neurobiology of emotions Flashcards
What structures make up the limbic system?
- hippocampus
- amygdala
- hypothalamus
- cingulate gyrus
- Basal ganglia
What is the function of the hippocampus?
episodic memories are sorted and transferred to long term memory
- links memories to senses
- spatial orientation
- centre neurogenesis
What is the function of the amygdala?
- regulates emotional reactions
- creates new memories
- attaches emotion to memories
- activates flight + fight
- fear learning
What is the neurological function of hypothalamus?
- control sexual drive and behaviour
- gathers info from other areas with receptive stimuli to regulate stress response
What is the function of the cingulate gyrus?
- monitors response to unpleasant stimuli
- fear, fear and avoidance of neg stimuli
What is the function of the basal ganglia?
- controls voluntary movements
- reward and reinforced behaviours
- addiction and habit formation
What can happen when amygdala is damaged?
- increased aggression
- loss of emotional control
- difficult to recognise emotions
What can happen when cingulate gyrus is damaged?
- lack of anxiety
- diminished pain
- improper emotions
What is the function of GABA?
- predominant inhibitory neurotransmitter
- regulatory role in amygdala & prefrontal cortex
- enhanced GABA action will reduce anxiety
- site of action of alcohol
What are the main excitatory and inhibitory neurotransmitters?
inhibitory - GABA (calms body down after threat)
Excitatory - Glutamate (increases stress response after threat)
What is the function of glutamate?
- involved in all aspects of brain function
- uses NMDA, AMPA and KA receptors
- in anxiety disorders will have an imbalance of GABA and glutamate (inc glut)
- also has role in developing psychosis
What is the function of serotonin?
- mood and emotion
- sleep
- cognition
- appetite
- memory
- perception
What is the function of dopamine?
- pleasure and reward
- attention
- motivation
- emotion
- motor function
What is the function of noradrenaline?
- concentration
- attention
- motivation
- energy
How does the brain normally react in response to a threat?
initiates two pathways
1) amygdala comes into high alert makes us anxious
- can trigger hypothalamus inc breathing + HR
2) prefrontal cortex analyses situation going on, decided whether response is necessary, can either inc or calm down body response
What is pathophysiology of PTSD?
- traumatic memories stored in hippocampus
- activate amygdalas threat response
- don’t need stimulus
What are the monoamines?
- serotonin
- noradrenaline
- dopamine
What neurotransmitters are involved in depression?
- possibly all monoamines
- serotonin is usually the one targeted by anti-depressants
Where are the receptors for serotonin?
- brain
- gut
- platelets
Where is serotonin made?
Raphe Nuclei
How are monoamines regulates?
auto regulated by themselves and the other monoamines
What is the role of dopamine in psychosis?
- excessive dopamine
- so medication reduces levels by blocking all pathways
- unsure how creates psychosis
- can be due to dopamines controlling attention and importance
- excess can cause tendency for irrelevant stimuli to be attributed motivational importance
What are the pathways of dopamine?
1) nigrostriatal (pathway faulty in Parkinsons)
2) mesolimbic (involved in psychosis)
3) mesocortical (involved in psychosis)
4) tuberoinfundibulnar
What are the positive and negative symptoms of schizophrenia?
positive - hallucinations
negative - decline in cognition
How does stress affect monoamines?
- stress represses BDNF
- results in reduced serotonin
- can inc noradrenaline and dopamine initially in response to stress but chronically reduces them if stress continues
What is BDNF?
Brain-derived Neurotrophic Factor (keeps neurones healthy and maintains monoamines)
What can reduced BDNF cause?
atrophy and apoptosis of hippocampus and prefrontal cortex
- dysfunction of hippocampus and amygdala can cause elevated glucocorticoids (can cause high BP and chronically high HR)
