challenge for laboratory scientists. We often experience strong emotions during important life events, such as when meeting loved ones or waiting for the results of a major medical examination. But brain imaging needs to be done in a very restricted environment, so can we create such experiences while the subject lies inside a brain scanner tube? Moreover, can such complex phenomena ever be revealed by brain signals? Our recent work has tried to overcome these limitations by two approaches. First, although it is difficult to make people fall in love or become terriﬁed in a lab, we can simulate such encounters quite accurately during a brain scan and measure the resulting brain activation. For example, watching highly engaging and affective movies, playing exciting and realistic video games or taking part in virtual social encounters are good ways to trigger strong emotions in participants. Recent developments in brain signal analysis enable us to reliably parse the neural signals measured during such complicated episodes. Second, we have been able to generate experimental designs that enable in vivo quantiﬁcation of brain activation and neurotransmission during real and simulated social interaction due to developments in brain imaging hardware. We can literally hook up two individuals during a brain scan and measure how their brains inﬂuence each other
during social interaction. This enables us to study actual interactive brains instead of ‘passive’ or ‘reactive’ brains, which was the standard way of studying social brain functions in the past.
How private are our emotions? We tend to consider our emotions as private and not accessible to others, but scientiﬁc studies have falsiﬁed this common conception. Unlike many other mental processes such as memory or attention, emotions are in fact exceptionally visible to others. Strong emotions are consistently associated with motor and vocal expressions like crying and laughing, or more subtle cues such as frowning or changes in posture. These signals serve an important social function, as they allow others to read our current mental state and intentions, and adapt their behaviour accordingly. Thus, we comfort a crying child, but know well to steer clear of a boss who puts on an angry face at the office. But what about the inner world of our private emotional feelings – is it beyond the scope of the microscope? Our recent work with statistical pattern recognition techniques has revealed that even the inner workings of emotions can be scrutinised externally. Training a pattern classiﬁer to recognise emotional states from an individual’s brain signal enables us to accurately predict subsequent
emotional states from his or her brain activation. This conﬁrms that emotions are not random events or brain noise – they occur consistently and different emotions like sadness and fear are associated with distinct brain function tuning patterns. If this was not the case, the classiﬁer would not work at all!
Emotions as social glue Emotional expressions allow us to ‘tune in’ with others. Seeing people express speciﬁc emotions like happiness or fear prompts us to automatically mimic the corresponding emotional states in our own minds and bodies. We have recently shown that the brains of different individuals tend to synchronise or ‘tick together’ when we ‘catch’ each others’ emotions. This tendency for emotions to synchronise our thoughts and actions may promote social interaction. Tuning into others’ emotional states provides us with a somatosensory framework that helps us understand intentions and feelings. The feeling of likeness may also make us interpret the world in a more similar fashion. Emotions also mediate social bonds in a powerful way. Our gait is light and the heart pounds with excitement when we go to meet a lover, whereas severing long-term social bonds may feel literally painful. Neurotransmitter studies of primates and rodents suggests that the endogenous opioid neurotransAALTO UNIVERSITY MAGAZINE 09 \ 31
The Aalto University Magazine issue 09 deals with questions related to health care.