neuro midterm

• developed by Ramon y Cajal

• the brain is made of separate neurons and other cells that are independent structurally and functionally

• info is transmitted through gaps/synapses

stain used to study brain cells that specifically takes neurons but not all neurons take it

stain used to study brain anatomy that stains whole cells and is not limited to neurons

make up 10% of cells in the brain and function in computation

• make up 90% of cells in brain function in support

• provide nutrients to neurons and regulate/buffer extra cell space

• structural framework for other type of cell in the brain

• make myelin

• guide other cells during development

• capable of regeneration at high rate

• type of glial cell

• make myelin in the PNS (peripheral nervous system) (travels through entire body)

• found in axon

• type of glial cell

• make myelin in CNS (brain and spinal cord) (central nervous system)

• connects to myelinated portion of axons

• type of glial cell

• regulate extracellular space and blood/brain barrier (system the protects / keeps things out of the brain)

• type of glial cell

• phagocytose

• removes/ engulfs debris and dying/dead nerons

• where neurons connect to communicate

contain chemicals that can be released into the synapse

• sends info to other neurons

• has myelinated portions (w nodes of Ranvier)

• inside is negative with respect to the outside

• can be recorded from

• where voltage - gated ion channels are found

• AP’s move down it

• difference in charge between inside and outside of cell

• Vm

• uses Goldman equation to be calculated

  • takes into account that membrane is permeable to more than one ion

• membrane potential becomes closer to zero

attract cations (-) are positive

attract cations (+) are negative

• the movement of a positive charge

• determined by voltage and electrical conductance

  • driving force + conductance

• when positive + there is movement out of the cell

• when negative - there is movement into the cell

• when the force of diffusion = electrical force

• Eion

• unique to each ion

• Nernst equation used to determine its value

equilibrium potential (Eion) of potassium K+

equilibrium potential (Eion) of sodium Na+

• net available force available to move across the membrane

• 0 when the equilibrium potential is 0

• planes that separate negative and positive charges

• ex. membrane

• can be generated by

  • injecting + current

  • synaptic activity that releases transmitter that activates chemically activated channels

• value of membrane potential that elicits an action potential

Na+ channels open Na+ rushes in

• depolarization/rising phase

• K+ channels open, K begins to leave the cell

• gNa > gK

• Na channels inactivate

• Na influx stops

• K continues to leave the cell

• causes membrane potential to return to resting potential

• after falling phase

  • where gNa < gK

• K channels close

• Na channels deinactivate

• undershoot

  • hyperpolarization

• under membrane potential

• maintain sodium/potassium gradient

• kicks out 3 Na+, brings in 2 K+

• brain used 70% ATP with these

• period after AP where it is impossible to shoot another AP

• this happens because of inactivation of sodium gated ion channels after AP

• 1-2 ms

• during peak and downfall

• period of time after an AP where another AP can be fired

• second initiation requires stronger stimulus than before

  • needed to reopen inactivated sodium channels

• right after other type of refractory period

• during undershoot/hyperpolarization

• stem cells residing in the adult brain divide and differentiate into neurons

• TX

• binds and blocks Na+ channels which can block AP’s (chart would be little bump but no AP)

• makes eating pufferfish wrong lethal

• fast acting poison, no antidote

• ri

• current that flows along the axon

• rm

• how easily current flows in and out of the membrane

• involved in passive propagation

• when current flows from node to node in the myelinated portion of the axon

  • AP’s happen in this node

• how AP’s move down the axon

• unmyelinated portion

• slower due to constant firing of AP’s

• how currents AP’s move down the axon

• myelinated portion of the axon

• faster because AP’s happen at nodes

  • saltatory conduction

• electrical synapses

• ions flow from cell to cell

• uses vesicles to release NT’s through a complex system

1. vesicles store NT

2. AP arrives at terminal button

3. Voltage gated Ca++ channels open

4. Ca++ enters terminal

5. Vesicles fuse with membrane

6. exocytosis

• ions flow in and out

• elicit EPSP’s

• ionotropic receptors

• bind to receptors that open Na+ channels

  • not voltage gated

• hyperpolarizes when it elicits and IPSP

• metabotropic receptors

• can open ion channels

• can activate second messengers

records multiple axons and adds EPSP’s

records multiple AP’s on the same axon and adds EPSP’s

• good model for behaviors in humans

• controllable conditions

• organizational similarities in brain structures

• simpler and easier to focus on certain aspects of neural behavior

• fact of the physical universe

• exist until disproven

• explanation that is broad in scope and supported by evidence

• can include laws

• proposed explanation from an observed phenomenon

• testable and falsifiable

group in an experiment where no effect is found from a given placebo

group in an experiment where an effect is expected from a known substance

• when a part of the brain is taken out/destroyed to learn its effects

• ablation - destruction

• one technique used to do this is lasers (RF) that can cause electrical destruction of certain parts of the brain

