What Brain Structures are Required for Consciousness?
I have no doubt that every structure in the brain influences consciousness. The specific question I ask here is, what structures are necessary? Phrased differently, are there any regions of the brain that, if injured or removed, cause a formerly conscious being to lose consciousness?
The answer below is based largely on lesion studies reviewed in “Neuropsychology of Consciousness: Some History and a Few New Trends,” by Giovanni Berlucchi and Carlo Alberto Marzi.
Importantly, in that same review they write the following:
“Attempts at localizing a hub for consciousness in the brain on the basis of the effects of brain lesions or dysfunctions that lead to unconsciousness are probably misconceived, insofar as consciousness is best seen as a global function of the brain in action.”
Is anyone home?
Lesions to the brain stem, thalamus, or large parts of the cerebral cortex all disrupt consciousness.
If an individual’s brain stem is damaged, they typically become comatose. The lights are off but someone might be inside.
If an individual’s thalamus or large parts of the cerebral cortex are damaged, they lose self awareness even though they are likely still awake. The lights are on but no one is home.
