of time are concrete too.
So what then is a thought? About 100 billion neurons, or brain cells, make up the average adult's brain. Each of these neurons is connected to between 5,000 and 200,000 other neurons, the number of ways that information flows among neurons in the brain is so large it is greater than the number of stars in the entire Universe. The function of a neuron is to recieve input 'information' from other neurons, to process that information, then to send 'information' as output to other neurons.The voltage that carries signals from one neuron to the other is determined primarily by the potassium and sodium ionic concentrations internal and external to the neuron. In 1/1000 of a second, the cell changes from a negative charge to a positive and then back again. In this way, nerve cells 'hum' with electricity. It is the pattern and speed of the hum which the brain transfers into data and creates thought. I found this site offers an excellent insight into what's happening under the bonnet:
The electrical signals in the brain are travelling at a speed of 100 meters per second (or 200 miles an hour), along pathways reminiscent of a labyrinth. The appearance of a stimulus evokes neural responses that are related to the processing of this stimulus. The mediated response of the neo-cortex to stimuli generally occurs in about 50 ms. A simple movement such as raising a hand requires electrical signals from many regions of the brain. Every sight, sound, touch, emotion, reaction, every memory and every thought in the history of mankind is a result of these electrical signals. So I ask what would happen if we were able to somehow speed up the signals in the brain? If they are defining my rate of perception, then surely an increase in their speed would force reality to 'slow down'?
I'll leave you with this thought experiment. Imagine you and me are in the same room (don't get any ideas) and that I have been shrunk to a size so small that the distance between the neurones in my brain have halved, and so the speed of my thoughts are twice as fast as yours. In my mind it would appear that you were walking and talking at half your normal speed, while I would appear manic to you. But because inside each one of our minds we are still producing one thought at a time, our own rate of perception and therefore our concept of 'time' shall remain normal within our own personal experience. Does this experiment show that effectively 'time travel' is possible? If it is possible to slow down our experience of reality, are we then looking at a contender for the elixir of life?