|Soul > Part III > Chapter 31 > Consciousness has two dimensions|
In the last decade, researchers have gradually reached a consensus that consciousness depends on the levels of two elements: arousal and awareness (Figure 31f). If the levels of both elements are very low, such as coma, there is no consciousness at all. The vegetative state has a high level of arousal, but its awareness is very low. Since awareness is required for being conscious, the vegetative patients do not have consciousness.
Researchers have further discovered that the branch of the ascending arousal system leading to BF is directly related to arousal, whereas the branch leading to the thalamus is responsible for awareness (Lutkenhoff et al., 2015; Hindman et al., 2018). Stimulation of BF cholinergic neurons increases transitions from NREM sleep to wakefulness (Zant et al., 2016). However, the arousal is not due to BF itself, and awareness is not induced by the thalamus per se. Both areas have widepread projection to the cerebral cortex. Over the past few decades, neuroimaging research has established that the functional connectivity between various regions of the brain is crucial for the emergence of consciousness (Wu et al., 2015).
Author: Frank Lee