The Cortico-Limbo-Thalamo-Cortical Circuits: An Update to the Original Papez Circuit of the Human Limbic System

The Papez circuit, first proposed by James Papez in 1937, is a circuit believed to control memory and emotions, composed of the cingulate cortex, entorhinal cortex, parahippocampal gyrus, hippocampus, hypothalamus, and thalamus. Pursuant to James Papez, Paul Yakovlev and Paul MacLean incorporated the prefrontal/orbitofrontal cortex, septum, amygdalae, and anterior temporal lobes into the limbic system. Over the past few years, diffusion-weighted tractography techniques revealed additional limbic fiber connectivity, which incorporates multiple circuits to the already known complex limbic network. In the current review, we aimed to comprehensively summarize the anatomy of the limbic system and elaborate on the anatomical connectivity of the limbic circuits based on the published literature as an update to the original Papez circuit.

Automated summary

The Papez circuit, proposed in 1937, is believed to control memory and emotions, consisting of several brain regions such as the cingulate cortex, hippocampus, hypothalamus, and thalamus. Recent advances in diffusion-weighted tractography techniques have expanded our knowledge of the limbic system, revealing additional connections between the prefrontal/orbitofrontal cortex, septum, amygdalae, and anterior temporal lobes. This review summarizes the anatomy of the limbic system and provides an updated understanding of its circuitry based on published literature.