Interlamellar CA1 network in the hippocampus

It has generally been thought that CA1 cells form only negligible connections with each other along the longitudinal axis of the hippocampus. But if CA1 cells were interconnected in an effective autoassociational network, this information would add a critical new dimension to our understanding of cellular processing within this structure. Here, we report the existence of a well-organized, longitudinally projecting synaptic network among CA1 pyramidal neurons. We further show that synapses of this network are capable of supporting synaptic plasticity, including long-term potentiation, and a short-term memory mechanism called "dendritic hold and read." These observations will contribute to the construction of more realistic models of hippocampal information processing in behavior, memory, and other cognitive functions.