M3-Lecture1 Flashcards
Early Brain Development
Human pelvis is tight fit for labour and has evolved to accommodate both bipedal motion and large fetal head
Newborn don’t have knee cap until age 3
Yes
Fetal brain changes shape in order to fit through the birth canal
Diet and pro-biotics affect microbiome
True
Brain development affects all area’s of child growth, state four areas of develoment:
Motor (physical)
Language and communication
Social and emotional
Cognitive
Two components of brain development
Structural development
- manifest in bev. dev. issues
Behavioural development
- reflect issues with structural or emerging underlying circuitry
Examples of factors that influence both brain and behav. development:
Hormones
Injury
Experience
Genes
Twins aren’t always the same.
Yes
Thickened ectodermal region that gives rise to neural tube:
Neural plate
Structure from which the brain and spinal cord develop:
Neural tube
What is the name of the process that lead to form the 3 germ layers:
Ectoderm (outer layer - skin, nails, the NS, including brain & spinal cord)
Mesoderm (Middle layer that gives rise to muscles, bones, circulatory system, kidneys, and other internal)
Endoderm (innermost that forms epithelial layer of digestive tract, respiratory system, - organs like liver and pancreas)
Gastrulation
What overlay the notochord that will generate the entire NS
Ectoderm
Mention the steps in the deve. of NS:
Gastrulation (three germ layers)
Mesoderm - notochord - then mesoderm and notochord signal ectoderm to form neural plate (which develop into neural tube) - edges of neural plate fold inward & create neural tube - (CNS & spinal cord) - cells differentiate into many glial cells & neurons.
What is an embryonic midline structure common to all members of the phylum Chordata, providing both mechanical and signaling cues to the developing embryo.
Notochord
See major brain divisions:
Myelinating cells of the central nervous system (CNS):
Oligodendrocytes
Whereas peripheral NS are Schwann cells
What are the primary immune cells of the CNS:
Microglia
Growth & deve. of neurons:
Birth
Migration
Differentiation
Maturation
Synaptogenesis
Synaptic pruning
Myelogenesis
What two terms refer to birth of cells in the NS:
Neurogenesis
Gliogenesis
Cell birth:
Beginning with neural stem cells, which are self-renewing and multipotential, giving rise to neural progenitor cells. These progenitor cells, derived from stem cells, migrate and differentiate into either neurons (neuroblasts) or glial cells (glioblasts).
Embryonic stem cell (Pluripotent - self-renewal) - (ex: blastocyte) - neural stem cell (self-renewing) (ex: Neural tube, multipotent) - Intermediate neural progenitor (Brain/SC) (limited self-renewal) - restricted neural progenitor (limited self-renewal), (neuroblasts - neuron, gluoblast - astrocyte, oligodendrocyre)
What are a type of neural progenitor cell that provide structural support and guidance for migrating neurons during brain development:
Radial glial cells
Migrating produces neuron or glial cells:
True
Dorsal - back or up side of an organism.
Ventral - front or lower side.
Cell migration takes place from the ventral to dorsal:
True
Signaling molecules regulate spatial and temporal patterns of development, with most signals secreted by one embryonic tissue or layer acting on adjacent tissues, leading to cell differentiation that is generally completed by birth.
Spatial refers to the arrangement or positioning of cells and tissues in a specific area, while temporal refers to the timing of developmental processes or events.
Components of cell maturation:
Axon growth - regulated by adhesion&tropic molecules
Dendrite growth
Neuron maturation goes on for years, and in some parts of brain throughout adulthood.
True
What increases rapidly in the first 12 months of life:
Formation of synapses
Cell death and synaptic pruning:
Decrease in # of cells & connections
A theory suggesting that the brain develops through a process similar to natural selection. ex:
Natural Darwinism
Neurons are selectively strengthened or weakened based on their activity and interaction. Survival of most useful connections.
What is an important part of growth & development:
Synaptic pruning
Genetic, experience, stress, hormones have similar effect to natural selection, where beneficial neural pathways are reinforced and less useful ones are pruned,
True
What term refers to formation of myelin, that begins after birth and early adulthood.
Myelogenesis
both astrocytes and oligodendrocytes are types of glial cells (maintain health & functionality of neurons:
True
Subtype of glial cells that make up majority of cells in the CNS:
Astrocyte
The function and role of astrocyte:
Metabolic, structural, homeostatic, clearing excess NS, stabilizing & regulating the BBB, synapse formation.
See the general points of critical windows of brain deve.:
During the window: appropriate influences or inappropriate stimuli can impact development.
After the window: has much less impact on bev. deve.
Envi. exposures such as nutritional, maternal (fetal) gut, Infection/inflammation, maternal metabolic state, birth trauma, post-natal envi. all affect epigenetics of the fetus, which then lead to structural changes, cellular aging, altered homeostatic setpoints:
True
Prenatal inflammation lead to risk of neurodevelopmental disorders:
True
What term refers to the connection btw. infection & inflammation in pregnancy * PTB, cervical disease, vascular disorders
Also stress & breakdown of maternal-fetal tolerance can lead to adverse pregnancy outcomes.
