During hippocampal inactivation, grid cells maintain synchrony, even when the grid pattern is lost

Area of Science:

• Neuroscience
• Computational Neuroscience

Background:

• Grid cells in the medial entorhinal cortex (MEC) are crucial for spatial navigation.
• Theories on grid cell network formation often involve hippocampal input.
• Previous studies have investigated grid cell activity during hippocampal manipulation.

Purpose of the Study:

• To investigate the dependence of grid cell firing associations on hippocampal inputs.
• To determine if network coherence in MEC grid cells persists without hippocampal influence.

Main Methods:

• Re-analysis of electrophysiological data from rat MEC recordings (Bonnevie et al., 2013).
• Examination of temporal and spatial firing correlations of simultaneously recorded grid cells.
• Analysis conducted before and during hippocampal inactivation.

Main Results:

• Grid cell network coherence was observed even when hippocampal input to the MEC was inactivated.
• This coherence was present in both regular grid cells and those that transformed into head-direction cells.
• Findings indicate network activity independent of hippocampal signals.

Conclusions:

• The intrinsic connectivity within the MEC likely plays a significant role in organizing grid cell network activity.
• Results support models where phase relations between MEC grid cells are determined by intrinsic network properties.
• Hippocampal input is not essential for maintaining MEC grid cell network coherence.