Acute stress modulates hippocampal to entorhinal cortex communication

Area of Science:

• Neuroscience
• Synaptic Plasticity
• Computational Neuroscience

Background:

• Feed-forward inhibition is essential for synaptic information processing in the hippocampal-entorhinal loop.
• While hippocampal targets are studied, entorhinal cortex feed-forward inhibitory interneurons remain unidentified.

Purpose of the Study:

• To identify cortical interneurons mediating feed-forward control in the entorhinal cortex.
• To investigate the function of these interneurons during hippocampal-driven activity.

Main Methods:

• Utilized sharp-wave ripple oscillations as a natural stimulus for the entorhinal cortex.
• Studied synaptic interactions in deep layers of the entorhinal cortex.

Main Results:

• Discovered CB1R-expressing interneurons in deep entorhinal cortex layers act as key relays.
• These interneurons translate hippocampal excitation into inhibition of cortical pyramidal cells.
• Endocannabinoid signaling strongly modulates this inhibitory impact.

Conclusions:

• CB1R-expressing interneurons are critical for feed-forward inhibition in the entorhinal cortex.
• Their function is regulated by endocannabinoids and influenced by neuronal activity and stress.