Paper 2: Biopsychology

Question 1

What is the CNS?

Answer 1

• CNS consists of the brain + the spinal cord.
• brain provides conscious awareness + is involved in all psychological processes.
• The brain consists of many regions, which are responsible for different functions. e.g. brain consists of four main lobes: frontal lobe, parietal lobe, temporal lobe and occipital lobe.
• occipital lobe processes visual information; temporal lobe processes auditory information; parietal lobe integrates information from the different senses and therefore plays an important role in spatial navigation;the frontal lobe is associated with higher-order functions, including planning, abstract reasoning and logic.
• The brain stem connects the brain and spinal cord and controls involuntary processes i.e. heartbeat, breathing and consciousness.
• The role of the spinal cord is to transfer messages to and from the brain, and the rest of the body.
• The spinal cord is also responsible for simple reflex actions that do not involve the brain.

Question 2

What is the PNS?

Answer 2

• role of peripheral nervous system (PNS) is to relay messages (nerve impulses) from the CNS (brain and spinal cord) to the rest of the body.
• The PNS consists of two main components:
  1) the somatic nervous system (SNS)
  2) the autonomic nervous system (ANS)
• SNS facilitates communication between the CNS and the outside world.
• SNS is made up of sensory receptors that carry information to the spinal cord and brain, and motor pathways that allow the brain to control movement.
• role of SNS is to carry sensory information from the outside world to the brain and provide muscle responses via the motor pathways.
• ANS plays an important role in homeostasis, which maintains internal processes like body temperature, heart rate and blood pressure.

Question 3

What are the two subdivisions of the ANS and their roles?

Answer 3

consists of motor pathways and has two components:

1) the sympathetic nervous system
2) the parasympathetic nervous system

• sympathetic nervous system typically involved in responses that prepare the body for fight/flight.
• Impulses travel from the sympathetic nervous system to organs in the body to help us prepare in dangerous situation. e.g. heart rate, blood pressure and breathing rate increase, while less important functions like digestion, salivation + desire to urinate are suppressed.
• The role of the parasympathetic nervous system is to relax the body, and return us to our ‘normal’ resting state.
• slows down our heart rate and breathing rate, and reduces our blood pressure.
• any functions that were previously slowed down during a fight or flight reaction are started again (e.g. digestion).

Question 4

Identify and explain the two features of the central nervous system.

Answer 4

• One feature is the brain. The brain is responsible for coordinating sensation, intellectual and nervous activity.
• Another feature is the spinal cord. This is a bundle of nerve fibres enclosed within the spinal column and which connects nearly all parts of the body with the brain.

Question 5

Identify and explain the two features of
the peripheral nervous system.

Answer 5

• One feature is the somatic nervous system. This is responsible for carrying sensory and motor information to and from the CNS.
• A second feature is the autonomic nervous system. This is self-regulating and governs the brain’s involuntary activities e.g. stress and heartbeat.

Question 6

What are neurons?

Answer 6

• Cells that conduct nerve impulses are called neurons

Question 7

Draw/describe diagram of a neuron

Answer 7

Question 8

What’s the role of Dendrites?

Answer 8

• communicate with other neurons

Question 9

What is the role of an Axon?

Answer 9

• Where the electrical signals pass from.

Question 10

What does the Myelin sheath do?

Answer 10

Insulates/protects the axon from external influences that might affect transmission of the nerve impulses down the axon.

Question 11

What is the role of the synaptic terminals

Answer 11

Terminal buttons send signals to an adjacent cell from the axon.

Question 12

What are the three different types of neurons?

Answer 12

Motor, Sensory and Relay

Question 13

What is the function of a motor neuron?

Answer 13

Carries messages from the CNS to effectors such as mucles and glands.

Question 14

What is the function of a relay neuron?

Answer 14

Transfers messages from sensory neurons to other relay neurons or motor neurons

Question 15

What is the function of a sensory neuron?

Answer 15

Carries messages from the PNS to the brain and spinal cord.

Question 16

Length of fibres of motor neurons?

Answer 16

Short dendrites and long axons

Question 17

Length of fibres of relay neurons?

