  Synchronization of finite spike sequences is the way two brain regions
compare their content and extract the most suitable sequence. This is the core
of the linguistic comparison between a word and a previous one retrieved by
memory. Classifying the information content of neural spike trains, an
uncertainty relation emerges between the bit size of a word and its duration.
This uncertainty affects the task of synchronizing spike trains of different
duration representing different words, entailing the occurrence of entangled
sequences, so that word comparison amounts to a measurement based quantum
computation. Entanglement explains the inverse Bayes inference that connects
different words in a linguistic search. The behaviour here discussed provides
an explanation for other reported evidences of quantum effects in human
cognitive processes lacking a plausible framework, since either no assignment
of an appropriate quantum constant had been associated, or speculating on
microscopic processes dependent on Planck's constant resulted in unrealistic
de-coherence times.
