Fig. 10.

Proposed model of feedforward inhibition involving R-LM and P-LM cells. Schaffer collaterals (SC) simultaneously excite R-LM and P-LM cells, as well as CA1 pyramidal cells (PC). Excitation of R-LM and P-LM cells then results in inhibition occurring at pyramidal cell distal dendrites in SLM. The effect of this inhibition is to selectively sequester information flow from the entorhinal cortex to CA1 by attenuating perforant pathway (PP) synapses on CA1 pyramidal cell distal dendrites. Thus in this model, R-LM and P-LM cells promote and isolate information flow from CA3 to CA1, and thereby act as “input-biasing” interneurons.