Lesson 3 - Ways of studying the brain

Question 1

What are 2 non-invasive ways of studying the brain?

Answer 1

C(A)T scans
MRI scans

Question 2

What is a C(A)T scan?

Answer 2

A computer assisted x-ray procedure where the x-ray scanner is rotated 1 degree at a time over 180 degree.
Images are stitched together to form 3d image.
Tomograms reveal structural abnormalities eg lesions caused by trauma or stroke or cortical atrophy

(Rotating x-ray)

Question 3

What is a tomogram?

Answer 3

A tomogram is the horizontal slices of the 3D images to look more in detail to reveal structural abnormalities in the brain

Question 4

What is an MRI Scan?

Answer 4

A strong magnetic field (up to 3 tesla) causes hydrogen nuclei (protons) to align in the same orientation.
(magnetic resonance imaging)
when a radio frequency is passed thru head, protons emit electro magnetic energy as they ‘relax’
MRI scanner is tuned to detect radiation emitted as protons relax

Question 5

in an MRI scanner, different tissues produce different types of what?

Answer 5

signals

eg
grey matter has little water so produces different signals and will move back/push back quickly, white matter has more water so hydrogen magnets will flip back slowly

Question 6

Without needing to crack open head to look inside of it, what are the two methods to study the brain?

Answer 6

fMRI scans
EEG & ERPS

Question 7

What is an fMRI scanner?

Answer 7

Oxygen and glucose are supplied by the blood as fuel for the brain
Brain doesn’t store fuel, blood supply changes as needs arise and the changes are regionally specific - following the local dynamics of neuronal activity within that region

Question 8

What do fMRI scans show?

Answer 8

Where functional activity occurs

Question 9

What is BOLD and what does it rely on

Answer 9

Blood Oxygen Level Dependent signal is the signal that relies on the difference between the haemoglobin that has oxygen and the haemoglobin that doesnt have oxygen

Question 10

What does an EEG do? (Electroencephalography)

Answer 10

Records the electrical activity of the brain
Using a net of electrodes placedo n the scalp (up to 256)

Question 11

What are 2 strengths of using an EEG and one weakness of using an EEG?

Answer 11

High temporal resolution
Less expensive than MRI scanner
Poor spatial resolution due to recordings being made at the scalp - hard to figure out exactly where in brain the activity is coming from

Question 12

What is an ERP? (Event related potential)

Answer 12

Look immediately afterwards how the brain responds to receiving a signal such as stimuli. Background EEG signal is removed by trial averaging revealing the response of a brain region to stimuli.
Portions of the EEG are time averaged together, extract the neural signature for the event

Question 13

What are the invasive methods of studying the brain?

Answer 13

Electrophysiological Techniques (Intracellular recording and Extracellular recording)

Stimulation techniques - electrical stimulation and Optogenetics

Question 13

What do ERP waveforms tell us info about?

Answer 13

The neural basis of processing is provided by the difference in activity

Question 13

What is Intracellular recording and what is Extracellular recording

Answer 13

A form of Electrophysiological techniques

Intracellular recordings place electrode directly into cell recording individual cells in animal brains
Extracellular recordings record the activity of the brain by having an electrode sit just outside the cell and pick up on the cell firing an action potential

Question 13

What is electrical stimulation

Answer 13

Using electricity, we can artificially activate the cell or turn on the cells

Question 14

What is Optogenetics?

Answer 14

Allows us to have some control over the brain activity
Neurons can be turned on or off and become sensitive to light by using the rodoxin / opsin gene to produce either polarisation (produced w light off/blue light) or hyperpolarisation (light on / yellow light)

Question 15

What is the assessment of species common behaviours?

Answer 15

Open field tests (grooming in chunking sequence behaviours)

rats groom from head to ears to body

Question 16

Aggression in rats is observed and loser feels a consequence

Answer 16

Species specific stressor

Intruder tends to be defeated and they experience the species specific stressor which
increase of stress w defeat

Question 17

what is the relation between social defeat and drug addiction?
(social defeat paradigm)

Answer 17

The way you respond to stress becomes how likely youll become addicted to drugs
There is an interaction between stress and the way drugs are metabolised by the body

social defeat ^ stress ^ response to drug^

Question 18

What are the 2 conditioning paradigms ?

Answer 18

Classical conditioning paradigm and operant conditioning paradigm

Question 19

What is place preference in addiction?

Answer 19

How classical conditioning can be used to test whether a drug is nice

test it on rats
give animal drug in the side it doesnt like and saline in the one it likes and see how much longer the animal spends in the bit it doesnt like
associates the bit it doesnt like w the drug

Question 20

How can you use operant conditioning to train rats?

Answer 20

Train rat to learn chunking behaviour (press down left then right bar to get food)

Question 21

What is a semi natural paradigm?

Answer 21

Halfway point between the lab experiment and an experiment involving the natural outside world

Question 22

What is an example of a semi natural paradigm?

Answer 22

Morris Water Maze

Question 23

What is the morris water maze?

Answer 23

A semi - natural learning paradigm
Tank filled w water (milk makes it opaque) and this tests spatial memory as a plank is put in the tank and the rat is put in and has to find the plank submerged in the water/

Question 24

What is spatial learning?

Answer 24

Learning due to cues in env

Question 25

How can you measure the spatial learning done by the rat?

Answer 25

Escape latency
Spatial transfer test

Question 26

What is escape latency?

Answer 26

How long it takes animal to find platform after putting it in

Question 27

What is spatial transfer test?

Answer 27

Do trial like normal but then take away platform and see where the animal spends most of its time swimming around (will show the animal learnt where the platform prev was)

Question 28

What are both the escape latency and spatial transfer test disrupted by?

Answer 28

Lesions in the hippocampus

hippocampus involved in spatial learning of the env

Question 29

What is a field observation?
(evolution) gene behaviour relationship

Answer 29

Observation of animal in natural context

Question 30

What 3 things can be observed of animal in field observations?

Answer 30

Aggression,

Social dominance,

Courtship display

Question 31

Why are animals aggressive?

Answer 31

there is a social organisation where animals are polygynous - competition between males for females > leading to intra-sexual aggression

aggression between members of the same sex
can occur in red deer stags in autumn rut

Question 32

What is a consequence of social dominance?

Answer 32

Common feature of social organisation of animals is dominant and submissive individuals

consequence has often negative consequences for reproductive success

Question 33

What is courtship display?

Answer 33

The effort put in by males to attract females , females choosy ab which males to mate w