Neuro 2620 Ch8

Structural, Functional, Environmental

the proposal that a human embryo is an adult mini and their development is to simply grow

privative neural tissue, the neural plate, folds to form the neural groove that curls to form the neural tube

embryo resembles a person

the brain looks distinctly human

brain begins to form gyri and sulci

line the neural tube and can self-renew

when they divide, they produce two stem cells, one dies and the other lives to divide again

formed by neural stem cells ling the ventricles

cell derived from stem cells that produce nerve and glial cells

formed from progenitor cell that makes different types of neurons

formed from progenitor cell that makes different types og glial cells

epigenetic mechanisms that suppress gene expression

compounds that signal cells to develope in particular ways (EGF & bFGF/FGF-2)

1. Cell birth (neuro & glial genesis)

2. Neural migration

3. cell differentiation

4. neural migration

5. synaptogenesis

6. cell death and synaptic pruning

7. Myelogenesis

generation of new nerve cells, complete after 25 weeks of gestation

chemicals that cause malformations and accidents that are detrimental to fetal development after full term birth

neurogenesis because once it it slowed it is hard to start up again

continues for ~6 weeks in the cortex a throughout life in the hippocampus

guide neurons out of the subventricular zone and throughout cortical regions

contains a primitive cortical map that predisposes cells to migrate to a certain cortical location and layer

predispose neurons to specified layers and zones in the cortex that start from layer VI to layer I building developing from the inside out

intercellular chemicals that make different cells differentitate

- cell-manufactured molecules that lie on the target cell surface or are secreted into the intercellular space

- they provide a surface for growth cones to adhere to others and serve to attract to repel growth cones

produced by the target cell

tell growth cones to either comes or go away depending on the cones

chemo-attractive tropic molecules that guide axon growth

chemo-repulsive molecules that deflect axons from inappropriate regions

growing tips of an axon that send out filopods that reach towards that target cell or explore the intracellular fluid

intracellular cells aid in neural maturation by dendritic arborization and growth of spines

~5 months simple synaptic contact

~7 months development of deep cortical learning

target cells produce nerve growth factor (NGF) which is manufactural by cortical cells & absorbed by cholinergic neurons in the basal forebrain

there is a limited amount of NGF

too many target neurons an "noise" in the neuronal system leading to fewer neurons receiving NGF and fewer connections being made

this leads to excessive cell growth and later cell death

pruning of synaptic errors

provides useful rough indexes of cerebral maturation begins after birth - 18 years

occurs after neurogenesis and continues to develop throughout life

noted that the earliest myelinated brain areas control simple movement or sensory analysis later myelinated areas control high mental functions

happens in the hippocampus, subventricular zone, hypothalamus, striatum, substantia nigra, neocortex, and amygdala

responsible for selecting behavior and movement with respect to temporal memory

frontal lobe

epigenetic influences like ACE's

the trajectory of frontal lobe development correlates with adult intelligence like the reduction of cortical thickness and increase in connectivity between medial regions of the frontal lobe

- scooping motions

- directing hands

- groping

- spontaneous hand & digits movements

- full hand grasps

- pincer grasp

cell and synaptic loss

myelination

decreased cortical thickness in the hand region dominant to you

phonological processing

1. sensorimotor

2. preoperational

3. concrete operational

4. formal operational

- object permanence

- stranger anxiety

experiences the world through senses and actions (looking, touching, mouthing)

- pretend play

- egocentrism

- language development

represents things with words & images but lacks logical reasoning

- conversation

- mathematical

- transformation

thinks logically about concrete events; grasps concrete analogies & performs arithmetical

- abstract logic

- potential for mature moral reasoning

reasons abstractly

subjects are presented with three items and must displace an object to receive a food reward

participants are shown an object to displace to receive a food reward; after a break they are presented with the original object and a novel object and must displace the novel object to receive a reward

participants are presented with a pair of objects and they had to learn that one of the objects is associated with a food reward

this i made more difficult by giving participants 20 different object pairs

peaking of cortical thickness being reached earlier, pruning beginning sooner and a faster overall decline

stress

lead to faster maturation of circuitry

increase glucocorticoid levels, prompting inflammatory processes and causing faster aging across the entire body, including the brain

accelerated development as a means of self protection and preservation

experiences that are negative and repetitive encourage faster maturation, thus possibly restricting plasticity

whereas experiences that are rare and positive are associated with signals that delay maturation and enhance plasticity

specific molecules in different cells in various midbrain regions give each cell a distinctive chemical identity and an identifiable biochemical label that can arrange neighboring cells into culumns

resulting loss of sharpness in an eye as a result of disuse

developmental window during which some event has long-term influence on the brain

formation of attachment by an animal to one or more objects or animals at a critical period in development

an epigenetic brake that leads to an increased expression of certain genes during development, which act to limit plasticity

specialized structure in the extracellular matrix that act as a molecular lattice-work over a neuron. once matured they can act a a physical barrier to morphological plasticity by blocking the generation of new synapse

a class of hormones that stimulate or controls masculine characteristic

treatment that uses live bacteria (probiotics) or compounds to enhance the growth of gut bacteria (prebiotics)

the last half of the intrauterine period and the first couple of months after birth language is almost never affected by this

the genetic blueprint goes awry and the neural tube does not close completely, leading to an incompletely formed spinal cord resulting in serious motor problems unless treated

failure of the forebrain to develop due to improper closure of the front end of the neural tube

the serotonin transporter is unusually efficient and serotonin is cleared from the synapse more rapidly than normal

this makes 5-HT less effective in regulating CO2 buildup during sleep

symptoms vary suggesting biological abnormalities like brains weighing less than normal, having enlarged ventricles, smaller frontal lobes, thinner parahippocampal gyri, progressive grey-matter abnormalities, and a more haphazard organization of neurons

fetal alcohol spectrum disorder (FASD)

cerebral palsy

kwashiorkor

spina bifida

ASD

growth and developmental deficits

phenylketonuria

down syndrome

ASD

developmental delays