BY DR. JOSE MA. EDUARDO PALU-AY DACUDAO
(January 2025 edition)
TO ELABORATE further, for the MIND to function we need be conscious in the Neurological sense of having an appropriately high enough sensorium. An unconscious person is a mindless one. That probably means that the ascending reticular activating system (ARAS), plays an indispensable role in whatever the MIND is. Nullifying the ARAS denies the MIND its grounding to one of its important anchors in the concrete anatomy of the brain.
For the nerds and intellectuals among readers, briefly the Ascending Reticular Activating System (ARAS) is made up of the neuronal cell bodies adjacent to the ventricular system in the upper pons (metencephalon), midbrain (mesencephalon), and thalamus (diencephalon). These neuronal cell bodies must be activated for the mind to do any minding at all.
To sum up so far, we have sensory inputs to the brain and their pathways as briefly explained above. We have an activated ARAS for us to be conscious enough to be aware of these sensory inputs and to subsequently act volitionally. We have the upper motor neurons (UMNs) to enact volitional movements through pathways briefly explained above.
So what connects the areas of the brain that senses to the decision to fire the UMN, thus initiating volitional movement? Generations of medical students have been taught that volitional movement is caused by UMNs firing, but what causes UMNs to fire? No one seems to really know. There lies a black hole.
Let’s look at it philosophically.
In the philosophy of the mind there is a thing called goal-directedness. We sense, perceive, integrate in memories, emotions, and aspirations, and after all that we use the data we had perceived to direct our actions in ways that can achieve our goals. But the devil is in the details. We have learned that there is a well-defined process by which the UMN directs the LMN to direct the muscle to move.
So what is the process by which the MIND chooses it options based on inputs from the sensory areas of the brain? It’s a blackhole. How does the MIND direct the upper motor neuron to fire? It’s another blackhole.
There are blackholes in between the MIND and volitional movement.
Let’s repeat it for its importance. For generations, medical students have been hearing countless lectures on the following process:
Upper motor neuron fires. Lower motor neuron fires. Muscle moves. But, the question remains: WHAT fires before the upper motor neuron?
As far as I know, there is nothing much in literature that offers testable hypotheses on the subject of how the mind creates volitional movement.
Perhaps it’s because we ourselves do not fully comprehend the MIND. Even if it’s our own personal MINDs. (To be continued)/PN
