Main Menu (Mobile)- Block
- Our Research
-
Support Teams
- Overview
- Anatomy and Histology
- Cell and Tissue Culture
- Cryo-Electron Microscopy
- Drosophila Resources
- Electron Microscopy
- Flow Cytometry Shared Resource (FCSR)
- Gene Targeting and Transgenics
- Janelia Experimental Technology
- Light Microscopy
- Media Prep
- Molecular Biology
- Project Pipeline Support
- Project Technical Resources
- Quantitative Genomics
- Scientific Computing Software
- Scientific Computing Systems
- Viral Tools
- Vivarium
- Open Science
- You + Janelia
- About Us
Main Menu - Block
- Overview
- Anatomy and Histology
- Cell and Tissue Culture
- Cryo-Electron Microscopy
- Drosophila Resources
- Electron Microscopy
- Flow Cytometry Shared Resource (FCSR)
- Gene Targeting and Transgenics
- Janelia Experimental Technology
- Light Microscopy
- Media Prep
- Molecular Biology
- Project Pipeline Support
- Project Technical Resources
- Quantitative Genomics
- Scientific Computing Software
- Scientific Computing Systems
- Viral Tools
- Vivarium

Note: Research in this publication was not performed at Janelia.
Abstract
Hippocampal neurons can display reliable and long-lasting sequences of transient firing patterns, even in the absence of changing external stimuli. We suggest that time-keeping is an important function of these sequences, and propose a network mechanism for their generation. We show that sequences of neuronal assemblies recorded from rat hippocampal CA1 pyramidal cells can reliably predict elapsed time (15-20 s) during wheel running with a precision of 0.5 s. In addition, we demonstrate the generation of multiple reliable, long-lasting sequences in a recurrent network model. These sequences are generated in the presence of noisy, unstructured inputs to the network, mimicking stationary sensory input. Identical initial conditions generate similar sequences, whereas different initial conditions give rise to distinct sequences. The key ingredients responsible for sequence generation in the model are threshold-adaptation and a Mexican-hat-like pattern of connectivity among pyramidal cells. This pattern may arise from recurrent systems such as the hippocampal CA3 region or the entorhinal cortex. We hypothesize that mechanisms that evolved for spatial navigation also support tracking of elapsed time in behaviorally relevant contexts.