The piriform cortex (PCx) is essential for learning of odor information. The current view postulates odor learning in the PCx is mainly due to plasticity in intracortical (IC) synapses, while odor information from the olfactory bulb carried via the lateral olfactory tract (LOT) is “hardwired”. Here we revisit this notion by studying location and pathway dependent plasticity rules. We find that in contrast to the prevailing view, synaptic and optogenetically activated LOT synapses undergo strong and robust long-term potentiation (LTP) mediated by only few local NMDA-spikes delivered at theta frequency, while global spike timing dependent plasticity protocols (STDP) failed to induce LTP in these distal synapses. In contrast, IC synapses in apical and basal dendrites undergo plasticity with both NMDA-spikes and STDP protocols but to a smaller extent compared with LOT synapses. These results are consistent with a self-potentiating mechanism of odor information via NMDA-spikes which can form branch-specific memory traces of odors that can further associate with contextual IC information via STDP mechanisms to provide cognitive and emotional value to odors.
Bibliographical noteFunding Information:
We thank Y. Schiller for helpful discussions throughout the project and helpful comments on the manuscript and B. Mel for helpful comments on the manuscript. We thank Irena Reiter for excellent technical assistance. This study was supported by Israeli Science Foundation (J.S.), German Israeli Foundation (J.S.) and Prince funds (J.S.).
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ASJC Scopus subject areas
- Neuroscience (all)
- Biochemistry, Genetics and Molecular Biology (all)
- Immunology and Microbiology (all)