The invention relates to brain signal tracking. In one embodiment, a brain signal tracking system includes a probe to be inserted into brain blood vessels, and including an electrode, a signal generator to generate a calibration signal to be emitted by the electrode at different locations in the blood vessels, a tracking subsystem to track locations of the electrode, head surface electrodes to beapplied to a head, head surface electrodes configured to detect the calibration signal at respective amplitude values, with a distribution of the respective amplitude values over the head surface electrodes being indicative of a corresponding one of the tracked locations from which the calibration signal was emitted by the electrode, and processing circuitry to find a function to compute a sourcelocation in the brain of a brain signal responsively to the distribution of the respective amplitude values of the calibration signal over the head surface electrodes for ones of the tracked locations.
BRAIN SIGNAL TRACKING