Lecture 8: Neuroplasticity Flashcards
what are the 10 principles of neuroplasticity ranked from most to least important
- Salience
- specificity
- repetition
- intensity
- use it and improve it
- use it or lose it
- time matters
- interference
- age matters
- transference
what is the principle of interference with neuroplasticity
sometimes new plasticity can be delayed
definition of neuroplasticity
ability of neural circuirs to change through growth and reorganization
naturally happens with development
can be used for specific activity guided training or rehab
can be adaptive or maladaptive
describe the natural development of the nervous system
stem cells align along the ventricular wall and central canal of the spinal cord
the cells differentiate to either glioblasts or neuroblasts
for the stem cells that differentiate into glioblasts, what happens next
radial glial cells (directly merging with the pia mater) form the scaffold and the other 4 types of glia cells are in the CNS
radial glial cells are first to develop
other 4 types of glial cells develop after neurons
for the stem cells that differentiate into neuroblasts, what happens next
they mainly migrate along the radial glial scaffold; these neurons form a columnar functional unit
some migrate horizontally after climbing the glial process; these are responsible for coordinating and modulating functions
what mechanism is post natal neuroplasticity mainly through
neuroblasts that migrate horizontally after climbing the glial process (responsible for coordinating and modulating function)
what is a neurite
extension from the neuron soma/cell body
defines the neuron type and function
in the beginning, neuroblasts develop neurites without differentiation
types of neurites , where to find them/what neurons generally fall into the category
multipolar: UMNs and LMNs and most interneurons
pseudounipolar: DRG, sensory neurons
Bipolar: olfactor receptor neurons, visual pathway, some interneurons
describe how the polarity of neurons works
they have functionally distinct proteins that are attracted to neurite tips by directional stimuli
works via chemoattraction and chemorepulsion
where can you find neurotrophins/how do they work (chemoattraction factors)
peripheral process of sensory neurons in the DRG
different target cells secrete different neurotrophins (called cytokines)
these send signals to different peripheral processes that conduct specific sensory modalities
function = transported back to the somata for the survival of the neurons (block apoptosis)
purpose/function of chemorepulsion
still through different cytokines; used to avoid abnormal interactions
self avoidance = intra-neuronal repulsion (dendrites of same neuron)
tiling = inter-neuronal repulsion (dendrites of different neurons)
how do chemo- repulsion/attraction control the direction of the neuron signals
chemoattraction = direction of the neurite extension
chemorepulsion = turning point along the extension
describe how CN II is an example of the balance of chemo repulsion/attraction
axons of ganglionic cells from the temporal retina extend ipsilaterally
axons of ganglionic cells from the nasal retina cross over to form optic chiasm
both chemoattraction and repulsion are at play
what gene defines the development of external genitalia
SRY gene on the Y chromosome
if expressed = male
if female, there is no SRY gene (XX chromosomes) or the SRY is mutated and non functional (XY)
male external genitalia if SRY is inserted into the father copy of X chromosome
describe the relationship/importance of male genitalia and sec hormones related to brain development
all hormones synthesized from cholesterol
only male sex hormones surge in the fetal brain; male and female both have active hormones but only females have this fetal surge
describe the phases of sexual hormones related to brain development in males vs females
male brain has 2 phases: prenatal and puberty
females only have 1 phase: puberty phase
differentially developed brains define different behaviors in males vs females
examples of how differentially developed brains define different behaviors
sexual activities = different LMN pools for mm and reflex
violence (in amygdala) = males have fewer astrocytes to insulate and inhibit neurons thus they tend to be more violent
sexual hormones improve genesis of what
neurites
dendritogenesis for dendrites
what is spinogenesis
spine sprouting along dendrites
dendritic spines = major synaptic points
i.e. pyramidal cells, medium spiny neurons, purkinje cells, etc
stimulated by sex hormones
describe the findings of oxytocin and ADH levels in prairie voles/montane voles and how it relates to behavior
oxytocin
- prairie = found in prefrontal cortex, caudate, putamen, and nucleus accumbens
- this is NOT true of montane voles
ADH
- prairie = ventral pallidum
- montane = lateral septal nucleus
behavior
- prairie = MONOGAMY
- montane = POLYGAMY
male brain larger areas and the effects this causes
orbitofrontal cortex = analysis of results
corpus callosum = more cross talking, but harder stroke recovery
amygdala = more fights/violence
female brain larger areas and the effects this causes
limbic lobe = more emotion
olfactory system = more sensation related to smell
SMA = like to work more?
hippocampus (smaller??) = more challenge with spatial orientation
stages of synaptogenesis
early stage = axons extend to target structures under over amount of neurotrophins; axons mainly extend to dendrites, other axons, cell bodies, and target cells
synapses are formed by complex proteins (electric vs chemical)
late stage = synapse pruning if not strengthened
