Internally generated time in the rodent hippocampus is logarithmically compressed
- Boston University, United States
- Brandeis University, United States
Abstract
The Weber-Fechner law proposes that our perceived sensory input increases with physical input on a logarithmic scale. Hippocampal 'time cells' carry a record of recent experience by firing sequentially during a circumscribed period of time after a triggering stimulus. Different cells have'time fields' at different delays up to at least tens of seconds. Past studies suggest that time cells represent a compressed timeline by demonstrating that fewer time cells fire late in the delay and their time fields are wider. This paper asks whether the compression of time cells obeys the Weber-Fechner Law. Time cells were studied with a hierarchical Bayesian model that simultaneously accounts for the firing pattern at the trial level, cell level, and population level. This procedure allows separate estimates of the within-trial receptive field width and the across-trial variability. After isolating across-trial variability, time field width increased linearly with delay. Further, the time cell population was distributed evenly along a logarithmic time axis. These findings provide strong quantitative evidence that the neural temporal representation in rodent hippocampus is logarithmically compressed and obeys a neural Weber-Fechner Law.
Data availability
The data and code for all the analysis is available on Open Science Framework under the corresponding author (https://osf.io/pqhjz/)
Article and author information
Author details
Funding
Multidisciplinary University Research Initiative (N00014-16-1-2832)
- Rui Cao
- Stephen J Charczynski
- Michael E Hasselmo
- Marc W Howard
National Institute of Biomedical Imaging and Bioengineering (R01EB022864)
- Rui Cao
- Stephen J Charczynski
- Marc W Howard
National Institute of Mental Health (R01MH112169)
- Rui Cao
- John H Bladon
- Stephen J Charczynski
- Marc W Howard
National Institute of Mental Health (R01MH095297)
- Rui Cao
- John H Bladon
- Stephen J Charczynski
- Michael E Hasselmo
- Marc W Howard
National Institute of Mental Health (R01MH132171)
- John H Bladon
- Michael E Hasselmo
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All procedures were conducted in accordance with the requirements set by the National Institutes of Health, and were approved by the Boston University Institutional Animal Care and Use Committee (BU IACUC protocol #16-021). Animals were given ad-libitum water and maintained at a minimum of 85% of their ad libitum feeding body weight during all behavioral training and testing. Surgeries were performed under isoflurane anesthesia, and analgesics were administered postoperatively.
Copyright
© 2022, Cao et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Internally generated time in the rodent hippocampus is logarithmically compressed
eLife 11:e75353.
https://doi.org/10.7554/eLife.75353
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