Answer 17

Short dendrites and short axons

Question 18

Length of fibres of sensory neurons?

Answer 18

Long dendrites and short axons

Question 19

What are neurotransmitters?

Answer 19

• Chemicals released from synaptic vesicle into the synapse by neurons. - affect the transfer of an impulse to another nerve or muscle - neurotransmitters taken back up to terminal buttons of neurons through process of reuptake

Question 20

What is the synapse?

Answer 20

The gap between the end of one neuron and the dendrites of the next neuron.

Question 21

Describe the process of synaptic transmission.

Answer 21

• Information is passed down the axon of the neuron as an electrical impulse known as action potential.
• Once the action potential reaches the end of the axon it needs to be transferred to another neuron or tissue. It must cross over a gap between the pre-synaptic neuron and post-synaptic neuron – which is known as the synaptic gap.
• At the end of the neuron (in the axon terminal) are the synaptic vesicles which contains chemical messengers, known as neurotransmitters.
• When the electrical impulse (action potential) reaches these synaptic vesicles, they release their contents of neurotransmitters.
• Neurotransmitters then carry the signal across the synaptic gap.
• They bind to receptor sites on the post-synaptic cell that then become activated.
• Once the receptors have been activated, they either produce excitatory or inhibitory effects on the post-synaptic cell.

Question 22

Describe excitatory and inhibitory effects.

Answer 22

• Some neurotransmitters make the neuron more negatively charged so less likely to fire = inhibitory effect e.g. serotonin. Other neurotransmitters increase the positive charge so make the neuron more likely to fire = excitatory effect. E.g. Adrenalin which is both a neurotransmitter and a hormone has an excitatory effect.

Question 23

Localisation of function:

Holistic theory replaced by localisation theory?

Answer 23

• early 19th centruy holistic theory suggested that all parts of brain were involved in processing though and action.
• But specific areas of the brain were later linked with sepcifc phsycial and pscychological functions (location theory)
• If an area of brain is damaged through illness or injury, the function associated with that area is also affected.

Question 24

Localisation of the brain:

Brain is divided into two hemispheres and lateralised?

Answer 24

• Lateralisation - some physical and psychological functions are controlled by a particular hemisphere.
• Generally, the left side of body is controlled by right hemisphere, vice versa

Question 25

Localisation of function:

Outer layer of brain is called the cerebal cortex?

Answer 25

• The cerebal cortex is lik a ‘tea cosy’ covering the inner part of the brain. About 3mm thick and is what seperates us frm lower animals as it is highly developed.
• Cortex appears grey due to the location of cell bodies - hence the phrase ‘grey matter’

Question 26

Localisation of function:

Cerebal cortex of both hemispheres is divided into four lobes. What are they?

Answer 26

• Frontal lobe
• Parietal lobe
• Occipital lobe
• Temporal lobe

Question 27

Localisation of function:

Name four areas of the brain and their functions.

Answer 27

• Motor area = back of frontal lobe for both hemps. Controls voluntary movement. Damage may result in loss of control over fine motor movements.
• Somatosensory area = Front of parietal lobes. Processes sesnory infp. from skin e.g. touch, heat. Amount of somatosensory area devoted to particular boy part denotes its sensitivity.
• Visual area = Occipital lobe at back of brain. Each eye sends info. from right visual field to left visual cortex, and from left visual field to right visual cortex.
• Audiroty area = temproal lobe. Analyses speech based info. Damage may produce partial hearing loss, more extensive damage, more serious the loss.

Question 28

The language centres: Broca’s area?

Answer 28

• Speech production.
• Identified by Broca in 1880s, left frontal lobe
• Damage to this area causes Broca’s aphasia which s characterised by speech that is slow, laborious and lacking in influency. Broca’s patients may have diffculty fidning words and naming certain objects.

Question 29

The language centres: Wernicke’s area

Answer 29

• Language understanding
• Identified by Wernicke in the 1880s, left temporal lobe
• People with Wernicke’s aphasia produce language but have problems understanding it. Fluent, meaningless language.
• often produce nonsense words (neologisms)

Question 30

(AO3)

Critiscm for localisation?

