What can small-animal Positron Emission Tomography tell us about memory expression, labilization and reconsolidation?

DE LA FUENTE V

Buenos Aires

Congreso; 2016. Second FALAN Congress; 2016

Sociedades de Neurociencias de varios países de Latinoamérica

Speaker: Verónica de la Fuente. Symposia: The consequences of memory retrieval: reconsolidation, extinction or nothing at all. Chair: Pedro Bekinschtein.Common techniques for studying memory have traditionally involved global processes affecting drugs, like protein synthesis or transcription inhibitors. In the past 15 years, more cellular specific-directed mechanisms drugs have been incorporated. The same rationale applies for brain areas affected by these drugs, while early studies involved systemic administrations, recent ones are directed to target specific areas or cell types. Within the advent of imaging techniques that allowed whole brain studies, memory has started to be considered in a ?brain wide? manner, mostly in humans. However, there were no available techniques that allowed scientists to study whole brain activity at the same time in small animals until few years ago. In this talk I will focus on our results using small-animal Positron Emission Tomography (PET) measuring differential glucose consumption. The main goal was to study the brain areas involved in labilization/reconsolidation of fear memory using a contextual fear conditioning paradigm in mice. We found differences in glucose consumption mainly in zones comprising the ectorhinal cortex, the temporal association cortex, hippocampus and amygdala in re-exposed animals compared to non-re-exposed animals. The differences in glucose consumption showed a marked temporal course, they were context-specific, and were either hyper- or hypo-consumptions. Moreover, animals that only evoked but did not labilized the memory trace showed significant differences compared to mice that labilized and reconsolidated. Our work opens new insights in the study of the dynamics of activation of brain areas during memory labilization/reconsolidation by using a novel technique for the field, which in combination with others like immunofluorescence, DREADDS and electrophysiology helps to unravel the pending question about circuits involved in labilization/reconsolidation.