San trance dance: embodied experience and neurological mechanisms

ABSTRACT The San trance dance has attracted considerable attention in terms of ethnography and rock art, as well as the human capacity for altered states of consciousness. However, its implications for shamanic ritual and associated states of consciousness remain undeveloped without understanding the brain mechanisms involved. Here I integrate previous models of trance with findings from neuroscience and ethnographic reports to outline a neurological model. I suggest that physical exertion leads to activation of the sympathetic nervous system and release of noradrenaline along the spine leading to the feeling of rising energy the San call !num. Associated hyperventilation activates the amygdala and insula producing fear and the experience of being underwater. With trance, changes in activity of the insula lead to disruption of the right temporal parietal junction, blurring self/other distinctions and leading to body distortion and the experience of flight. Resulting changes in face and body perception are integrated with pre-existing social information in the anterior temporal lobes generating images of human, animal and theriomorphic figures. I also suggest that persistent hunting leads to sustained focus underlying the ability of San men to undergo trance, and makes the Eland central to images of trance in San rock art.