Ch. 18. Brain Mechanisms of Emotion Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, pp 564-583.
WHAT IS EMOTION? Love, hate, disgust, joy, shame, envy, guilt, fear, anxiety, etc. Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 564.
Theories of Emotion James-Lange Theory Stimulus physiological change in body brain receive emotion Weak point: One who cannot sense physilogical change can experience emotion. Cannon-Bard Theory Stimulus brain receive emotion physiological change in body Weak point: Similar physiological changes can be induced by some disease. Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 566.
THE LIMBIC SYSTEM CONCEPT Broca s limbic lobe Limbic (border) system ( 변연계 ) Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 569.
The Papez circuit Neocortex (emotional coloring) James Papez emotion system (limbic system) linking Hypothalamus (emotional expression) Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 569.
Relationship between certain brain regions (such as limbic system) and emotion Removal of or electrical stimulus to certain brain areas from experimental animals Clinical observations for patients with brain damage Removal of or electrical stimulus to brain areas of schizophrenia patients fmri The Amazing Case of Phineas Gage most efficient and capable foreman with well-balanced mind A person like an ill-tempered child (strong emotions) both frontal lobes damaged Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 587.
FEAR AND ANXIETY The Klϋver-Bucy syndrome Rhesus monkey: temporal lobectomy Psychic blindness: they could see, but they could not recognize. Oral tendencies: place each object in their mouth Hypermetamorphosis: they appeared to be obsessed by urge to run around and touch everything and place each found object in the mouth Changes in sexual behavior Flattened emotions: decrease in fear removal of amygdala
The Amygdala Anatomy of the amygdala Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 573.
The effect of amygdala destruction and stimulus Amygdala: removal disappearance of fear: ex) treated rats nibble cat s ear S.M. (patient with damage to amygdala) has difficulty to discriminate angry and fear full expression from people s photographs. electrical stimulus to amygdala induces fear and aggression Fear, anxiety: amygdala aggression: amygdala+hypothalamus A Neural Circuit for Learned Fear Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 594.
A Neural Circuit for Learned Fear Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 575.
ANGER AND AGGRESSION Predatory aggression: involves attacks against a member of a different species for the purpose of obtaining food, typically achieved by few vocalizations and aiming at the head and neck of the prey. In human this aggression used to be praised as a good aggresiveness. Affective aggression: is for show rather than to kill for food and it involves high levels of activity in the sympathetic division of the ANS. An animal in this state will typically make vocalizations while adopting a threatening or defensive posture. Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 596.
The Hypothalamus and Aggression Sham Rage: Animals show rage behavior in response to very mild stimuli (such as scratching a dog s back) that normally would not cause anger. This condition resulted from removing all of both cerebral hemispheres. Posterior hypothalamus anger, aggression inhibited by cerebral cortex Sham rage: O Sham rage: O Sham rage: X Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 579.
Electrical Stimulation of the Hypothalamus Electrical stimulus to medial hypothalamus Removal of medial hypothalamus disappearance of affective aggression Electrical stimulus to lateral hypothalamus Removal of lateral hypothalamus disappearance of predatory aggression Bear et al., Neuroscience: Exploring the Brain, 3 rd ed., Lippincott Williams & Wilkins, 2006, p 580.
Two pathways for aggression Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 598.
The Frontal Lobotomy To medically treat severe behavioral disorders, clinicians have attempted frontal lobotomy. reported to be effective on people with number of disorders, including psychosis, depression and various neuroses. Side effects (such as flattened emotion) emerge. the operation was replaced by drug therapy Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 599.
The Amygdala and Aggression Most dominant monkey amygdala removal it fell to the bottom of the hierarchy :Amygdala is important for the aggression normally involved in maintaining a position in the social hierarchy (affective aggression). Serotonin (5-HT) and Aggression Mice that are isolated in a small cage for four weeks hyperactive and extremely aggressive in these mice: decrease in serotonin turn-over rate decrease in serotonin action ex) injection with serotonin synthesis inhibitor increase aggression Serotonin Receptor Knockout Mice 5-HT 1A knockout avoid open space, unusually anxious. 5-HT 1B knockout show increased aggression in a stressful situation Treatment with 5-HT 1A and 5-HT 1B agonists decrease fear and aggression
REINFORCEMENT AND REWARD Dopamine agonist increase self-stimulation Dopamine antagonist decrease self-stimulation Ventral tegmental area (dopamine neurons) mesocorticolimbic dopamine system Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 601-602.
Brain Stimulation in Humans Patient A Septal area alert, good feeling self-stimulation Hippocampus mild pleasure Tegmentum alert, unpleasure Patient B Septal area, tegmentum pleasure Mid brain happy drunk feeling Medial thalamus unpleasure remind memory self-stimulation Bear et al., Neuroscience: Exploring the Brain, 2 nd ed., Lippincott Williams & Wilkins, 2001, p 603.