Answer 30

P - THE CLAIM THAT FUNCTIONS ARE LOCALISED TO CERTAIN AREAS OF THE BRAIN HAS BEEN CRITICISED.

E/E - LASHLEY PROPOSED THE EQUIPOTENTIALITY THEORY, WHICH
SUGGESTS THAT THE BASIC MOTOR AND SENSORY FUNCTIONS ARE LOCALISED, BUT THAT HIGHER MENTAL FUNCTIONS ARE NOT. HE CLAIMED THAT INTACT AREAS OF THE CORTEX COULD TAKE OVER RESPONSIBILITY FOR SPECIFIC COGNITIVE FUNCTIONS FOLLOWING BRAIN INJURY.

L - THIS THEREFORE CASTS DOUBT ON THEORIES ABOUT THE LOCALISATION OF FUNCTIONS, SUGGESTING THAT FUNCTIONS ARE NOT LOCALISED TO JUST ONE REGION, AS OTHER REGIONS CAN TAKE OVER SPECIFIC FUNCTIONS FOLLOWING BRAIN INJURY.

Question 31

(AO3)

Case studies supporting Broca’s and Wernicke’s areas?

Answer 31

P - THERE IS A WEALTH OF CASE STUDIES ON PATIENTS WITH DAMAGE TO BROCA’S AND WERNICKE’S AREAS THAT HAVE DEMONSTRATED THEIR FUNCTIONS.

E/E - E.G. BROCA’S APHASIA IS AN IMPAIRED ABILITY TO
PRODUCE LANGUAGE; IN MOST CASES, THIS IS CAUSED BY BRAIN DAMAGE IN BROCA’S AREA. WERNICKE’S APHASIA IS AN IMPAIRMENT OF LANGUAGE PERCEPTION.

L - THIS IS DEMONSTRATING THE IMPORTANT ROLE PLAYED BY THIS BRAIN REGION IN THE COMPREHENSION OF LANGUAGE.

COUNTER:

HOWEVER, ALTHOUGH THERE IS EVIDENCE FROM CASE STUDIES TO SUPPORT THE FUNCTION OF THE BROCA’S AREA AND WERNICKE’S AREA, MORE RECENT RESEARCH HAS PROVIDED CONTRADICTORY EVIDENCE.

DRONKERS ET AL. (2007) CONDUCTED AN MRI SCAN ON TAN’S BRAIN, TO TRY TO CONFIRM BROCA’S FINDINGS. ALTHOUGH THERE WAS A LESION FOUND IN BROCA’S AREA, THEY ALSO FOUND EVIDENCE TO SUGGEST OTHER AREAS MAY HAVE CONTRIBUTED TO THE FAILURE IN SPEECH PRODUCTION.

THESE RESULTS SUGGEST THAT THE BROCA’S AREA MAY NOT BE THE ONLY REGION RESPONSIBLE FOR SPEECH PRODUCTION AND THE DEFICITS FOUND IN PATIENTS WITH BROCA’S APHASIA COULD BE THE RESULT OF DAMAGE TO OTHER NEIGHBOURING REGIONS.

Question 32

(AO3)

Focus how brains communicate instead of regions>

Answer 32

P - FURTHERMORE, PSYCHOLOGISTS SUGGEST THAT IT IS MORE IMPORTANT TO INVESTIGATE HOW THE BRAIN AREAS COMMUNICATE WITH EACH OTHER, RATHER THAN FOCUSING ON SPECIFIC BRAIN REGIONS.

E - WERNICKE CLAIMED THAT ALTHOUGH THE DIFFERENT AREAS OF THE BRAIN ARE INDEPENDENT, THEY MUST INTERACT WITH EACH OTHER IN ORDER TO FUNCTION.

E- AN EXAMPLE TO DEMONSTRATE THIS IS A MAN WHO LOST HIS ABILITY TO READ, FOLLOWING DAMAGE TO THE CONNECTION BETWEEN THE VISUAL CORTEX AND THE
WERNICKE’S AREA, WHICH WAS REPORTED BY DEJERINE.

