P1 - Biological Approach - Brain and Behaviour

Question 1

what does localisation of function mean?

Answer 1

specific parts of the brain are responsible for specific behaviours or cognitive processes

Question 2

what is the study used for localisation of function?

Answer 2

Maguire et al (2000)

Question 3

what does the hippocampus control?

Answer 3

• critical memory formation
• helps consolidate or reorganise and stabilise memory

Question 4

what is the aim of Maguire et al (2000)

Answer 4

to investigate the brains of London taxi drivers and if the structure of their hippocampus would be different due to spatial memory

Question 5

why were london taxi drivers used in Maguire et al (2000)

Answer 5

because they undergo an intensive training programme on how to navigate the city and have to pass a set of exams to be licensed.

Question 6

what was the procedure of Maguire et al (2000)

Answer 6

16 right handed male taxi drivers, their average experience as a driver was 14.2 years

MRI brain scans of control subjects were taken from a databased

subjects below 32 and above 62 were excluded, females, left handed were eliminated

this meant comparison sample was 50 healthy right-handed male subjects who did not drive a taxi

Question 7

what were the findings of Maguire et al (2000)

Answer 7

increased brain matter volume in the brains of taxi drivers

control subjects had greater volumes of grey matter in the anterior hippocampus.

no significant difference between general volume of hippocampus, but significant distribution of grey matter from anterior to posterior hippocampus in the brains of taxi drivers

Question 8

What was the conclusion of Maguire et al (2000)?

Answer 8

The researchers concluded that spatial memory is localised to the hippocampus as the taxi drivers, who have to remember large amounts of information, had bigger parts of the posterior hippocampus.

Link back: environmental stimulus in the form of intense spatial memory of taxi drivers, led to an increase in density in the posterior hippocampus.

Question 9

What is neuroplasicity?

Answer 9

Brains ability to rearrange the connections between its neurons as a result of learning or experience

Question 10

Explain the process of neuroplasicity

Answer 10

• every time we learn something new, neurons repeatedly fire, this is known as long-term potentiation
• leads to an increase in dendritic branching
• dendrites of the neurons grow in numbers and connect with other neurons
• leads to increased number of synapses
• more synapses - stronger the pathway
• when a synapse is not used, it may go through synaptic pruning
• this is our body’s way of maintaining more efficient brain function as we get older and learn more complex information

Question 11

What study do we use for neuroplasicity?

Answer 11

Maguire et al (2000)

Question 12

How is maguire linked to neuroplasicity?

Answer 12

Environmental stiumulus in the form of the intense spatial memory of taxi drivers, led to an increase in density in the posterior hippocampus through the process of dendritic branching.

This shows that not everyone’s brain is not the same and that individuals neural networks can change based on environmental inputs.

Question 13

what is a neurotransmitter?

Answer 13

chemicals that allow neurons to communicate with each other

Question 14

what is an excitatory neurotransmitter?

Answer 14

neurotransmitters which make the target neuron more likely to “fire” an action potential

Question 15

what is an example of an excitatory neurotransmitter?

Answer 15

glutamate

Question 16

what is glutamate?

Answer 16

• one of the most common neurotransmitters
• facilitates neural connections and the “turning on” of neurons

Question 17

what is an inhibitory neurotransmitter?

Answer 17

neurotransmitters which make the target neuron less likely to “fire”

Question 18

what is an example of an inhibitory neurotransmitter?

Answer 18

serotonin as it has inhibitory effects on neurons, decreasing the likelihood of neurons firing an action potential.

it does not stimulate the brain, but balances out the excessive effects of other neurotransmitters

Question 19

what is serotonin??

Answer 19

inhibitrory neurotransmitter

• plays a role in emotion, sleep and memory
• links to mood disorders such as depression

Question 20

what is an agonist molecule?

Answer 20

any chemical that binds to a receptor site on a post-synaptic neuron causing the neuron to fire

Question 21

what is an antagonist molecule?

