Persistent activity and memory in the entorhinal cortex.

The entorhinal cortex (EC) is an essential component of the medial temporal lobe long-term-memory system. Recently, Egorov et al. demonstrated that neurons in layer 5 of the EC show graded persistent activity: each neuron could maintain a constant rate firing over several minutes, even in the absence of input from other neurons. These findings suggest that layer-5 EC neurons could play a central role in the formation of associations among stimuli that occur at different times.