The presubiculum is a subarea of the parahippocampal region and plays a crucial role in spatial navigation. In particular, excitatory neurons in the presubiculum selectively fire when the head of the animal points to a specific direction. This head-direction selectivity emerges before eye opening in rodents and is maintained in adulthood through synaptic interactions between excitatory and inhibitory neurons. Although the developmental spatial representation of the presubiculum has been electrophysiologically studied, the histological characteristics of the developing presubiculum are poorly understood.
In this study, we anatomically identified the presubiculum using an anterograde tracer injected into the anterior thalamic nucleus and found that the superficial layers of the presubiculum could be delimited by the expression of vesicular glutamate transporter 2 (VGluT2). We also immunostained the brain slices of mice aged from neonates to adults using antibodies against parvalbumin (PV) and somatostatin (SOM) and found that in the presubicular superficial layers, PV-positive interneurons progressively increased in number during development, whereas the number of SOM-positive neurons exhibited no specific trend.