Biopsychology

Question 1

Describe the nervous system

Answer 1

central nervous system
- brain
- spinal cord
peripheral nervous system
- autonomic nervous system, governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
- somatic nervous system, governs muscle movement and receives information information from sensory receptors

Question 2

Describe the endocrine system

Answer 2

• made up of glands that produce hormones
• these hormones affect cells in more than one organ, leading to diverse and powerful responses
• the pituitary gland controls the release of hormones from all the other endocrine glands in the body

Question 3

Describe how the endocrine and autonomic nervous systemic systems work together during fight or flight

Answer 3

• a stressor is perceived by senses and the hypothalamus activates the pituitary gland and triggers activity in the sympathetic branch of the ANS
• the body is then in a physiologically aroused state

adrenaline - released from the adrenal medulla into the blood triggering physiological changes in the body creating the arousal necessary for fight or flight
Immediate and automatic - happens very quickly and causes a sick feeling in the stomach
parasympathetic action - returns the body to its resting state

Question 4

what are the biological changes during fight or flight

Answer 4

increases heart rate
increases breathing rate
dialates pupils
inhibits digestion
inhibits saliva production
contracts rectum

Question 5

what is the structure of a neuron

Answer 5

cell body with nucleus
dendrites
axon
myelin sheath
nodes of ranvier
terminal buttons

Question 6

where are the neurons located

Answer 6

motor - cell bodies located near the CNS and the axons form part of the PNS
sensory - PNS in clusters known as ganglia
relay - within the brain and visual system

Question 7

what causes an electrical transmission

Answer 7

when the inside of the neuron becomes positively charged from its negatively charged resting state, stimulating an action potential

Question 8

explain the process of synaptic transmission

Answer 8

an action potential reaches the synaptic knob of the presynaptic neuron and causes vesicles containing neurotransmitters to be released into the synaptic cleft. the neurotransmitters then diffuse across the cleft and bind to complementary receptors
neurotransmitters can either be excitatory or inhibitory, making the post synaptic either more or less likely to fire
the action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold

Question 9

Explain localization of function in the brain

Answer 9

localization versus holistic theory
- Broca and Wernicke argue for localization of function, the idea that different parts of the brain perform different tasks and are involved with different parts of the body
- holistic suggests that all parts of the brain are involved in the processing of thought and action

Hemispheres of the brain
- left side of the brain controls the right side of the body
- right side of the brain controls the left side of the body

The motor, somatosensory, visual and auditory centers
- the motor cortex is in the frontal lobe and controls voluntary movement
- the somatosensory area is in the parietal lobe and is where sensory information from the skin is represented
- the visual area is the occipital lobe
- the auditory area is located in the temporal lobe and analyzes speech based information

The language centers of the brain
- Brocas area is responsible for speech production. damage to it causes brocas aphasia where speech is slow and lacking in fluency
- wernickes area is responsible for language understanding. damage to it causes wernickes aphasia where nonsense words are produced as part of the content of their speech

Question 10

Evaluate localization of function in the brain

Answer 10

Strengths
Evidence from neurosurgery
- Dougherty reported on 44 people with OCD who had undergone a cingulotomy
- at post-surgical follow up after 32 weeks, 30% had met the criteria for successful response to the surgery and 14% for partial response
- this suggests that behaviors associated with serious mental disorders may be localized

Evidence from brain scans
- Petersen used brain scans to demonstrate how wernickes area was active during a listening task and brocas area was active during a reading task
- buckner and petersen revealed that semantic and episodic memories reside in different parts of the prefrontal cortex
- however, lashley removed areas of the cortex in rats that were learning the route through a maze
- no area proved to be more important than others in terms of the rats ability to learn the route, and therefore learning required every part of the cortex rather than a specific area
- this suggests high cognitive processes like learning are not localized but distributed in a more holistic way

