Chapter 3 - 'First Brain Experiments'

Question 1

Under what circumstances is ‘ablation’ acceptable on humans?

E.g?

Answer 1

If the patient is in a life or death situation

E.g cancerous tumour

Question 2

Give examples of Pierre Flouren’s findings due to brain ablation.

Answer 2

Established the brain stem was responsible for respiration.

Established that the cerebellum was responsible for coordination.

Established the ‘holistic’ view of brain function.

Question 3

BONUS QUESTION!!!

Why was Flourens criticised?

Answer 3

His surgical procedures were believed to be imprecise.

He did not write detailed reports on his research.

Question 4

What does brain ‘ablation’ involve?

What is consequently followed by ablation?

Answer 4

Brain ablation involves the disabling, destroying or removing of selected brain tissue.

Subsequent change in behaviour.

Question 5

How was ‘ablation’ approached?

AKA?

Answer 5

Ablation was most often done in scalpel cuts, most often referred to as ‘lesioning’ as it caused irreversible damage to the brain.

Question 6

What does ‘ESB’ stand for?

What does ESB involve?

Answer 6

Electrical Stimulation of the Brain

ESB is the procedure where electrical signals are transmitted throughout the brain, consequently involving the stimulation of a specific area of the brain.

Through a small, electrified fine wire or disc. (Electrode)

Question 6

What was the first ESB experiment conducted on?

Briefly explain what occurred?

Answer 6

Within the motor cortex of a dog.

It triggered distinct responses in the opposite side of the body.

Question 7

BONUS QUESTION!!!

What did Penfield uncover using ESB?

Answer 7

Penfield mapped the entire cerebral cortex using ESB

Question 8

Briefly summarise the split brain experiment?

What it does it combat?

Answer 8

The disconnection of the left and right hemispheres through severing the corpus callosum.

Combats life threatening epileptic seizures.

Question 9

How did Sperry prove that the split brain experiments had impairments to brain function?

Answer 9

Patient was put in front of a screen with a black dot in the centre.

Patients were told to stare at the black dot, images or words were quickly flashed either on the right or left side.

If flashed on the right, split brain patients would accurately recall seeing the image or words whilst if the image was flashed on the right, patients would not be able to accurately recall what they had seen or in some cases deny seeing anything.

To ensure patients could actually see the image or word presented on the left, several items that represented the image or word were hidden and accessible through a hole, the patient would be able to identify the word or image through feeling the hidden object.

Question 10

What are the two neuroimaging categories?

How do they differ?

Answer 10

Structural and functional.

Structural refers to techniques that provide scans showing brain structure and anatomy.

Functional refers to techniques that provide views of some particular aspect of brain function through showing images of the brain ‘at work’.

Question 11

I’m what ways does neuroimaging overcome previous restraints?

Answer 11

Neuroimaging overcomes the ethical constraints in studying the live, intact brain.

This is due to it being relatively non invasive.

Question 12

What does CAT, MRI, PET and fMRI stand for?

Answer 12

Computerised Axial Tomography

Magnetic Resonance Imaging

Positron Emission Tomography

functional Magnetic Resonance Imaging

Question 13

How do CAT's gather a scan of the brain?
How is the brain portrayed in the scan?
What are they used for?
Example?
How do they compare to other types?

Answer 13

CAT scans use X Ray’s and a substance called contrast in order to highlight the brain’s blood vessels.

The brain is portrayed as a horizontal cross section.

CAT scans are used to identify brain abnormalities

An example is a cancerous tumour.

CAT scans are not as preferred as MRI’s, they are slower and require more effort to achieve the same quality MRI’s give.

Question 14

How do MRI's gather a scan of the brain?
How is the brain portrayed in the scan?
What are they used for?
Example?
How do they compare to other types?

Answer 14

MRI’s use harmless magnetic fields to vibrate atoms in the brains neurons. The patient must stay still.

The brain is portrayed as a 360 view. Can be portrayed in colour.

They are used for identifying brain abnormalities.

An example are blood clots and tissue degeneration.

They are faster, more detailed and precise compared to CAT scans.

Question 15

How do PET's gather a scan of the brain?
How is the brain portrayed in the scan?
What are they used for?
Example?
How do they compare to other types?

Answer 15

PET’s track a glucose solution filled with radioactive tracers in order to achieve its image.

The brain is seen as a variation of colours, depicting areas of most activity.

PET scans are used to record the level of activity in different areas of the brain whilst the patient carries out a specific activity.

Example is reading.

PET scans are less detailed than fMRI’s

Question 16

How do fMRI's gather a scan of the brain?
How is the brain portrayed in the scan?
What are they used for?
Example?
How do they compare to other types?

Answer 16

fMRI’s detects and records brain activity by measuring oxygen consumption across the brain.

The brain is portrayed as a variation of different colours, warmer ones showing areas of more activity.

They are used to obtain information on brain activity during an activity.

E.g reading a book

fMRI’s are more precise and detailed, they can scan images in rapid succession and also do not need any type of radioactive tracer.