Stress, anxiety and aggression Flashcards
What system is required in the stress response?
Sympathetic adrenal medullary system
The hypothalamus released CRH which causes the release of what 2 things?
ACTH and glucocorticoids such as cortisol, which act upon the adrenal medulla
What are the effects of 1) epinephrine 2) norepinephrine
- Increased blood glucose
- Increases blood pressure
Explain how stress can be neurotoxic
Chronic exposure to glucocorticoids leads to decreased glucose entry and glutamate reuptake, this leads to excessive stimulation on the post-synaptic neuron and excessive calcium influx. The hippocampus is sensitive to this over-excitation
Diamond et al, 1999 found impairments in a spatial task, how does this provide evidence for stress-induced neurotoxicity
The hippocampus is involved in spatial tasks, showing that the experimentally induced stress had an affect on the hippocampus
Who found out that bottom rank velvet monkeys have enlarged adrenal glands and hippocampus degeneration?
Uno et al, 1989
What did Son et al (2006) find out about pre-natal stress?
Interferred with the establishment of LTP in the offspring
What are some predisposing factors of PTSD?
Differences in the genes for the D2 receptors and the dopamine and 5HT transporters
What brain changes occur in PTSD?
Smaller hippocampus
What is the role of the medial prefrontal cortex, in the context of PTSD?
Inhibits the amygdala
Name the three treatments for PTSD
- Psychotherapy
- Anti-depressants
- Exposure/cue therapy
The finding that rats spend more time on the anxiogenic open arm following BZD administration indicates what?
That BZD helps to relax you due to the hyperpolarisation of the neuron, hence spending more time in the more fearful condition
In humans Paulus found that BZDs reduce what activity, when looking at emotional faces?
The amygdala
During anxiety attacks, neurosteroid synthesis is suppressed, how would this affect anxiety levels?
Increases them due to the fact that they usually increase the function of the GABAa receptor
D-cycloserine is a direct agonist of the NMDA receptor and reduced panic like symptoms. How?
By increasing the excitation of the neuron, d-cycloserine helps regulate the excessive firing that occurs with panic symptoms
The periaqueductal grey is involved in defensive and predation behaviours. Which parts of the PAG are involved in each of these behaviours?
Defensive = dorsal PAG
Predation = ventral PAG
What is the link between seretonin and aggression
Increasing seretonin transmission decreases aggression
What did findings show was implicated in rhesus monkeys and their increased aggression?
Low levels of the seretonin metabolite 5-HIAA
What are the gender findings surrounding aggression in rodents?
Females are less likely to fight when they meet a neutral animal than males, however they are more likely to attack when slightly androgenized
Conditioned place preference shows what about rats?
They will spend more time in the paired side of the chamber, anticipating the intruder
What are the findings in the intruder chamber studies?
Rats will continue to lever press, even in the absence of an intruder
What protein can be measured to measure brain activity?
Fos protein
What is the process called in which Fos is detected in the post-mortem brain?
Immunohistochemistry
What brain areas are involved in reward and motivation
nucleus acumbens and the VTA
What study shows that the self-administration of aggression in rats is rewarding?
There is more Fos activation in the nucleus acumbens of self-administrated aggression rats, compared to the control group
What is optogenetics?
The process of artificially turning on neurons with light
What does optogenetic stimulation of the VTA do?
Results in more aggressive behaviours towards the intruder
What is the main process called in optogenetics?
Transfection
c-Fos protein is an example of what type of gene?
Immediate early gene
What do electrophysiological reports measure?
The response of neurons in the brain in response to specific stimuli and movements
What is the Daun2 inactivation technique?
Allows us to selectively silence cells that are activated during expression of cocaine-induced locomotive sensitization
