What should happen to memory for events that occur within an emotional context?

Before addressing what happens to memories within an emotional context, I would first like to argue that there is no such thing as not having an emotional context during encoding or retrieval of memories. We may not always have a strong valence for everything that happens in our lives, but we are constantly experiencing emotion of some sort. Whether that experience is low-level like boredom or fatigue, or high level such as in deep sorrow or great joy, I cannot imagine a time where I have not experienced some mood. But for the sake of argument, I will focus on memories that occur during a strong emotional context.

            According to current memory literature, both positive and negative memories are better encoded than less emotionally salient experiences. Based on fMRI studies, (among other mechanisms) this deeper encoding is most likely due to amygdala activation- both for positive and negative memories. In a 2006 study by Kensinger and Schacter, they found activation of the amygdala during encoding for positive and negative items. This activity later predicted recall for these emotionally salient items. However, this effect did not extend beyond highly emotional items. In keeping with my earlier statement, I would argue that the amygdala actually was engaged even during the more neutral items, but that the activation was so weak that it could not be picked up in the fMRI BOLD signal. In any case, this research demonstrates that the limbic system, and the amygdala in particular, are more active during emotionally charged situations and allow for deeper encoding.

It makes evolutionary sense that emotionally engaging experiences (especially negative ones) should be better encoded. It’s beneficial for an organism to remember to avoid negative experiences that hurt its chance of survival, and positive experiences should be better remembered in order to seek out similar beneficial situations. Thus, it is unsurprising that highly emotional memories engage neural systems beyond the medial temporal lobe.

However, extreme mood at memory retrieval can occasionally be detrimental. In a 2005 research study, researchers found that inducing a positive mood during recall led to more false memories in the Deese-Roediger-McDermott paradigm. However, inducing negative mood during recall did not show this effect. This research demonstrates that while heightened emotion during encoding can be overall beneficial, that same state during retrieval ends up causing people to falsely identify lure items as old. Thus, extreme emotion can be a double-edged sword when it comes to memory.

Works Cited:

Guastella, A. J., Mitchell, P. B., & Mathews, F. (2008). Oxytocin enhances the encoding of positive social memories in humans. Biological psychiatry, 64(3), 256-258.

Kensinger, E. A., & Schacter, D. L. (2006). Amygdala activity is associated with the successful encoding of item, but not source, information for positive and negative stimuli. The Journal of Neuroscience, 26(9), 2564-2570.

Storbeck, J., & Clore, G. L. (2005). With sadness comes accuracy; with happiness, false memory mood and the false memory effect. Psychological Science, 16(10), 785-791.

A Clockwork Orange

In high school, I managed to read A Clockwork Orange.  For those of you who haven't attempted this, be warned that it's  like reading a foreign language.  The author uses words from Russian, Spanish, English, and Japanese to create a very unique street dialect.  The first few chapters are spent trying to figure out what the hell the main character (whose point of view the reader shares) means.  Pretty soon though, you pick up what's going on and you start to realize how truly creepy this futuristic world is.

But it took me watching the 1971 film to start to wonder about the neurological implications of the movie.

One of the key plot points (*SPOILERS*) is that Alex, the protagonist, is brain-washed to feel sick every time that he sees sex or violence or considers doing either of the two.  In the movie, he's portrayed as gagging and nearly throwing up after his "treatment".  I know that the idea behind his brainwashing is that they give him a drug that activates a particular center in his brain and they correlate this with horrific videos of sex and violence to make Alex associate the two.

I suppose this could be considered a form of classical conditioning.  Like Pavlov with his dogs, Alex is trained to match a physiological response with an external stimulus.  So Pavlov's dogs were trained to salivate when they heard a bell.  Alex was trained to feel sick whenever he witnessed or thought about "evil impulses" of violence (and sex).  They even give an example of generalization where the subject is not trained to differentiate to one particular stimulus.  In Alex's case, he was accidentally also trained against Beethoven's 9th.

Not exactly a hero but definitely the protagonist.

But the question I have, is what part of the brain were they activating for revulsion?  I know the amygdala is activated for fear and that can modulate emotions and memories.  But I don't know where the center of revulsion is.  Anyone have a suggestion on what Alex's doctors were activating?

In any case, I do suggest you read this classic novel.  (Yes, it's 50 years old so it's officially a classic.)  It's disturbing and confusing at times but the political messages it contains shouldn't be ignored.  And if you're too lazy to read the book, the movie is on netflix instant play.