Abstract
The brain's ability to associate different stimuli is vital for long-term memory, but how neural ensembles encode associative memories is unknown. Here we studied how cell ensembles in the basal and lateral amygdala encode associations between conditioned and unconditioned stimuli (CS and US, respectively). Using a miniature fluorescence microscope, we tracked the Ca 2+ dynamics of ensembles of amygdalar neurons during fear learning and extinction over 6 days in behaving mice. Fear conditioning induced both up- and down-regulation of individual cells' CS-evoked responses. This bi-directional plasticity mainly occurred after conditioning, and reshaped the neural ensemble representation of the CS to become more similar to the US representation. During extinction training with repetitive CS presentations, the CS representation became more distinctive without reverting to its original form. Throughout the experiments, the strength of the ensemble-encoded CS-US association predicted the level of behavioural conditioning in each mouse. These findings support a supervised learning model in which activation of the US representation guides the transformation of the CS representation.
Original language | English (US) |
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Pages (from-to) | 670-675 |
Number of pages | 6 |
Journal | Nature |
Volume | 543 |
Issue number | 7647 |
DOIs | |
State | Published - Mar 30 2017 |
Funding
G. Venkatraman, B. Ahanonu, J. Li, B. Rossi, C. Herry, S. Ciocchi and J. Bacelo provided technical assistance. We appreciate Swiss National Science Foundation (B.F.G.), Swiss National Science Foundation, Ambizione (J.G.), US National Science Foundation (L.J.K.), Stanford University (L.J.K., J.D.M.), Simons Foundation (L.J.K.), and Helen Hay Whitney Foundation (M.C.L.) fellowships. A.L. received support from the Swiss National Science Foundation, Novartis Research Foundation, and an ERC Advanced grant. M.J.S. received support from HHMI and DARPA.
ASJC Scopus subject areas
- General