  "Flow" is a hyper-engaged state of consciousness most commonly described in
athletics, popularly termed "being in the zone." Quantitative research into
flow has been hampered by the disruptive nature of gathering subjective
reports. Here we show that a passive probe (suppression of Auditory Evoked
Potential in EEG) that allowed our participants to remain engaged in a
first-person shooting game while we continually tracked the depth of their
immersion corresponded with the participants' subjective experiences, and with
their objective performance levels. Comparing this time-varying record of flow
against the overall EEG record, we identified neural correlates of flow in the
anterior cingulate cortex and the temporal pole. These areas displayed
increased beta band activity, mutual connectivity, and feedback connectivity
with primary motor cortex. These results corroborate the notion that the flow
state is an objective and quantifiable state of consciousness, which we
identify and characterize across subjective, behavioral and neural measures.
