Today is a special day. As each ticking second brings us all closer to another year, we reflect upon and discuss what transpired with those closest to us. This is an act of consciousness, a communicable self awareness. You will find out the inner workings of your own light bulb.
"Please count to 10." "One...two...thr.." Your eyes refocus. The surgeon stands in front of you congratulating you for a successful operation. What just happened? How can two hours of your life be taken in a mere flash?
If the brain were represented by a 1960s telephone network, the thalamus would the switchboard operator. Any call made would have to be manually rewired to reach the intended location. It is the George Washington Bridge for the lower Central Nervous System's commute to the higher cortex, the neuroplastic cap of judgement, thought and sensorimotor action. You can thank your thalamus for not dropping the call from your foot to your frontal cortex.
The wind lifts a leaf up to the nape of your arm. Swoosh. Leaf. Tickle.
Much can be learned by approximating the speed of signals going through the thalamus. 1000 Hz. 30 Hz. 10 Hz. These are, in order, the processing speeds of hearing, vision and motor tactile sensation. While vision may monopolize an entire lobe of your brain, hearing is the most fine tuned of the classic senses. In the heat of a tricky moment where every millisecond counts, trust your ears over your eyes.
At this point you might be forgiven for thinking that the thalamus is the organ for consciousness, a simple on or off switchboard for what makes us tick. This is not merely the case. Our consciousness has a beat . A ryhthym that, if perturbed, results in an instant coma. 40 Hz. Measured via magnetocephalogram by Rudolfo Llinás, MD/PhD; it appears that the intralaminar nuclei of the thalamus is responsible for the spaced firing of our cortex. We are synchronized . "Syn", same. "Chronos", time.
This sheds light on the mystery of coma. The term brain dead is a misnomer: EEGs of coma patients show cortical activity upon grabbing their hands. It is not the lack of cortical activity that is of concern. It is the timing of it. Comatose patients appear to have asynchronous intralaminar thalamic nuclei. Their switchboard operator does not heed the warning signals of waiting for other calls to finish. This explains why many coma patients recall hearing, given the brain processes sound (1000 Hz) faster than our own consciousness (40 Hz). What are the physical implications of this finding? We are inside time. And time is inside us. Our wakeful existence depends on a rhythmic 40 beat per second progression through the fourth dimensional space-time fabric. Consciousness is not terribly different from a metronome, which reveals the beat of music.
As the countdown ticks off each second remaining of this year, your own consciousness dances to the programmed rhthym of thought. Each a wave in a sea of amber glass. Like any radio at the same frequency, any clock adjusted to match the correct time; it is a comforting thought that we all are calibrated to a very real beat. That comforting thought itself is what keeps us awake, ticking to a bright and hopeful New Year. Part I