Lecture 4 (brain development) Flashcards
What are the six stages of nervous development?
Neurogenesis, cell migration, differentiation, synaptogenesis, neuronal cell death, and synapse rearrangement.
Neurogenesis?
the mitotic division of nonneuronal cells to produce neurons
Cell migration?
the movements of cells to establish distinct nerve cell populations (brain nuclei, layers of the cerebral cortex etc.) Cells in the developing brain move along the surface of a particular type of glia cell.
Differentiation?
the transformation of precursor cells into distinctive types of neurons and glia cells. They learn to fit into their given environment and do their thing there.
Synaptogenesis?
the establishment of synaptic connections, as axons and dendrites grow.
Neuronal cell death?
the selective death of many nerve cells. In some regions of the brain and spinal cord, most of the young nerve cells die during prenatal development.
Synapse arrangement?
the loss of some synapses and development of others, to refine synaptic connections.
How does neuronal cell death take place?
The intracellular levels of calcium (Ca+) will raise. When this high intracellular level of calcium invades the mitochondria, the Diablo (devil) protein will be released. Diablo binds to IAPs (inhibitors of apoptosis proteins), so they can no longer block caspases. Then, a cascade of enzymes destroys various proteins and the DNA of the cell, making it incapable of survival.
When does differentiation take place?
From early fetal until end of childhood.
When does migration take place?
Before we are born. From embryonic until the middle of preterm
When does neuronal cell death take place?
From preterm until late infancy (spædbarn).
When does synaptogenesis take place?
Begins slowly in early fetal and ends when we die.
What is the proces of synaptogenesis?
Synaptogenesis is the formation of synapses between neurons in the nervous system. Although it occurs throughout a healthy person’s lifespan, an explosion of synapse formation occurs during early brain development, known as exuberant synaptogenesis. Synaptogenesis is particularly important during an individual’s critical period, during which there is a certain degree of synaptic pruning due to competition for neural growth factors by neurons and synapses. Processes that are not used or inhibited during their critical period will fail to develop normally later on in life.
Some development characteristics of people with autism?
o The fiber bundles that connect the language areas with the front limbic systems are diverging in people with autism.
o People with autism is also found to have larger striatum volume and caudates asymmetry.
o In the beginning, the brain is bigger in people with autism.
Some development characteristics of people with ADHD?
There aren’t that big of a difference in people with ADHD and normal people. But the accumbent, amygdala, caudate, hippocampus, putamen, and ICV were found to be smaller in people with ADHD.
Explorative lifespan modeling suggested a delay of maturation and a delay of degeneration.
Where does the nervous system develop from?
The outer layer, ectoderm.
What is the neural groove?
The midline of the brain
Where is adult neurogenesis especially prominent?
In the dentate gyrus of the hippocampal formation, where it’s been estimated we add 1400 new neurons per day, replacing neurons that have died.
How can the adult neurogenesis be increased?
By enriched experience.
Which part of the brain matures last?
Prefrontal cortex.
What is the prefrontal cortex important for?
Inhibiting behavior.
What is the relation between prefrontal cortex being the last to develop and psychiatric diseases?
Because the synaptic pruning (beskæring) going on at this stage is critical for future functioning of the brain, the tendency of psychiatric disorders, such as schizophrenia and mood disorders, to emerge in adolescence reflects the vulnerability of this developmental stage.
Retrograde degeneration?
Destruction of the nerve cell body following injury to its axon.
Anterograde degeneration?
The loss of the distal portion of an axon resulting from injury to the axon.
