Neuroanatomy & Research Methods ( + Textbook Chapter 3 )

Question 1

At the highest organisation ‘level’, what are the TWO branches of the nervous system?

Answer 1

Central Nervous System (CNS)
&
Peripheral Nervous System (PNS)

Question 2

Fill-in-the-Blank:

It is important to remember that ‘brains are ____, and therefore do not ____ ____ ____’.

Answer 2

It is important to remember that ‘brains are networks, and therefore do not work in isolation’.

It is the communication between and coordination of the different regions that drives functionality.

Question 3

List:

The TWO main branches of the Peripheral Nervous System (PNS).

Answer 3

1. Autonomic Nervous System.
2. Somatic Nervous System.

Question 4

List:

The TWO main branches of the Somatic Nervous System.

Answer 4

1. Motor
2. Sensory

Question 5

List:

The TWO main branches of the Autonomic Nervous System.

Answer 5

1. Sympathetic (‘Fight or Flight’).
2. Parasympathetic (‘Rest and Digest’).

There is also the enteric/intrinsic subdivision, which has functions associated with the gastrointestinal tract and digestion.

Question 6

What is the main purpose of the somatic nervous system?

Answer 6

Allowing the brain/CNS to sense and interact with the external environment.

It does this by taking in afferent information via the sensory nervous system, and sending out signals/efferent information via the motor nervous system to initiate responses.

Question 7

What TWO things constitute the central nervous system (CNS)?

Answer 7

The brain & spinal cord.

Question 8

How might case studies of people with unique brain damage contribute to the study of biological psychology?

Answer 8

Patterns of damage and subsequent dysfunction can reciprocally give insights into which brain regions are correlated with particular behaviours/functions.

H.M is a particularly famous case study which gave immense insights into the relationship between our hippocampus and the forming of episodic and autobiographical memories.

Question 9

Define:

Ablation

(In the context of neuroanatomy).

Answer 9

Removal of particular sections of the brain.

Usually carried out with sugical knives.

Question 10

Explain:

A ‘sham lesion’ and its purpose.

Answer 10

These are procedures whereby you carry out all steps of an induced lesion with a control group, butwithout applying the electrical current.

This helps explore if there are any confounding factors beyond the lesion itself leading to behavioural changes.

If there are behavioural differences between the lesion group and control group, then you can be more certain the change is due to the lesion.

Question 11

Why are electrical lesions considered a ‘crude technique’?

Answer 11

Alongside target neurons, they damage any axons/nerve fibres running through the that area too.

Question 12

What is an alternative technique to electrical lesions?

And what is its benefit?

Answer 12

Chemical lesions .

They allow neurons in a particular area to be targeted, without outright damaging axons running through that same region.

This is because the axons lack the receptors required for the chemical to have an effect on them, unlike the cell bodies.

Question 13

Describe:

The ‘gene knockout approach’.

Answer 13

This involves targetting (via mutations) specific genes that regulate a certain type of cell, neurotransmitter, receptor, etc.

Question 14

Describe:

TMS

(Transcranial Magnetic Stimulation)

Answer 14

Application of a magnetic field to the scalp.

This either stimulates or inhibits cortical neurons in the area below the magnet.

Stimulation occurs with ‘milder’ and shorter applications.

Inhibition (or ‘virtual/reversible lesions’) occur when a sufficiently strong field is applied.

Comparisons of behaviour are made between ‘active’ and ‘inactive’ states of particular brain regions.

Question 15

Compare & Contrast:

An ablation vs. a lesion.

Answer 15

Lesions involve damaging/inactivating structures, whereas ablations typically involve removing structures.

Question 16

What are the TWO key limitations of stimulating brain regions using electrodes?

Answer 16

• It will stimulate all types of neurons in that area, which may have varying functions to each other.
• It also stimulates any axons running through that region

Question 17

List:

The THREE key steps leading to the development of optogenetics.

Answer 17

1. Finding/creating a light-sensitive protein (microbial opsins) that can initiate ion channels to open.
2. Developing viruses that can insert the gene that codes for these opsins into neuronal DNA.
3. Developing thin optical fibres for precise, targeted light exposure.

Question 18

Define:

Optogenetics

Answer 18

A biological technique that uses genetic engineering to control the activity of targeted cells.

The genetic engineering aspect involves inserting genes into the DNA of cells that causes them to express light-sensitive proteins called opsins.

When light is directed at the genetically altered cells and hits the opsin proteins, they will trigger certain ion channels to open.

If sodium channels are opened, an excitatory response occurs, but if chloride channels are opened, an inhibitory response would instead occur.

Question 19

Define:

EEG

(Electroencephalography)

Answer 19

A brain activity recording technique that uses superficially located electrodes to detect electrical activity of cortical neurons under particular regions of the scalp.

Question 20

What are evoked potentials/responses?

(In relation to EEG)

Answer 20

Patterns of electrical activity in stimulated neurons.

Stimulation can come in many forms such as common sensory information (i.e. light, sound, touch, etc.)

These can be used to detect responses from non-verbal subjects (such as infants).

Question 21

Define:

MEG

(Magnetoencephalography)

Answer 21

A brain activity recording technique that measures the small magnetic fields generated by neuronal electrical activity.

Question 22

List:

The TWO advantages and TWO limitations of TMS.

(Trasncranial Magnetic stimulation)

Answer 22

Advantages:
- Reversible.
- No surgery required.

Limitations:
- All cells in the region get stimulated/inhibited.
- Mostly limited to cortical areas.

This also applies to electrical stimulation.

Question 23

List:

The TWO advantages and FOUR limitations of chemical injections.

(Local and/or Systemic)

Answer 23

Advantages:
- Reversible.
- Relatively selective.

