Chapter 18: Brain Mechanisms of Emotion - Part 1 (Monday Lecture)

Who identified the limbic lobe and when?

Paul Broca in 1878

What is the limbic lobe?

It is defined as the cortex on the medial surface surrounding the corpus callosum and the brain stem.

What are the surfaces surrounding the corpus callosum and the brain stem?

1. Cingulate gyrus

2. Medial surface of the temporal lobe

3. Hippocampus

Who discovered the papez circuit and when?

In the 1930s by James Papez

What is the papez circuit?

Limbic structures involved in the emotion system that link cortex with the hypothalamus

Trace the papez circuit

Neocortex - (cingulate cortex - hippocampus - hypothalamus - anterior nuclei of thalamus - cing….)

In the papez circuit , what is the hypothalamus critical for ?

The autonomic and somatic responses for the behavioral expression of emotion.

In the papez circuit , what is the Cingulate cortex responsible for ?

Emotional expirience

In the papez circuit , what is the neocortex critical for ?

Emotional coloring

In the papez circuit , what is the circular connection from and to the hippocampus and hypothalamus critical for ?

The fornix

What was the logic behind the papez circuit system?

1. Major change in expression after damage to some cortical regions

2. Tumors near cingulate cortex are associated with increased fear, irritability and depression

3. Since rabies = hyperemotional response, hippocampus = rabies

4. Some reports have linked anterior thalamus with spontaneous laughter / crying

When and who popularaized the limbic system popularized?

1952 by Paul mclean as it was similar to the papez circuit

In the papez circuit what does the bidirectional communication of the hypothalamus and the neocortex indicate?

It indicates a bidirectional means of emotional expirience and expression

Which theory of emotion of the 3 are compatabile with the papez circuit?

james lange and cannon bard - both are compatible

What is Affective Nueroscience?

The study of emotion and mood

What kind of a reaction is emotion?

It is a short term affective reaction

What kind of a reaction is mood ?

It is a long term Affective reaction

What is emotion?

It is an immediate and specific reaction that is either positive or negative to external or internal stimuli. This reaction interrupts anything that happens in the moment.

What is mood?

It is a diffuse and a long lasting emotional state that does not have a specific trigger. It can influence over one’s thoughts and behaviors

What is an emotional expirience? Give Eg.

It is what we feel based on cognitive appraisal of the situation and a internalized interpretation of bodily states. Such as I’m scared.

What is emotional expression?

This is the behavioral manifestation of what we feel

What is the Body’s response

This is a physiological process like the heart racing or sweatig profusely

What are two ways or models we can study emotion?

Animal models AND Human Studies

What are two methods used to study emotions in the 2 types of models?

Animal and human models can be studied through both brain imaging / activity AND lesioning studies

What are the three theories of emotion?

1. The james lange theory

2. The cannon bard theory

3. Schachter singer theory or the two factor theory

When was the James Lange Theory proposed?

1884

What is the hypothesis of James Lange Theory of emotion? Give eg

People percieve specific patterns of bodily responses and as a result of that perception they feel emotion. I feel afraid because im trembling

What is the facial feedback hypothesis for the James Lange theory of emotion?

Faial expression of an emotion activates the expirience of the said emotion; not the other way around

According to the James Lang Theory of emotion, if you stop the physiological response, can you stop the emotion itself? ; that is if you stop crying, do you stop feeling sad?

Yes that is true

When was the cannon bard theory proposed?

1972

What is the hypothesis of James Lange Theory of emotion? Give eg

Emotiona expirience is independent of emotional expression. One feels afraid or sad before we tremble or cry.

What is the reasoning for the hypothesis of the cannon bard’s theory of emotion?

The mind responds to stimuli more quickly than the body does. The body is much slower than the mind

What evidences did cannon-bard have against james-lange’s theory?

1. Patients and animals with spinal cord transection, i.e lost the ability to sense their physiological states, can still feel emotions

2. Some individual physiological states have multiple emotions associated with one

What were some of the evidences against james-lange’s theory?

1. There was evidence to prove that people’s expirience of emotions are different after a spinal cord injury

2. Fear and rage both activate the same physiological parts (the sympathetic nervous system) yet have distinct physiological responses

What is the Schachter - Singer theory?

The two factor theory hypothesizes that when we label a physiologically aroused states, we expirience an emotion.

In the schacter singer theory, what is missattribution of arousal?

It is the misidentification of one’s arousal

What is unconsicous emotion?

External stimuli can cause an emotional response without one being conscious of the stimuli

Masked stimuli

A partial or complere obscuring / masking of one stimulus with an another

What do the masking experiments teach us about emotional processing?

You can process emotion without consciously perceiving the stimulus

What was MacLean’s logic behind the The Limbic System?

MacLean suggested that the Limbic System evolved to free us from stereotypical brain stem behaviors, like fight or flight, allowing us to experience and express emotion

Why is the limbic system not the system of emotion?

It has amygdala thats definitely involved in emotion but it also has the hippocampus thats involved in cognition, not emotion.

What roles does the prefrontal cortex have?

PFC play a critical role in personality and emotional regulation

What did earlier theories of emotion theories rely on?

• Relied on introspection and inference from brain injury and disease

• Disease and injury are not ideal for studying normal function

• For example, The hippocampus not involved in emotion)

What are recent theories of emotion?

1. Basic Emotion Theories

2. Dimension Emotion Theories

Name 3 hypothesis that support the basic theories for emotion.

1. Different emotions are correlated with activity of multiple different brain regions

2. Each emotion is correlated with the activity of one brain region

3. Different emotions are correlated with the activity of different networks of brain regions

What are the Hypothesis of Dimension Emotion Theories?

1. Emotions can be broken down into smaller elements that can be combined in different ways

2. Emotions correspond to brain activity along different dimensions

In Dimension Emotion Theories, what is valence?

how negative or positive emotions are

In Dimension Emotion Theories, what is Arousal?

Intensity of emotion