Quiz #4: The Brain That Changes Itself

Determine whether neurons develop from ectoderm, mesoderm, or endoderm.

ectoderm (epidermis & nervous system)

Outline the steps of neurulation.

1. neural plate elongates (day 17-18 after fertilization)
2. neural plate folds (day 22)
3. neural tube closes (day 25-27)

neural plate --> neural groove --> neural tube --> neural axis --> brain & spinal cord

Identify the active ingredients in acne medication which can cause birth defects.

isotretinoin (13-cis-retinoic acid)

Identify the direction in which the layers of the cortex develops.

cortex develops inside out

inner cortical layers develop first, then layer outer cortical layers

Acknowledge that neural stem cells have the potential to become neurons and glia (astrocytes & oligodendrocytes).

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Distinguish ES cells, somatic stem cells, and iPS cells.

ES cells = embryonic stem cells
- totipotent (can give rise to ANY cell type)

somatic stem cells = adult stem cells
- pluripotent (can give rise to most but not all cell types)

iPS = induced pluripotent stem cells
- derived from differentiated cells that have received treatment to revert back to immature cells that can give rise to multiple cell types

Explain why researchers using neural stem cells to treat Parkinson's disorder should check that grafted cells are not rejected, express dopaminergic markers, and don't have proliferative potential.

- if grafted cells are rejected, the body's immune system will destroy the transplanted tissue
- dopaminergic markers will be flagged by dopamine neurons
- proliferative potential may lead to tumors

Determine whether a treatment was effective for treating Parkinson's disorder by interpreting graphs showing the effect of vehicle vs. treatment conditions on PD score and mobility.

PD score:
- vehicle = flat line; treatment = negative slope

mobility:
- vehicle = flat; treatment = positive slope

Illustrate how a biology core concept is exemplified in experience-dependent plasticity.

the shape of an object relates to its intended function (structure informs function)

ex: a larger brain structure (larger hippocampus) allows for greater capacity (enhanced ability to navigate London's streets)

Recall the structural and functional changes that occur in licensed London taxi cab drivers.

structural change: increased hippocampus

functional change: increased hippocampal activity

Distinguish the brains of licensed London taxi cab drivers from bus drivers.

the hippocampi of bus drivers and failed cabby trainees look like the general public

Describe how the auditory cortex reorganizes when trained to listen to a sound of a particular frequency.

the auditory cortex reorganizes to expand regions that are used more often

Describe how the motor cortex reorganizes when trained with a particular motor task.

larger representation for a body part when those muscles are used more often

specific brain regions expand when we use them more, but brain regions can also shrink when we don't use them

Provide an example of lost brain function due to experience-dependent loss.

when you amputate digit 3, the homunculus in somatosensory cortex loses representation of digit 3

Define synaptic plasticity.

the ability of a synapse to strengthen/weaken over time, depending on its activity or lack thereof

Compare and contrast AMPA receptors and NMDA receptors and draw implications to synaptic plasticity.

AMPA receptors:
- open when glutamate binds --> allows cations to flow in

NMDA receptors:
- open when glutamate binds & when postsynaptic neuron is already depolarized (needs to dislodge Mg+ plug)

Provide an example from synaptic plasticity studies which distinguishes sufficiency from necessity.

protein synthesis is required for LTP (protein synthesis blockade has lower % of EPSP --> blocking tests for necessity)

Draw a postsynaptic recording which shows synaptic plasticity or long-term potentiation.

check slides

synaptic plasticity: enhanced amplitude
LTP: looks like logarithmic graph

Describe how number of postsynaptic receptors, dendritic spine volume, and number of synapses change with increased or decreased synaptic transmission.

increased synaptic transmission:
- more AMPA receptors
- bigger synapses (grows bigger to fit more AMPA receptors)
- more synapses

decreased synaptic transmission:
- less AMPA receptors
- smaller synapses
- fewer synapses