Brain Development Flashcards
What are the three stages of the pre-natal period?
Conceptual
Embryonic
Foetal
What occurs in the conceptual period?
Union of reproductive cells
Nuclei merge - result in 23 chromosomes
What occurs in the embryonic period?
Major organs begin to form
Heart begins to beat, blood is circulated
Cell division and differentiation
What occurs in the foetal period?
Origins of motor, sensory and learning behaviour
Continued development and differentiation of structures
What are the 8 stages of neural development?
Natalie puke maggots and Dan sings something French
Neuralation
Proliferation
Migration
Aggregation
Differentiation
Synaptogenesis
Selective cell death
Functional validation
What are the steps of embryonic formation?
Cells multiply & differentiate
Inner cells cluster to leave a cavity
The outer walls implant into the uterine wall
Two types of tissue form from inner and outer cells
What are the three layers of the trilaminar disc?
Ectoderm
Mesoderm
Endoderm
What is the endoderm?
Inner layer - Internal organs (digestive, respiratory, etc)
What is the mesoderm?
Middle layer - skeletal and muscular structures
What is the ectoderm?
Outer layer - skin surface, nervous system
What is the primitive streak?
Marks bilateral symmetry in embryos
Where does the neural plate form?
On the ectoderm layer, opposite the primitive streak
What is the notochord?
Plays a core role in vertebrate development
Releases proteins that drive neuralation
What occurs during neuralation?
Edges of the neural plate curve and close from head to tail - becoming the complete central nervous system
What severe disorders occur due to failures during neuralation?
Spina Bifida
Anencephaly
How does Spina Bifida occur?
Failure of the closure of the spinal cord to close at the caudal end
How does Anencephaly occur?
Failure of the neural tube to close at the cranial end.
Foetus develops with a major portion of the brain, skull and scalp missing
What do the three swellings of the neural tube form?
Basis of human brain structure
Forebrain, midbrain and hindbrain
What five brain regions develop from the forebrain, midbrain and hindbrain?
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
Spinal cord
What occurs during proliferation?
New cells are produced by dividing or proliferating
Stem cells, glial cells and neurons
What occurs during migration?
The movement of cells from the wall of the neural
tube to their end goal
Cells move in different directions according to their
specific cellular ‘destiny’
What occurs during aggregation?
Once they have reached their final destination, new cells line up with other neurons to make up the new brain
What occurs during differentiation?
Neurons do not take their final form until they have reached their final destination.
Once cells settle, they network.
What does cell-autonomous differentiation mean?
Cell growth and development that is pre-defined by a genetic programme
Ex: Purkinje cells
What occurs during synaptogenesis?
The development of synapses
Communication with each other and with organs
Continues throughout a person’s lifespan
What occurs during selective cell death?
Neural pruning
Survival of the fittest: neurons that have made
successful connections will survive
Occurs at different times in different areas of the
brain
What occurs during functional validation?
The process of growth (plasticity) and pruning across a lifespan
Nerve cells & axons continue to adapt their structure and function dependent upon environment input
What structural changes occur in between the ages of 0 and 6?
Dramatic period of synaptogenesis
Overproduction of synapses leads to competition between neurons
Neural pruning
Strengthening & elimination of neurons is dependent upon environmental demands and experience
What structural changes occur after the age of 7?
Development is far from complete
Notable surge in synapse growth just before puberty
Prominent period of pruning & plasticity during adolescence
Thought to contribute to refinement of brain connectivity
What are the specific changes in brain structure during adolescent brain development?
Prefrontal cortex – ‘higher order cognition’
Amygdala - emotions
Hypothalamus - hormones
Corpus callosum – connection between
hemispheres
What are the global changes in during adolescent brain development?
Increase in myelination – processing speed
Increase in pruning – fine tuning
What changes occur to grey matter during adolescent brain development?
Grey matter = cell bodies, dendrites & axon terminals
Inverted U-shaped curve across childhood & adolescence
Decrease in grey matter in adolescence represents the
process of fine-tuning
What does regional maturation correlate with?
Prefrontal cortex - intelligence and impulse control
Left hemisphere - language processing
What changes occur to white matter during adolescent brain development?
White matter = myelinated axons
Largely linear increase across development
Substantial maturation during adolescence especially those involved in emotional, social and cognitive control
What is connectivity?
The neural circuitry of the brain
What changes occur to connectivity during adolescent brain development?
Networks consist of brain regions that activate
and work together through their
interconnections
The formation & development of these
networks leads to more sophisticated
processing in maturity
Leads to more efficient and controlled
information processing
What are the two major changes in connectivity during adolescent brain development?
Cortical connections change from being large
and non-specific, to being more smaller and
more specialised
Dramatic increases in long-range connections
How does adolescent brain development impact emotional processing?
Amygdala volume increases over adolescence and young adulthood
Why does social exclusion cause issues in adolescence?
Adolescents show decreased activity in regions associated with regulation of rejection-related distress
compared to adults
When experiencing distress, adolescents aren’t able to recruit frontal regions needed to effectively
control feelings of rejection
How does adolescent brain development impact social processing?
Development of Theory of Mind/Mentalising
What is Theory of Mind/mentalising?
The ability to attribute mental states
(thoughts, intentions, desires, feelings, beliefs)
to others on the basis of their
social/emotional cues
How does adolescent brain development impact ris-taking behaviours?
Hormonal changes prompt changes in brain
regions associated with learning, memory &
experience of emotion
Prefrontal cortex is continuing its fine-tuning
in a largely linear pattern
How does puberty impact risk-taking behaviours?
Hormonal changes prompt changes in the amygdala and hippocampus associated with learning, memory &
experience of emotion.
Leads to increased sensitivity to emotion and reward = increase in sensation seeking behaviours
How does executive function impact risk-taking behaviours?
Prefrontal cortex is continuing its fine-tuning
in a largely linear pattern
Cognitive control & executive function
increasing with age over the adolescent
period (into early adulthood: up to 25)
What are the implications for understanding prevention and intervention in the adolescent brain?
Education
Law
Parenting
Advertising
Technology
How does development happen?
Development = genes * environment
it’s nature and nurture interacting
How are learning and development related?
Learning is supported by development and contributes to development
