  The human brain is ultimately responsible for all thoughts and movements that
the body produces. This allows humans to successfully interact with their
environment. If the brain is not functioning properly many abilities of human
can be damaged. The goal of cerebral signal analysis is to learn about brain
function. The idea that distinct areas of the brain are responsible for
specific tasks, the functional segregation, is a key aspect of brain function.
Functional integration is an important feature of brain function, it is the
concordance of multiple segregated brain areas to produce a unified response.
There is an amplified feedback mechanism in the brain called reentry which
requires specific timing relations. This specific timing requires neurons
within an assembly to synchronize their firing rates. This has led to increased
interest and use of phase variables, particularly their synchronization, to
measure connectivity in cerebral signals. Herein, we propose a comprehensive
review on concepts and methods previously presented for assessing cerebral
synchrony, with focus on phase synchronization, as a tool for brain
connectivity evaluation.
