Unit 4 - Neurodevelopment Flashcards
What method is used to generate images of the brain during neurodevelopment?
structural MRI
The fertilized egg starts to develop after about ____ hours, then becomes the blastocyst.
12
An embryo develops 3 distinct layers: the ________, ________, and __________.
endoderm, mesoderm, endoderm
The __________ is the outer layer of cells that gives rise to the nervous system
ectoderm
During the first 4 weeks of development, the neural plate becomes the neural __________ with a neural __________. These form together to make a neural ________.
groove, crest, tube
After 4 weeks of development, the neural tube forms what 3 sub-division?
forebrain, midbrain, and hindbrain
Brain and body weigh typically increase together until __________.
adulthood
The earliest stage of neurodevelopment is ___________.
neurogenesis
Cell division (mitosis) to make newly born neurons
Neurogenesis
neurons are created from undifferentiated ____________ cells
precursor
Precursor cells are made on the inside of the neural tube in the ____________ zone.
ventricular
By birth, mammals will have most of the ___________ they will every have.
neurons
Neurogenesis in adulthood may be possible in the _____________ (dentate gyrus) and __________ in some species (plays a role in learning and memory)
hippocampus, olfactory
Research on ________ has shown newly made cells to be neurons.
rodents
Movement of neurons or their precursors to establish distinct populations
Cell Migration
During cell migration neurons stop at different points to form different _______________.
populations
Neurons are born in the _________ zone then migrate through the _______ tube via radiaglia.
ventricular, neural
Refining of cells into distinct types of neurons or glia
cell differentiation
Cell differentiation occurs due to turning specific genes on or off (changing ____________ patterns). This changes cell __________ and __________.
gene expression, appearance, function
Selective death of many nerve cells
Cell death
What are the two types of cell death in the body?
Necrosis & apoptosis
Provoked cell death (e.g., by accident)
necrosis
Programmed cell death (cell turns on death genes causing it to die in a planned manner)
apoptosis
How many neurons typically die during normal development?
1/2 or more
During cell death, cells compete for ___________ and ___________ and losers die. Cells that win are the ones that survive.
synapses, growth factors
__________ syndrome results in less cell death during neurodevelopment caused by a mutation in the X chromosome.
Fragile X
Establishment of synaptic connections as axons and dendrites grow
Synaptogensis
Fate of synaptogenesis is determined by ________ the cells is and what the __________ are doing (cell-cell interactions)
where, neighbors
Synaptogenesis is influenced by outside chemical signals, known as ______________.
neurotropic factors
Chemicals that facilitate many aspects of neural development including cell migration, differentiation, and synaptogenesis.
neurotropic factors
What are some examples of neurotropic factors?
Nerve growth factors (NGF) and Brain derived neurotropic factor (BDNF)
_________’s research on neurotropic factors earned her a nobel prize.
Rita Levi Montalcini
Attracted towards neutropic factoors and “pull” the neurons toward the cells
Growth cone
___________ neurotropic factor is also important for learning and memory development
brain derived
Loss, growth, and competition of synapses to refine connections between
Synapse rearrangement or remodeling
Initially the ________ becomes more elaborate with more synapses, but, like neurons, not all synapses are kept.
cortex
The prefrontal cortex usually peaks in synapses around ____ years old.
5
The auditory cortex usually peaks in synapses around _____ years old .
5
The visual cortex usually peaks in synapses around ____ years old.
1
What synapses are kept and lost is determined by neural _________ because active synapses take up ________ neurotropic factors.
activity, more
During cell differentiation, different target cells produce different ___________ that are taken up by neurons.
neurotropic factors
Neurotropic factors change gene __________ and cell _________, which affects cell death.
expression, differentiation
Neurons with enough _____________ survive, but neurons with too little die.
neurotropic factors
Because neurotropic factors match target cell number, leads to a rough matching of ________ and ____________ neurons.
target, innervating
During synaptogenesis and synapse rearrangement, processes grow in response to ____________ signals.
neurotropic
Axonal processes compete for ____________.
neurotropic factors
____________ synapses get more neurotropic factors
active
_______/__________ of synapses can change which connections are kept.
activity, experience
Addition of myelin to axons
myelination
Glial cells and neurons start from the same population of undifferentiated cells. Glial cells then differentiate as well, including _____________, which form myelin in neurons, leading to more efficient signaling.
oligodendrocytes
__________ allows insulation to allow faster transmission of signals.
myelin
Myelination starts ____ weeks post-conception.
24
The myelination process starts in the _____, then proceeds up the _____. It reaches the __________ cortex and __________ last.
PNS, CNS, frontal, cerebellum
Unlike neurons, glial cells are myelinating ___________.
continually
Volume of white matter in the frontal lobe peaks around mid ____-____s.
20-30s
Teenage years are characterized by continued development of frontal _________ matter, frontal __________, and __________ functions.
white, synaptic rearrangement, executive
Adolescence results in well developed _________ system, and less developed __________ cortex, which could be the cause of so many mental health issues.
striatal, frontal
The genetic information (DNA) that an individual has inherited
Genotype
Genes and experience influence ___________.
behavior
The physical characteristics of an organism.
Phenotype
The __________ of an organism is constantly changing.
phenotype
Autosomal recessive disorder (carried by 1/100 individuals, affects 1/10000 births) that causes the absence of enzyme for breaking down the amino acid phenylalanine. This damages the brain and can lead to intellectual disability.
Phenylketonuria (PKU)
PKU proves that _________ is not everything.
genotype
Study of factors that change gene expression without changing DNA
epigentics
Chemical modification to DNA that doesn’t change the sequence, but changes likelihood of gene expression
methylation
Glucocorticoid (stress hormone) can change __________ of receptor for glucocorticoids in the brain. This leads rat pups to become hyper-responsive to _________.
methylation, stress
Everything in the visual system is __________ and _________.
upside down, backwards
A mapping that preserves the point-to-point correspondence between neighboring parts of space
topographic retinotopic mapping
Information from the left and right side of space are sent to the ____________ hemispheres.
opposite
Information from the two eyes is combined in V1 to help with depth __________.
perception
Depth perception is present in ___ mo. old infants.
6
Interocular distance and size of the eyes grow and alter the geometrical relations underlying most ________ cues.
depth
_____________ in V1 carry separate information from right and left eyes.
Ocular Dominance Columns
Are ocular dominance innate or dependent on experience?
both
Biasing visual experience, _____________, affects ocular dominance during critical periods.
monocular deprivation
A window of time in which an organism’s experience can dramatically reshape the connectivity/function of neurons
Critical/sensitive period
__________ can interact with and alter typical developmental trajectories.
experience
___________ may be necessary for typical development to proceed.
Experience
Critical periods are more sensitive to ____________.
experience
