Lecture 26- Emotion I: Fear Flashcards
1What was the cat experiment with removing her cerebrum?
- when whole cerebrum removed, animal extremely aggressive= sham rage
- if cerebrum removed but hypothalamus remained= docile
- means hypothalamus is an organisational centre of fear an aggression
Does the emotional system in humans develop with age?
-yes -the things we fear change with age
What are the fears at the age of 4-6?
-kidnappers, robbers, ghosts and monsters
What are the fears at the age of 6?
-fears of bodily injury, death and failure develop -these may continue into early adolescence
What are the fears at the age of 10-11?
-fears regarding social comparison, physical appearance, personal conduct and school examinations may predominate
What are the consequences of the emotional system becoming dysfunctional?
-abnormal experiencing of anxiety can occur in variety of ways -this is when you are scared and shouldn’t be -very common 1: Generalized anxiety disorder (GAD) 2: Panic attack 3: Panic disorder 4: Phobias 5: Obsessive compulsive disorder 6: Post-traumatic stress disorder
What are the normal Panic attack symptoms? (13)
1.Pounding heart 2. Chest pains 3. Light-headedness or dizziness 4.Nausea or stomach problems 5.Flushes or chills= autonomic system goes wrong, control of temperature 6. Sweating= autonomic system 7. Shortness of breath or a feeling of smothering or choking 8. Tingling or numbness= somatosensory system 9. Shaking or trembling= over-excitation of autonomic system 10. Feelings of unreality 11. Terror 12. A feeling of being out of control or going crazy 13. Fear of dying
What are the nervous system components that organise expression of emotional experience?
- same motor neurons and same muscles for smile but different pathway
- medial /lateral organisation
- motor control but not the primary pyramidal (the main pathway)
- here it goes via different pathway
Can you activate the muscles needed for facial expressions without feeling the emotion?
-by activating the muscles can mimic the emotional pattern -but do not feel anything
What is voluntary facial (motor) paresis?
- there are two pathways that control muscles for smiling
a) volitional movement= the pyramidal and extrapyramidal projections from motor cortex and brainstem and
b) neural systems for emotional expression= descending extrapyramidal (not the main pathway) projections from the medial forebrain and hypothalamus - here we have a problem in the voluntary pathway
- cannot smile properly voluntarily
- can smile normally when find something funny
Where do the projections of the neural systems involved in emotional expression come from?
-medial forebrain and hypothalamus
What is emotional (motor) facial paresis?
- there are two pathways that control muscles for smiling
a) volitional movement= the pyramidal and extrapyramidal projections from motor cortex and brainstem and
b) neural systems for emotional expression= descending extrapyramidal (not the main pathway) projections from the medial forebrain and hypothalamus - here we have a problem in the voluntary pathway
- can smile properly voluntarily
- cannot normally when find something funny
What is the smile of emotional paresis called?
-Duchenne smile
What is the voluntary facial paresis smile called?
-Pyramidal smile
What does the existence of voluntary and emotional facial paresis tell us?
-there are two systems controlling the facial muscles involved in smiling
What is the so called limbic lobe?
-cingulate gyrus, associated with emotions
What is the modern concept of the limbic system?
- emotions last after the stimulus is gone
- continuous stimulation must occur
- amygdala and cingulate gyrus are the main components
- expression of emotion downstream via hypothalamus and autonomic etc.
Where is the amygdala and what three subgroups is it divided into?
- Baso-lateral group
- Medial group
- Central group
What are the inputs and outputs of the amygdala?
-orbital and prefrontal cortex are involved in the awareness of what is happening; interpretation
What is the pathway in a rat brain that mediates the association of auditory and aversive somatic sensory stimuli?
-fear is plastic= can learn to fear -
auditory fear conditioning= fearful stimulus, electrical shock
- do that and get fear response
- classical conditioning= beep and shock at the same time
- then have fear just from the beep
- beep= auditory pathway
- can interrupt the pathway, do not need the auditory cortex -
need the auditory pathway
Where does the amygdala get convergent inputs from and where does it project to?
- primary reinforces (taste, touch, pain)
- neural sensory stimuli=visual, auditory stimuli related to an object)
What is the pattern of activation of the AMPA and NMDA receptors at resting potential?
- when very weak stimulation only AMPA is activated and lets some Na+ in
- NMDA is blocked by a Magnesium ion
What is the pattern of activation of the AMPA and NMDA receptors at during postsynaptic depolarisation?
- if more glutamate comes then the NMDA is unblocked and the Mg ion dissociates -NMDA lets in Ca2+ and Na+ in
- it also activates CAM kinase
- CAM kinase adds more AMPA receptors therefore the postsynaptic membrane is more conductive
- thus the response to glutamate can be stronger than before -LTP= long term potentiation
What are the signaling mechanisms underlying LTP?
- NMDA lets in Ca2+ and Na+ and activates Ca2+/Calmodulin kinase II and Protein kinase C
- these two kinases phosphorylate substrate and make more AMPA receptors that are then inserted into the postsynaptic membrane and the response to glutamate is enhanced
What is specific LTP?
- One synapse is active and another one is not active
- only the active one is strengthened
- specific to a stimulus
What is associative LTP?
- one synapse strongly stimulated
- second one weakly stimulated
- stimulated together
- both synapses strengthened and when one fires later the other is associated and will fire too (this is in the amygdala
- changes in synapses together
- if tone carried by one and the renforcing one
- must be active at the same time -can associate thing that happen at the same time)
What is the neural model for the awareness of emotional feelings?
-
How can you suppress fear pharmaceutically?
- via benzodiazepine
- enhances the effect of GABA at the GABA a receptor
- resulting in relaxed, sleepy individual
