Neuro: Emotion Flashcards
What are the different aspects of emotion?
- Emotional expression (mainfestation of emotion - facial expression)
- Emotional experience (feeling of emotion)
Explain how the elevated-plus maze experiment is used to measure the emotional expression of anxiety in mice
- Mice were placed in the centre of a plus-maze and left to explore the plus-maze for 5 mins
- Plus-maze is elevated off of ground and consists to two open arms and two closed arms
- During 5 mins you measure amount of time mouse spends in each portion of elevated-plus maze
- If mouse feels anxious of height it’ll spend more time in closed arms and if it feels less anxious of height it’ll spend more time in centre/open arms
Explain how the forced-swim test is used to measure the expression of depressive-like behaviour/emotion in mice
- Forced-swim test involves placing a mouse inside a beaker filled with water (5L beaker)
- Initially when mouse placed in wateer it’ll start swimming around in the beaker for about 4-5 mins
- After this time mouse will want stop swimming and get out of the water so will start to try and get out of the water
- After it realises it can’t get out mouse will only move to stop its head from entering water (immobilisation)
- The time mouse spends immobilisised in water indicates depressive-like behaviour
- If mouse spends more time in immobilisied state it shows depressive-like behaviour but if it continues to try and get out for longer it shows non-depressive like behaviour
What does the James-Lange theory of emotions state?
- States that we experience emotions in response to physiological changes in our body
- E.g. When you see a cobra you will first express that emotion - start sweating/heart beats faster and then because of that expression of emotion you will then experience/feel that emotion (fear)
What does the Cannon-Bard theory of emotions state?
- States that we can experience emotions independently of emotional expression
- E.g. When you first see a cobra you will experience that emotion (feel fear) and because of this you then express that emotion - you start to sweat/heart beats faster
What area of the brain is resonsible for producing emotion?
- Limbic lobe - Areas of brain that form a ring around corpus callosum
- These areas include - cingulate gyrus, medial surface of temporal lobe and hippocampus
Explain the papez circuit of the limbic system and how it allows us to experience and express emotion
- Necortex gets activated in response to a stimuli
- In neocortex emotional colouring takes place (value added to emotion)
- Neocortex then sends signal to cingulate cortex
- Cingulate cortex is where emotional experience occurs
- After this cingulate cortex activates hippocampus which goes on to activate hypothalamus via the fornix
- Hypothalamus is where emotional expression then takes place
- Hypothalamus then activates ANS and endocrine which allow for physical manifestation of emotion - e.g. crying
- Hypothalamus activates anterior nuclei of the thalamus which then further activates the cingulate cortex
What brain structures are part of the limbic system?
- Cingulate gyrus/cortex
- Parahippocampal structures
- Amygdala
- Enthorinal cortex
- Hippocampus - (dentate gyrus, CA1-CA4 areas)
What are some functions of the cingulate gyrus?
- Complex motor control
- Pain perception
- Social interactions
What are some functions of the hippocampus and parahippocampal structures?
- Memory (specifically memory consolidation)
What are some functions of the Amgydala?
- Involved in learning and storage of emotional experiences
- Critical in feelings of fear, aggression and anxiety
Where specifically within the brain is amygdala located?
- The amygdala are underneath the hypothalamus on either side of it within the two hemispheres
What are the names of the different nuclei within the amygdala?
- Central nucleus
- Basolateral nuclei
- Corticomedial nuclei
What areas of the brain does the amygdala receive input from?
- Receives input from the neocortex, hippocampus and cingulate gyrus
- Basolateral nucleus specifically receives input from sensory systems
What areas of the brain does the amygdala output to?
Amygdala sends output to the hypothalamus
What is Kluver-Bucy syndrome and what are the symptoms?
- Kluver-Bucy syndrome is a syndrome resulting from the lesioning of the medial temporal lobe in monkeys
- The medial temporal lobe contains the amygdala and hippocampus so some of the symptoms include:
- Psychic blindness - couldn’t place emotional importance/meaning to an object
- Oral tendencies
- Reduced fear
- Hypersexual behaviour
What symptoms occur in humans when subjected to an Amygdalectomy (removal of the amygdala)?
- Reduced fear
- Reduced aggression
- Flattened emotions
- Reduced ability to reconise fear in someone else
What symptoms occur in humans as a result of eletrical stimulation of the amygdala?
- Anxiety
- Fear
- Aggression
Apart from processing fear, what other aspects of fear is the amygdala involved in?
- Involved in learning and memory of fear
- Also involved in attaching emotion to specific memories
How do we know that the amygdala is involved in attaching particular emotion to memories?
- In an experiment participants were shown a series of images and when shown some of the images they were given an electric shock while with other imgaes they weren’t
- The brains of each of the participants were then imaged using PET scans and the participants were shown those same images
- The scans showed that when the participants were shown the images in which were paired with the electric shock there was increase in activity of the Amygdala
What are the two types of aggression?
- Predatory aggression
- Affective aggression
What is predatory aggression?
- Attacks made against a member of a different species with a specific motivation for the attack e.g. for food
What is affective aggression?
- Aggression for show - aggression to exert dominance over someone or a group
Apart from the amygdala what other brain regions are involved in aggression?
Hypothalamus
Describe the experiment that showed that the hypothalamus is involved in aggression
- Removal of cerebral hemispheres but not the hypothalamus in cats resulted in sham rage
- When experiment was repeated but they also removed the anterior hypothalamus the cats also experinenced sham rage
- However, when the experiment was repeated a third time but they removed the cerebral hemispheres, and both the anterior and posterior hypothalamus the cat didn’t experience sham rage
What type of aggression was exhibited in cats when their medial hypothalamus was stimulated? What type of aggression did they then exhibit when their lateral hypothalamus was stimulated?
- Stimulation of medial hypothalamus - Affective aggression
- Stimulation of the lateral hypothalamus - Predatory aggression
Describe the neural circuit pathway for anger and aggression
- Specific stimuli leads to activation of cerebral cortex
- Cerebral cortex then activates Amygdala
- Amygdala then sends signal to hypothalamus as well as ventral tegmental area (VTA) and periqueductal grey area (PAG)
- Hypothalamus also signals to VTA and PAG
- Ventral tegmental area and Periqueductal grey area then produce aggressive response
How is serotonin correlated with agression?
- Serotonin levels inveresly related to aggression - low serotonin levels associated with increased aggression
- Serotonin antagonists increase aggression
- Agonists of 5-HT1A or 5-HT1B decrease anxiety and agressivness
