Age-Dependent Oscillatory Dynamics Underpinning Theta Sequences in the Developing Hippocampus

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Rafael Pedrosa² (rhapedrosa@gmail.com), Jake Swann¹, Laurenz Muessig¹, Thomas Wills¹, Francesca Cacucci²; ¹Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK, ²Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK

The hippocampus gradually matures during early postnatal development, supporting the emergence of cognitive functions such as spatial memory emerging from 3 weeks of age onwards. Here, we investigate the emergence of gamma oscillations and their relationship with hippocampal theta sequences in pre, post-weaning and adult rats, during spatial exploration. Using a combination of spiking, local-field potential and current source density (CSD) analysis, we demonstrate that medium gamma oscillations in CA1 increase in power and become more prominent from adolescence to adulthood. Notably, gamma-theta coupling also strengthens during this period. Furthermore, our findings suggest that the emergence of theta sequences—temporally compressed representations of spatial trajectories—may be facilitated by the maturation of medium gamma oscillations. These results shed light on the developmental dynamics of hippocampal network oscillations and their role in supporting memory consolidation and spatial coding.

Topic Area: LONG-TERM MEMORY: Development & aging