Granger causal connectivity dissociates navigation networks that subserve allocentric and egocentric path integration

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Spatial Navigation

Background:

• The retrosplenial complex (RSC) plays a key role in transforming egocentric and allocentric spatial information into spatial reference frames (SRFs).
• Its extensive connections with other brain regions highlight its importance in the human navigation network.
• Understanding the dynamic interactions within this network is crucial for deciphering spatial navigation mechanisms.

Purpose of the Study:

• To investigate the dynamic causal interactions between brain regions involved in a virtual navigation task.
• To identify information flow patterns within the human navigation network using EEG data.
• To explore the specific role of the RSC in different navigation strategies and orientation changes.

Main Methods:

• Electroencephalography (EEG) signals were recorded during a virtual navigation task.
• Independent Component Analysis (ICA) was used to decompose EEG signals.
• Direct short-time Directed Transfer Function (sdDTF) was applied to analyze information flow between independent components (ICs).

Main Results:

• Significant information flow was observed in the theta (4-7 Hz) and alpha (8-13 Hz) frequency bands between various cortical regions, including the RSC.
• An occipito-parieto-RSC network showed dominant activity in participants using allocentric spatial reference frames.
• The RSC exhibited the strongest causal flow during orientation changes, indicating its role in processing heading information.

Conclusions:

• The findings support the involvement of the RSC, parietal, and occipital cortices in transforming egocentric visual-spatial information into an allocentric reference frame.
• The RSC appears to be a critical hub for processing heading changes during human navigation.
• Dynamic causal interactions within the navigation network, especially involving the RSC, are essential for effective spatial orientation and navigation.