Abstract
A consensus on the prefrontal cortex (PFC) holds that it is pivotal
for flexible behavior and the integration of the cognitive, affective,
and motivational domains. Certain models have been put forth and
a dominant model postulates a hierarchical anterior–posterior gradient.
The structural connectivity principles of this model dictate that
increasingly anterior PFC regions exhibit more efferent connections
toward posterior ones than vice versa. Such hierarchical asymmetry
principles are thought to pertain to the macaque PFC. Additionally,
the laminar patterns of the connectivity of PFC regions can be used
for defining hierarchies. In the current study, we formally tested the
asymmetry-based hierarchical principles of the anterior–posterior
model by employing an exhaustive dataset on macaque PFC connectivity
and tools from network science. On the one hand, the
asymmetry-based principles and predictions of the hierarchical
anterior–posterior model were not confirmed. The wiring of the
macaque PFC does not fully correspond to the principles of the
model, and its asymmetry-based hierarchical layout does not follow
a strict anterior–posterior gradient. On the other hand, our results
suggest that the laminar-based hierarchy seems a more tenable
working hypothesis for models advocating an anterior–posterior
gradient. Our results can inform models of the human PFC.
