Development & Plasticity
Compare the two types of stem cells
Unipotent stem cells can only form one type of cell
Totipotent stem cells can form any cell type
What is a type of movement that cannot be changed once started
Ballistic movements
Which memory has a limited capacity and fades without rehearsal
Short-term memory
What is the James-Lange theory
That autonomic arousal and skeletal action occur first in an emotion rather than the emotional feeling
Sperry and the newts (1954)- what did they do, why, and what did they find?
Cut the optic nerve (goes from the eye to visual area of the brain) and turned the eye 180 degrees.
Wanted to know if the axons go back to the target consistent with their old position of their new position.
Found that nerves go back to their original target!
How do axons know where to go as they grow?
Chemical trail
Describe slow-twitch fibers
Less vigorous, no fatigue, aerobic, used during endurance, darker color
What is Korsakoff's Syndrome
It is drain damage caused my a lack of thiamine leading to memory problems, confusion and apathy
What does MAOa gene have to do with aggression
Low activity is linked to aggressive behavior
Ferret experiment- what was their question, what did they do, what did they find?
Q: Are cells destined to be a certain type of cell?
On one side of the brain, damage the visual part of the thalamus and the auditory nerve- the optic nerve can't go to it's usual target and the auditory part of the thalamus lack auditory input
The previously "auditory" thalamus starts to look and act more like the visual thalamus, so no, cells can change what cell type they were originally supposed to be.
Describe the development of neurons
Proliferation: production of new cells
Migration: movement of cells
Differentiation: axon and dendrites form
Myelination: glia produce myelin sheaths
Synaptogenesis: formation of synapses
Describe a muscle spindle
a type of proprioceptor that responds to stretch and is parallel to the muscle
What is Hebb's Rule
What fires together, wires together
What are the effects of low serotonin turnover
fighting, antisocial behaviors, violent behaviors, impulsiveness
Explain Libet's study
Participants instructed to move their wrist when they choose to. 3 measurements are taken: EEG over motor cortex in brain, sensor attached to hand, self-report of where the light is on the clock when you decide to move.
People reported decision to move about 200 ms before movement, but the motor cortex starts firing for movement before decision to move.
What are the types of strokes
Ischemia: blood clot or other obstruction in artery; more common
– Neurons without blood lose oxygen and glucose
Hemorrhage: ruptured artery
– Neurons get flooded with blood and oxygen
How are basal ganglia involved in movement
They select for a movement by removing inhibition of it
Explain sensitization
Increase in response to mild stimuli due to previous exposure to more intense stimuli
It takes longer for the membrane to repolarize due to strong stimulation, released neurotransmitter for longer, so prolonged sensitization
How do benzodiazepines work?
They bind to the GABAa receptor and facilitate GABA effects which reduce anxiety
Explain Lashley's work in searching for the engram
Maze learning in rats
He cut the cortex in these rats. No cuts = no impaired performance. Lots of cuts = more impaired performance than when just a few cuts are made.
Suggests the cortex works as a whole and all parts contribute to complex behaviors
What are the explanations for reorganization in the brain?
Collateral sprouting- Amputation of a body part means that axons from that region degenerate, leaving vacant synapses, other axons responsible for neighboring fingers grow in that area
Denervation supersensitivity- Axons from other fingers were always present in small numbers and they lose competition from the other fingers so pre-existing synapses become stronger
What is a major difference between Parkinson's and Huntington's disease
Huntington's has too little inhibition from basal ganglia so it's harder to stop moving
Explain the steps of LTP
Multiple axons fire on the same dendrite causing a release in glutamate.
Glutamate binds to AMPA receptors- sodium enters.
Dendrite depolarizes- magnesium is displaced and opens the NMDA channel
Sodium and Calcium enter cell- Ca increases communication
What structures are in the HPA axis and when does it work?
Hypothalamus, anterior pituitary, adrenal cortex. Occurs during periods of prolonged stress
How can the startle response be studied in a lab setting
fMRI while showing the participant photos that arouse fear or photos of somebody who is afraid