Coordinated head direction representations in mouse anterodorsal thalamic nucleus and retrosplenial cortex

Area of Science:

• Neuroscience
• Spatial Navigation
• Systems Neuroscience

Background:

• A robust sense of direction is vital for survival, integrating self-motion and external sensory information.
• The mechanisms by which visual cues update head direction (HD) representations are not fully understood.
• The retrosplenial cortex (RSC) is crucial for spatial representation and encodes HD information.

Purpose of the Study:

• To investigate the temporal dynamics and coordination of HD representations between the RSC and the anterodorsal nucleus of the thalamus (ADn).
• To elucidate the role of visual cues in updating HD representations.
• To examine the anatomical and functional connectivity underlying HD information flow.

Main Methods:

• Simultaneous two-area tetrode recordings were performed in rodents.
• HD representations in the RSC and ADn were monitored during visual cue rotation and in darkness.
• Anatomical and functional connectivity between ADn and RSC were assessed.

Main Results:

• HD representations in the RSC were found to be nearly synchronous with those in the ADn, even during visual cue rotation.
• This coordination between RSC and ADn was maintained even in the absence of visual cues (darkness).
• Connectivity analysis supported a strong feedforward drive of HD information from ADn to RSC, with limited feedback.

Conclusions:

• The findings suggest a concerted, global update of the HD reference frame across both thalamus and cortex.
• This coordinated activity ensures a stable and accurate sense of direction, critical for spatial orientation.
• The results highlight the importance of the ADn-RSC pathway in integrating sensory information for navigation.