Limitation
Language localization questioned
- Dick and Tremblay found that only 2% of researchers think that language is soley controlled by broca and wernicke
- fMRI and other imaging techniques have shown that language is distributed far more holistically in the brain than thought
- therefore, rather than being confined to a couple of key areas, language might be holistically organized

Question 11

Explain hemispheric lateralization

Answer 11

Left and right hemispheres
- the two language centers are located in the LH, so language is lateralized to the left side
- therefore the RH can only produce rudimentary words and phrases but contributes emotional context
- vision, motor, and somatosensory areas appear in both hemispheres, but are cross-wired, so the RH controls the left side of the body and the LH control the right side of the body
- for sight, the left visual fields of the eyes go to the RH and the right visual fields go to the LH

Question 12

Describe split brain research

Answer 12

Sperry
- 11 people who had a split brain operation
- because the corpus callosum was severed, information could not be passed between hemispheres
- when a picture of an object was shown in the RVF, the person could describe the object, but not if shown in the LVF
- however, they could select a matching object out of sight using their left hand
- if a pinup picture was shown to the LVF there was an emotional reaction, but the participants reported as having seen nothing
- therefore, this shows that certain functions are lateralized in the brain and support the view that the LH is verbal and the RH is ‘silent’ but emotional

Question 13

Evaluation of hemispheric laterization

Answer 13

Strength
Lateralization in the connected brain
- Fink used PET scans to identify which areas of the brain were active during a visual processing task
- when they looked at the global elements of an image, regions of the RH were more active
- when looking at specific details, the LH dominated
- this suggests hemispheric lateralization is a feature of the connected brain as well as split brain
Limitation
One brain
- there may be different functions in the LH and RH, but people don’t have a dominant side which determines their personality
- Nielsen analyzed brain scans from over 1000 people aged 7-29 years and did find that people used different hemispheres for different tasks, however there was no evidence of a dominant side
- therefore the notion of right or left brained people is wrong

Question 14

Evaluation of split brain reseach

Answer 14

Strength
Research support
- Gazzinga showed that split brain participants actually performed better than connected on certain tasks, such as identifying the odd one out in an array of similar objects
- therefore this supports that the ‘left brain’ and ‘right brain’ are distinct

Limitation
Generalization issues
- none of the participants in the control group had epilepsy, and this is a confounding variable, as any differences may have been due to the epilepsy rather than the split brain

Question 15

Describe plasticity of the brain after trauma

Answer 15

• the brain has the ability to change throughout life
• during infancy, there is rapid growth of synaptic connections peaking at about 15000 at 2-3 years, which is twice as many as there are in an adult brain
• rarely used connections are deletes and frequently used ones are strengthened, ie, synaptic pruning
• synaptic pruning enables lifelong plasticity where new neural connections are formed in response to new demands on the brain

research into plasticity
- maguire studied the brains of london taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group
- this part of the brain is associated with the development of spatial and navigational skills in humans and other animals
- she found that learning the knowledge of the streets alters the structure of the taxi drivers’ brains and the longer they had had the job, the more pronounced the structural difference, suggesting a positive correlation
- draganski imaged the brains of medical students three months before and after final exams
- learning induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex

Question 16

Evaluation of plasticity of the brain after trauma

Answer 16

Limitation
Negative Plasticity
- brains adaptation to prolonged drug use leads to poorer cognitive functioning later in life and an increased risk of dementia
- 60-80% of amputees have been known to develop phantom limb pain, which is unpleasant
- therefore the ability to readapt is not always a good thing

Strength
Age and plasticity
- Bezzola demonstrated how 40 hours of golf training produced changes in the neural productions of movement in participants aged 40-60
- using fMRI, researchers observed reduced motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training, showing that plasticity can continue throughout the lifespan

Question 17

Explain functional recovery of the brain after trauma

Answer 17

after brain trauma
- an example of neural plasticity as healthy brain areas may take over the functions of those areas that are damaged, destroyed or even missing
- this can happen quickly after trauma, and then slow down after several weeks or months, where the individual may require rehabilitative therapy to further recovery