L - THIS SUGGESTS THAT INTERACTIONS BETWEEN DIFFERENT AREAS PRODUCE COMPLEX BEHAVIOURS SUCH AS LANGUAGE. THEREFORE, DAMAGE TO THE CONNECTION BETWEEN ANY TWO POINTS CAN RESULT IN IMPAIRMENTS THAT RESEMBLE DAMAGE TO THE LOCALISED BRAIN REGION ASSOCIATED WITH THAT SPECIFIC FUNCTION. THIS REDUCES THE CREDIBILITY OF THE LOCALISATION THEORY.

Question 33

(AO3)

Localisation fail to take into account indivudal diff?

Answer 33

P- FINALLY, SOME PSYCHOLOGISTS ARGUE THAT THE IDEA OF LOCALISATION FAILS TO TAKE INTO ACCOUNT INDIVIDUAL DIFFERENCES.

E/E- HERASTY (1997) FOUND THAT WOMEN HAVE PROPORTIONALLY LARGER BROCA’S AND WERNICKE’S AREAS THAN MEN

L- THIS CAN PERHAPS EXPLAIN THE GREATER EASE OF LANGUAGE USE AMONGST WOMEN.

COUNTERARGUMENT- HOWEVER, THIS SUGGESTS A LEVEL OF BETA BIAS IN THE THEORY: THE DIFFERENCES BETWEEN MEN AND WOMAN ARE IGNORED, AND VARIATIONS IN THE PATTERN OF ACTIVATION AND THE SIZE OF AREAS OBSERVED DURING VARIOUS LANGUAGE ACTIVITIES ARE NOT CONSIDERED.

Question 34

Discuss localisation of function in the human brain (16 marks)

Answer 34

DISCUSS LOCALISATION OF FUNCTION IN THE HUMAN BRAIN (16 MARKS).

Localisation of function refers to..

Each part of the brain serves a specific function. The main divisions of it are… Name and
explain the purpose of each, as well as where it’s located in the brain.

A03 1: THE CLAIM THAT FUNCTIONS ARE LOCALISED TO CERTAIN AREAS OF THE BRAIN HAS BEEN CRITICISED- explain the equipotentiality theory

A03 2: THERE IS A WEALTH OF CASE STUDIES ON PATIENTS WITH DAMAGE TO BROCA’S AND WERNICKE’S AREAS THAT HAVE DEMONSTRATED THEIR FUNCTIONS. Explain and add a counterargument.

A03 3: PSYCHOLOGISTS SUGGEST THAT IT IS MORE IMPORTANT TO INVESTIGATE HOW THE BRAIN AREAS COMMUNICATE WITH EACH OTHER, RATHER THAN FOCUSING ON SPECIFIC BRAIN REGIONS. add a counterargument.

A03 4: FINALLY, SOME PSYCHOLOGISTS ARGUE THAT THE IDEA OF LOCALISATION FAILS TO TAKE INTO ACCOUNT INDIVIDUAL DIFFERENCES.

Question 35

What is Hemisphereic lateralisation?

Answer 35

• The brain is lateralised i.e. two sides

Question 36

What does localised mean?

Answer 36

• Some functions are localised and appear in both left and right hems.
• e.g. auditory, visual, motor, somatosensory areas

Question 37

What is localised and lateralised?

Answer 37

• Two main language centres are in LH, Broca’s area, Wernicke’s
• RH produces rudimentary words, but provides emotional context. LH may be analyser, RH synthesiser

Question 38

What is contralateral?

Answer 38

• motor area, RH controls left side body and vice versa

Question 39

What is contralateral and ipsilateral?

Answer 39

• LVF of both eyes is connected to RH and vice versa
• Enables visual areas to compare slightly diffferent perspective from each eye and aids depth perception
• Same arrangement for auditory areas.

Question 40

Desbribe Sperry (1968) split-brain research.

