Lecture 9 - Neurodevelopmental Disorders Flashcards
What are the different stages of brain development ?
- Cell birth (neurogenesis)
- Cell migration
- Cell differentiation
- Cell maturation (dendrites & axons growth)
- Synaptogenesis
- Cell death (apoptosis) & synaptic pruning
- Myelogenesis
What are neural stem cells ?
Undifferentiated cells that develop into brain & spinal cord
When is neurogenesis largely complete ?
Around 4.5 months after conception
In which parts of the brain does neurogenesis continue into adulthood ?
- Olfactory bulb
- Hippocampus
- Striatum
From where do stem cells migrate to the developing parts of the brain ?
From neural tube/subventricular zone
How do cells ‘know’ where to migrate ?
Following road formed by radial cells
How long does migration continue after birth ?
Around 8 months
How do layers develop during cell migration ?
From the inside out
Into what types do migrated cells differentiate ?
Neurons or glia cells
When is cell differentiation essentially complete ?
At birth
What are the key processes involved in neural maturation ?
- Dendritic arborization (branching)
- Growth of dendritic spines
- Growth of dendrites, axons & synapses
When does neural maturation begin and how long does it continue ?
- Begins prenatally
- May continue into adulthood
What are the neurobiological processes underlying the critical period of plasticity ?
- Onset : inhibition-excitation balance & deprivation
- Duration : pruning, rewiring & environmental enrichment
- Closure : structural brakes, functional brakes epigenetics silence genes rewiring & attentional arousal
What are the key features of neural development in the adolescent brain ?
- Rapid synaptic pruning & growth of connections
- Especially in PFC
What neural changes occur during adolescence ?
- Differences in GM & WM volume
- Changes in levels of dopamine & GABA
What are some types of abnormal brain development ?
- Anencephaly
- Holoprosencephaly
- Lissencephaly
- Micropolygria
- Microencephaly
- Porencephaly
- Heterotopia
- Callosal agenesis
- Cerebellar agenesis
What’s brain plasticity ?
Nervous system’s potential for physical or chemical change that enhances its adaptability to environmental change & its ability to compensate for injury
What are epigenetic changes & can they be inherited ?
- Altered gene methylation & gene expression
- Can cross to subsequent generations
What internal factors influence brain development ?
- Hormones
- Injury
- Nutrients
- Microbiota
- Gestational stress
What external factors influence brain development ?
- Environment : exposure to complex vs impoverished environment
- Experiences : adverse childhood experiences
How does diet and nutrition affect brain development ?
- Gene expression (dry/rainy season)
- Gut microbiome (& immune function) : brain development, myelination, formation of blood-brain barrier
- Iron deficiency : anxiety, ADHD…
What are the effects of lead poisoning on brain development ?
- ADHD
- Autism
How does early visual deprivation affect vision ?
- Long-lasting impairment of vision after optical defects are corrected
- Amblyopia
How does socioeconomic status (SES) affect brain development ?
- High SES : exposure to more words , more one-on-one conversations, child-directed speech
- Low SES : associated with lower cortical volumes in frontal, temporal & parietal cortex
How does early auditory experience shape language development ?
- Shape brain’s ability to distinguish sounds of native language