Lecture 4: Neuroscience techniques

Question 1

molecular neuroscience

Answer 1

study of the brain at the most elementary level

Question 2

what are 3 important neuronal molecules?

Answer 2

messengers = neuronal communication
sentries = control of what can enter/leave neurons
conductors = neuron growth

Question 3

cellular neuroscience

Answer 3

how molecules work together to give neurons their special properties?

Question 4

systems neuroscience

Answer 4

how different neural circuits analyse sensory information?

Question 5

behavioral neuroscience

Answer 5

how neuronal systems work together to produce integrated behaviors?

Question 6

cognitive neuroscience

Answer 6

understanding neural mechanisms responsible for higher levels of human mental activity => how brain creates bind?

Question 7

in vitro models

Answer 7

1) bacteria/yeast cells -> easy to study receptors
2) cell culture -> cells interacting with each other, informs how receptors work in more complex environment
3) tissue slice -> kept alive in Petri’s dish, soaked in nutrient dense fluid = access to different structures and cells

Question 8

in vivo models

Answer 8

1) invertebrates - no bones, simple nervous system
2) vertebrates - studying particular brain structures; humans = with very specific questions in mind

Question 9

in-silico models

Answer 9

computers - simulated nervous system -> can span multiple organizational levels

Question 10

What animals are used in majority in research?

Answer 10

rodents - 90%

Question 11

Why rats are so popular in research?

Answer 11

cheap housing/maintenance/breeding
friendly disposition
relatively intelligent and agile
resistant to infection
many inbred stains available
background data

Question 12

Why mice are less popular than rats in research, but still useful?

Answer 12

They are less intelligent and smaller than rats. However, they can be used for convenient genetic manipulation

Question 13

manipulation techniques

Answer 13

1) lesions -> if function is gone, presumably lesioned brain area was affected
2) electrical stimulation
3) pharmacology = effects of drugs
4) genetic manipulation
5) behavioral manipulation

Question 14

What are types of lesions?

Answer 14

can be mechanical, chemical or induced via electrolysis

Question 15

in vivo monitoring techniques

Answer 15

1) electrophysiology -> passive electrodes recording currents
2) microdialysis -> record chemical consequences of drug administration
3) behavioral evaluation

Question 16

ex vivo monitoring techniques

Answer 16

1) localization/quantificaiton of tissue in situ (=in their original place)
2) histology = staining
3) immunohistochemistry = using antibodies that are attaching to tissue components
4) in situ hybridization of mRNA/DNA to visualize genetic material

Question 17

Why is stereotaxic surgery performed?

Answer 17

1) lesions
2) microinjections
3) cannula placement
3) microdialysis
4) electrodes
5) headsets

Question 18

stereotaxic brain atlas

Answer 18

information about brain areas of animals and humans
3-axis coordinate systems
enables localization of structures of interest in relation to bregma

Question 19

what is microdialysis?

Answer 19

in principle, you insert thin probe into brain tissue
it enables drug application via diffusion through permeable tube
at the same time, compounds which are part of your brain fluid can flow into the tube
so you can record how composition of brain fluid changes as a result of drug application

Question 20

what are applications of microdialysis?

Answer 20

continuous monitoring of chemical events in living tissue; drug delivery; monitoring drug effects with high temporal information

Question 21

electrophysiology

Answer 21

the branch of physiology that studies the electrical properties of biological cells and tissues; it involves measurements of voltage changes or electric current

Question 22

patch clamp recording

Answer 22

recording current from single channel
small patch of membrane is plaed under hollow glass pipette with electrode inside
it enables measuring changes in membrane potential or amount of current passing through cell

Question 23

intracellular recording

Answer 23

the measurement of voltage or current across the membrane of a cell. It typically involves an electrode inserted in the cell and a reference electrode outside the cell

Question 24

extracellular recording

Answer 24

ecordings of electrical potentials produced by a cell, either in extracellular fluid near the cell of interest, or non-invasively. These types of recordings can be divided into three main groups; single/multiple unit recordings, whole nerve recordings, and field potentials

Question 25

What is difference between intacellular and extracellular recordings?

Answer 25

intracellular recordings occur inside an individual cell, whereas extracellular recordings occur outside the cell and often result in the recording of activity from several different cells

Question 26

recording field potentials

Answer 26

recording of synchronous activity from many cells

Question 27

EEG - electroencephalogram

Answer 27

potential differences between electrodes on the scalp vs reference electrode OR average potential of all electrodes
it measures synchronous electrical activity of neurons (records from dendrites)

Question 28

why not record from axons?

Answer 28

because you need synchronized activity of many cells, dendrites are continuously modulated, whereas axons fire sporadically = so they don’t fire synchronously, unless you are having the seizure

Question 29

What is actually recorded in EEG?

Answer 29

MODULATION - to make a network to be in certain state
mostly oscillating potentials with characteristic frequency bands with different spatial distributions

Question 30

fMRI

Answer 30

based on blood oxygenation
BOLD - blood-oxygen-level-dependent imaging
theory: active brain areas need more oxygenated blood

Question 31

genetic manipulation

Answer 31

refers to direct manipulation of organism’s genes
should not be confused with: inbreeding, spontaneous mutations

Question 32

transgene

Answer 32

foreign DNA inserted into host organism

Question 33

transgenic organism

Answer 33

organism transformed with transgene

Question 34

what are two main possibilites in transgenic manipulation?

Answer 34

1) foreign DNA can exist in cell in the form of plasmid = prokaryote hosts
2) foreign DNA can be integrated with host genome = eukaryote hosts

Question 35

what are principles of recombinant technology in bacteria?

Answer 35

1) gene of interest should be isolated
2) gene can be modified
3) then gene should be combined with plasmid
4) insertion of plasmid into bacterial cell
5) cloning

Question 36

how to check whether bacteria contains gene of interest (f.ex. antibiotic resistence)?

Answer 36

planting bacteria in agar with antibiotics -> if bacteria contains resistant gene, it will grow (otherwise it should die)

Question 37

applications of recombinant technology in neuroscience

Answer 37

1) knock out mice - gene altered to cripple its function
2) knock in mice - gene altered to increase its function
3) tracking experiments to clarify where protein is produced

Question 38

chimera

Answer 38

single organism composed of cells with more than one distinct genome

Question 39

optogenetics

Answer 39

used to manipulate activity of specific cells in the brain
using light-sensitive ion channels
- different versions can be genetically transferred → either excitatory or inhibitory for neuron’s firing
- insert into virus the genetic material that codes for manufacture of photoreactive ion channels from light-sensitive algae, and then inject the virus into specific brain area
- expression of inserted genetic material in the neurons of injected area leads to the production and incorporation of these ion channels into neuronal membranes
- shining light on the brain tissue can then selectively activate (or inactivate) these neurons and modulate their signals to the other brain areas to which they project, thereby influencing behavior