Emotion (neuro) Flashcards
1
Q
What is emotion?
A
- Emotional expression • Animal and human studies - Emotional experience • Human studies - Affective Neuroscience • neural basis of emotion and mood • (mood as an emotion extended in time)
2
Q
Drug influence
A
- increase of anxiety-like behaviour following long-term opioid abstinence
- increase in depressive-like behaviour following long term-opioid abstinence
- long-term morphine abstinence abolishes social preference
3
Q
Brain mechanisms of emotion
A
- Emotions:
• Love, hate, disgust, joy, shame, envy, guilt, fear, anxiety, etc. - Theories of emotion:
• James- Lange: - We experience emotions in response to physiological changes in our body
• Cannon-Bard: - We can experience emotions independently of emotional expression (dissociations)
- Emotions are produced when signals reach the thalamus either directly from sensory receptors or by descending cortical input
4
Q
James-Lange vs. Cannon- Bard
A
- The James–Lange theory: emotion experienced in response to physiological changes in body
- The Cannon–Bard theory: emotions occur independent of emotional expression - no correlation with physiological state
5
Q
Is there a brain system responsible
for Emotions?
A
- Broca’s Limbic lobe • Limbus (latin) means border • primitive cortical gyri that form a ring around the brain stem - Broca’s limbic lobe includes • the parahippocampal gyrus • the cingulate gyrus • the subcallosal gyrus
6
Q
The Limbic system
A
- Broca’s limbic lobe
• Areas of brain forming a ring around corpus callosum: cingulate gyrus, medial surface temporal lobe, hippocampus
7
Q
The Papez circuit
A
- Limbic structures, including cortex, involved in emotion
- Emotional system on the medial wall of the brain linking cortex with hypothalamus
- Cortex critical for emotional experience
- Hippocampus governs behavioral expression of emotion:
• Rabies infection implicates hippocampus in emotion -> hyperemotional responses - Anterior thalamus:
• Lesions lead to spontaneous laughing or crying. - Paul MacLean popularized the term limbic system:
• Evolution of limbic system allows animals to experience and express emotions beyond stereotyped brain stem behaviors.
8
Q
Limbic system as we define it
A
- Cingulate gyrus
- Parahippocampal structures
- Septal nuclei
- Amygdala
- Enthorinal cortex
- Hippocampal complex:
• dentate gyrus
• CA1-CA4 subfields
• subiculum - Difficulties with the single emotion system
concept - Diversity of emotions and brain activity
- Many structures involved in emotion
• No one-to-one relationship between structure and
function - Limbic system: use of single, discrete emotion
system questionable
9
Q
Functions of limbic system
A
- Anatomically the limbic system appears to have a role in attaching a behavioral significance and response to a stimulus, especially with respect to its emotional content
- Damage to the limbic system leads to profound effects on the emotional responsiveness of the animal
- Cingulate gyrus:
• role in complex motor control
• pain perception
• social interactions-mood - Hippocampus proper and parahippocampal areas:
• primary function in memory (critical role in
connecting certain sensations and emotions to these memories) - Amygdala:
• involved in learning and storage of emotional
aspects of experience
10
Q
Emotion theories and neural representations
A
- Early theories of emotion and limbic system
built on introspection and inference from
brain injury and disease. - Studies of disease and consequences of
lesions not ideal for revealing normal
function. - More recent theories of emotion
• Basic emotion theories
• Dimension emotion theories
11
Q
Amygdala
A
- Greek word for almond
- Critical structure for emotion in particular
• fear and aggression, anxiety
12
Q
Human brain activity in response to emotional stimuli
A
- neutral and fearful faces were used as visual stimuli
- fearful faces produced greater activity in the amygdala than neutral faces
- no difference in amygdala activity occurred in response to happy/neutral faces
13
Q
Amygdala structure and connections
A
- Receives input from neocortex
• All lobes, including hippocampal, and cingulate gyri - Basolateral nuclei
• Receives information from all sensory systems - Corticomedial nuclei
- Central nuclei
- Output to hypothalamus (region involved in expression of emotion)
• Stria terminalis
• Ventral amygdalofugal pathway
14
Q
Amygdala fear
A
- The Kluver-Bucy syndrome (rhesus monkeys)
- Temporal lobe removal (temporal cortex, amygdala, hippocampus):
• Good visual perception but poor visual recognition
• psychic blindness
• oral tendencies
• emotional changes (reduced fear)
• altered sexual behaviour - Amygdalectomy (humans):
• Reduce fear
• Reduce Aggression
• Hypersexuality
• Oral tendencies
• Reduce ability to recognize a fearful expression (can recognise happiness):
• Flattened emotions - Electrical stimulation:
• Increased vigilance
• Anxiety
• Fear
• Aggression
15
Q
Learned fear
A
- amygdala involved in forming memories of emotional and painful events
- confirmed by fMRI images and PET imaging