• Pros: Provides strong evidence for the necessity of a brain structure for a process

• Cons: does not actually investigate the function of the brain region, just what everything else can do without it

• ip

• drugs administered through the abdominal cavity

• sc

• drugs administered under the skin

• iv

• drugs administered into vein

• ic

• drugs administered into brain tissue

• icv

• drugs administered into the ventricle

• drugs administered by something placed into skin/ body

• drugs administered through the skin

• ex. nicotine or testosterone patch

• drugs administered through the mouth

  • ex. pills

• uses a stereotaxic atlas to input certain coordinates on the brain and target certain areas using electrodes

  • stereotaxic apparatus - used to place electrodes into brain

  • bregma - juncture of coronal and sagittal suture (point 0)

  • cannula - rods placed into brain (cannot be felt by patient)

• pros:

• cons:

• measures brain activity in animals using electrodes

  • macroelectrodes - records many neurons

  • microelectrodes- records only one neuron

• pros:

• cons:

• uses antibodies to label proteins in the brain in response to stimuli

• c-fos

• pros:

• cons:

• snapshot of the brain at a certain point in time

• pros: noninvasive can be used on humans

• cons: only gives a snapshot of the brain and doesn’t study brain activity

• electroencephalogram

• measures real time brain activity

• macroelectrodes on the skull

• pros: real time measurements, very mobile

• cons: restricted to outermost layer of the cortex

• looks for increase in blood oxygen level to study brain function

• pros: can look at entire brain, non invasive

• cons: complete immobilization and delay

• used to detect MRNA at a cellular level one gene at a time

• brain section exposed to radioactively labeled RNA probe

• pros: cellular resolution

• cons: time consuming, one gene at a time

• Create a piece of RNA and inject it into the brain; the siRNA recognizes the strand of mRNA of interest, and destroys it such that it cannot be translated for protein expression

• cons: potential off-target effects

• grind up tissue; extract RNA; reverse transcribe to become DNA; fluorescently label; add to microarray chip; DNA binds to complementary strand on chip; ratio of different samples shows ratio of gene expression

• pros: can assay of 1000’s of genes

• cons: no cellular resolution, expensive

• studying cellular proteins

• in tissue slices, antibodies recognize the protein they are targeted against; label fluorescently to see under confocal

• pros: cellular resolution, double label proteins

• cons: time consuming, not as quantitative

activate receptors

drug that activated receptors

drug that blocks receptors

• removes a gene to be studied

• Knockout the gene in the mice embryo; no mRNA and therefore no protein products are made from

• cons: May Interacts with other processes we want to control for

• specific times (age) and specific tissue (area) where gene is knocked out

• pros: doesn’t disrupt as much the developmental process

• uses light to activate/ inhibit neurons

• Use virus to inject a channel (eg. Rhodopsin 2/halorhodopsin); simulate with blue/yellow light to activate/inhibit neurons via ion flow

• pros: Allows for bidirectional control of the neural activities simultaneously / allows for real-time investigation of function of neurons in behavior

• monozygotic - same egg (identical)

• dizygotic - (fraternal)

• concordant - when both twins have the same disorder

• used to study genetic effect on certain diseases

• pros: Allows for the disentanglement of shared genetic and environmental factors for the trait of interest

• cons: many confounding variables

• used to study the effect of environmental factors

• pros: Allows for the disentanglement of shared genetic and environmental factors for the trait of interest

• cons: information about biological parents isn’t always available

• localized in neurons

• synthesized by neurons

• released by neurons

• NT of neuromuscular junctions

• motor neuron synapses

• Ach

• physostigmine

• black widow spider venom

• botulinum toxin

• myasthenia gravis

• NT that assists in movement, attention, learning, addiction, and reward

• cocaine is an agonist

• methylphenyl (Ritalin) is an agonist

• chlorpromazine is an antagonist

• amphetamine both increases activity and release of this NT

• type of NT

  • dopamine (DA)

  • norepinephrine (NE) - assists in attention

  • epinephrine (Epi) - adrenaline

• bind to alpha and beta renergic receptors

• serotonin (5-HT)

• NT involved in mood, eating, sleeping, and arousal

• antagonist is fluoxetine (Prozac)

• agonists: LSD, Ecstasy/Molly (stimulates release, inhibits uptake), Psilocybin (mushrooms) >> Psilocin (binds to receptors

• small

• allylglycine

  • inactivates GAD

  • used to make experimental animal models for epilepsy

• Glutamate - often excitatory

• GABA (gamma-aminobutyric acid) - often inhibitory

• bind to opioid receptors: opium, morphine, heroin

• endogenous opioids

  • enkephalins (involved in reward pathway and pain reduction [analgesia])

• projection of (in this case) dopamine neurons from VTA to NA