Sylviane--Week 3

Sylviane Boddy

Like Amy, I found Demasio’s analysis of the prefrontal cortex, and its implications on connections between emotions and decision making, very interesting. This idea, which was also brought up Davidson and Irwin in regard to its role in positive and negative affect, was particularly intriguing to me because while I had already known that the prefrontal cortex played a major role in decision making, I was relatively unaware of its role in emotion. Because emotion plays a large role in decision making, it seems fit that these two functions would be in a sense, anatomically connected. Gage, who appeared to have trouble with emotional reasoning, seems to perfectly personify the link between emotion and decision making, revealing the important affect one has on the other.

Amy Fleischer

This week we have touched on some important implications for affective neuroscience, including the de-stigmatization of mental illness and potential improvement of treatment for affective dysfunction. Now that we’ve asserted these very practical reasons for the onslaught of questions I am about to present, I feel less guilty for the confusion I may cause!

Common to all of our readings so far has been a concern for the concepts, methods, and implications of conducting research into emotional processes of the brain. The major task of breaking down exactly how we conduct such an inquiry is essential to the topic itself. In other words, our study of the brain is at once conceptual and concrete- it is also an immediate example of how we understand or process information. In this case, of course, our focus is the emotional content of experience and our aim should be to discover the neural correlates of emotion. However, I hope that we can be attentive to the technical content of each study while remaining aware of the more emotional aspects involved in learning. (Despite LeDoux: remember to observe how we perceive and understand information whether it is explicitly emotional or only referentially so.)

In his book, Descartes Error, Demasio probes the function of emotion by telling the story of Phineas Gage, a man who suffered a ghastly blow to the head and lived to tell about it. When a metal rod pierced his skull at tremendous speed, vital parts of his brain were destroyed. After the accident, Gage lost his ability to reason based on emotional information, which also meant that he could not sustain jobs or social relationships. He had lost his personality, an extremely significant yet elusive element of any person’s life.

From his story, we have learned that emotions direct bodily action and organize behavior that is motivationally consistent. Demasio's account suggests potential connections between decision-making and emotional processing. Furthermore, the studies that have followed serve to transform our understanding of the brain: whereas it was previously believed that regions of the brain possessed isolated functions, they actually perform as parts of a system.

In order to try and understand this endlessly complex system, Adolphs has distilled a two-part process consisting of a) the perceptual awareness of emotional information and b) the recognition of emotional meaning. (Before I continue, does this correspond to the assertion that emotional expression takes place in the hypothalamus and emotional experience occurs in the cerebral cortex?) His theory, as well as those of Feldman-Barrett and Wager, also involves a method of categorizing emotion that proves useful because of the problem it contains.

Perhaps I am stumbling over semantics, but I struggled with the debate between “categories” and “dimensions” of emotions. Such a classification does not seem accurate because the resulting groups are not mutually exclusive or fully comprehensive. Barely do they even seem comparable, since the list of “categories” is too limited and the list of “dimensions” too vague. Even though the latter may better account for varieties in emotional experience, it still presents a form of dualistic thinking that is restrictive. For example, approach/withdrawal cannot account for a multilayered experience of love, wherein a person can be compelled and repulsed at the same time. This and other so-called “social” emotions (in the service of communication) are deemed too complex for consideration. However, we should never cease to ask such difficult questions if we intend to understand such difficult topics.

Despite the fact that this type of categorization proved weak as a tool for analysis, it has led to more important questions. In the field of cognition, our attention has been turned to the activity of circuits in the brain. Neuroimaging techniques, such as PET and fMRI, have proved especially useful for exploring connections and finding patterns. A question that drives this method of research is how affective qualities of experience are linked with autonomic and behavioral control systems during the genesis of emotion. More specifically, one might ask (as MacLean has already) how these qualities unfold in the establishment and maintenance of psychosomatic diseases. Based on further research, another question posed in this weeks’ reading asks how the limbic system depends upon or interacts with the neocortex.

Over the years, the theory of localization has been challenged by theories of connectivity. Language becomes an issue, not only at the level of human interaction, but within individuals as well, which brings our curiosity to how regions of the brain may speak foreign languages to various other parts of the same brain. What results is a lack of communication between conscious and unconscious levels of experience.

A potential metaphor for our transformation in understanding that began with phrenology, or the study of bumps on the head, and evolved into the field of affective neuroscience might go like this: the early phase is like studying geography, the political divisions of land on earth’s surface, while the second phase attempts to be concerned with planet earth at every level. Not only might the inquirer of the second practice ask how continents are defined, or where tectonic plates exist, but he or she may also ask why it is that they move in the first place and what are the potential consequences of this action.

