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Emotions in the brain – Are there little people living inside my head?

Updated: Oct 14, 2019

Authored by Jenna Pfeifer


Emotions govern our experiences, choices and intuitions. They are the foundation of human connection and crucial to the way in which we live our lives. Emotion is commonly divorced from rationality when it is in fact, critical for adaptive behaviour. Emotions aid us in decision-making, strengthen our memories and perceptual capabilities, inform us of the outcome of our actions. Yet the science behind this phenomena of what, how and why we feel remains enigmatic.


Affective neuroscience is the scientific discipline dedicated to understanding the neural mechanisms that precipitate emotion. The field was pioneered by Jaak Panksepp. His work has led him to identify seven primal emotions in the brain; RAGE, FEAR, LUST. CARE, PANIC/GRIEF, and PLAY which he capitalised in academic papers to emphasise that these are evolutionarily analogous and universal across mammals1. He is perhaps most memorable for an experiment where he tickled rats and was able to elicit high-frequency squeaks which he recognised as laughter. From his research into play he concluded that basic emotion arises from some of the deepest primal brain structures (the amygdala and the hypothalamus – see figure 1), instead of the cerebral cortex2.These evolutionary memories are primary processes. The basal ganglia covers secondary processes which are involved in learning and connecting observation to feeling. At the top of the hierarchy, tertiary processes governed by the neocortex are involved in thinking, planning and other higher cognitive systems. The capacity to think and feel at such a high level is fuelled by memories constructed by these ancient emotional states. Panksepp translated this research into a therapeutic approach to depression via deep brain stimulation of the seeking system in ancient neural structures, which had some promising results3.

Pixar’s award-winning motion picture Inside out reduces emotions to five characters; fear, sadness, disgust, joy and anger. However this assumption, as well as Panksepp’s seven categories implies emotions are irreducible and can be described by the words of the English language. Weltschmerzdirectly translated from German means “world pain” or bearing the weight of the world on your shoulders. We don’t have a word for this in English, but does that mean we don’t recognise that feeling? The metaphor that there are little people in our head directing our actions in response to external stimuli also suggests emotions are reflexes, and somehow control our behaviour. However we know this is not true because humans exhibit extraordinary flexibility of emotion and respond differently to different stimuli4. Indeed, Lisa Feldman Barrett has developed the theory of constructed emotion in which she suggests that emotions are not triggered, but created by a flexible brain responding to the culture and environment we were raised in5. Therefore, in contrast to popular opinion, we actually have the ability to regulate our own nervous system.


In The neuroscience of emotion: A new synthesis, Adolphs and Anderson present a new scaffold for the neuroscientific study of emotion, composed of states and features. “All emotion states have most of the building blocks, and we can find precursors to emotions states in simpler organisms that already show many of the properties of building blocks. Features, on the other hand, are more elaborated, derived, and variable properties of emotions, and not all emotions have them,” write Adolph and Anderson.


They attempt to answer the question: What is occurring inside the brain when it is in a state of anger or fear? Emotions are referred to as internal brain states that result in observable changes in behaviour, physiology, and perceivable conscious changes (we are aware of “feeling” a certain way). These states have characteristic patterns of neuronal (electrical) activity and are associated with differences in brain chemistry.



Figure 1. The human brain and the structures known to facilitate emotion.

Neuroimaging studies of emotions highlight that they cannot be localised to just one brain region6. Alternatively, they trigger a neuronal network that incorporates sub-cortical structures (the primal capacities discussed earlier) and the higher brain areas (particularly the pre-frontal cortex). Although, it has been shown that certain patterns of neural activity can be associated with different emotions. A recent study revealed patterns of activity in the parietal operculum, secondary auditory cortex and the posterior insula (using fMRI) that were predicative of the emotional content of auditory stimuli from various instruments, mapping the emotion behind music in the brain7. Furthermore lesions in various regions of the brain have been found to have effect regulation of emotion (as in the impairment of disgust in the damaged insula, or the impairment of fear in the amygdala4, see figure 1).

Many neuroscientists have made advances in this field and there are examples that we can now 1) Predict fear by decoding brain activity 2) Elicit the experience of particular emotions by electrically stimulating certain brain regions (i.e. panic in rat models) 3) Treat depression, or obsessive compulsive disorder with deep brain stimulation3. However,there are only a few examples of these developments and as Adolphs and Anderson point out “It is still early days for the science of emotion”.


References

1. Panksepp, J., & Biven, L. The archaeology of mind: Neuroevolutionary origins of human emotions, WW Norton & Company, 2012.

2. Panksepp, J., Lane, R. D., Solms, M., & Smith, R.Neuroscience & Biobehavioral Reviews, 2017, 76, 187-215.3. Schlaepfer, T. E., Bewernick, B. H., Kayser, S., Mädler, B., & Coenen, V. A., Biological psychiatry, 2013, 73,1204-1212. 4. Adolphs, R., & Anderson, D. J, The neuroscience of emotion: A new synthesis, Princeton University Press, 2018.5. Barrett, L. F., How emotions are made: The secret life of the brain, Houghton Mifflin Harcourt, 2017.6. Lindquist, K. A., Wager, T. D., Bliss-Moreau, E., Kober, H., & Barrett, L. F, Behavioral and Brain Sciences, 2012, 35, 172.7. Sachs, M. E., Habibi, A., Damasio, A., & Kaplan, J. T. Neuroimage, 2018, 174, 1-10.