Session: 4

PS4-14 | Structural plasticity of hippocampal dendritic spines following contextual fear memory reactivation

Candela Medina

Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA) - CONICET, Buenos Aires, Argentina

The processes of learning and long-term memory formation have been associated with changes in synaptic efficacy, which, in turn, tightly correlate with morphological alterations in dendritic spines. This structural plasticity can occur on previously existing or newly formed spines, thus allowing new information to be encoded. But, what happens with spine morphology when a consolidated memory trace is reactivated? Using a contextual fear conditioning paradigm in mice, we studied long-term morphological changes associated to the process of reconsolidation, by assessing spine density and morphology in pyramidal neurons of the dorsal hippocampus CA1 area. For this purpose, we modulated memory reconsolidation by inhibiting nuclear factor κB (NF-κB), a transcription factor that not only has a well described role in synaptic plasticity and memory, but which is also an important regulator of activity-induced synaptogenesis. Measuring multiple morphological variables (total spine length, neck width, head diameter and head volume) and using a semi-automatic high-throughput methodology, we classified dendritic spines according to their maturity and related their structural plasticity with memory recall and restabilization.