This 2015 Belgian human study found:
“Medial temporal lobe structures (perirhinal cortex, amygdala, hippocampus) and anterior inferior temporal cortex responded abruptly when sufficient information for familiar face recognition was accumulated.
Activation in ventral occipitotemporal face-preferential regions increased with visual information, independently of long-term face familiarity.
[The researchers] isolated the discriminative neural responses to unfamiliar and familiar faces by slowly increasing visual information (i.e., high-spatial frequencies) to progressively reveal faces of unfamiliar or personally familiar individuals.”
A limitation of the study was, however:
“Behavioral data were acquired from only 11 subjects because of a technical error.”
http://www.pnas.org/content/112/35/E4835.full “Neural microgenesis of personally familiar face recognition”