Maggie Fenwood
The Feeling Brain
3/2/08
Week 7: Memory and Emotion
I have to say that it took me a little longer to get through these readings because of my limited knowledge on the structures of the brain but it was interesting to learn exactly where exactly in the brain these functions of memory take place. These readings were good for understanding where the current stance on memory and emotion evolved from, with a shift away from stimulus-response and purely behavioral explanations. Mostly focusing on amygdala and the medial temporal lobe Dolcos, LaBar and Cabeza looked at the memory-enhancing effect of emotional stimuli. Although they were looking at recollection from only one year later it did show the way in which retrieval activity for emotional and neutral pictures differs in favor of emotional stimuli enhancing the ability of the participant to remember it. Furthermore, they were looking for a distinction between knowing and remembering. This seems like a difficult thing to try to test, which they did in terms of activation in the brain. In the fMRI scans they found that the region of the medial temporal lobe may be sensitive to the reinstatement of sensory details but the hippocampus is critical for binding content and context in order to distinguish between knowing and remembering. As such, Dolcos et. al. conclude: “the Amygdala, Hippocampus, and Entorhinal Cortex all contribute to the enhancing effect of emotion on retrieval processes and only the first two regions can additionally differentiate between emotion effects on recollection and familiarity” (p. 6). So, the emotional content of the neural stimulus is important to retention and recollection although it might just be a memory-enhancing effect rather than a familiarity. This makes a distinction between remembering a stimulus in the form of an emotion-evoking picture and actually being familiar with or having knowledge of the picture in some other context. It is interesting to consider the degree to which the participants were exposed; although the stimulus was emotional it obviously would not be enough to traumatize them. So, in the case of someone who has PTSD it is even more so a familiarity than just a remembering of the event. The level of context and content play a very important role in the level of emotion and recollection in this sense. It would be interesting to know if any of the participants had other associations with the pictures that also enhanced their memory of the emotional pictures.
I thought that LeDoux’s chapters pointed out some interesting things about fear response, thinking about it in an evolutionary sense, as a mechanism for conditioning a response that is quick and long lasting. The fear stimulus only needs to occur a relatively limited number of times in order for the conditioned response to kick in. Where the declarative memory, in this sense, was developed for the preferential retention of information associated with motivational goals, emotional arousal can also enhance encoding and consolidation of memories that in an evolutionary sense are part of survival. So, learned, defensive behavior comes from fear response and the conditioned fear response involves unconscious or implicit processes. This multiplicity of memory is something that LeDoux talks about in terms of the brain having different systems which mediate different kinds of memory. The area that mediates explicit or declarative memory is different from the areas for classical conditioning or implicit learning. For example, the woman whose doctor pricked her with the tack in his hand, obviously she remembered that a negative stimulus came from shaking the man’s hand but she could not attribute any explicit knowledge to this fear condition. It seems as though these systems work with each other but are not dependent on one another. LeDoux states that the multiplicity of memory idea was obvious because of the role of the hippocampus, where information is transferred from the perceptual cortical sensory system and into the conceptual domain of the brain. So, it makes sense that researchers would not be looking for these things in non-human animals per se, because the animals they were testing could do most memory tasks without the hippocampus, it didn’t seem relevant. Now it seems as though the hippocampus plays a very important role in what goes beyond purely behavioral aspects of memory. The emotional aspect of memory is wrapped up in the way it is conceptualized and consolidated in the mind.
McGaugh makes a good point in saying that memory is not only the lasting consequence of experience but it is also what we learn from that experience. Once researchers were able to figure out that memory was a separate from the physicality of it, (i.e. a paralyzed rat still remembering the maze route) that was the key to understanding memory as a system with multiple methods of learning and ways of remembering. As such, McGaugh explains that slow development and consolidation of memory allows for recollection of detail and strength of memory. As an evolutionary adaptation implicit memory allows for us to learn new things constantly. Lasting memories are not formed instantly just like poorly learned material is quickly forgotten like learning an instrument takes practice. We are not simply conditioned to live in reaction to stimulus but we are constantly incorporating information and depending on the emotional content and/or context it will be consolidated in some capacity into the implicit memory.
2 comments:
I found this week’s readings to be very complimentary to one another as well as comprehensive and interesting. We discussed the difference between explicit and implicit memories in class, and I enjoyed reading further about it. I found one part of LeDoux’s Chapter 7 especially interesting. I think it’s a common experience for a person to feel a certain way and not know why. Sometimes one can become extremely anxious, sad, etc. for seemingly no reason at all. It was interesting to learn that some of these cases may be caused by stimuli that our declarative memory has no recollection of, but our unconscious memory didn’t “forget.” LeDoux gave the example of being in a traumatic car accident and the horn getting stuck on. The sound of the horn can become a conditioned fear stimulus, and even if years down the road one no longer consciously associates a car horn with the accident, it’s possible he/she will find him/herself in an emotionally aroused state upon hearing a horn when just walking down the street. The memory systems in the brain made a connection without the person even thinking about the accident. It’s similarly interesting when McGaugh notes in Chapter 2 the conclusion the children’s brains drew about eating ice cream after radiation treatments for cancer. The children stopped eating ice cream after several treatments because their brains now associated the horrible feelings they had after the radiation with the ice cream the hospital staff gave them.
Mikal Shapiro
Maggie wrote, “It would be interesting to know if any of the participants [of the Dolcos, et al. study] had other associations with the pictures that also enhanced their memory of the emotional pictures.”
Even if the participants had no direct association with the pictures, Maggie’s comment made me think of how images and other modern media can elicit emotion in response to situations that we may not actually ever experience. How do we process these abstractions? To what extent do these images become embedded emotionally into our memory systems? For instance, when we regard a photograph of some horrific scene, would the extent to which we could envision the scene in our imaginations create a sort of pseudo “re-membering” of a physical reality as “real,” felt, etc. as a memory drawn from experience? Perhaps this may only apply to explicit memory because it already involves a symbolic abstraction--the use of language. Then again, as dream research suggests in studies conducted on physical responses during REM (Stephen LeBerge, 1986), maybe our imaginations are capable of producing somatic reactions that in turn create implicit memories (i.e.--Dreaming of a tack pressed into our hand.) Could that be a possible basis for “déjà vu?”--an act of remembering something that we may have only experienced in our heads? Deja-vu may also be a link from a current experience to a past feeling state or “enception.” As concepts are related: red, apple, fruit, hunger; so are enceptions--similarly felt concepts: mother, blanket, summer. Enceptive processing can lead to alogical but valid memory associations (Amy F. lent me a great article on Metaphor and Emotion that investigations “enceptive” connections but I can’t remember the authors name! Ask me about it if you’re interested.) Does the strength of our recall rely on the flexibility of our imaginations?
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