It has been a very very very full day – with a few more “very”s in there. Even though I was in class all day Saturday, it really flew by with such interest and application – well this could be a very long blog – we’ll see how it turns out.
As always, if there are any questions, email me or post a comment – I’m happy to answer to the best of my abilities.
Our instructor for the entire day was Joseph Kable. As a corporate trainer, I have great empathy for what he was up against – lecturing a group of 40 people from 9am to 4:30pm and keeping the energy going. He did a fabulous job.
Our topics for the day included Emotion and the Brain, Reward Systems, Negative Affect, Executive Function, Applied Affective Neuroscience, and Social Neuroscience. Doesn’t that sound like a great day! It’s my candy store. I think I got a lot of dopamine from the day. Though I learned a lot about dopamine as well.
Emotion and the Brain
The notion of the “limbic system” may not be a useful construct any further. It used to be that researchers thought there was an anatomical structure that corresponded to where emotion lives in your brain. Now, researchers are thinking that it’s not quite so clear or evident.
As an example, Liz Phelps was quoted:
“However, in spite of extensive investigation, there has yet to be any defining criteria for regions that are, or are not, included as part the limbic system. In addition, there is little evidence that regions often included as part of the limbic system function as a network or system. Because of its historical prominence in theories of brain function, the term limbic is still frequently used today, but many affective scientists question whether the limbic system is still a useful concept. In fact, some have suggested that the use of term limbic and the corresponding implication that there is a clearly defined emotion system in the brain may actually impede scientific progress.”
E. A. Phelps (2009) in Neuroeconomics: Decision Making and the Brain (P. W. Glimcher et al., eds.)
Role of Dopamine in Reward Systems
Dopamine is often considered to be the pleasure-provider of the brain and considered a “reward” to the brain for doing something that elicits more dopamine. You may have seen or know of rats that get a stimulus implanted into their brain to make the brain produce dopamine, and then the poor little rat (or mouse) pushes on the lever forever and ever, forgoing food and water to get the dopamine fix.
However, it turns out that the role of dopamine is a lot more complicated – dopamine may not be the reward itself, but may help the brain to account for prediction error in learning.
Here’s how it works (in my understanding – and this is a huge simplification):
If you expect that something will be pleasurable, your brain gives you a squirt of dopamine. If you get the something pleasurable, then your dopamine stays at the normal level. If you don’t get what you expected and it’s worse, then your brain’s dopamine actually goes down. You then learn either that the thing is pleasurable or not, and you adjust your expectations the next time around.
How this has been proven is through classical conditioning – in the first trials, the dopamine squirt comes at the pleasurable thing. During conditioning, the dopamine squirts start to come at the stimulus. When conditioning is complete, the dopamine squirt comes only at the stimulus, and not at all at the reward that’s given. So it appears as though the dopamine is geared towards the expectation, and not the reward itself.
Interestingly, this happens on the level of seconds, rather than milli-seconds, so it appears to be a system that’s geared to work at the level of human consciousness – we are meant to be aware of this prediction error for conscious learning.
Also, dopaminergic projections go throughout the brain (though some areas are more concentrated than others) so it’s a pretty powerful reinforcement and the whole brain seems to get in the game.
Finally, when your brain is learning (say, like a rat in a maze), and you take a series of wrong turns, the dopamine system is geared to go back to the first reliable cue, and start over. So when you are looking for your keys, going back to the last place you remember having them and tracing your steps is using your dopaminergic prediction error system.
As someone who studies positive psychology, I was the one asking annoying questions like “And does this also apply to positive affect?” Often the answer was “yes” or “we don’t know that yet” or “I’m not sure if that research has been done”. Things like that. So I’ll add in what I learned about positive affect throughout this section. But it does seem to be true that negative affect is more powerful on the brain, and is more often used in conditioning experiments rather than positive affect.
The amygdala does, indeed, seem to be the most important structure for fear, but the amygdala is also involved in positive affect. It’s not as simple as “threat or no threat” – it does seem to have a “towards” or “away from” assessment, which implies to me that it’s more actively involved in positive affect than I had previously believed. Just saying “threat or no threat” implies that you’d run if it was a threat, and you’d leave it alone if it wasn’t a threat (whatever “it” is…) But the amygdala does have an “approach” function as well. Interestingly, there appears to be no difference in how much the amygdala responds whether the event is positive or negative – those associations (e.g. if negative affect is really three times more powerful than positive) seem to be held elsewhere in the brain. We didn’t learn that part – yet. Maybe it’s coming.
This “approach” or “flight” assessment is also important in learning, and it’s in the amygdala that there seems to be the strongest evidence for the theory that “neurons that fire together are wired together” – evidence for neural pathways and the creation of reinforced learning networks and creating long-term associations in the brain.
Our amygdala is also activated when we see others experience pain – we don’t have to experience the pain ourselves. So we can learn through association, which is a more sophisticated response. (I asked if this research has been done with positive affect – he wasn’t sure. I also asked if the research has been done with the individual seeing someone else experience social pain, as opposed to physical pain – he wasn’t sure. We do know, however, that the amygdala does activate when the test subject experiences social pain, such as exclusion from a computer-generated ball game.)
Executive Function is the system in the brain that seems to regulate and delegate to other systems, especially when more than one task is involved. For example, if you are in a testing condition where you need to push one button when you see a specific letter, and push another button when you hear a specific sound, your pre-frontal cortex (PFC), which seems to be the home of the executive function, is active.
We do know that this part of the brain is among the last to mature in humans (so your children and teens don’t have as much EF as most mature adults do). Sorry.
The theory is that activity in the PFC biases the flow of activity in other regions. If you think about the Stroop test, for example, the PFC will try to suppress the reading part of your brain (which is a very well-learned neural pathway by the time you are an adult) in favour of the colour-naming part of your brain (which would otherwise get over-ridden by the reading part).
In theory, behaviour that becomes automatic (like reading) would no longer require the PFC, allowing you do walk and chew gum at the same time, for example, while still dialing your cell phone. Walking and chewing gum don’t need the PFC – dialling your phone accurately probably does. However, we may not be able to automatize all tasks.
It does seem to me that the PFC / EF is equivalent to willpower, and there is much more research to be done in this area. We do know that it’s an energy-hungry area of the brain. It is very powerful, but breaks down often.
There were many other learnings around applications to economic and consumer behaviour (some evidence that the brain can predict commercial success better than self-reported preferences), social interactions (the brain lights up differently depending on if we judge someone to be trustworthy or not), empathy (fMRI studies are starting to show where this might live in the brain) and social decision making (moral vs. basic emotions). I’ve written my biggest take-aways above in some detail, and now my PFC is tired and needs a break. I wonder if chocolate is good brain food?
Thanks for keeping with me on this brain learning journey!
And just for fun, try the Stroop test!