Electrophysiological and cellular imaging studies show that only a portion of neurons are involved in a given memory. Why is one neuron, rather than its neighbor, included in a particular memory? Han et al. found that neurons in the lateral amygdala that show the greatest activity of the transcription factor CREB at the time of the encoding of an auditory fear memory are those that preferentially express the activity-regulated gene Arc after the recall of the memory. Thus, neurons compete during memory formation, and CREB helps to determine the winners.
J.-H. Han, S. A. Kushner, A. P. Yiu, C. J. Cole, A. Matynia, R. A. Brown, R. L. Neve, J. F. Guzowski, A. J. Silva, S. A. Josselyn, Neuronal competition and selection during memory formation. Science 316, 457-460 (2007). [Abstract] [Full Text]