Development & Adaptation (Edan) Flashcards
What is the neural plate?
- thickened plate of ectoderm
- goes on to form neural tube and neural crest, subsequently the entire nervous system
- forms day 21
state the time durations pertaining to the following stages of development:
a. ) zygote
b. ) embryo
c. ) fetus
a. ) fertilization to first 2 weeks
b. ) 2 to 8 weeks
c. ) >8 weeks to birth
briefly explain how the neural plate forms the three primary germ layers?
- neural folds (ends of neural plate) push the ends of the neural plate up together
- thus neural tube forms
- this goes on to form 3 primary germ layers: ectoderm (skin), mesoderm (muscle and bone), endoderm (organ lining of digestive/ respiratory tracts)
what day does neural plate form?
21
the forebrain envelopes the midbrain by _ ____
6 months
when do gyri and sulci form?
7 months
explain pre-natal brain at 9 months?
has appearance of adult brain but cellular structure different
Explain the origins of neurons/ glial cells?
- neural stem cells line neural tube (these are self-renewable)
- neural stem cells differentiate into progenitor cells (these may divide a limited number of times)
- after day 40, progenitor cells produce non-dividing cells
- non-dividing cells become neuroblasts and glioblasts
- neuroblasts become neurons and glioblasts become glial cells (specifically astrocytes and oligodendrocytes)
t/f: neuroblasts are the main precursors to neurons during development only, playing no role in adult neurogenesis
false - do play role
define glial cells? provide examples?
- non-neuronal cells in CNS
- maintain homeostasis, form myelin, support and protect neurons
- astrocytes, oligodendrocytes
explain the role of astrocytes?
- form BBB
- provide nutrients
- maintain extracellular ion balance
- reparation of brain and SC post injury
- produce neurotrophins to aid neuronal health
explain the role of oligodendrocytes?
- help produce myelin sheath
- thus provide support and insulation to neurons
- produce neurotrophins to aid neuronal health
both astrocytes and oligodendrocytes produce neurotrophins augmenting neuronal health. What neurotrophins?
- brain derived neurotrophic factor (BDNF)
- glial cell derived neurotrophic factor (GDNF)
- insulin like growth factor (IGF)
In peak development, how many neurons may you grow per minute?
250 000
neurogenesis is complete by __ months
5
brain is most resistant to injury in (early/ mid/ late) development
early
explain stages of brain development? (on neuronal level)
- neurogenesis & gliogenesis
- cell migration - cells travel to correct location
- differentiate appropriately
- maturation - grow axons/ dendrites
- synaptogenesis - form synapses
- cell death & then synaptic pruning - remove redundant/ faulty neuron
- myelogenesis - myelination of axons
t/f: soon after birth babies can flex their joints and direct their hand
true
when do babies begin to make spontaneous hand and finger movements?
1-3 months
dendritic branching AKA?
dendritic aborisation
dendritic aborisation allows a single neuron to receive up to _____ inputs
100 000
explain some physiological developments occurring as baby develops motor skills?
- dendritic aborisation - branching, up to 100 000 to a single neuron
- connections between neocortex and spinal cord
- myelination of axons from motor cortex (when pincer grasp develops)
name a type of grasp baby may develop by around 10 months?
pincer grasp (index and thumb)
as baby undergoes motor development, what may be seen on MRI?
increased cortical thickness in line with baby’s development of dexterity
state the name (and time frame) of all piaget’s stages of development?
- Sensorimotor birth - 24 months
- preoperational 2-6 years
- concrete operational 7-11 years
- formal operational 12+ years
describe, and state the developmental phenomena for the following stage of development (piaget): sensorimotor
- experience world through senses and actions (looking, touching, mouthing)
- object permanence, stranger anxiety
describe, and state the developmental phenomena for the following stage of development (piaget): preoperational
- represents things with words and images but lacks logical reasoning
- pretend play, egocentrism, language development
describe, and state the developmental phenomena for the following stage of development (piaget): concrete operational
- thinks logically about concrete events, grasps concrete analogies and performs arithmetical operations
- conservation, mathematical transformations
describe, and state the developmental phenomena for the following stage of development (piaget): formal operational
- reasons abstractly
- abstract logical, potential for mature moral reasoning
t/f: experience changes the structure of neuroglial cells but not neurons
false - neurons
experience changes structure of neurons especially in the ____
cortex
differentiate between brains of children raised in an experienced enrichment environment against those in a barren environment?
rich - larger and more synaptic connections
explain the kitten example of experience and neuroconnectivity?
- normally as kitten develops axons from each eye develop toward cortex and develop large dendritic branching
- sew one eye shut of kitten
- in 30-60 days terminations from that eye do not develop
briefly define critical periods, with reference to the CP hypothesis in language?
- time span wherein brain development most sensitive to specific experience
- if such an experience is lacking abnormal brain development may occur, ie. not develop properly
- CP language hypothesis is that for first few years of life CP for language exists, so from 5-puberty much more difficult for language acquisition
imprinting AKA?
filial imprinting
what is imprinting?
