Saturday, September 1, 2018
Love and fear are visible across the brain instead of being restricted to any brain region - NEUROSCIENCE
In the field of affective neuroscience, rivaling theories debate whether emotional states can be regarded as an activity of only certain brain regions. According to a new doctoral dissertation at Aalto University, an emotional state affects the operation of the entire brain instead of individual emotions being localized only in specific regions in the brain.
‘From the biological point of view, an emotion is a state of the entire brain at a given moment. For example, the brain may interpret certain action models, memories and bodily changes altogether as anger,’ explains Doctoral Candidate Heini Saarimäki.
Different emotional states of the participants were evoked with films, mental imagery or guided imagery based on narratives. After that, a classifier algorithm based on machine learning was trained to connect the specific emotions and the brain data related to them. The classifier algorithm was then tested by giving it new brain data and by measuring how successfully the algorithm recognized the correct emotion solely on the basis of the brain data. The method for measuring brain activity is based on measuring the changes in the blood oxygen content in the brain and it provides information on the activation of the brain with millimeter-accuracy.
The researchers were particularly interested in emotion-specific brain maps, that is, maps on the localization of emotions in various areas across the entire brain. By analyzing the activity of the entire brain, a machine learning algorithm may be able to determine the emotional state in question.
Saarimäki and her colleagues discovered that the brain maps of basic emotions such as anger, happiness, sadness, fear, surprise and disgust were to some extent similar across people. Basic emotions seem to be at least partially biologically determined, whereas social emotions – gratitude, contempt, pride and shame – are to a greater extent built on experience. In social emotions, the differences in brain activity between people are greater than in basic emotions.
Image: An emotional state mainly activates wide, overlapping neural networks. When comparing groups of emotions, positive emotions activate the anterior prefrontal cortex, negative basic emotions tend to activate the somatomotor and subcortical regions, and negative social emotions activate brain areas that process motor and social information.
Image credit: Heini Saarimäki.
Source: Corina Marinescu