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Feb28-13, 12:38 AM
zoobyshoe's Avatar
P: 5,630
To question #1:

Everything I've read implicates the thalamus as the critical structure whose function is being disrupted when people lose consciousness due to trauma, seizure, disease.

The thalamus also plays an important role in regulating states of sleep and wakefulness.[9] Thalamic nuclei have strong reciprocal connections with the cerebral cortex, forming thalamo-cortico-thalamic circuits that are believed to be involved with consciousness. The thalamus plays a major role in regulating arousal, the level of awareness, and activity. Damage to the thalamus can lead to permanent coma.

Although the shape of the whole brain is distorted by the kind of impact a hard punch represents, it is specifically distortion of the thalamus which probably causes temporary unconsciousness.

However, the thalamus itself is regulated by the reticular formation of the brainstem:
Sleep and consciousness - The reticular formation has projections to the thalamus and cerebral cortex that allow it to exert some control over which sensory signals reach the cerebrum and come to our conscious attention. It plays a central role in states of consciousness like alertness and sleep. Injury to the reticular formation can result in irreversible coma.
So, trauma to one, the other, or both at once, could cause temporary unconsciousness.

Apropos: I can't recommend any activity that involves blows to the head: