brain and neuro

Question 1

Explain the function of the nervous system

Answer 1

• Collects, processes and responds to information from the environment
• Coordinate the working of the different organs and cells in the body

Question 2

Outline the function and structure of the Central Nervous System

Answer 2

• The CNS division consists of the brain and spinal cord
• It coordinates incoming information and makes decisions about movement and other activity
• The brain is divided into two hemispheres each controlling the opposite side of the body

Question 3

Outline the function and structure of the Peripheral Nervous System

Answer 3

• The PNS receives messages from the CNS and sends messages to it
• It is divided into the Somatic Nervous System and the Autonomic Nervous System
• The SNS controls voluntary muscle movement and takes in sensory info from the eyes and skin
• The ANS acts involuntarily, coordinating important functions for life, like breathing and heart rate, and it is also responsible for the stress response

Question 4

Explain/outline the ANS’ response to stress (fight or flight)

Answer 4

• When a person experiences a threatening or stressful situation, the body responds with a flight or fight response
• This is an evolutionary adaptive mechanism enabling us to react quickly
  FIGHT OR FLIGHT RESPONSE TO STRESS
• When faced with a threat, the amygdala is activated
• It associates sensory signals with emotions
• A signal is then sent to the hypothalamus which uses the sympathetic nervous system to communicate with the rest of the body
  RESPONSE TO ACUTE STRESS
• When is SNS is triggered it sends a signal to the adrenal medulla which releases adrenaline into the blood streams
• Adrenaline causes the heart to beat faster, pushing more blood into the muscles and vital organs, increasing blood pressure too
• Increased breathing rates gets more oxygen into the blood stream
• Pupils dilate and non-essentials like digestion shut down
  THE PARASYMPATHETIC NERVOUS SYSTEM
• When the threat has passed the PNS branch of the autonomic nervous system dampens down the stress response and returns the body to homeostasis
• The PNS causes the heart rate to slow down and reduces blood pressure and reactivates any non-essential systems that were shut down eg. digestion

Question 5

Outline and evaluate the James-Lange theory of emotion

Answer 5

• William James noticed how the fight-flight reaction happens. He gave the example of tripping as you go down the stairs, and saving yourself from falling by grabbing the banister. Your reaction happens very quickly, but afterwards you feel your heart speeding up, your breathe deeply, and you start sweating - in short, arousal kicks in. James said that it is then that you begin to feel scared. You experience the changes felt by your body and interpret these as emotion. James believed that our emotions are really us perceiving physical changes in the body. The brain makes sense of these changes by concluding that we are feeling certain emotions. This theory led to a number of studies investigating different aspects of this idea
  
  • A weakness of this theory is that other researchers have not been convinced that the theory is an accurate explanation of how we experience emotional arousal. This is especially the case because for the theory to be correct, there would have to be separate and distinctive patterns of psychological arousal - a different pattern for each emotion, which is not something researchers have found. Therefore, this decreases the validity of the theory
  • Another weakness is that the two factor theory of emotion criticizes James-Lange because it suggests we also need social cues to correctly label the emotion we are feeling - eg. A racing heart could be a threat situation or a romantic one. The two factor theory explains how we can interpret the same physical state in very different ways, whereas the James Lange theory overlooks this, hence decreasing the validity of the theory
• A strength of this theory is that there are real life examples of emotions following physiological arousal such as phobias - eg. A person may trip in public which leads to an emotional reaction like anxiety or embarrassment. This then may lead to them avoiding public situations due to associations between the situation and the emotion being formed. Therefore, this supports the theory increasing its reliability

Question 6

Explain the process of synaptic transmission

Answer 6

• Electrical signals travel to the end of the presynaptic neuron (this is known as action potential)
• The signal reaches the terminal button
• Vesicles release a chemical called neurotransmitter
• Neurotransmitter crosses the synaptic cleft
• Receptor sites on the postsynaptic neuron take up the neurotransmitter
• Chemical message is turned back into an electrical impulse
• Electrical impulse travels along postsynaptic neuron
• Any neurotransmitters left behind in the synaptic cleft are broken down and reabsorbed
• The effect of a neurostransmitter on a postsynaptic neuron is either excitatory or inhibitory
• An example of an excitatory neurostransmitter is adrenalin
• This increases the postsynaptic neurons positive charge, which makes it more likely to fire
• An example of an inhibitory neurostransmitter is serotonin
• This increases the negative charge of the postsynaptic neuron, which makes it less likely to fire