Answer 40

• Aim: The aim of their research was to examine the extent to which
  the two hemispheres are specialised for certain functions.
• Method: An image/word is projected to the patient’s left visual field
  (which is processed by the right hemisphere) or the right visual field
  (which is processed by the left hemisphere). When information is
  presented to one hemisphere in a split-brain patient, the information
  is not transferred to the other hemisphere (as the corpus callosum is
  cut).
• Sperry conducted many different experiments, including describe what you see tasks, tactile tests, and drawing tasks.
• In the describe what you see task, a picture was presented to either the left or right visual field and the participant had to simply describe what they saw.
• In the tactile test, an object was placed in the patient’s left or right hand and they had to either describe what they felt, or select a similar object from a series of alternate objects.
• Finally, in the drawing task, participants were presented with a picture in either their left or right visual field, and they had to simply draw what they saw.

Findings:

• Object shown to RVF: Particpant can describe what is seen
• Object shown to LVF: Particpant name object, slect matching object behind screen using left hand, select object closely associated with pic. and pinup pic shown to LVF, participant giggled but reported seeing nothing.

Demonstrates how certain functions are lateralised, LH verbal and RH ‘silent’ but emotional.

Question 41

(AO3)

Split-brain research

Answer 41

P- It is assumed that the main advantage of brain lateralisation is that it increases neural processing capacity (the ability to perform multiple tasks simultaneously).

E- Rogers et al. (2004) found that in a domestic chicken, brain lateralisation is associated with an enhanced ability to perform two tasks simultaneously (finding food and being vigilant for predators). Using only one hemisphere to engage in a task leaves the other hemisphere free to engage in other functions.

L- This provides evidence for the advantages of brain lateralisation and demonstrates how it can enhance brain efficiency in cognitive tasks.

CP: However, because this research was carried out on animals, it is impossible to conclude the same of humans. Unfortunately, much of the research into lateralisation is flawed because the split-brain procedure is rarely carried out now, meaning patients are difficult to come by. Such studies often include very few participants, and often the research takes an idiographic approach. Therefore, any conclusions drawn are representative only of those individuals
who had a confounding physical disorder that made the procedure necessary. This is problematic as such results cannot be generalised to the wider population.

Question 42

(AO3)

Research suggest lateralisation changes age?

Answer 42

P- Research has suggested that lateralisation changes with age.

E/E- Szaflarki et al. (2006) found that language became more lateralised to the left hemisphere with increasing age in children and adolescents, but after the age of 25, lateralisation decreased with each decade of life.

L- This raises questions about lateralisation, such as whether everyone has one hemisphere that is dominant over the other and whether this dominance changes with age.

Question 43

(AO3)

Could be argued language not restricted to left hem?

Answer 43

P- It could be argued that language may not be restricted to the left hemisphere.

E/E- Turk et al. (2002) discovered a patient who suffered damage to the left hemisphere, but developed the capacity to speak in the right hemisphere, eventually leading to the ability to speak about the information presented to either side of the brain.

L- This suggests that perhaps lateralisation is not fixed and that the brain can adapt following damage to certain areas.

Question 44

(AO3)

Split-brain rarley carried out?

Answer 44

P- A further limitation of the research into split-brain research is that the split-brain procedure is rarely carried out nowadays.

E/E- Andrewes has pointed out that may studies are presented with as few as three pps or sometimes just one. They’ve claimed that conclusions are sometimes drawn from participants who either have a confounding physical disorder that made the split-brain procedure necessary, or have had a less complete sectioning of the two hemispheres that was originally believed.

L- As a result, patients who have had this procedure without these confounding factors are rarely encountered in sufficient numbers to be useful for research.

CP: however, despite the fact that the sample size is small, all patients are studies in a lot of detail, as this metod allows a researcher to investigate this area (split-brain research) in far more detail than might be possible if they were trying to deal with a large number of research participants. Because of their in-depth, multi-sided approach case studies often shed light on aspects of human thinking and behavior that would be unethical or impractical to study in other ways.

Question 45

What is brain plastcity and functional recovery?

Answer 45

• Brain plasticity refers to the brain’s ability to change and adapt
  because of experience.
• Functional recovery is the transfer of functions from a
  damaged area of the brain after trauma to other undamaged areas.

Question 46

(AO1) - Describe research into brain plasticity.

Answer 46

• Davidson et al. demonstrated the permanent change in the brain generated by prolonged meditation: Buddhist monks who meditated frequently had a much greater activation of gamma waves (which coordinate neural activity) than did students with no experience of meditation.
• This study highlights the idea of plasticity and the brain’s ability to adapt as a result of new experience, in this case meditation.

