Coherence is a measure of the similarity in field-potential waveforms in different areas. Our hypothesis would thus predict that the coherence between the EEG in the fusiform gyrus and that in many other structures will phasically increase at around 200ms. In fact, this is what was observed. High Frequency Coherence and Phase Maps. Face stimuli elicit a sharp and transient increase in coherence centered at 200 ms.
Words fail to produce a similar change in coherence.
This was also observed, and indeed the phase lag from the fusiform to the other structures was a monotonic function of their separation, with the slope of the function corresponding to the conduction velocity that one would expect for cortico-cortical connections. Phase Angle Versus Distance. The phase measured between the fusiform gyrus and other regions increased with increasing distance separating the two electrode contacts. Phase is measured in 0-2pi radians and is assumed to be positive based on the role of the fusiform in early face processing. Studies of the mnestic processing of faces are described on the declarative memory page of this site.