The contribution of oscillatory synchrony in the primate amygdala-prefrontal pathway to aversive learning remains largely unknown. We found increased power and phase synchrony in the theta range during aversive conditioning. The synchrony was linked to single-unit spiking and exhibited specific directionality between input and output measures in each region. Although it was correlated with the magnitude of conditioned responses, it declined once the association stabilized. The results suggest that amygdala spikes help to synchronize ACC activity and transfer error signal information to support memory formation.

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In this paper, the problem of carrier synchronization for coded signals in burst communications is addressed. Low SNR, phase jitter, and relatively large initial frequency offset are assumed. A new concept is introduced: synchronization using an array of Kalman trackers, where each tracker is associated with different initial conditions. Based on this concept, an improved joint data detection and carrier synchronization scheme for trellis coded signals is proposed. The proposed scheme uses an array of decision directed Kalman trackers, each initialized with different initial conditions and updated based on tentative decisions from the Viterbi decoder. This scheme reduces drastically the number of cycle slips and hang-ups encountered in the classical PLL and improves significantly the receiver's BER performance. The implementation complexity is relatively low and no special hardware is required.