The fact there are so many levels at which to study the earth is exciting and overwhelming! Likewise, the brain is infinitely complex and invites equally complex methods of examination. Much of this discussion presupposes that emotion can be categorized in the first place. What do you think? Have we approximated a system already? I would like to discuss this and the many implications of neuroimaging in class. While I appreciate a very tangible approach to understanding emotions, it seems like technology is advancing at a pace that exceeds our ability to understand and use it well.

Ledoux and Damasio

Oliver Edwards

1/3/08

 

            I wonder if I’m the only one who felt that Ledoux was a bit harsh with James’ theory of emotion. I was actually confused about how he seemingly refutes James in the previous chapter, claiming that James was wrong in assuming that emotional responses take place before any conscious awareness. It seems Ledoux has constantly courted the notion that the majority of emotional life is unconscious, yet he shoots James’ theory down on the basis of the very opposite claim. In the fourth chapter, Ledoux says flat out that James was wrong in claiming that the cerebral cortex was needed to produce an emotional response. First of all, I’m not sure if that was part of James’ theory. He may have claimed that the production of ‘feeling’ required the cortex, but it seems that James never got as far as localization of emotion. He was more interested in the nature of how it functioned.

           

            I was very interested in the difference in style and approach between Ledoux and Damasio. Damasio’s writing is much more centered around the telling of a good story. He spends two chapters discussing Phineas Gage, a subject that Ledoux maybe would have crammed into two paragraphs. But I don’t think his ventures into storytelling are a waste of time, mainly because they bring us towards an intimacy with the process of neuroscience. Understanding how Gage’s injury affected his personality, how it made him suffer, really brought home the notion that certain very specific parts of the brain (the prefrontal cortex and others) are extremely important for the subtle interplay that we call our emotional life. Damasio unravels his theory of the emotional brain very carefully, revealing only with extreme tact his own position on the subject of emotional neuroscience.

            It is interesting to note that Damasio does not spend much time enumerating the many theories of emotion that he judges to be wrong. Whereas Ledoux gives us a kind of history of failures, leading perhaps towards a constructive process of understanding, Damasio seems to stick to cases and findings that will support a theory that he seems to be pretty confident about. Although he also discusses phrenology, and has the same sense of humor about it, Damasio brings it up only to demonstrate that Gall was in fact correct about the notion of brain localization. The merit of Damasio’s writing is not the encyclopedic quality with which Ledoux constructs his book, but in the richness of his stories.

            I was very interested in the case of Elliott, and would be interested to know how much more has been gleaned about emotional neuroscience through studying people like him. The damage caused to his prefrontal cortex seemed to create quite a distinct psychological phenomenon, that of completely sound judgment and understanding of emotion without the ability to decide on an issue involving emotional preference. Did he remind anyone else of the women in James’ What is an Emotion? It seems that with the advent of PET and MRI, more precise evaluations of brain anatomy and function could be executed in the study of people like Elliott Would it be effective to examine the brains of healthy but affectively varied subjects? To what extent could MRI studies evaluate the abnormal emotional behavior of people with diseases like Aspergers and schizophrenia?

emotions and reason

Endira Ferrara

One of the most interesting themes in the reading for this week I found to be the idea that reason and emotion intersect in various parts of the brain structure.  In "Descartes Error," the suggestion that certain psychological illnesses tend to damage not only one's ability to make decisions, but also one's capacity to exhibit feeling, reveals that the respective realms of rationality and emotion are linked.  The idea that the systems in the brain related to the thinking process are the same as those which govern emotion is contrary to the common assumption that reason and emotion counteract one another.

LeDoux describes some of the various theories concerning the structure of the brain, which help to explain the link between reason and emotion.  For example, the Papez hypothesis advocates that sensory inputs absorbed by the brain split into different systems - one into the stream of thought (the cortex), and another into the stream of feeling (the hypothalamus).  In other words, emotions arise out of direct sensory experience, and are processed as both thought and feeling.  Through the stream of thought, the sensations are processed into information consisting of memory or perception of that experience.  It makes sense to perceive of the act of processing emotional experience occurring simultaneously with behavioral expression.  The fact that one exhibits emotion and attains a consciousness of the feeling itself stems from the thought process, and in part from the desire to understand and categorize the feeling.  This may be one way to explain the notion that the thought and emotional processes in the brain are inextricably linked.  The attempt to rationalize, understand, or categorize experience in terms of emotion also demonstrates the way in which reason and emotion are connected.

