Invasive Neuroscientific Techniques

Question 1

What structures do we pass through before reaching the brain?

Answer 1

The skull, dura mater, subdural space, arachnoid membrane, and pia mater.

Question 2

What is the skull composed of?

Answer 2

Multiple bone plates fused together; cracks between plates are called sutures.

Question 3

What is the dura mater?

Answer 3

A tough, elastic membrane that covers the brain and acts as the protective outer layer of the meninges

Question 4

What is the subdural space?

Answer 4

A potential space beneath the dura mater, usually empty unless filled by fluid due to injury.

Question 5

Describe the arachnoid membrane.

Answer 5

A soft, mesh-like layer that resembles a spider web, cushions the brain, and is part of the protective layers.

Question 6

What is the pia mater?

Answer 6

The innermost, delicate membrane covering the brain, similar to the dura mater but thinner, closely following the brain’s surface.

Question 7

What are the meninges?

Answer 7

The protective layers covering the brain, consisting of the dura mater, subdural space, arachnoid membrane, and pia mater.

Question 8

How is the brain protected?

Answer 8

By the skull and the meninges

Question 9

What is a brain atlas?

Answer 9

A map of brain structures used to study the inside of the brain by showing where different regions are located.

Question 10

What are “landmarks” in the context of brain atlases?

Answer 10

Key points within the brain that help define the structure and guide the creation of brain atlases.

Question 11

How many orientations are brain atlas sections typically taken from?

Answer 11

Three orientations: horizontal, sagittal, and coronal.

Question 12

What does a horizontal section show in a brain atlas?

Answer 12

A view parallel to the ground, often used to study top and bottom regions.

Question 13

What does a sagittal section show in a brain atlas?

Answer 13

A lengthwise view dividing the brain into left and right halves.

Question 14

What does a coronal section show in a brain atlas?

Answer 14

A view perpendicular to the ground and sagittal plane, dividing the brain into front and back parts.

Question 15

What are lesion techniques used for?

Answer 15

Lesion techniques involve removing, damaging, or destroying a part of the brain to study its function, remove tumors, or treat epilepsy.

Question 16

How is behavior used in lesion studies?

Answer 16

The behavior of the subject is assessed after the lesion to determine the function of the affected brain area.

Question 17

What is an aspiration lesion?

Answer 17

A technique for removing small areas of the brain’s cortex using a suction cannula, commonly used for tumors or specific cortical areas.

Question 18

What are the advantages and limitations of aspiration lesions?

Answer 18

Effective for cortical areas but unsuitable for deeper structures, as it is limited to removing surface brain tissue.

Question 19

What is a radio-frequency lesion?

Answer 19

A technique that uses a high-frequency current to destroy targeted subcortical tissue through heat, affecting both axons and cell bodies.

Question 20

What is a disadvantage of radio-frequency lesions?

Answer 20

They may sever connections between brain regions, potentially influencing experimental results by affecting interconnected areas.

Question 21

What is a neurotoxin lesion?

Answer 21

A lesion technique using neurotoxins to selectively destroy cell bodies in subcortical structures while sparing axons.

Question 22

What is the advantage of neurotoxin lesions?

Answer 22

Allows precise targeting of neurons without disrupting axonal connections to other areas.

Question 23

What are knife cuts used for in lesion studies?

Answer 23

Knife cuts create precise cuts in subcortical regions to sever specific neural pathways, isolating certain brain areas.

Question 24

What are the benefits and risks of knife cuts?

Answer 24

Provides controlled pathway isolation but is invasive and can have significant side effects.

Question 25

What is a cryogenic blockade?

Answer 25

A technique that temporarily halts neural activity in specific brain areas by cooling neurons without causing permanent damage.

Question 26

How does a cryogenic blockade work?

Answer 26

A cryoprobe is implanted, and a coolant is passed through it to cool neurons, stopping their activity until the area is rewarmed.

Question 27

What makes cryogenic blockade unique compared to other lesion techniques?

Answer 27

It is reversible; once the tissue is warmed, normal neural activity resumes.

Question 28

Why is cryogenic blockade ideal for experimental studies?

Answer 28

It allows for temporary, non-destructive manipulation of brain regions, making it useful for reversible brain function studies.

Question 29

What is a limitation of cryogenic blockade?

Answer 29

It is used exclusively in experimental research and is not applied in medical procedures.

Question 30

Why can lesion effects be difficult to interpret?

Answer 30

Lesions may unintentionally destroy multiple structures, and observed changes may result from disinhibition of other structures. Also, partial recovery of function can occur over time.

Question 31

What are staining techniques used for?

Answer 31

Primarily in animal research, staining techniques visualize brain structures and individual neurons in tissue samples.

Question 32

What is the Golgi stain?

Answer 32

A stain that colors the entire structure of individual neurons, including soma, dendrites, and axon, allowing detailed study of neuron shape and branching.

Question 33

What is the advantage of the Golgi stain?

Answer 33

Only a small percentage of neurons are stained, making it easier to study single neurons without overcrowding.

Question 34

What is the Nissl stain?

Answer 34

A stain that colors all cell bodies (somas) in a tissue section, typically blue or purple, but does not stain axons or dendrites.

Question 35

What is the advantage of the Nissl stain?

Answer 35

The simplified staining highlights cell density and organization, making it useful for identifying and counting neurons.

Question 36

What are tracing techniques used for?

Answer 36

To map connections between brain regions, showing where regions send or receive information.

Question 37

What is anterograde tracing?

Answer 37

A technique used to trace where a brain region sends its axonal projections.

Question 38

What is retrograde tracing?

Answer 38

A method to identify where a brain structure receives its information from, tracing projections back to the cell soma.

Question 39

What is electrophysiology?

Answer 39

The study of electrical activity in neurons, allowing researchers to record and analyze action potentials from single neurons.

Question 40

What can single-neuron recordings reveal?

Answer 40

Activity in specific neurons like place cells (location-responsive), head-direction cells (direction-responsive), and color-responsive cells.

Question 41

How are electrodes used in brain stimulation?

Answer 41

Electrodes can stimulate specific brain areas, enabling researchers to observe changes in behavior and function.

Question 42

What are electrodes in electrophysiology?

Answer 42

Tiny devices, about the diameter of a hair, inserted near or within neurons and connected to an amplifier to boost weak electrical signals.