1. An apparatus comprising: an ambulatory intrinsic brain signal processor circuit, configured to be coupled to a plurality of electrodes, the signal processor circuit comprising: a digital multiplexer circuit, configured to be coupled to the electrodes, and configured to multiplex brain signal data from different electrodes together into a multiplexed data stream; an ambulatory transceiver circuit, configured to wirelessly communicate information to a remote transceiver, and configured to wirelessly receive user-programming information from the remote transceiver; and a controller circuit, configured to: select N user-specified electrodes that contribute data to the multiplexed data stream; select a data resolution of the electrodes that contribute data to the multiplexed data stream; and select, for each particular electrode that contributes data to the multiplexed data stream, one, from between user-selectable choices including all three, of the following settings: (1) neural action potential data, from which neural field potential data has been reduced or removed; (2) neural field potential data, from which neural action potential data has been reduced or removed; and (3) both neural action potential and neural field potential data, and wherein the user-selected one of the three settings is used to automatically select an appropriate gain or frequency setting of a sense amplifier corresponding to the particular electrode; and a Normal template, providing an indication of a set of correlations of brain potentials between all N user-specified electrodes contributing to the multiplexed data stream, during at least one neurologically non-abnormal time period of the subject; a Non-Normal template, providing an indication of a set of correlations of the brain potentials between all N user-specified electrodes contributing to the multiplexed data stream, during at least one pre-neurologically-abnormal time period or neurologically abnormal time period of the subject; a monitoring circuit, configured to form, during a sampling time period, an indication of a set of correlations of the brain potentials between all N user-specified electrodes contributing to the multiplexed data stream, using the at least two different locations of a brain of the subject; and an upcoming neurologically-abnormal-state prediction circuit, configured to predict an upcoming neurologically abnormal state at least in part by comparing the indication of the set of correlations obtained during the sampling time period to each of the Normal and Non-Normal templates.