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 are the most important parts of the brain involved in emotions?
-cingulate gyrus and the amygdala
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 activated in the brain when making judgments of trustworthiness?
-the amygdala -amygdala is activated when you make judgments about trustworthiness -some difference in left and right -implicit= only pic, explicit= some info
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 are the outputs from the amygdala to the orbital and medial prefrontal cortex about?
-implicit motor actions -explicit conscious processing to obtain rewards, avoid punishments and implement long-term plan
What are the outputs from the amygdala to the hypothalamus and brainstem about?
-visceral motor effector systems to prepare body fro action
What are the AMPA and NMDA receptors activated by?
-glutamate
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 are the two types of LTP?
- selective, specific (homosynaptic) 2. associative (heterosynaptic)
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 happens when you have bilateral loss of the amygdala?
-no concept of fear -maintain all the other feelings but don’t know what fear is -cannot draw it (the funny baby picture)
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
