An article was covered in class and showed brain tissue growth-red and decrease-blue over time. What were the key takeaways from this? (4)
- see that brain is growing and increases in size until teen years
- also occurs in animals (but smaller volume)
- indicates that brain is growing and that this developmental process is ongoing
- the developmental processes are very susceptible to environmnetal stimuli
what is neurogenesis?
formation of new neurons in the brain
what article was provided in class as evidence for adult neurogenesis?
hippocampus and olfactory bulb in adult rodents
- controversy: is there really adult neurogenesis in adult humans?
what were the conclusions of the article covered on learning and brain plasticity? (3)
- evidence that suggests that representation of hand digits can be modified by training
- comparing dipole strength of regions representating finger position and can be stored in string players
- if you use a finger more, its representation strengthens/increases
how does allosteric load relate to the impact of chronic stress on our bodies?
- bc chronic stress can lead to long term increase of cortisol, this can induce changes in the brain that have pathological changes
- NE is responsible for acute stress responses (like flight or fight response) -> cortisol helps bring aroused state back to baseline
- if you have high level of cortisol due to stress, can have adaptation changes (that used to be healthy) that are maladaptive
what is allostatic?
low allostatic load (also involved in brain plasticity)
what results were shown to explain the relationship btw life events and mood disorders?
Negative life events near the onset of depressive episode
Negative life events associate with the severity of cognitive impairment of depression
Levels of cortisol in plasma and CRH in aCSF are increased in patients with depression
When you compare the number of negative life events in months before an episode of depression, the trend is ____ for the general population while ____ for those with depression and suicide attempters
steady; increased
explain the results of the following study (4):
Injected cortisol in rats to induce stress and compared the dendritic representations of CA3 in the hippocampus
- see more changes after chronic injections of cortisol –> see shrinking of dendrites in ca3
- these changes also found in aging –> suggests that chronic stress might make you age faster
- when they quantify the dendrites from the cell body, dendrites away from the cell body are shortened (reduce in length, size)
- if you remove cortisol/stress, the dendrites grow back (in rats) –> dynamic process
what might stress induce for it to be a risk factor for mood disorders?
- using scans to measure brain volume in people with diff mental dx (ie dep)
- meta analysis supports findings of animal studies that theres a decrease in hippocampal volume in people with depression
who were the subjects in the study on the impact of traumatic events (PTSD) on brain health?
- ExP+ : combat exposed subjects WITH ptsd
- UxP+ : co-twins of ExP+ with NO ptsd
- ExP- : combat-exposed subjects with NO ptsd
- UxP- : co-twins of ExP- with NO ptsd
who were the 3 possible scenarios in the study on the impact of traumatic events (PTSD) on brain health?
1: ptsd is related to stress on hippocampus – expect those with ptsd to have smaller hippocampal volume
2: some genetic makeup causes smaller hippocampus to begin with – expect both twins (co-twin WITH and WITHOUT) to have smaller hippocampus
3: whether u have combat experience (independent of ptsd or not) you will have smaller volume
what were the results of the study on the impact of traumatic events (PTSD) on brain health?
found similar relationship: even without experience of combat, size of hippocampus of twin can predict your vulnerability to ptsd
- second scenario is supported by findings
lower hippocampal volumes for twins with ptsd
the presence of _____ factors –> more biological factors that could explain our vulnerability to stress
vulnerability
what are characteristics of stress resilient mice?
- lower HPA axis activity
- higher exploration
- lower anxiety
- lower submissive behavior
what are characteristics of stress resilient mice?
- greater HPA axis activity
- lower exploration
- greater anxiety
- greater submissive behavior
what is early life stress?
Encompasses early traumatic experiences during childhood and adolescence
what are the subtypes of ELS? (5)
emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect
what are the symptoms of those who experienced ELS?
internalizing symptoms (e.g. anxiety, avoidance), externalizing symptoms (e.g. aggression, hyperactivity), and social impairment
ELS ____ the risk of psychiatric disorders
increases
what were the results of the study on ELS on depression?
individual with short form SERT has high risk but ONLY when they experience child maltreatment
indicates that while genetic factors can make you more susceptible, it also has to do with their environmnent
how did they study ELS on brain development?
study individual differences in how moms care for their pups and see if changes in maternal behaviours impact the expression of behaviour in the pups (related to mental dx)
individual diff: some moms spend less time grooming/licking
what were the maternal effects on the HPA-axis?
GR are receptors for glucocorticosteroids (low affinity receptors that detect stress levels of cortisol)
in animals with low LG, have higher level of cortisol
increase in GR in the high-LG offspring in the hippocampus
–due to negative feedback system
what was the conclusion of the study of epigenetic programming by maternal behavior?
low LG pups had more methylation and could be reversed if placed in the care of high LG moms
