Psychology- Brain and Neuropsychology

How is the nervous system organised?

NS → CNS & PNS, PNS → Somatic NS & Autonomic NS, ANS → Sympathetic division & Parasympathetic division

What is each part of the CNS responsible for?

CNS- Decision-making, basic functions and carrying messages
PNS- Relays info to and from CNS through actions of neurons. Carries out all actions and conserves energy

SNS- Takes info. from sense organs and controls voluntary movement of muscles also reflexes
ANS- Homeostasis and involuntary responses such as breathing

Sympathetic division- flight or fight response and a state of psychological arousal
Parasympathetic division- Rest and digest response- works in opposition to sympathetic to keep body in balance. Maintains and restores energy

How is the Fight or flight response stimulated?

Hypothalamus identifies stressor (threat)
Instructs sympathetic division of ANS to act
ANS changes from resting state to arousal
Adrenaline released from adrenal gland into blood stream

Changes as a result of fight or flight response

Dilation of pupils
Increased heart and breathing rate
Slow digestion
Tensed muscles
Sweaty palms but dry mouth

Describe James-Lange Theory of Emotion

Event → Arousal → Interpretation → Emotion

Psychological arousal- Event activates hypothalamus which instructs hypothalamus, Leads to release of adrenaline creating psychological arousan. Experienced increase of bodily activity

Emotions afterwards: Brain interprets these changes, Result of interpretation is emotion

No physical changes/unnoticed = no emotion, Physical changes first then emotion

Evaluate James-Lange Theory of Emotion

+ Emotional states follow physiological change in cases such as phobias. Person may fall over and become anxious which leads to avoidance of public situations due to link between situation and emotion. Suggest emotion occurs result of situation

- Disconnecting nerves that tell brain what’s going on doesn’t prevent emotional response. Emotion not only based on bodily response
- Injection of adrenaline doesn’t lead to experience of emotion when people expect the change

What are the 3 types of neurones and their function

Sensory neurones- carry messages from PNS to the CNS (long dendrites, short axons)

Motor neurones- carry messages from CNS to effectors eg. muscles (short dendrites, long axons)

Relay neurones- Connect two other types of neruones (short dendrites, short axons)

How does communication between neurons happen

Very fast rate
Neurons send signals to one another to communicate through electrical and chemical signals
One neurone connected up to 10,000 other neurons
Billions of neurons in the nervous system

What happens in Electrical neurotransmission for stimulated neurons?

When a neuron fires, Electrical impulse passes along axon which is insulated by a myelin sheath.
Increases speed of impulses and also has noids of Ranvier that make the signal go even faster.
At the end of axon, there are terminal buttons which communicate with next neuron across synaptic cleft

What happens in synaptic transmission

Electrical signal travels down axon to terminal button
Vesicles move to presynaptic membrane
Vesicles bind to membrane and release neurotransmitter into synpatic cleft
Neurotransmitters diffuse across synaptic cleft
Receptor sites on postsynaptic neuron take up neurotransmitter
Neurotransmitter left behind diffuses away or broken down by enzymes
Taken either increases (excitatory) or decreases (inhibitory) likelihood of next neuron firing

Define Neuroplasticity

Neuroplasticity- Brain’s ability to change and reorganise. Form new neural connections and changes strength of existing ones

What was Hebb’s Postulate

When excitatory link between 2 neurons is used repeatedly, it gets stronger/more efficient
Cells that fire together, wire together

Key features of Hebb’s Postulate

Neuroplasticity
Cell assemblies fire together, making synaptic connections stronger (neuronal growth)
New learning causes brain to adapt in structure and connections
Engrams- learning leaves trace in brain which can be made permanent if we keep practising

Evaluate Hebb’s theory

+ Scientific + objective, raises psychology’s status as a science. Led to increased focus on brain as basis for behaviour
+ Research shows Taxi drivers have bigger posterior hippocampi but smaller anterior compared to non-taxi drivers. Show evidence of neuroplasticity
+ Application to education- creates more stimulating environments to encourage learning

- Reductionist theory- reduces learning to activity of brain cells but there are other things that may affect it eg. cognitive factors

What is each part of the brain responsible for

Frontal lobe- Speaking, voluntary motor activity, higher processes “planning and thinking”
Temporal lobe- Understanding language, hearing (auditory cortex)
Parietal lobe- Sensation and somatosensory area: receives info from sense organs
Occipital lobe- Vision, processing visual information
Motor area- Controls movement
Cerebellum- Balance, coordination of voluntary movement, fine movements