Question 7

Outline and evaluate Hebb’s theory

Answer 7

• Hebb suggested that when we learn, our brain changes, neural pathways expand, and connections become stronger
• He said the brain is like plastic because it is not fixed in structure but constantly developing and changing
• When you learn something new, it leaves a trace in the brain called an engram. An engram is like a sparkler because it will fade as the spark dies out. However, unlike a sparkler the trace the learning makes can be made permanent by practising and rehearsing that thing
• This is done through cell assemblies
• Cell assemblies are collections of groups of neurons that fire across the neural pathways, leading to stronger more efficient synoptic connections
• To describe this, Hebb said ‘cells that fire together, wire together’
• One weakness of Hebb’s theory is that it is reductionist. This means it explains learning in terms of neurons only. This is a weakness because learning is a complicated activity that involves a range of levels and understanding. This reduces the validity of Hebbs theory as it fails to consider a range of factors
• A strength of the theory is that it has real world application to education. Originally a school headmaster, Hebb believed that a rich and stimulating environment leads to more cell assemblies growing to learn. He found that raising rats in this environment were way better at finding their way through a maze. This could be applied to education by creating more stimulating environments to encourage learning
• A weakness of Hebbs theory is that it was developed in the 1950s. This is a weakness because, since then, there have been many more psychological advancements as well as improvement in science and technology. Hence, this reduces the validity of the theory

Question 8

• Outline and evaluate Penfield’s study of the interpretative cortex

Answer 8

• The aim of the study was to investigate the workings of the conscious mind
• The experimental method was a lab experiment
• Patients with epilepsy laid on the operating table conscious
• Local anaesthetic was used
• Penfield stimulated different parts of the brain using the montreal procedure, and recorded the patients’ response
• Stimulation of the temporal lobe made one patient report that he heard the piano playing and could even name the song
• When a different place was stimulated, the patient reported clear memory
• As a control, the surgeon told the patient he was about to stimulate again but didn’t turn on the electrodes, after a pause, the patient reported nothing
• Penfield concluded that there was clear evidence for localisation of function in the cerebral cortex and that the temporal lobe is active in interpreting meaning.

Question 9

Outline the different types of scanning

Answer 9

CT scan
- Large doughnut shaped scanner rotates around the person to take lots of X rays of the brain
- Computed Tomography
- Useful for revealing abnormal structured like tumors
- Quality of images produced is higher than x rays
- Required more radiation than X rays
- Only produces still images

PET scan
- Patient is injected with a radioactive substance like glucose
- Brain activity shown on a computer screen
- Positron Emission Tomography
- Shows brain in action
- Shows localisation of function when person is asked to perform a specific task
- Expensive
- Images difficult to interpret
- Ethical issues due to the injection of radioactive substance

FMRI scan
- Measure changes in blood oxygen levels in the brain
- Brain activity displayed as 3D images placed on a screen
- Functional magnetic resonance imaging
- Shows brain in action
- Clear images
- No radiation
- Expensive
- Person must stay very still
- Time lag between activity and image appearing

Question 10

Define cognitive neuroscience

Answer 10

• the study of how cognitive processes connect with brain activity and structure
• one aim of cognitive neuroscience is to create a detailed map of the brain so that we can understand the relationship between the brain and cognitive processes

Question 11

Explain how the structure of the brain is related to behavior

Answer 11

We know that different structures within the brain control different behaviors, eg. the frontal lobe contains the motor cortex which controls movement on the opposite side of the body. The amygdala in the temporal lobe plays a key role in processing emotions like fear, and has even been linked to agression.

Question 12

Explain how the structure of the brain relates to cognition

Answer 12

Cognition refers to the mental processes of the brain eg. memory and perception. Tulving’s studies have shown that different aspects of memory are located in different parts of the brain.

Question 13

Outline and evaluate Tulving’s Gold Mine study

Answer 13

• Aim was to investigate the connections between types of memory and brain activity
• 6 volunteers including Tulving himself and his wife, were injected with a small amount of radioactive gold
• Once the substance reached the brain, a PET scan was used to measure the blood flow to different areas of the brain
• The study compared episodic memory (eg. something they had experienced personally) to semantic memory (eg. facts they learnt from a book).
• Each participant performed 8 trials - 4 episodic and 4 semantic in a random order
• A repeated measures design was used as participants took part in all conditions
• Clear differences in blood flow were found
• When participants were thinking of episodic memories, there was greater flow of blood to the frontal and temporal lobe
• Semantic memories resulted in greater activation of the occipital and parietal lobes
• Tulving’s study suggests that episodic and semantic memories are separate forms of long-term memory. It also seems likely that these types of memory are located in different parts of the brain. This would support the idea that memory has a biological basis, and that different types of memory are localised in different areas of the brain
• A strength is that the study produced scientific evidence.
  It used evidence from brain scans that is difficult to fake, unlike other psychological investigations where you can be less sure that participants are behaving genuinely.
  This means that Tulving produced unbiased evidence.
• A weakness is the participants used. Only six participants including Tulving were used and differences in blood flow for episodic and semantic memories were seen in only three participants. This means the results were inconclusive.
• A weakness is that episodic and semantic memories are
  often very similar. Memories for personal events also contain facts and knowledge about the world so it is difficult to work out which type of memory is being studied. This may explain why the evidence from Tulving’s study was inconclusive.