1. Emotions and biophysiology
Seminar 3

2. Today’s questions How does the brain create emotions? (Or does it?)
Note: There are other similar questions, e.g., what are the emotional networks (“neural pathways”) in the brain, how does the body contribute to emotional experiences, etc. But I will not cover these.
If you want to learn about these, take “Affective Neuroscience”

3. Golden rules about brains in psychology
Every psychological process involves the brain
Philosophers may disagree (dualist vs. materialist)
The question is, what does “involve” really mean?
When you read brain articles on emotion, always ask: are the experiments performed on humans or animals?
Very often, articles don’t make it clear whether the particular conclusion is derived from animals or human research. A general rule is, when it is overly specific, it probably is from animal studies.

4. How can you tell whether research is from animals or humans?
Here’s a general heuristic
Overly specific – from animal models
General – from human models

5. Example
During fear conditioning, the conditioned stimulus (CS) and unconditioned stimulus (US) are relayed to the lateral nucleus of the amygdala (LA) from thalamic and cortical regions of the auditory and somatosensory systems, respectively. As shown in Fig. 3, the CS inputs enter the dorsal subregion of the LA, where interactions with the US induce plasticity in two functional cell types (so-called 'trigger' and 'storage' cells). CS information is then transmitted through further stations in the LA to the central nucleus of the amygdala (CE). Interactions between the lateral and central amygdala are more complex than illustrated, and involve local-circuit connections (see main text). The LA also communicates with the CE by way of connections with other amygdala regions (not shown), but the direct pathway seems to be sufficient to mediate fear conditioning. CG, central grey; LH, lateral hypothalamus; PVN, paraventricular hypothalamus.
Medina et al. Parallels between cerebellum- and amygdala-dependent conditioning. Nat Neurosci Rev.

6. Why is this heuristic generally true?
The AMG has many layers. FMRI (for humans) does not have such a fine spatial resolution to distinguish Lat AMG vs. Central AMG activation.
Only single cell recordings can do that, and that is unethical to do in humans

7. Part 1
The “emotional” brain

8. The limbic system
A collection of structures thought to be involved in emotion processes
Limbic structures: olfactory bulbs, hippocampus, hypothalamus, amygdala, anterior thalamic nuclei, fornix, columns of fornix, mammillary body, septum pellucidum, habenular commissure, cingulate gyrus, parahippocampal gyrus, limbic cortex, and limbic midbrain areas.
A concept that is often found in many readings

9. Image from Wikipedia

10. Does the limbic system exist?
Some neuroscientists (Annette Schirmer, Joseph LeDoux) oppose the limbic system concept altogether
For a system to exist, there must be a demarcation of its boundaries
System :: Boundaries
Countries :: Borders

11. Does the limbic system exist?
Grounded mainly in historical concepts of brain anatomy that are no longer accepted as accurate
What boundaries are we talking about? Neuroanatomical? Functional? Cell shape, cell content, projections patterns?

12. The concept of boundaries
In politics
Geographical borders
Non-distinct
Distinct
Functional
India
EU, NATO, etc.
Present-day Syria
India, Pakistan, etc.
In brains
Neuroanatomical
Non-distinct
Distinct
Functional
Unified system ?
Separate system

13. Does the limbic system exist?
If emotion depends on cognition (in neocortex) which depends on hippocampus (in “limbic” system), where is the boundary of the limbic system?
The boundaries are so unclear such that one can say the whole brain is the limbic system
(Remember a general principle of science: “something that explains everything explains nothing”)
Nevertheless, many people still use the term – it is imprecise, but useful (?)

14. Moving on from the limbic system
Part 2
Moving on from the limbic system

15. 9 years ago, I learnt these:
Fear  Amygdala (AMG)
Disgust  Anterior insular
Anger  Orbital frontal cortex (OFC)
Sadness  Anterior cingulate cortext (ACC)

16. Two views about brains  emotions
Locationist view: discrete emotions originate from specific brain regions
Constructionist models: discrete emotions are constructed of general brain networks
Lindquist et al. (2015). The brain basis of emotion: A meta-analytic review. Brain Beh Sci.