Limitations:
- Short-term effects.
- Non-brain regions may be affected with systemic applications.
- Involves surgery.
- Only used with animals so far.

Question 24

List:

The advantage and limitation of genetic alterations.

(In studying the brain).

Answer 24

Advantage:
- Aids in deducing the origins of mental disorders.

Limitation:
- Mutations occur everywhere from conception onwards.

Question 25

List:

The FIVE key types of ‘manipulations’ in studying the brain.

Answer 25

• Damage (‘spontaneous’ or induced).
• Direct stimulation (electrical or magnetic).
• Drug injections (systemic or local).
• Genetic alterations (spontaneous or induced).
• Optogenetics.

Question 26

List:

The advantage and limitation of optogenetics.

Answer 26

Advantage:
- Precise and localised activation/inhibition of neuron populations.

Limitation:
- Complex technique requiring surgery and genetic manipulation.

Question 27

Define:

PET

(Positron-Emission Tomography)

Answer 27

A functional brain imaging technique that utilises radioactively tagged chemicals injected into the bloodstream and records their radioactive emissions to give high resolution images of activity.

Activity can include blood flow to certain regions, metabolic activity, regional chemical composition, absorption, etc.

Question 28

List:

The advantage and limitation of microscopic imaging.

(When studying the brain)

Answer 28

Advantage:
- Very high resolution for a wide range of subjects of measurement.

Limitation:
- Must be completed post-mortem for proper effects.

Question 29

List:

The TWOadvantages and TWO limitations of electric imaging.

Answer 29

Advantages:
- High temporal resolution (records as fast as cells fire).
- Synchrony (measure multiple regions simultaneously).

Limitations:
- Average activity of millions of neurons.
- Cortical regions mostly (without surgical/invasive methods).

Question 30

Compare & Contrast:

Structural vs.functional MRI.

(Magnetic Resonance Imaging)

Answer 30

• Both: use magnetic fields to measure changes/responses in brain chemicals.
• fMRI records changes in blood-flow and concentration of oxygentated haemoglobin in certain regions during cognitive activities.
• Regular MRI records energy released from hydrogen in water molecules ‘swinging back’ to their original tilt/orientation to generate images of detailed anatomical structure.

Question 31

What is an important step required to get meaningful insights from fMRI?

Answer 31

Measuring a comparison task alongside the experimental task and recording the difference in regional activity between the two.

An example provided by Kalat’s Biological Psychology textbook includes an experimental task being people reading a passage, and then getting them to perhaps read another passage in a foreign language as the comparison task.

This would activate visual pathways, but not necessarily the same structures used for language-comprehension.

Question 32

The TWOadvantages and THREE limitations of magnetic imaging.

(i.e. structural and functional MRI)

Answer 32

Advantages:
- Reasonably high spatial resolution.
- Ability to record structural and functional information.

Limitations:
- Comparatively low temporal resolution.
- Measures correlations between regions and activities only.
- No insights on neurotransmitters.

Question 33

The TWOadvantages and FOUR limitations of chemical imaging.

(i.e. PET)

Answer 33

Advantages:
- Reasonable spatial resolution.
- Ability to record structural and functional information.

Limitations:
- Low temporal resolution.
- Requires radioactive ligands to be synthesised.
- Expensive.
- Exposure of the brain to radioactivity.

Question 34

Which TWO imaging techniques have the highest temporal resolution?

(Use this as a hint if needed)

(Note: ‘LM’ and ‘EM’ are ‘Light Microscopy’ and ‘Electron Microscopy’ respectively).

Answer 34

EEG
&
MEG

(Electroencephalography & Magnetoencephalography)

Question 35

Which TWO imaging techniques have the highest spacial resolution?

(Use this as a hint if needed)

(Note: ‘LM’ and ‘EM’ are ‘Light Microscopy’ and ‘Electron Microscopy’ respectively).

Answer 35

LM
&
EM

(Light microscopy & Electron Microscopy)

Question 36

Define:

SPECT

(Single Photon Emission Computerised Tomography)

Answer 36

A three-dimensional brain imaging technique that involves detecting gamma rays emitted by a radioactive isotope ‘probe’.

It is similar to MRI in the sense of using radioactively tagged chemicals and detects blood flow to certain areas of the brain.

Question 37

In New Zealand, what is one of the first steps you must take in order to conduct animal research?

Answer 37

Receive approval from the AEC.

(Animal Ethics Committee)

Some key figures comprising the committee are usually a layperson, an SPCA representative, and an independent veterinarian.

Question 38

List:

The three ‘R’s that NZ animal ethics guidlines are based upon.

Answer 38

• Refinement
• Reduction
• Replacement

The final replacement goal is a major one for most scientists.

Question 39

True or False:

fMRI can be used to infer someone’s psychological processes.

Answer 39

True

But only under very limited/controlled circumstances - don’t worry, scientists can’t effectively read your mind (yet)!

Question 40

What does fMRI measure?

Answer 40

It detects increased blood supply to more highly active brain region, and the slower rise in proportion of oxygen-lacking haemoglobin in the area afterwards.

Both indicate increased oxygen supply being provided to neurons in the region to carry out their functions.

Question 41

Define:

CAT/CT Scan

(Computerised Axial Tomography)

Answer 41

A brain imaging technique that involves taking a series of x-rays at each angle over 180 degrees, and then compiling these into one overall image.

First a dye is injected into the patient’s blood though to increase contrast.

These kinds of scans are often used to detect tumours or abnormalities in structures.

Question 42

Define:

Phrenology

Answer 42

An antiquated neuroanatomical pseudoscience relating skull anatomy to behaviour/personality.

This derives from the 1800s, and is largely attributed to Franz Joseph Gall.