- young animal acquires its behavioural characteristics from its parent
- Konrad Lorenz: geese imprint on first moving stimulus within 13-16 hrs of hatching, even inanimate objects
Deprivation of sensory experience and maternal contact is catastrophic for brain and behaviour development. Provide an example?
- abortion banning –> lots orphans –> kids with mentally ill and disabled people
- conditions bad
- little to no developmental stimulation for first 6 months
- severe brain abnormalities in children
t/f: Severe stimulatory (sensory) deprivation of more than a few months is associated with smaller brains & behavioural abnormalitities.
true
t/f: SES predicts cortical thickness in children
true
from birth - 2 year mark, cortical thickness should increase by about __%
35%
(Evidence suggest that many neurodevelopmental and psychiatric disorders are the result of abnormal brain development in this stage of rapid cortical growth)
brain injuries produce abnormal brains, especially if …?
injury occurs during critical period
when is the worst time for brain injury?
last 1/2 of intrauterine period –> first few months of birth
name a condition that may be caused by brain injury during intrauterine period?
cerebral palsy (most of the time
describe the 2 main ways baby may develop cerebral palsy?
- brain injury - during intrauterine period up to first month of birth, 13/14 cases
- stroke - post one month birth
post-mortem examination of intellectually disabled children reveals what?
significantly less dendritic growth + synaptic connection
describe fetal alcohol syndrome? (FAS)
- alcohol cross placental barrier
- impact neuronal and facial growth of fetus
- permanent CNS damage
- cognitive disability, predisposition to mental health issues and drug addiction
in schizophrenia, neurochemical imaging shows psychotic state associated with?
increased dopamine synthesis and release
in schizophrenia, fMRI shows?
- abnormality in cortical response to cognitive task
- abnormal network response (hyper-activity and hypo-activity)
in schizophrenia, which brain regions are associated with functional difference?
frontal lobe, hippocampus, temporal lobe
what is the leading cause of intellectual disability in the western world?
FAS
in schizophrenia, reduction of brain volume in which regions?
frontal and temporal
those with schizophrenia show signs of what?
clincial frontal lobe dysfunction - impoverished thinking, difficulty problem solving, blunted effect
t/f: those with shizophrenia show signs of decreased brain activity in executive functioning under fMRI
true
t/f: those with shizophrenia show signs of decreased brain activity in the prefrontal area
true
how do oligodendroglial cells relate to schizophrenia?
- lower density –> this may contribute to atrophy of prefrontal neurons
- also seen in bipolar disorder
overall, schizophrenia is associated with dysfunction of which brain region?
frontal lobe
function of oligodendroglial cells?
- make myelin sheath
- support and insulate neurons
define neuroplasticity?
- changes in neural pathways/ synapses due to behavior, environment, neural processes, thinking, emotions, injury
- essentially reorganization
- can occur on cellular level or on large scale things such as cortical remapping
define phantom limb?
person feels sensation in amputated body part
phantom limb occurs how common?
80% amputees
cause phantom limb?
neuroplasticity - neuronal reorganization of somatosensory cortex
where is somatosensory cortex?
postcentral gyrus
Phantom limb: Ramachandran et al. (1992) found that stroking different parts of the face led to what?
Explain it further?
this is an example of?
perceptions of being touched in different parts of missing limb
face next to hand in homonculus
example of maladaptive neuroplasticity
exlplain neuroplasticity following stroke?
- brain is able to reorganize neuronal connections to move an associated function to different location
- away from damaged/ dead neurons
t/f: neurogenesis does not occur in adult mammalian brain
false
where does neurogenesis occur in adult brain?
mainly olfactory bulb and hippocampus but cerebellum may be involved
t/f: experience changes structure of neurons, meaning an enriched environment leads to larger brain and more synaptic connections
true
state the term related to the text below:
due to ______, the brain is able to form new pathways and connections following injury, allowing for functionality to be maintained
neuroplasticity
The midbrain and hindbrain are first visible in a human embryo after about __ days
28
Exposure to an enriched environment during development does not increase the:
A.
size of ventricles
B.
size of neurons
C.
number of astrocytes
D.
number of synapses
a
The brain is more able to cope with injury during:
A.
differentiation
B.
cell migration
C.
neuronal maturation
D.
neurogenesis
d
what does CNS originate from?
neural tube
If you house rats in complex environmental housing, you will observe:
A.
no effect on dendritic growth in the visual cortex of either sex, but an increase in the number of glial cells
B.
increased dendritic growth in the hippocampus of male rats more than in female rats
C.
increased dendritic growth in the hippocampus of female rats more than in male rats
D.
increased dendritic growth in the visual cortex of both sexes equally
c
__________ in cortical thickness in the hand area of the primary motor cortex are associated with:
A.
decreases, increases in hand size
B.
decreases, increases in manual dexterity
C.
increases, increases in grip strength
D.
All of the answers are correct
b
