Prenatal And Infant Brain Development Flashcards
(44 cards)
Outline the development of the brain during fertilisation
Germinal : 0-2 weeks (accumulation of little cells)
embryonic: 3-8 weeks
(fetus looks more human like, brain structure starts to come together)
Fetal stage: 9 weeks-birth
(Brain is full structure)
What are characteristics of an adult brains network?
-Laminar organization of the cortex: neurons are organised across different layers
Each layer is responsible for different functions and have different roles in the brain network
All areas communicate due to neural connections in the brain
When do aspects of the structure of an adult brain start to develop?
Is birth a big event for Brian development?
Aspects of the structure will be in place before birth, birth is not a big event for the Brain as a lot more maturation comes post birth
Describe prenatal brain structure?
The early brain is a tube, called the neural tube
Describe the structure of the brain during pre natal development. (4 weeks old)
At 4 weeks of prenatal development It will consist of Primary brain vesicles (the prosencephalon, mesencephalon, rombencephalon) then the neural tube
Describe the pre natal brain from a lateral view (4 weeks old)
The cephalic flexure which is at the mesencephalon and cervical flexure which is in between the rombencephalon and the neural tube
How does the neural tube rapidly evolve?
Differentiates by a series of thickenings and constrictions.
Describe micro development of the brain
The embryonic brain undergoes a series of massive cellular change
Before birth a series of genetically programmed events create a brain
However the brain is far from being mature at birth
Following what stages does the neural structure start to develop?
- Cell proliferation
- cell migration
- cell differentiation
- programmed cell death
- synaptic rearrangement
Describe the stage of neural (cell) proliferation
Massive production of cells (both glial and neurons)occurs from approximately 2 to 4 months of gestation but continues until birth and after
Humans are more or less born with all the neurones they will possess during their life and can only crate new glial cells
describe cell migration
All neurons come from neural precursor cells.
These undifferentiated cells can become neurons or glia cells
Then the immature neurons migrate to colonise all parts of the embryonic brain
What does the migration of cells cause during prenatal development in the brain?
- The migration of neurones creates the layers of the cortex
- Immature neurones migrate to reach their target layer.
- The first cells to arrive at their own layers are those that will be in deepest layer(layer)
- Therefore the cortex is said to be assembled form inside out.
Describe cell differentiation?
The adult brain has different types of neurones
- They come from precursor cells
- When the cells migrate they start to differentiate and become the neural cells they will be throughout your life.
- cells also specialise into glial cells
What is genesis of connection?
Neuron is formed of a cell body, a receiver part - dendrites - and an output - the axon. So neurons interconnect through their axons to form a network.
-connected neurons process the same information in chain
How are synapses created during cell differentiation?
-synapses are created by axons connecting when neurons differentiate and find their appropriate targets.
How is the axon when growing guided towards their target neuron?
The tip of axon is guided by special proteins and repulsed by others until it finds a proper target neruon to connect with.
Describe cell death (apoptosis)
A key step in brain development involves the loss of entire populations of neurons. (Programmed cell death or apoptosis)
-Neurons that did not connect to another neuron without a proper receiving neuron will disappear.
How many more synapses are there in an infants brain compared to an adult and what is the problem with that?
50% more synapses than in the adult brain due to the crazy wiring during synapse formation.-Not efficient
What occurs during synaptic pruning?
Synapses enter competition called synaptic re-arrangement.
Synapses are eliminated that don’t receive a signal (survival of the most efficient)
-this arrangement is activity dependent.
How does the environment influence the visual system?
- before birth there is no visual stimuli therefore the neurons responsible for visual processing are not organised
- when the child experiences vision the cells start to organise themselves and rearrange themselves (information received by the left is transmitted to the right visual cortex, while information received by the right eye is transmitted to the left visual cortex)
What is the multimodal experience of the world?
We can perceive and locate things in the world using 2 senses and good localisation is achieved with both
Describe the study that displays what occurs if we disturb either touch or sight senses?
- chicks were given prism goggles.
- they were supposed to find food in their cage using either a visual or auditory stimuli.
- Before prism they could find it well with both stimuli, after prism those with auditory stimuli performed better
- brain then rewires so both visual and auditory cells can find objects better in response to its environment.
Outline how the plastic brain is influenced by both nature and nurture
- Genes put in place the map of connections of the visual system, but experience can modify it.
- Brain is shaped by the interaction of genes/experiences
What is plasticity ?
The brains ability to modify or reorganise
