Kap 5. Methods and strategies

Question 1

Experimental ablation

Answer 1

is an reseach method used to investigate brain functions. It involves removing or inactivating part of the brain and evaluating an animal´s subsequent behavior

• removing brain tissue, or damaging the tissue to disrupt its functions
• it is one of the oldest methods used in neuroscience

Question 2

lesion studies / method

Answer 2

patients with brain damage are examined to determine which brain structures are damaged and how this influences the patient’s behavior

Goal = understand what functions are perfomed by different regions in the brain and how this influences behavior

Some of the oldest and most famous studies in neuroscience are lesion studies.

Question 3

Lesion

Answer 3

wound / injury

Question 4

Brain lesion

Answer 4

a reaschers who destroy part of the brain, refers to the damage as a “ brain lesion”

“damage of the brain”

Question 5

sham lesion

Answer 5

the name given to a control procedure during a lesion experiment

(placebo)

Question 6

Exitotoxic lesions

Answer 6

lesions produces Excitotoxic lesions are permanent lesions that have been created through the injection of a neurotoxin, whichs kills neurons by stimulating them to death

Question 7

Stereotaxic surgery

??

Answer 7

To target a specific brain region, stereotaxic surgery is used.
A stereotaxic brain atlas is used to find the coordinates required.
Use a grid system to pinpoint exact regions in a repeatable way.

Question 8

Stereotaxic atlas

Answer 8

a book contains images that correspond to frontal sections of the brain taken at various distances rostral and caudal to bregma

Question 9

Fontanelle

Answer 9

is a soft spot at the junction of the coronal and sagittal sutures of the head of babies

Question 10

Bregma

Answer 10

Once the gap cloces in the fontanelle, it is called bregma “front of head”

Question 11

Stereotaxic apparatus

Answer 11

is a device that includes a head holder, which maintains the skull in the proper orientation

• f.eks brukt på brainsurgery on rats

Question 12

Autolytic

Answer 12

self-dissolving

Question 13

Anterograde means …

Answer 13

moving forward

Question 14

Anterograde labeling method

Answer 14

employ chemicals that are taken up by dendrites or cell bodies and are then transported through the axons toward the terminal buttons.

Question 15

Immunocytochemical method

Answer 15

take advantage of an immune reaction

Question 16

Antigens

Answer 16

proteins/peptides found on the surface of bacteria or viruses

Question 17

Antibodies

Answer 17

proteins produced by white blood cells to destroy invading microorganisms

• either secreted by white blood cells, or located on their surface in the way neurotransmitter receptors are located on the surface of neurons

Question 18

VMH

Answer 18

ventromedial nucleus of the hypothalamus

Question 19

Retrograde means

Answer 19

moving backwards

Question 20

Retrograde labeling methods

Answer 20

employ chemicals that are taken up by teminal buttons and carried backward through the axons toward the cell bodies

Question 21

CT

Answer 21

computerized tomography

X - ray donutshaped ring tube

uses X-rays to image “slices” through the brain (or other tissues)

Question 22

MRI

Answer 22

Magnetic resonance imaging

• uses a strong magnetic field to image the brain; better resolution than CT scans

Question 23

DTI

Answer 23

Diffusion tensor imaging

– uses an MRI scanner to identify bundles of axons so connections between brain regions can be studied.

• takes advantage of the fact that the mocement of water molecules in budles of white matter will not be random but will tend to be in a direction parallell to the axons that make up the bundles

Question 24

Retrograde tracing

Answer 24

Retrograde tracing involves putting a tracer where the axon terminals are which will travel backward along the axons to the cell bodies.

Question 24

Histology

Answer 24

Histological techniques include a number of ways of examining brain tissue.

Question 25

Anterograde tracing

Answer 25

Anterograde tracing involves putting a tracer where the cell bodies and dendrites are which will travel forward along the axons to the axon terminals.

Question 26

Electrophysiology.

Answer 26

A technique, recording electrical activity from cells

• We can record the electrical activity from single neurons or the combined activity from multiple neurons.

This technique allowed us to understand the action potential and how neurons work at a fundamental level.

But it also lets us understand how the activity in neurons is linked to behaviour and psychology.

Question 27

Calcium imaging

Answer 27

The electrical activity of neurons can be visualised by using an fluorescent molecule.

Calcium is generally used as a marker of electrical activity because it increases when neurons are active.

This allows us to target groups of neurons more precisely using genetic methods, for example, just the dopamine neurons.

Question 28

EEG

Answer 28

Electroencephalogram

The electrical activity of many neurons sums together and can be recorded using macroelectrodes.

This can be easily performed in humans as the electrodes sit on the surface of the scalp.

Question 29

fMRI

Answer 29

Functional MRI is the method of recording activity with the best spatial resolution.

It works by comparing blood flow between different conditions.

(regional activity)

Question 30

Name 3. Single unit activity methods

Answer 30

“a unit refers to an individual neuron”

n vivo electrophysiology
In vitro electrophysiology
Calcium imaging

Question 30

Name 2. multi unit activity methods

Answer 30

EEG
fMRI

Question 31

TMS

Answer 31

Transcranial magnetic stimulation

can be used to control the brain in humans.

Applying a magnetic field can induce electrical activity in neurons.

Ongoing work is attempting to use TMS as a therapeutic option, for example, for neurological and mental disorders.

Question 32

Optogenetics

Answer 32

Optogenetics is a modern technique (~15 years old) that allows neurons to be controlled by light.

A main advantage over traditional techniques is that it can targeted very precisely to just one type of neuron.

Light can also be controlled very precisely and has no effect on neurons normally.

Question 33

Chemogenetics

Answer 33

is another modern technique that involves adding a designer receptor to neurons.

These are known as DREADDs*. They are completely artificial and respond to a drug called CNO that has no effect on normal neurons.

As with optogenetics, these DREADDS can be targeted very precisely to one type of cell.

This means when you inject the CNO it will only affect the neurons that you have targeted and not the others near it.

Question 34

In voltammetry experiments, ……

Answer 34

In voltammetry experiments, neurochemicals can be detected by oxidation/reduction with higher time resolution (sub-second).

Question 34

In microdialysis experiments…..

Answer 34

In microdialysis experiments, tiny amounts of fluid can be extracted from a region of the brain and chemically analysed.

Question 35

MRS

Answer 35

(magnetic resonance spectroscopy)

uses the same technology as MRI but analyses the signal to detect different chemicals based on how they react to the magnetic field.

Question 36

PET

Answer 36

(positron emission tomography)

indirectly can measure a neurochemical by observing how concentration of a radioactive drug changes.

Question 37

Twin studies

Answer 37

– examine heritability of a trait by comparing monozygotic and dizygotic twins.

Question 38

Adoption studies

Answer 38

– examine effect of environment and interaction by looking at different upbringings.

Question 39

Genomic studies

Answer 39

include linkage studies and genome wide association studies (GWAS), examine how a particular gene is linked to a behavior.

Question 40

We can study the effects of a particular gene on behavior in a few different ways:

Name two

Answer 40

Targeted mutations – e.g. “knockout” mouse studies allow us to answer more focused questions.

Antisense oligonucleotides – can turn genes off buy stopping them being translated into protein.