Fully consolidated associative memories are differentially affected by conditioned stimulus (CS) presentations at retrieval. Whereas a brief CS exposure promotes memory maintenance through reconsolidation (R), a prolonged one induces extinction (E) and inhibition of the conditioned response. Recently we have shown in rats that an intermediate CS exposure session fails to engage either R or E, leaving the consolidated memory in a so-called limbo state. Limbo is characterised by the absence of plasticity markers (present in R and E) and the insensibility of the original memory to amnestic treatments. Limbo has been observed in humans and non-human animals, including vertebrates and invertebrates. Little is known about the brain activity patterns that support memory maintenance or inhibition after retrieval. This project aims to study the neural activity landscapes associated to R, E and limbo during the retrieval of an aversive memory in humans.

The project will be based on analyzing behavioural performances during learning and retrieval of an aversive memory task in humans and registering and analyzing electroencephalographic (EEG) activity of the brain at the individual level. The project involves conducting the behavioural task with healthy volunteers, and acquiring and analysing individual EEG data. This is a collaborative project between Dr. Emiliano Merlo and Dr. Bekinschtein based on previous work from Emiliano and techniques developed in the Consciousness and Cognition Lab. The student researcher will have also the opportunity to visit Sussex University where Dr. Merlo has his new lab and perform some analyses there.

Merlo E., Milton A. L. & Everitt B. J. (2018). A Novel Retrieval-Dependent Memory Process Revealed by the Arrest of ERK1/2 Activation in the Basolateral Amygdala. The Journal of Neuroscience, 38 (13), 3199-3207. doi: 10.1523/JNEUROSCI.3273-17.2018.

Merlo E., Milton A. L., Goozée Z. Y., Theobald D. & Everitt B. J. (2014). Reconsolidation and extinction are dissociable and mutually exclusive processes: behavioural and molecular evidences. The Journal of Neuroscience, 34 (7), 2422-31. doi: 10.1523/JNEUROSCI.4001-13.2014.

Mueller EM, Panitz C, Hermann C, Pizzagalli DA. (2014). Prefrontal Oscillations during Recall of Conditioned and Extinguished Fear in Humans. The Journal of Neuroscience, 34 (21), 7059-7066. doi: 10.1523/JNEUROSCI.3427-13.2014.