17. Locationist view
A particular emotion is consistently and specifically associated with an increased activity in a brain region

18. Pictorially, this is what it means
Fear
AMG
Or this:
Fear
AMG1
AMG2
AMG3
But not this:
Fear
AMG V1
OFC

19. It also implies…
AMG
Fear
But not this
AMG
Fear
Disgust
Sadness

20. Evidence for locationist view for Fear-AMG
Rats:
Electrical stimulation of AMG  startle response
Humans:
Fear-conditioned tones  AMG activation
AMG lesions  impaired ability to perceive fear expressions (in voice, face, etc.)
Clinical anxiety associated with hyperactive AMG

21. Problem 1: AMG is activated in many non-fear situations
The AMG is activated in the processing of fear, happy, sad, and angry facial expression
What do all these faces have in common?
They signal ambiguity in the environment.

22. Problem 2: AMG is not always activated during fear
Most fMRI experiments manipulate fear by exposing participants to fear-inducing stimuli, e.g. snakes, fear facial expressions, etc.
When people are asked to recall fearful situations, AMG activation is absent
Damasio et al. (2000). Subcortical and cortical brain activity during the feeling of self-generated emotions. Nature Neuroscience.

23. Problem 3: What does “involve” mean?
Processing of fearful stimuli ≠ phenomenological experience of fear
When you say a brain is “involved” in fear, what do you mean?
“Involve”
= causes one to experience fear? [causality]
= is an outcome of fear? [correlation]
Damasio et al. (2000). Subcortical and cortical brain activity during the feeling of self-generated emotions. Nature Neuroscience.

24. How do you reconcile the findings claiming fear  AMG?
Current thinking is that AMG plays a vigilance monitoring role.
Vigilance for…possible threat.
Evidence
AMG neurons are active when stimuli is
Novel
Unusual
Unpredictable
Whalen. (1998). Fear, vigilance, and ambiguity: Initial neuroimaging studies of the human amygdala. Curr Dir Psychol Sci.

25. Let’s look at another example: disgust-insula
Evidence for locationist view for disgust-insula
Neurodegenerative diseases affecting insula (Huntington’s/Parkinson’s)
 diminished disgust response to foul odors
 less accurate perception of disgust facial expressions

26. Problems with the locationist disgust-insula view
Fear, sadness, happiness also activates insula - perhaps less strongly
Visceral sensations (gastric distention, orgasm, etc.) also activate insula activation
Lane et al. (1997). Neuroanatomical correlates of happiness, sadness, and disgust. Am J Psychiatry
Wager (2002). Functional neuroanatomy of emotion: A meta-analysis of emotion activation studies in PET and fMRI. NeuroImage
Craig (2009). How do you feel — now? The anterior insula and human awareness. Nat Rev Neuroscience.

27. So what does the insula do?
Interoception – awareness of bodily states

28. We can go on and on… Fear  Amygdala (AMG) Disgust  Anterior insular
Anger  Orbital frontal cortex (OFC)
Sadness  Anterior cingulate cortext (ACC)

29. But there is a more general problem
We can only examine a few “classical” emotions. What about other emotions? (We will examine jealousy on Thurs)
Even if the locationist view could be correct, you would need x brain areas for x emotions
So if there is a culture that doesn’t experience emotion k, people of this culture don’t have brain area k?

30. But here’s the constructionist view
Emotions are constructed from various pieces of information that the brain receives
This information can originate from somatosensory organs (e.g., body, vision, odors)
Or from self-generated events (e.g., appraisals)

31. Part 3
Unsolved mysteries

32. Mystery 1
Constructionist models (see similar terms e.g., “binding problem”) suggests that there is a specific region where things come together (“constructed”).
But where is this place?
Does this place exist?
Do you need this place?

33. Mystery 2
Emotion research using biophysiological methods often use visual stimuli
Faces (greyscale, with hair remove)
IAPS (may be gray scale or not, which actually also affects the measurement)
Are you studying emotion processing, emotional experiences, or…?

34. Choice of stimuli
Choice of stimuli to induce emotion also depends on the dependent variable (recall Week 1 L2)
EEG: Good temporal resolution, poor spatial resolution
fMRI: Good spatial resolution, poor temporal resolution
HR, SCR: …

35. Ultimate mystery for neuroscience
(9:19)

36. Take home messages Limbic system is probably a wrong concept
Locationist view of emotions is probably wrong.
The hard problem is intractable.
Does it mean affective neuroscience is worthless? NO!