Investigating neural correlates of positive affect using functional magnetic resonance imaging and naturalistic stimuli

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Sullivan, KiAnna
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience
Positive affect is the extent to which an individual experiences positive moods, encompassing a broad scope of positive emotions including happiness, joy, optimism, interest, and contentment (Lyubomirsky et al., 2005; Qi et al., 2021). Previous research using simplistic stimuli has struggled to form a consensus on a general model of positive affect in the brain. Of current significance in the field of cognitive neuroscience is the utilization of naturalistic stimuli to better emulate “real-world” experiences. Previous research has demonstrated that movies can evoke robust correlations in brain activity across participants, suggesting a shared processing pattern for naturalistic stimuli (Hasson et al., 2004; Jääskeläinen et al., 2008). Nevertheless, amidst this shared overarching response of integrated brain regions, individual differences in processing arise, influenced by specific personality traits (e.g., paranoia: Finn et al., 2018). In line with this, a behavioural study by Sullivan & Ekstrand (2021) showed that participants with higher positive affect scores had significantly higher correlations in a keypress response task than those with lower positive affect scores. To explore deeper, the current study employs the Naturalistic Neuroimaging Database (NNdB) (Aliko et al., 2020, v2.0) to examine the impact of different levels of self-reported positive affect on neural synchrony during movie viewing and functional magnetic resonance imaging (fMRI). Results showed that individuals with higher levels of positive affect exhibited greater neural synchrony in higher-order cognitive regions such as the bilateral precuneus, inferior frontal gyrus (IFG), posterior cingulate cortex (PCC), and superior temporal gyrus (STG), while individuals with lower levels of positive affect exhibited greater synchrony in rudimentary audiovisual regions such as the bilateral planum temporale (PT), STG, fusiform gyrus (FG), and lateral occipital cortex (LOC). Overall, this study contributes valuable insights into the influences of positive affect trait levels on neural synchrony, emphasizes the importance of using naturalistic stimuli in neuroscience research, and furthers our understanding of how individuals process “real-world” stimuli.
Positive affect , Naturalistic stimuli , Functional magnetic resonance imaging , Intersubject correlation , Neural synchrony