Answer 21

any substance that fits into a receptor site on the post-synaptic neuron, inhibiting the neuron

Question 22

what is ketamine?

Answer 22

high doses - glutamate antagonist, its an excitatory neurotransmitter that facilitates neural network connection making it an anaesthetic

low doses - ketamine acts as a glutamate agonist, enhances stimulation of AMPA glutamate receptors

Question 23

what study do we use for agonist molecules?

Answer 23

siegel et al 2021

Question 24

what study do we use for antagonist molecules?

Answer 24

arnone et al 2013

Question 25

what study do we use for inhibitory neurotransmitters?

Answer 25

arnone et al 2013

Question 26

what study do we use for excitatory neurotransmitters?

Answer 26

siegel et al 2021

Question 27

what is the aim of siegel et al 2021

Answer 27

to investigate the effiacy of a longer infusion of ketamine in regard to reducing depressive symptoms and link to neural network activity

Question 28

what is the procedure of siegel et al 2021

Answer 28

- University of Washington School of Medicine - 23 individuals from treatment resistant depression - 27 matched non-depressed controls MADRS at baseline, 24hrs, 2 weeks, 8 weeks and resting state fMRI

Question 29

what were the findings of Siegel et al 2021

Answer 29

participants had significantly reduced scores ketamine - decrease in hyperconnectivity within limbic system and increase in connectivity between limbic system and frontal areas smaller right hippocampus at baseline had largest reduction

Question 30

what was the conclusion of Siegel 2021

Answer 30

infusion of ketamine provides a sustained response and normalises depression related hyperconnectivity in the limbic system and frontal lobe

Question 31

link siegel to excitatory and agonist questions

Answer 31

- demonstrates how glutamate has a role in encouraging neurogenesis and treating depression. Participants demonstrated increased connectivity between limbic system and frontal lobe as ketamine would have increased levels of glutamate excitatory - facilitates neural network connections and turning 'on' neurons resulting in decrease of depressive symptoms agonist - ketamine caused neurons to fire encouraging production and passing of glutamate receptors in the brain

Question 32

what was the aim of arnone 2013

Answer 32

to investigate the role of SSRIs in neurogenesis and role in reducing symptoms of depression

Question 33

what was the procedure of arnone 2013

Answer 33

lab experiment uni of manchester 64 unipolar depressed participants with half having citalopram and half not compared to 66 healthy controls all had MRI scans to measure grey matter concentration in hippocampi

Question 34

what were the findings of arnone 2013

Answer 34

after 8 weeks, participants with depression who were assigned to the citalopram had an increase in grey matter and decrease in depressive symptoms

Question 35

what was the conclusions of arnone 2013

Answer 35

citalopram increases grey matter which correlates with a decrease in depressive symptoms

Question 36

link arnone with inhibitory/antagonist molecules

Answer 36

inhibitory - serotonin in SSRIs are inhibitory neurotransmitters decreasing the neurons will fire actiion potential. it balances out excessive excitatory effects antagonist - inhibits neurons to fire, which stops reuptake of transmitter leaving more available in the synaptic gap

Question 37

what are MRIs used for?

Answer 37

- creating detailed images of human body - used in research to measure brain structure and function - can be used to diagnose strokes, tumours etc

Question 38

how does the human body work?

Answer 38

- human body is mostly water - protons become aligned in a magnetic field - MRI scanner applies a strong magnetic field which aligns the protons 'spins' - scanner produces a radio frequency - protons absorb this from the magnetic field and flip their spins - when field is off, protons return to normal spin called precession - return process produces a radio signal that can be measured

Question 39

what study do we use for scanning?

Answer 39

Maguire 2000

Question 40

link scanning to Maguire

Answer 40

- provides evidence for both neuroplasicity and localisation of function - achieved through comparison of MRIs between taxi drivers and control group - can be inferred the differences in the hippocampi could be attributed to the use of spatial memory by studying change in structure through MRI