Thesis defence : Elie PONCET

The prevalence of negative stimuli conventionally observed in young adults decreases during normal aging, oreven evolves into a prevalence of positive stimuli. This age-related effect is called the "positivity effect". Observedin emotional appraisal tasks, this effect disappears in action tendency tasks, suggesting a dissociation betweenemotions and action behaviors. Better understanding the evolution of the link between emotional processes andaction behaviors in normal aging would allow to specify the conditions for the emergence of the positivity effectand to better understand the motor and affective disorders associated with some neurodegenerative pathologiessuch as Parkinson's disease (PD). The first section of my PhD thesis consisted in evaluating the evolution ofemotional processing during normal aging. During a free exploration task of emotional image pairs, a first studyin oculometry show in the elderly a reduced automatic orientation of attention and a more spatially focusedattentional exploration for positive scenes, compared to young and middle-aged adults. At the cerebral level, asecond functional MRI study (fMRI) suggests a cerebral reorganization in normal aging which would reflect anevolution of emotional processing strategies: while young people would rather activate a fronto-limbic networkassociated with the emotional evaluation and regulation and a more complex cognitive processing, the elderly (vsyoung) would activate more regions related to viscero-somatosensory integration, spatial imaging and motorprogramming and regulation in a more embodied strategy of the emotional appraisal. In contrast, the two groups,young and older, differed less in the action tendency task, suggesting similar emotional processing strategies fordeciding motivated action. The second section of my PhD thesis consisted in evaluating the evolution of emotionalprocessing in de novo PD patients using the same protocols of previous studies. The oculometry study (3rd study)reveal in patients, a reduced automatic orientation of attention for emotional scenes (vs neutral) and even more forpositive scenes and an overall more extensive attentional exploration, compared to healthy controls. The fMRIstudy (4th study) reveals, for its part, an hyperactivation of a large temporo-parieto-fronto-limbic networkspecifically in the action tendency task in patients (vs healthy controls), suggesting a mechanism of compensationfor the difficulties encountered by the patients in this task, while their emotional appraisal is relatively preserved.The oculomotor and cerebral patterns specifically observed in de novo PD patients pave the way for theidentification of new early (bio)markers of Parkinson's disease and the action tendency task seems to be a relevanttool in this perspective.

Encadrantes :
- Directeur de thèse : Elena MORO - emorochu-grenoble.fr (emoro[at]chu-grenoble[dot]fr) -
- Co-encadrant : Aurélie CAMPAGNE -  aurelie.campagneuniv-grenoble-alpes.fr (aurelie[dot]campagne[at]univ-grenoble-alpes[dot]fr)

Keywords: emotion, cognition, Parkinson’s, healthy aging, pathological aging