neuro 6&7

• Emotion


  Defined by psychologists in terms of three components: Cognition, Readiness for action, Feeling
• James-Lange theory of emotion


  Suggests that the autonomic arousal and skeletal action occurs first in an emotion. The emotion that is felt is the label that we give the arousal of the organs and muscle.
• James-Lange theory


  • People with a weak autonomic or skeletal response should feel less emotion
  • Increasing one's response should enhance an emotion
• People with damage to the spinal cord generally report experiencing emotions about the same as before their injury
• People with pure autonomic failure say they feel their emotions much less intensely than before
• People with BOTOX injections that temporarily paralyzed all the facial muscles reported weaker-than-usual emotional responses
• Although physiological responses are seldom sufficient to produce emotional feelings, they increase the feelings
• Increases in heart rate intensify ratings of both pleasant and unpleasant emotions, especially in people who are most sensitive to their internal state
• Limbic system


  • Traditionally been regarded as critical for emotion
• Frontal and temporal lobes


  • PET and fMRI studies suggest many other areas of the cerebral cortex are activated during an emotional experience
• Serotonin


  Its is very complicated and should not be thought of as the "antiaggression" transmitter
• Amygdala


  • Output from the amygdala to the hypothalamus controls autonomic fear responses
  • Axons extending from the amygdala to the prefrontal cortex regulate approach and avoidance responses
  • Damage to the amygdala interferes with the learning and retention of fear responses, interpreting or understanding stimuli with emotional consequences, and the ability to judge "trustworthiness" in people and recognize emotions in photographs or pictures
• Genetic variations in amygdala arousal may underlie some of the variations of anxiety in the population and related disorders
• Excessive fear and anxiety disorders are associated with hyperactivity in the amygdala
• Steroid hormones


  Derived from cholesterol, contain four carbon rings, and exert effects by binding to membrane receptors, entering cells and activating certain proteins, and binding to chromosomes to activate or inactivate certain genes
• Sex hormones


  A special kind of steroids, released mostly by the gonads and to a lesser degree by the adrenal glands, affecting the brain, genital and other organs. Two types: Androgens (e.g. testosterone) and Estrogens (e.g. estradiol, progesterone)
• Biologists assumed that hormones account for all the biological differences between males and females, but later research demonstrated that the X and Y chromosomes control some differences independently of hormones
• For most brain areas, the male-female differences are less well understood than they are for the hypothalamus, but researchers have established that the mechanisms include not only testosterone and estradiol but also close to a hundred genes that are more active in one sex or the other
• Very few people have a brain that is male-typical or female-typical in all regards. Instead, almost anyone's brain is a mosaic of male-typical, female-typical, and approximately neutral areas
• Males


  • Testosterone, essential for male sexual arousal, acts partly by increasing touch sensitivity in the penis
  • Testosterone primes the MPOA and several other brain areas to release dopamine, which is important for sexual arousal and activity
  • Levels of testosterone correlate positively with men's sexual arousal and their drive to seek sexual partners
  • Decreases in testosterone levels generally decrease male sexual activity
  • Castration generally decreases a man's sexual interest and activity
• Females


  • The hypothalamus and pituitary interact with the ovaries to produce the menstrual cycle
  • A woman's menstrual cycle depends on a feedback cycle that controls the release of several hormones
  • Women can respond sexually at any time in their cycle, but on average, their sexual desire is greatest during the fertile period when estradiol levels are high
  • Sex hormones also influence behaviors not directly related to sexual reproduction, such as the ability to recognize emotional expressions
  • Oxytocin is important for reproductive behavior, stimulating contraction of the uterus during delivery, milk release, and facilitating pair bonding
• What you experience as an emotion is the label you give to your responses: You feel afraid because you run away, and you feel angry because you attack
• People with damage to the spinal cord have no sensations or voluntary movements from the level of the damage downward but they generally report experiencing emotions about the same as before their injury.
• People with damage to the spinal cord's experience then suggest that emotions don’t depend on feedback from movement, but these people continue to have facial expressions and changes in heart rate, which they can detect.
• In pure autonomic failure, output from the autonomic nervous system to the body fails, either completely or almost completely.
• Someone with pure autonomic failure Sdoes not react to stressful experiences with changes in heart rate, blood pressure, or sweating. However, they say they feel their emotions much less intensely than before.
• Botulinum toxin (“BOTOX”) blocks transmission at synapses and nerve– muscle junctions.
• Implication of Botulinum toxin is that feeling a body change is important for feeling an emotion
• Walter Cannon (1927) objected that feedback from the viscera is neither necessary nor sufficient for emotion, that it does not distinguish one emotion from another, and that it is too slow to account for how fast we identify an event as happy, sad, or frightening.
• The limbic system includes the forebrain areas surrounding the thalamus.
• During aggression, the brain releases serotonin.
• Clinical depression is linked to low serotonin
• High levels of serotonin may inhibit a variety of impulses.
• The amygdala, in the brain’s temporal lobe, is important in the experience of emotions for it provides a link between the perception of an emotion-producing stimulus and the recall of that stimulus later leading to a conditioned response later on.
• Damage to the amygdala interferes with the learning of fear responses, retention of fear responses previously learned, and interpreting or understanding stimuli with emotional consequences
• In humans, damage to the amygdala does not result in the loss of emotion.
• Damage to the amygdala impairs the processing of emotional information when the signals are subtle or complicated
• Amygdala damage affects the ability to judge “trustworthiness” in people.
• People with amygdala damage focus on emotional stimuli the same as irrelevant stimuli or details.
• Amygdala damage also affects the ability to recognize emotions specifically in photographs or pictures.