Question 47

AO1 for functional recovery?

Answer 47

Following physical injury or other forms of trauma such as infection or the experience of a
stroke, unaffected areas are sometimes able to adapt or compensate for those areas that are
damaged. The functional recovery that occurs in these cases is an example of neural plasticity. Neuro scientists suggest that this can happen quickly after trauma (spontaneous recovery) and then slow down after several weeks or months. Therapy may then be needed.

The brain is able to rewire and reorganise it’s self by forming new synaptic connections close to the area of damage. Secondary neural pathways that would not typically be used to carry out certain functions are ‘unmasked’ to enable functioning to continue. This process is supported by a number of structural changes.

Question 48

(AO3)

Research support for plasticity from human studies?

Answer 48

P- There is research support from human studies regarding plasticity.

E/E- Maguire et al (2000) studied the brains of London taxi drivers using an MRI and found significantly more
grey matter in the posterior hippocampus than in the matched control group. This part of the brain is
associated with the development of spatial and navigational skills in humans and other animals. As part of
their training London Cabbies must take a complex test called ‘the knowledge’, which assesses their recall of
the city streets and possible routes. It is also noteworthy that the longer they had been doing the job the
more pronounced was the structural difference (a positive correlation).

L- This not only shows that that hippocampal volume was greater in those individuals with job-related
experience of spatial navigation, but also that the highest levels of plasticity were evident in those with more
extensive experience.

Counterargument: However, some psychologists suggest that research investigating the plasticity of the brain
is limited. For example, Maguire’s research is biologically reductionist and only examines a single biological
factor (the size of the hippocampus) in relation to spatial memory. This approach is limited and fails to take
into account all of the different biological/cognitive processes involved in spatial navigation which may limit
our understanding. Other psychologists suggest that a holistic approach to understanding complex human
behaviour may be more appropriate.

Question 49

(AO3)

Research support plasiticty from animal studies?

Answer 49

P- Further support for the brain’s ability to change as a result of experience comes from animal studies.

E/E- Kempermann et al found evidence of an increased number of new neurons in the brains of rats housed in complex environments compared to rats housed in lab cages.

L- This suggests that one’s environment can have an effect on the brain’s ability to change.

Counterargument:However, animals have been used, so generalising the results to humans is rather difficult.

Question 50

(AO3)

Support for brains ability for functional recovery?

Answer 50

P- Support for the brain’s ability to functionally recover after trauma comes from animal studies.

E/E- Tajiri et al (2013) provided evidence for the role of stem cells in recovery from brain injury. They randomly assigned rats with traumatic brain injury to one of 2 groups. One group received transplants of stem cells into the region of the brain affected by traumatic injury. The control group received a solution infused into the brain containing no stem cells. Three months after the brain injury, the brains of stem cell rats showed clear development of neuron-like cells in the area of injury. This was accompanied by a solid stream of stem cells migrating to the brain’s site of injury. This was not the case with the control group.

L- This provides support for the important role played by stem cells in recovering from brain injury.

Question 51

(AO3)

Ability of functional recovery deteriote with age?

Answer 51

P- While there is evidence for functional recovery, it is possible that this ability can deteriorate with age.

E/E- Elbert et al. concluded that the capacity for neural reorganisation is much greater in children than in adults, meaning that neural regeneration is less effective in older brains. This may explain why adults find change more demanding than do young people.

L- Therefore, individual differences must be considered when assessing the likelihood of functional recovery in the brain after trauma.

Question 52

Describe an fMRI.

Answer 52

Functional magnetic resonance imaging (fMRI) is a brain-scanning technique that measures blood flow in the brain when a person performs a task. fMRI works on the premise that neurons in the brain that are the most active during a task use the most energy.

Energy requires glucose and oxygen. Oxygen is carried in the bloodstream attached to haemoglobin (found in red blood cells) and is released for use by these active neurons, at which point the haemoglobin becomes deoxygenated.

Deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin.

