Authors:

PULVERMULLER, F. & SHTYROV, Y.

Reference:

Year of publication:

2007

CBU number:

6918

Abstract:

We report here a new brain signature of memory trace activation in the human brain revealed by magnetoencephalography and distributed source localization. Memory circuits distributed over distant cortical areas can activate these areas in a fine-grained temporal order, similar to the spatio-temporal patterns previously known from local cortical circuits called synfire chains. The large-scale spatio-temporal patterns can be picked up in the source images underlying magnetic brain responses. We found that acoustic signals perceived as speech sounds elicited a well-defined spatio-temporal pattern of sequential activation of superior temporal and inferior frontal cortex, whereas the same identical stimuli, when perceived as noise, sparked the same areas without a significant difference in activation delays. The strength of local cortical sources reflected additional lexical, semantic and syntactic features of speech. We conclude that spatio-temporal patterns, especially cortical activation latencies in the millisecond range, represent a brain code of memory circuits.