Difference between Broca’s and Wernicke’s area

Broca’s area- Producing speech
Wernicke’s area- Understanding speech

Define “Localisation"

Localisation- specific parts of the brain responsible for specific behaviours and certain functions

Define The “Montreal Procedure”

Montreal Procedure- Patients remained awake and described reactions whilst surgeons stimulated diff. areas of brain by using an electrode

Describe Penfield’s interpretative cortex study

Over 1000 case studies where patients remained awake whilst surgeon probed diff. areas of the cortex using gentle electrical stimulation and asked patients to report what they experienced

Produced Qualitative results eg. 1 person had temporal lobe stimulated and reported they could hear a piano playing and identify the song.
Stimulation of motor and sensory areas produced movements or sensations of being touched

Concluded evidence for localisation of function

Evaluate Penfield’s interpretative cortex study

+ Demonstrated how certain areas of cerebral cortex involved in particular functions of the brain.
+ His study successfully isolated precise area where patient’s memories were triggered and he re-tested same area over, increasing reliability

- Patients were epileptic so not representative of general population. Epilepsy may havechanged structure and functions of their brains in some way
-Results diff for each person so hard to generalise findings. Research didn’t always support original findings eg. only 40/520 ppts recalled past experiences when temporal lobe stimulated. May lack validity as interpretative cortex doesn’t always respond in same way

Define cognitive neuroscience

Cognitive neuroscience- How mental processes and brain activity/structures are connected/influence one another

What is a CT scan and advantages/disadvantages

Brain examined by large number of x-rays
Person lies inside donut-shaped scanner
Scanner rotated around body and images taken from many diff. angles
Images each cross-section of brain, gives very detailed picture when put together

+ Can reveal abnormal structures in brain such as tumours
+ Quality of image higher than that of traditional X-rays

-Requires more radiation than x-rays. Can’t be used on same person often
- Only provides structural info. and nothing about brain activity

What is a PET scan and advantages/disadvantages

Person injected with small amount of radioactive substance
Substance taken up by brain, areas most active absorb it
Info sent to computer; red and yellow areas more active than blue areas

+ Shows brain in action which is useful for psychological research
+ Shows localisation of function eg. solving a puzzle and linked area identified

-Extremely expensive so not easily available
- Results difficult to interpret. Scans on people doing same task shows diff brain activity
- Ethical issues for injections of radioactive glucose. Only used a few times

What is a fMRI scan and advantages/disadvantages

Measure change in blood oxygen levels in the brain
More active areas use more oxygen so blood directed to that area in brain
Haemodynamic response picked up through radio signals which produce 3D image

+ Shows important info about areas being used at any time
+ Doesn’t use radiation so safer than other two
+ Images extremely clear and can show brain activity to the mm

- Very expensive so not easily available
- Only effective if person stays perfectly still which may be a problem
- 5-second time lag between brain activity and image appearing. Can cause interpretation problems

What are the effects of a stroke

When brain deprived of oxygen because of disruption to blood supply, specific areas affected will die. Effects may not be permanent if other parts of brain take over localised functions

What are the effects of neurological damage on motor ability

Damage to motor area can lead to person struggling with fine and complex movements
Damage to left hemisphere affects right side of body and vice versa

What are the effects of neurological damage on behaviour

Can lead to “aphasia”
Broca’s aphasia- problems producing speech
Wernicke’s area- problems understanding speech

Describe Tulving’s “Gold” Study

6 ppts injected with radioactive gold which went into brain
Ppts underwent 8 trials- 4 semantic (eg. recall historical fact), 4 episodic (eg. recall past memory) in a repeated measures design
Ppts think about topic when signalled and blood flow monitored
Active brain areas show up on PET scan as blood flow measured

Parietal lobe responsible for semantic memory
Frontal lobe responsible for episodic memory
Different types of memory activate different parts of brain

Evaluate Tulving’s “Gold” Study

+ Produced scientific evidence as used brain scans that are difficult to fake. Other investigations you’re less sure if ppts behaving genuinely. Tulving produced unbiased evidence.

- Low population validity- only 6 ppts where 3/6 produced clear results. Inconclusive results and also not representative of general population. Conclusions drawn may not affect everyone
- Episodic and semantic memories often similar. Memories for personal events contain facts and knowledge so difficult to work out which type of memory being studies. May explain why evidence from Tulving’s study was inconclusive