Another important theory described by LeDoux is that of MacLean's, which suggests that emotions are inherently involved in the maintaining of survival for the human being.  They are the result of visceral sensations (i.e. those that are instinctual), and thus reflect the evolution of the brain.  MacLean argues that the visceral brain "eludes the grasp of the intellect because its animalistic and primitive structure makes it impossible to communicate in verbal terms (p.96, The Emotional Brain)."  If this is the case, then emotions stem from an arguably conscious, reasonable place - in part, the desire to communicate that which is essential to human survival and unable to be communicated in words.

LeDoux's conclusion, however, that there may not be one emotional system in the brain, but instead several, does leave room for the possibility that these emotional systems may be connected to the more reasonable, practical, decision-making aspects of the brain.  The article on the "Structure of Emotions" describes emotions as psychological events, which are the product of an elaborate process within the brain.  LeDoux stresses the desire on behalf of scientists to locate the emotional system's position in the brain, and the concept of emotion as a process or event also suggests that emotions are involved in a variety of systems with the brain and are not localized to a specific place.  

Interconnectivity in the Brain (Week 3)

Maggie Fenwood

The Feeling Brain

1/31/08

I found this week’s readings interesting if not purely for the fact of the diverse body of theories that are still influencing current neuroscience. I also want to say that I found it interesting that Wager and Barrett also quote Shakespeare in their article. I found it to be a nice connection to Darwin and pointed the importance of understanding emotion as it is manifested in scientific and literary works alike.

I felt like LeDoux gave a good account of how emotion came to be considered an important part of what goes on in the brain. He does this by starting with concepts of phrenology and then moving on the theories of the limbic system. We get a sense of the origins of neuroscience of emotion and how these theories can be adapted and cited in a contemporary setting. LeDoux emphasizes the importance of these origins but also explains their inadequacy. In this chapter her focuses on the Limbic system and where he feels it goes wrong in terms of localizing brain function. Now that we have access to neuroimaging technology we can see that the limbic system theory does not account for all of the emotion functions in the brain. So instead of localizing brain function so exclusively, LeDoux suggests that brain regions pertaining to emotion also have functions which interact with a larger system. This seems to make the most sense to me because of the interconnections and overlapping in brain activation that have been shown by MRI and fMRI. Given these assumptions LeDoux makes the conclusion that there might be more than one emotional system in the brain. He goes on to give examples of when parts of the brain are removed certain functions remain intact such as in the case of ‘psychic blindness’ where the removal of the temporal lobe leaves sight intact but inhibits the sense of fear toward psychologically significant stimuli. It seems to be a more practical way to look at a phenomenon such as this; in terms of subsystems that contribute to overall brain function. For example, vision is not solely localized in the visual cortex it is a necessary part of the system that makes seeing possible, so there can be other contributing systems to sight that is not solely located in the portion of the brain that is directly connected to the eyes.

I felt LeDoux’s chapter related to the Barret and Wager meta-analysis of neuroimaging studies in that they were also emphasizing the evidence of a more integrative system in which emotion is not just localized in one particular area. In their section on ‘specificity’ they cite a study by Wager et. al (2003) in which they found that “many of the same regions showing emotion-category effects also showed specialization for the broader category of withdrawal related affects” (p.82). The example they give is that fear-related stimuli may activate the dorsal region of the amygdala because they are part of a broader class of aversive stimuli that engage in that region. So, as well as being an important area for memory consolidation and emotion processing the amygdala is visually responsive so it can compute the significance of stimuli.

If I haven’t totally misinterpreted this information, then my question is: does this mean that emotion could be registered in a number of different regions of the brain depending on the stimulus? Wager and Barrett cite studies where very specific brain regions are activated for specific emotions, however the Phan et al. (2002) and the Murphy et al. (2003) studies do not show the all the same findings. This leads me to back to the more integrative approach LeDoux talks about. It also reminds me of the discussion we had last class in which it was brought up that it is difficult to put emotion and subsequent events caused by it into a linear order. It seems like going back and forth between stages of appraisal, cognition, reaction, etc., should be taken into account instead of a strictly linear view. So, the interaction of different brain subsystems should be taken into account as well, when trying to localize brain function. Perhaps, just as it is not so simple to pin point the order of emotion stages, it also not so clear cut where these functions occur in the brain and whether maybe different stimuli activate different regions even if the emotional reaction is the same.