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Biology 463 - Neurobiology
Topic 19
Brain Mechanisms of
Emotion
Lange
Introduction
Significance of Emotions
– Emotional experience; Emotional expression
– Study behavioral manifestations
• Animal models, brain lesions
– Human brain imaging techniques
• Renaissance in the study of emotion
• Affective neuroscience
• Neural basis of emotion and mood
What Is Emotion?
•
Theories of Emotion
– The James-Lange Theory of Emotion - within human beings, as a response to
experiences in the world, the ANS will create physiological events such as
muscular tension, a rise in heart rate, perspiration, and dryness of the mouth etc.
Therefore, emotions are feelings that arise as a result of these physiological
changes, rather than being their cause.
– The Cannon-Bard Theory - also known as the thalami theory, suggests that
individuals experience emotions and physiologically react simultaneously.
William James & Carl Georg Lange
William Cannon and Phillip Bard
The Limbic System Concept
Broca’s Limbic Lobe
– Cortex forming a ring around corpus callosum: Cingulate gyrus, medial
surface temporal lobe, hippocampus
What Is Emotion?
Unconscious Emotions
– Stimulus can have emotional impact without conscious awareness
and increased activity in the amygdala
The Amygdala and Associated
Brain Circuits
Anatomy of the Amygdala
The Limbic System Concept
The Papez Circuit – the major pathway of the limbic system chiefly involved in the cortical control of
emotion.
This circuit plays a role in storing memory.
Papez discovered the circuit after injecting rabies virus into a cat's hippocampus and monitoring its
progression through the brain. The initial pathway was described as follows:
James Papez
The Limbic System Concept
The Papez Circuit
–
Cortex: Emotional experience
–
Hippocampus: Behavioral expression of emotion
• Rabies infection:Implicates hippocampus
in emotion, -> Hyperemotional responses
–
Anterior thalamus
• Lesions lead to spontaneous laughing,
crying
–
Paul MacLean popularized term “limbic system”
• Evolution of limbic system allows animals
to experience and express emotions
beyond stereotyped brain stem behaviors
Paul MacLean
Serotonin and Aggression
• Neurotransmitter Serotonin
Serotonergic raphe neurons
project to the hypothalamus
and limbic structures via the
medial forebrain bundle
Serotonin turn-over
aggression in rodents
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