Postnatal development of the entorhinal cortex: A stereological study in macaque monkeys

Area of Science:

• Neuroscience
• Developmental Biology
• Cognitive Neuroscience

Background:

• The entorhinal cortex is crucial for neocortex-hippocampus communication.
• Hippocampal formation structures show diverse postnatal maturation patterns.

Purpose of the Study:

• To quantify neuron number, soma size, and layer volumes in the developing monkey entorhinal cortex.
• To investigate developmental differences across entorhinal cortex subdivisions and layers.

Main Methods:

• Postnatal developmental analysis of the monkey entorhinal cortex.
• Estimation of neuron number, neuronal soma size, and layer volumes.

Main Results:

• No significant changes in neuron number were observed across development.
• Distinct developmental trajectories for neuronal soma size and layer volumes were found in different entorhinal cortex subdivisions.
• Early maturation of superficial layers (I, II) and caudal regions (Ec, Ecl) contrasted with late maturation in rostral regions (Er).

Conclusions:

• Differential maturation of entorhinal cortex circuits supports distinct hippocampus-dependent memory functions.
• Early caudal maturation may facilitate spatial processing, while late rostral maturation aids episodic memory formation.