An fMRI can detect these different magnetic qualities and can be used to create a dynamic (moving) 3D map of the brain, highlighting which areas are involved in different neural activities.

fMRI images show activity approximately 1-4 seconds after it occurs and are thought to be accurate within 1-2 mm.

An increase in blood flow is a response to the need for more oxygen in that area of the brain when it becomes active, suggesting an increase in neural activity.

Question 53

Evaluate fMRI.

Answer 53

• Invasive or Non-Invasive: An advantage of fMRI is that is non-invasive. Unlike other scanning techniques, for example Positron Emission Tomography (PET), fMRI does not use radiation or involve inserting instruments directly into the brain, and is therefore virtually risk-free. Consequently, this should allow more patients/participants to undertake fMRI scans which could help psychologists to gather further data on the functioning human brain and therefore develop our understanding of localisation of function.
• Spatial Resolution: fMRI scans have good spatial resolution. Spatial resolution refers to the smallest feature (or measurement) that a scanner can detect, and is an important feature of brain scanning techniques. Greater spatial resolution allows psychologists to discriminate between different brain regions with greater accuracy. fMRI scans have a spatial resolution of approximately 1-2 mm which is significantly greater than the other techniques (EEG, ERP, etc.) Consequently, psychologists can determine the activity of different brain regions with greater accuracy when using fMRI, in comparison to when using EEG and/or ERP.

Question 54

Describe EEG.

Answer 54

• An electroencephalogram (EEG) works on the premise that information is processed in the brain as electrical activity in the form of action potentials or nerve impulses, transmitted along neurons.
• EEG scanners measure this electrical activity through electrodes attached to the scalp. Small electrical charges detected by the electrodes are graphed over a period of time, indicating the level of activity in the brain.
• There are four types of EEG patterns including alpha waves, beta waves, theta waves and delta waves.

Question 55

Describe ERP.

Answer 55

• Event-Related Potentials (ERP) use similar equipment to EEG, electrodes attached to the scalp. However, the key difference is that a stimulus is presented to a participant (for example a picture/sound) and the researcher looks for activity related to that stimulus. However, as ERPs are difficult to separate from all of the background EEG data, the stimulus is present many times (usually hundreds), and an average response is graphed. This procedure, which is called ‘averaging’, reduces any extraneous neural activity which makes the specific response to the stimulus stand out.
• The time or interval between the presentation of the stimulus and the response is referred to as latency. ERPs have a very short latency and can be divided into two broad categories. Waves (responses) that occur within 100 milliseconds following the presentation of a stimulus are referred to as sensory ERPs, as they reflect a sensory response to the stimulus. ERPs that occur after 100 milliseconds are referred to as cognitive ERPs, as they demonstrate some information processing.

Question 56

Evaluate ERP and EEG.

Answer 56

• Invasive or Non-Invasive: An advantage of EEG and ERP is that both techniques are non-invasive. Unlike other scanning techniques, such as Positron Emission Tomography (PET), EEG and ERP do not use radiation or involve inserting instruments directly into the brain and are therefore virtually risk-free.
• Furthermore, EEG and ERP are much cheaper techniques in comparison with fMRI scanning and are therefore more readily available. Consequently, this should allow more patients/participants to undertake EEG/ERPs, which could help psychologists to gather further data on the functioning human brain and therefore develop our understanding of different psychological phenomena, such as sleeping, and different disorders like Alzheimer’s.
• Temporal Resolution: An advantage of the EEG/ERP technique is that it has good temporal resolution: it takes readings every millisecond, meaning it can record the brain’s activity in real time as opposed to looking at a passive brain. This leads to an accurate measurement of electrical activity when undertaking a specific task. o However, it could be argued that EEG/ERP is uncomfortable for the participant, as electrodes are attached to the scalp. This could result in unrepresentative readings as the patient’s discomfort may be affecting cognitive responses to situations. fMRI scans, on the other hand, are less invasive and would not cause the participants any discomfort, leading to potentially more accurate recordings.
• ERP: However, ERPs enable the determination of how processing is affected by a specific experimental manipulation. This makes ERP use a more experimentally robust method as it can eliminate extraneous neutral activity, something that other scanning techniques (and EEG) may struggle to do.