Coherence among head direction cells before eye opening in rat pups

Area of Science:

• Neuroscience
• Cognitive Science
• Developmental Biology

Background:

• Mammalian navigation relies on an internal spatial map.
• Specialized cells in the hippocampus and parahippocampal cortices form this map.
• Head direction cells are key for directional tuning in navigation.

Purpose of the Study:

• Investigate head direction cell expression before sensory exploration.
• Determine the necessity of vision for developing directional tuning.
• Examine the developmental trajectory of head direction tuning.

Main Methods:

• Recorded neural activity in rat pups from postnatal day 11 (P11) onward.
• Focused on the pre- and parasubiculum, and medial entorhinal cortex.
• Analyzed head direction cell firing patterns before and after eye opening.

Main Results:

• Head direction cells were present from P11, prior to eye opening.
• Early firing rates were lower and directional tuning less stable than in adults.
• Cells exhibited coherent drift, maintaining relative directions between trials.
• Directional tuning stabilized post-eye opening.

Conclusions:

• Head direction tuning develops intrinsically before visual input.
• A hardwired attractor network likely underlies head direction representation.
• Visual input is essential for anchoring directional firing to the external world.