Ongoing projects
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Improving episodic memory through laughter: Unraveling the underlying neural circuit dynamics
Episodic memory, our fascinating ability to mentally relive past experiences, lies at the core of human cognition. Emotions affect the accuracy and the amount of details we are able to recall from memories. While most studies so far have focused on negative emotions, recent behavioral findings suggest that laughter has the ability to boost memory. Memory enhancement through positive emotions has remained dramatically underexplored and its precise neural underpinnings are unknown. We will first seek to quantify the specific impact of laughter on episodic memory formation and retrieval. Second, we will characterize the involved brain networks using magnetoencephalography and connectivity techniques. This multidisciplinary project carries promising mid- and long-term implications for enhancing memory and learning in healthy participants and has potential therapeutic applications.
Keywords: Episodic memory, Laughter, Positive emotion, MEG, Functional Connectivity.
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Oscillatory representations of olfactory stimuli during episodic memory encoding and retrieval
Episodic memory, our ability to encode and retrieve past events, is a reconstructive process prone to errors and distortions (Schacter, 1999). Compared to other sensory modalities, odor-evoked memories are more detailed and more emotional (Saive et al., 2014a, 2014b). While olfactory memory has been largely investigated in fMRI, changes in patterns of rhythmic neuronal activity during odor perception and odor-cued episodic memory remain largely unknown. Only two studies have explored olfactory perception using electrophysiology, revealing that odors elicited evoked potentials in the amygdala and amplitude changes in beta and low gamma bands (Hudry et al., 2003; Jung et al., 2006). To go further on the understanding of olfactory and memory processes, we recently developed a behavioral paradigm (Saive et al., 2013) with which we demonstrated the distinct involvement of distributed brain regions during accurate and inaccurate retrieval of complex olfactory episodes in fMRI (Saive et al., in prep). In this study, we aimed at characterizing oscillatory representations of odors during both encoding and retrieval in the identified brain regions using multi-site intracerebral EEG (iEEG) recordings.
Keywords: Episodic memory, Olfaction, Time-frequency Analysis, multi-site intracerebral EEG recordings.
PhD research: Investigating complex episodic memories triggered by odors
Episodic memory is the memory that permits the conscious re-experience of specific personal events and associated with a specific context. This doctoral research aims at investigating the cognitive processes and the neural bases of episodic retrieval in humans. Odor-evoked memories are known to be more detailed and more emotional than memories triggered by other sensorial cues. These specificities explain why we studied odor-evoked memories. First, a novel behavioral task has been designed to study in a controlled way the memory of complex episodes comprising unfamiliar odors (What), localized spatially (Where), within a visual context (Which context). From this approach, we suggest that when the binding between the episodes’ dimensions is strong, the odor perception evokes the whole episodic memory. The episodic retrieval is mainly based on recollection processes, the feeling of knowing being insufficient to induce complete memory recovery. Moreover, emotion carried by odors, whatever its valence, promote accurate episodic retrieval. Functionally, episodic memory is underpinned by a distributed network, constituted of regions typically found in laboratory and autobiographical memory approaches. Accurate memories are associated with a specific neural network, from odor perception to memory re-experience. Modularity analyses show that neural interactions within this network also depend on memory accuracy. Altogether, results of this research suggest that episodic retrieval is a dynamic and complex process, triggered by odors perception, closely linked to other memory systems such as perceptual and semantic memories.
You can find the whole manuscript here
Anne-Lise Saive 