Neurobiology of Emotions and Behaviour Flashcards
What is the role of the Hippocampus
1- Episodic memories are sorted and transferred to long term memory
2- memories linked with senses
3- spatial orientation and navigation
4- centre of neurogenesis
What is the role of the Amygdala
1- Regulates emotional reactions : happiness, fear, anger , anxiety
2- creation of new memories
3- attaches emotional content to memories
4- fear learning
5- Activates flight or fight response
Damage to the Amygdala can result in ?
- Agression / irritation
- loss of emotional control
- difficulty recognizing emotion, esp. fear
What is the role of the Hypothalamus
1- maintains homeostasis and controls most autonomic functions
2- controls sexual drive and behaviour
3- links neurological and endocrine systems
4- combines information from other brain areas with receptive stimuli to regulate stress response
What is the role of the Cingulate Gyrus
1- Monitors Body’s response to unpleasant stimulus
2- through to be involved in fear and prediction/avoidance of negative stimuli
What is the main anatomical area responsible for emotional response
The limbic system : hippocampus, hypothalamus, and amygdala
Damage to Cingulate Gyrus results in what
- Improper emotions to situations
- don’t feel anxiety or pain
- patient puts themselves in risky situations and won’t realize
What is the role of the Basal Ganglia
1- Primary controls voluntary movements
2- Involved in reward and reinforcing behaviours
3- addiction and habit formation
Neurotransmitters involved with Anxiety ( normal anxiety that everyone feels ) and the 2 pathways
2 main pathways : Amygdala & Prefrontal cortex
Neurotransmitters:
1- GABA : inhibitory
2- Glutamate : excitatory
Role of GABA in Anxiety
1- predominant inhibitory neurotransmitter
2- important regulatory role at amygdala and prefrontal cortex
3- enhanced GABA relives anxiety
Explain the pathways of anxiety
1- See dangerous stimuli ( ex: dog barking )
2- amygdala is triggered , making you alert
3- Prefrontal cortex will asses situation and either reinforce amygdala reaction or calm things down
Which medications target GABA for anxiety
1- Benzodiazepines
2- sedative hypnotics
3- barbiturates
4- alcohol
Explain what is involved with Effects of the past ( PTSD )
1- Memories are stored in hippocampus
2- Traumatic memories activate amygdala
3- Hippocampus and amygdala will generate fear response when re-experiencing a traumatic event ( ex: PTSD )
What imbalance happens with Anxiety disorders
GABA imbalance
Glutamate is used as a therapeutic target for which other condition than anxiety
Psychosis
Neurotransmitters involved with Depression ( monoamines )
1- Noradrenaline
2- Dopamine
3- Serotonin
What neurotransmitter is target of antidepressants
Serotonin
Serotonin is produced from what ( explain in detail )
Tryptophan , an essential amino acid we have to get form diet
1- Tryptophan converted into 5-Hydroxytrptophan via tryptophan hydroxyls
3- 5-HTP converted to Serotonin ( 5-TH) via decarboxylase
Where are receptors for serotonin found
1- Brain
2- Gut
3- Platelets
What is serotonin involved in
1- Mood and emotion 2- sleep 3- cognition 4- appetite 5- Memory 6- Perception
Can memory be affected in depression
Yes since memory is affected by serotonin levels. Could show pseudodemntia
Dopamine is made from which amino acid ? ( explain in detail )
Phenylalanine –> Tyrosine –> L-Dopa –> Dopamine
What is dopamine involved in
1- Pleasure , reward and goal directed behaviour 2- attention 3- motivation 4- emotion 5- motor function
What is Noradrenaline involved in
1- Concentration
2- Attention
3- Motivation
4- Energy
Map the symptoms of depression to the Brian
PFC: concentration , interest , pleasure , psychomotor mental fatigue , guilt , suicidality , worthlessness , mood
Nucleus accumbens: pleasure, interests, fatigue, energy
Striatum: psychomotor physical fatigue
Amygdala: guilt, suicidal , worthlessness , mood
Hypothalamus: sleep, appetite
spinal cord: fatigue physical
cerebellum: psychomot
Explain Dopamine pathways in Psychosis and effects of medication on them
Too much dopamine resulting in Psychosis
1- Nigrostriatal : involved in motor control of voluntary movement, medications can cause extrapyramidal side effects ( ex: pseudo Parkinsonism)
2- Mesolimbic: involved in positive symptoms ( hallucinations/delusions) ,
3- Mesocortical : Cognitive and affective symptoms ( apathetic, planning, judgement impaired ) ,
4- Tuberoinfundibular : Dopamine inhibits prolactin release , medications could cause hyperprolactinaemia
How does excess dopamine cause Delusions
Dopamine modulates attention and salience ( how much attention/relevance something needs form us ).
Irrelevant stimuli will attract patient and get motivational salience and thus influence behaviour. Stimuli are attended to, explored and given meaning = leading to delusions.
Explain Effect of Stress on Monoamines
Brain-derives neurotrophic factor keeps neurones/brain healthy.
Under stress BDNF will be repressed and thus lower 5ht levels.
Initially there will be higher NA and dopamine levels but if stress is chronic then they will decrease too
Without BDNF : it causes atrophy , apoptosis in hippocampus and PFC
What is the affect of Hippocampus and Amygdala dysfunction as a result of stress affecting BDNF
Hippocampus and amygdala dysfunction leads to overactivity of hypothalamic pituitary axis = elevated glucocorticoids and insensitivity to feedback inhibition
= Effects BP , HR , diabetes , etc.
