Class 3, Chapter 23 - Development Flashcards
Postnatal brain growth is due to
differentiation, mylenation, growth of EXISTING neurons
How many cells are made per minute during prenatal development?
250,000 cells
What are the two stages of CNS development?
Prenatal development (structural formation, genetically determined) and postnatal development (susceptible to environmental influences)
What are the two opposing developmental processes?
Additive development (myelination, dendritic arborization). Regressive processes (apoptosis, synaptic pruning)
When is the embryonic period? And what is formed in general?
Conception to 8 weeks. Rudimentary CNS structures made
When is the fetal period? And what is formed, in general?
9 weeks to birth. Rapid cortical and subcortical structure growth
What produces neural stem cells through the creation of 3 tissue layers?
Gastrulation
What layer from the embryonic disc results in the CNS?
Ectoderm
When and how does the neural tube develop?
Develops by week 4 of gestation. Gastrulation of ectoderm > neural plate forms > neural groove from folding > neural tube
What is the process of forming the neural tube called? When does it happen?
Neurolation (2nd and 4th week gestation)
What are the three vesicles that form at the anterior end of the neural tube?
Prosencephalic (forebrain), mesencephalic (midbrain), rhombencephalic (hindbrain)
What happens in the 5th week of gestation?
Prosencephalic vesicle becomes telencephalon and diencephalon. Rhombencephalic vesicle becomes metencephalon and mylencephalon.
What happens in the 7th week of gestation?
Telencephalon becomes cerebral hemispheres. Diencephalon divides into thalamus. Myelencephalon becomes medulla. Metencephalon becomes cerebellum and pons.
What are the 7 stages of brain development?
- Cell birth
- Cell migration
- Cell differentiation
- Cell maturation
- Synaptogenesis
- Cell death and synaptic pruning
- Myelogenesis
What is nerve cell production called and where and when does it happen?
Neurogenesis within the neural tube and starts at 40 days gestation
What is cell migration guided by?
Radial glial cells
When does cell migration happen?
Fetal week 8 to week 16
What is dendritic arborization?
Growth of dendritic spines that continues after birth
What is synaptogenesis?
Development of axons
What is synaptic pruning?
Neurons that don’t make good connections undergo apoptosis. Up to 50% will DIE :(
What are the three synaptogenic processes?
Experience independant (will always happen) Experience expectant (need environmental cues to happen) Experience dependant (development that is personal/unique to a species)
As we age, synaptic density _____
Decreases
Where does postnatal myelination start and end?
Starts at spinal cord, ends at telencephalon/diencephalon
What do animal models tell us about brain development?
Complex environments increase brain growth. Old/young brains respond differently to experiences
Musicians who use their left hand to play violin have ____?
Larger representation for their fingers on their brain
What do imaging studies tell us about brain development? (In terms of grey and white matter volume)
Grey matter decreases, white matter increases. Cortical thickness and SA both decrease.
What does “small world” mean in the context of brain networks?
Neurons are lazy, they will make the most efficient connections possible and stay local
What are salience, executive function and default mode networks in the brain?
Salience = readiness/motivation to act in response something
Executive function = planning, thinking, being humans
Default mode = not doing anything
What are the three types of functional brain development?
Maturation (brain structures mature and behaviors mature) Skill learning (you activate brain regions when you learn things and your brain becomes better) Interactive specialization (cortical regions interact with each other and acquire certain roles)
Why are teens impulsive and dumb?
Their emotional response in striatum is not well modulated by their inhibition response in the frontal cortex
ADHD is characterized by what structural brain changes?
Decreased brain volume
Does the brain grow uniformly?
No, the brain increases in mass in growth spurts
What matures faster, the basal ganglia or temporal lobe?
Basal ganglia as shown by nonmatching-to-sample and concurrent discrimination tasks
What happened to the Romanian orphans?
Their shitty orphan conditions gave them developmental delay and lower than average IQ
What did studies where vision of kittens were restricted suggest?
The visual system can lose capacity if not exercised during early months of life
