01. Neurodevelopment I Flashcards
What influences behaviour?
Motivational state
Evolutionary & genetic influences
Environmental & social influences
Previous experience
What is the embryonic disc?
The 2 layers of cells that form in an embryo
What’s the hierarchy of organisation in brain formation?
Genes
Proteins
Protein complexes
Organelles (synapses/axons)
Cells (neurons and glia)
Brain Regions
Brain Circuits
Whole brain
Brain weight at birth is…
350g
Brain weight in adulthood is…
1300g
There are _ neurons and _ synapses in the mature brain
85 million, trillions
The germinal stage lasts…
1-2 weeks
The embryonic stage lasts…
3-8 weeks
The foetal stage lasts…
9-38 weeks
From ovum to foetus:
Ovum -> zygote -> morula -> blastocyst -> embryo -> foetus
The zygote divides at _ hours in a process called _
12, cleavage
The blastocyst contains _ cells
200-300
What is the embryonic disc?
The 2 layers of cells that form in an embryo
What layers form within the embryonic disc?
Ectoderm
Mesoderm
Endoderm
What layer does the brain develop out of?
Ectoderm (skin)
How does the ectoderm form the brain & spinal cord?
Top of the ectoderm forms the brain and the bottom forms the spinal cord
At 2 weeks the neural tube…
‘Zips up’
How is the brain ‘convoluted’?
It is highly folded (has many sulci and gyri) which increases surface area
Neural tube defects: Spina bifida
Neural tube does not close (‘zip up’)
This causes small openings in the spine
Larger openings cause paralysis and limb deformities
Neural tube defects: Anencephaly
The brain fails to develop
Generally results in stillbirth
Synapse formation theories: Experience expectant (Greenough and Black, 1992)
Development depends on a critical period (species-specific)
Synapse formation theories: Experience dependent
Development is not predetermined, it is generated in response to the environment & varies between individuals
(e.g. epigenetics, brain growth in adulthood)
