What significant observation did Pierre Jean Georges Cabanis make after witnessing decapitation?

Cabanis made the significant observation that movements can occur after death, particularly in the context of his studies related to decapitation. This observation highlighted the disconnection between the brain and voluntary movement, challenging existing notions about the brain's exclusive role in generating consciousness and movement. His experiences with observing decapitated animals demonstrated that, even after such a severe trauma, certain reflexive movements persisted, leading to a deeper inquiry into the mechanisms of the nervous system and the relationship between the body and consciousness. This was an important contribution to the understanding of physiological processes in the absence of brain activity, suggesting that not all movements are solely dependent on conscious control.