There is a region of our brain that maps our emotions. Just about 3 cm for happiness, surprise, fear, sadness, anger and disgust, the most frequently identified set of basic emotions. The discovery comes by a recent work conducted by the Molecular Mind Laboratory (MoMi-Lab) at the IMT School for Advanced Studies Lucca, directed by Professor Pietro Pietrini. The study “Emotionotopy in the Human Right Temporo-Parietal Cortex” has been just published in the international journal Nature Communications, one of the main scientific journals in the world.
Giada Lettieri, a young PhD student of the IMT School, together with her collaborators, discovered that three orthogonal and spatially overlapping gradients encode the polarity, complexity and intensity of emotional experiences in right temporo-parietal territories. The spatial arrangement of these gradients allows the brain to map a variety of affective states within a single patch of cortex. As this organization resembles how sensory regions represent psychophysical properties (e.g., retinotopy), the researchers proposed emotionotopy as a principle of emotion coding.
So the results show how a brain region called right temporo-parietal junction can topographically represent the complexity of what we feel: which emotions we feel in a specific moment and how much we perceive them. The modality would be more or less the same of basic functions like sight, hearing, smelling, touching, tasting.
Emotions like senses? Historically, even philosophically, emotions have always been considered as a different, higher human faculty. Emotional aspect has always been seen as something different compared to cognitive one. The starting point of this research has been exactly the opposite: and what if the principles that guide the perception of emotions are the same to the ones underlying the perceptions of sensory stimuli, for example?
The research team was right and an iconic and emotionally charged movie as Forrest Gump has helped them. The researchers asked 15 people watching the movie: during the experience, they had to report carefully, frame by frame – using an ad hoc designed software – the corresponding emotions they felt and how strong, or not, they were, on a scale from 1 to 100.
In the meantime in Germany, 15 people had already watched the same movie, but during functional magnetic resonance imaging, a neuroimaging technique able to detect brain activation. Thanks to open science, that promote the sharing of results between scientists all over the world, the researchers at IMT School compared behavioural data from the italian group to brain data from the german group. “A very interesting aspect of this study is that it proves how important are open science and data sharing initiatives in neuroscience”, said Luca Cecchetti, Assistant Professor at the IMT School and researcher at MoMi-Lab. “As a matter of fact, fMRI data were collected by Michael Hanke and collegues and publically released at studyforrest.org. This allows us to exploit these high-quality neuroimaging data, saving resources and time. Following the same principle, we realease data and code at https://osf.io/tzpdf/”.
To unveil cortical regions involved in emotion processing, behavioral ratings were used as predictors of fMRI activity. The correspondence between functional characteristics and the relative spatial arrangement of distinct patches of cortex was then used to test the topography of affective states, proving that there are brain regions able to predict the affective states we feel in an exact moment, providing us the map of our emotional experience. A valuable development to better understand human social abilities.
“The study of the brain correlates of elementary factors that modulate intensity and quality of our emotions, has major implications in order to understand what happens when emotions get sick, as in case of depression and phobia. These studies are getting psychiatry closer to other fields of medicine”, commented Professor Pietro Pietrini, psychiatrist and co-author of the research, director of MoMi-Lab at the IMT School.
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Emotionotopy in the Human Right Temporo-Parietal Cortex
Giada Lettieri, Giacomo Handjaras, Emiliano Ricciardi, Andrea Leo, Paolo Papale, Monica Betta, Pietro Pietrini and Luca Cecchetti - doi: 10.1038/s41467-019-13599-z.