Casual links
What is the leading cause of neonatal mortality + morbidity worldwide:
Risk factor for neurodeve. disorders.
PTB
Prenatal maternal infection:
Severe or urinary tract } risk factor of autism spectrum disorders, depression.
Induced by immature lung development, injures vulnerable neurons and glia
Perinatal hypoxia
is a major risk factor for the development of cerebral palsy, lower educational attainment and deficits in cognitive functioning, and individuals born preterm have higher rates of schizophrenia, autistic spectrum disorder and attention deficit/hyperactivity disorder.
PTB
There are differences in outcome between males and females born preterm, with males having a higher incidence of most neurodevelopmental disorders following PTB
an infection that occurs within the uterus, potentially affecting the fetus
Common in most cases PTB <30 weeks
Risk factor of early autistic features, cerebral palsy + chronic lung disease
Intra-uterine infection
is an infection of the fetal membranes (chorion and amnion) surrounding the fetus, often resulting from bacteria ascending from the vagina into the uterus. It can lead to complications such as preterm labor, preterm birth, and increased risks for neonatal infections and respiratory problems.
Chorioamnionitis
Exposure to low doses of lipopolysaccharide (LPS) in the uterus can significantly increase the mRNA expression of pro-inflammatory markers such as IL-1β, TNFα, and COX-2, indicating an inflammatory response.
True
Exposure to LPS on E15 or E18 can lead to decreased dendritic processes.
Yes
Mother-to-child HIV transmission is declining
True
Pregnant people with HIV on ART experience immune dysfunction, inflammation, metabolic abnormalities, intestinal dysbiosis
True
Infants who are HIV-infected characteristics:
- Poor growth & cognitive deve. after birth
- More & severe secondary infection
- Greater risk for disease in later life
Population of infants born HIV exposed but uninfected (HEU) is rising
Yes
HIV exposed but uninfected have poorer neurodevelopmental outcomes
cognitive
expressive language.
True
HEU influences infant head circumference at birth
True
Pro-inflammatory cytokines and monocyte activation is increased in HEI infants
True
See: Neurodevelopment in HEU InfantsNutritional Interventions
Zika infection in pregnancy: mention two effects -
PTB
FGR
Is characterized by a spectrum of neurological abnormalities in childhood, including microcephaly and dyskinetic signs, resulting from Zika virus infection during pregnancy.
Congenital Zika virus
Zika virus infects neural progenitor cells, leading to reduced proliferation and differentiation, which causes cell death and decreased thickness in the cortical plate and (sub)ventricular zones, ultimately - diminished postnatal neurogenesis in the SVZ and hippocampal dentate gyrus.
Maternal immune activation can be influenced by maternal gut microbiome, and changes in gut microbiome can alter immune system and lead to inflammation, which can negatively affect how the fetal brain develops:
True
is associated with immune dysfunction and intestinal dysbiosis
A role for maternal gut microbiome??
ASD
Maternal depression in the third trimester associated with Child Behavior Checklist (CBCL) measures of externalizing behaviour in males (such as aggression, hyperactivity)
True
Mean diffusivity (MD) of the right amygdala - mediates relationship between third trimester depressive symptoms and externalizing behaviour in males implying that changes in brain connectivity may play a role in this association.
True
The 2-Hit Hypothesis:
1st hit: genetic susceptibility + insult during the prenatal period (programming of disease risk & resiliency across life course)
2nd hit: More insult during postnatal period. Amplifies effect of 1st hit, more developmental problems.
Opportunity to mitigate the effects of the first hit, improves developmental and health trajectories:
Postnatal Enrichment
Potentially leading to absence of disease
Early childhood deprivation lower total brain volume
Deprivation duration impacts outcomes
True
ACEs linked to chronic inflammation across the life course
increased circulating levels of C-reactive protein (CRP), IL- 6, TNF-a in adulthood
True
How ACE-associated inflammation may contribute to poor mental health outcomes is unclear:
True
Four ACE categories:
abuse
family dysfunction
poor parent–child bonding
loss of an attachment figure
What does cumulative exposure to ACEs lead to:
high CRP
Depressive symptoms
Weak associations between CRP and depressive symptoms, no indirect effects of ACEs on depression mediated by CRP
True
Increased circulating CRP conc. does not lead to depressive symptoms.
Yes
prenatal stress (PS) can lead to neruo-deve changes, cognitive changes, behavioural changs in the offspring:
However (PS + EE):
Reversed neurodevelopmental changes
restored and improved learning & memory impairments
Reduced anxiety-like and fear behaviors.
True
Probiotic (Lactobacillus rhamnosus GG) intervention: lead to ADHD or ASD diagnoses
Differences in gut microbial composition (placebo vs the intervention - without ADHD.ASD