Conference 2002

Workshop I
Workshop II
Workshop III
Workshop IV
Final Group Discussion and Summary
Schedule

Photos of the June 2002 Meeting

Workshop I: What is Emotion
Chair: SN Haber; Scribe; S. Seasack; Spokesperson; A. Kelley

Suzanne Haber introduced the topic and how the questions were derived. Ann Kelley described the first MNN meeting and the evolution of the questions.

Derek Van der Kooy asked about the difference between emotion and motivation.

John Salamone described what definitions he uses for teaching. Emotion is the experience of internal sensations. Motivation is that which drives behavior. Both are present in all situations. He then gave facial expressions as an example of overlap between emotion and motivation. Stress is a subset of the other two and reflects what the environment does to the organism; it is a disruption of homeostasis.

Derek Van der Kooy asked how these things could be measured. Motivation can be measured, but what about emotions?

There was then general agreement that emotion can be measured in humans because they can self report but that it is much harder to measure in animals, especially in rodents.

Derek Van der Kooy then stated that he did not believe that emotions drive behavior. He felt that the initial stimulus drove both the emotions and the subsequent behavior in parallel; emotions are ephemeral and occur after the fact. For example, pleasure is a reaction to having achieved a certain state.

Jack Gorman then focused the discussion on the topic of temperament, which is present from birth and a product of genetics. Temperament can drive behavior differently and determine an emotional "style." It serves as an input-output function determining the probability of a particular output for a given input. According to this view, emotions function as cues to drive future (not immediate) behavior.

Ann Kelley then offered that one possible function of emotions is to generate energy. For example, in response to stressors the energy required for escape or fight could be driven by emotions.

The discussion then turned to the old Schacter-Singer experiments in which subjects were given adrenaline. Some were told that they were being given a drug that would affect their emotions; others were not told. They were then exposed to different environments designed to trigger different emotions. The subjects who were told that they were receiving a drug subsequently labeled their emotions as drug-related. Those not told that they received adrenaline reported that they felt an emotion that matched the environment they were exposed to, and the intensity of the emotion they reported correlated to the amount of adrenaline they received.

From these experiments it was determined that emotional experience requires both arousal (the adrenaline in the experiment) and a label from the environment. Labels are often learned, although some are innate or instinctive. Fear was then discussed as an example of an innate emotion, an aversive reaction. Derek Van der Kooy then clarified that in his view, the original stimulus triggers both the fear and the subsequent behavior. He does not believe that fear (the emotion) drives the behavior.

Ann Kelley mentioned that the arousal associated with fear can be rewarding; skiing, driving fast and watching horror movies were noted as examples. For this reason, people will seek out fear provoking experiences. It was then noted that there is survival value in seeking stimulation and that risk of harm is the price paid for being able to experience the advantages of stimulation.

Someone mentioned that lesions of the orbitofrontal cortex increase risk taking behavior without an accompanying physiological reaction as measured by the galvanic skin response (GSR; Damasio’s data). In this regard, psychopathic behavior is often considered to result from orbitofrontal damage and the associated lack of physiological reaction.

Jack Gorman noted a recent study published in Science from the Max Planck Institute examining the total gene expression in the liver, cerebellum and prefrontal cortex of humans and monkeys (the actual study should be examined for details). It was determined that gene expression in liver was roughly equivalent between humans and chimpanzees, both of whom had greater expression than in macaque monkeys. The cerebellum was similar to the liver in this regard. However, in the prefrontal cortex, humans had far greater gene expression than chimpanzees, who were roughly equivalent to macaques. This is interesting because of the number of mental disorders that appear to be unique to humans. The evolutionary time period between chimpanzees and humans is relatively short to have generated so many novel genes. Perhaps a sufficient period of natural selection has not yet passed in order to determine their usefulness.

It was then considered whether mental illnesses are truly unique to humans and to what extent they might also plague monkeys. Suzanne Haber mentioned that female monkeys appear to express a degree of grief that resembles depression upon the death of their infants. It was also noted that the literature on primates in the wild is limited and that abnormal behavior might occur in monkeys but result in their isolation and death. In the old studies of Kluver and Bucy, monkeys with temporal lobe lesions were ultimately isolated until they died. Ann Kelley also noted that low levels of serotonin in monkeys has been correlated with high risk taking behavior. Perhaps such monkeys in the wild die from falls after climbing to heights that other monkeys would not attempt.

The subject of commonality of emotion was then discussed, and facial expressions were mentioned as the best example that most emotions occur in common across all human populations. Studies have shown that facial expressions translate across all cultures, even primitive. Children across cultures develop the same facial expressions, even if they are blind from birth, which is evidence for their fundamental, in-born nature.

Someone mentioned that Damasio's work with patients suggests that amygdala lesions cause the absence of GSR but not verbal reporting of emotions, whereas hippocampal lesions result in loss of verbal reports but not GSR. This suggests that different aspects of emotions are mediated via different circuits.

Sarah French asked about positive emotions and whether there were any that were not in response to something. It was decided that there probably were none. Happiness was suggested as a uniquely human emotion, with animals experiencing only contentment at best. This seemed to annoy the dog lovers in the group, who insisted that their dogs were happy. They did not, however, think that cats ever attained happiness.

Various emotions were discussed as to valence. It was noted that novelty and surprise are examples of emotions that are hard to fit into positive or negative valence. They are thought to span positive and negative and that perhaps emotions should be considered to include a measure of intensity so that they would assume a U-shaped curve. For example, rats prefer novelty unless it is too intense. They will approach a novel environment unless the lights are too bright, the noise too loud, etc.

Jack Gorman returned the group to a consideration of temperament by noting that children who are resistant to novelty as infants are often cranky and irritable and grow up to be anxious. As far as can be measured, these traits seem to be present at birth. However, there is an extent to which the environment can also determine these outcomes through interactions between parent and child. For example, when novelty creates a situation that makes foraging for food difficult, macaque mothers, who normally like novelty, have to work hard to find sufficient food. Under these conditions, they become anxious, and their offspring also become anxious and resistant to novelty.

The discussion then moved to consideration of the role of temperament in drug abuse liability. Suzanne Haber mentioned a Nature Neuroscience study in which monkeys with low social rank had low D2 receptor affinities and high tendency to self-administer cocaine. Conversely, monkeys with high social rank had high affinity D2 receptors and low self-administration tendencies. The best adjusted animals are often second rank females. They may be less anxious because there are fewer demands on their behavior.

A short time was spent considering question #5 on laterality. It was noted that in imaging studies left prefrontal activity is generally associated with positive affect and right with negative affect in both humans and monkeys. However, lesion data is not that clear.