What happens in the brain during recovery
- axonal sprouting - the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
- denervation supersensitivity - occurs when the axons that do a similar job become aroused to a higher level to compensate, however can have a negative consequence, pain neurons
- recruitment of homologous areas - if broca’s area was damaged on the left side of the brain, the right side equivalent would carry out its function

Question 18

Evaluation of functional recovery of the brain after trauma

Answer 18

Strength
Real world application
- encourages new therapies to be tried
- constraint-induced movement therapy is used with stroke patients whereby they repeatedly practice using the affected part of their body while the unaffected one is restrained
- therefore useful as it helps medical professionals know when interventions need to be made

Limitation
Cognitive reserve
- Schneider revealed that the more time people with a brain injury had spent in education, the greater their chance of a disability free recovery
- 40% of those who achieved DFR had more than 16 years of education compared to about 10% of those who had less than 12 years education
- this implies that people with brain damage who have less of a cognitive reserve are less likely to achieve full recovery

Question 19

Describe functional magnetic resonance imaging

Answer 19

detects changes in blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain, producing a 3D image showing parts of the brain

Question 20

Evaluation of fMRI

Answer 20

Strengths
- doesn’t rely on radiation
- non-invasive and risk free
- provides a clear detailed picture of brain activity

Limitation
- expensive
- poor temporal resolution, as there is a 0.5 second delay
- may not truly represent moment-to-moment brain activity

Question 21

Describe an electroencephalogram

Answer 21

measures electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap
provides an overall account of brain activity through brain wave patterns, to identify unusual arrhythmic patterns that can indicate abnormalities such as epilepsy or tumors

Question 22

Evaluate EEG

Answer 22

Strengths
- extremely high temporal resolution
- can detect brain activity in a single millisecond
- useful for sleep and epilepsy

Limitations
- generalized information is received
- can’t pinpoint the exact source of neural activity and therefore can’t distinguish between activities in adjacent locations

Question 23

Describe event-related potentials

Answer 23

the electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data

Question 24

Evaluate ERP

Answer 24

strengths
- brings more specificity to the measurement of neural processes
- excellent temporal resolution
- used to measure cognitive functions and deficits such as the maintenance of working memory

limitations
- lack of standardization between research studies
- not always easy to eliminate extraneous material

Question 25

Describe post-mortem examinations

Answer 25

the brain is analyzed after death to determine whether certain observed behaviors during the persons lifetime can be linked to structural abnormalities in the brain

Question 26

evaluate post-mortem examinations

Answer 26

strengths
- provide useful information
- around before neuroimaging
- HM
-broca and wernicke

Limitations
- may not be causation
- damage to the brain may not be linked to what is being researched
- informed consent
- ethical issues

Question 27

Describe circadian rhythms

Answer 27

a biological rhythm which is governed by endogenous pacemakers and exogenous zeitgebers that lasts 24 hours. examples include the sleep wake cycle and core body temperature
the sleep/wake cycle
- daylight is an exogenous zeitgeber
- the suprachiasmatic nucleus (SCN) is an endogenous zeitgeber which can be reset by light

Question 28

Describe research into circadian rythms

Answer 28

• siffre deprived himself of exposure to natural light and sound but with access to adequate food and drink
• lasted 2 months in the southern alps and 6 months in the texan cave
• he found that his free running biological rhythm settled to one that was around 25 hours though he did continue to fall asleep and wake up on a regular schedule
• aschoff and wever convinced a group of participants to spend 4 weeks in a world war 2 bunker deprived of natural light
• found that all of the participants displayed a circadian rhythm between 24 and 25 hours except for one whose cycle extended to 29 hours
• therefore the natural sleep/wake cycle may be slightly longer than 24 hours but that it is entrained by exogenous zeitgebers associated with our 24 hour day, such as meal times, number of daylight hours, etc.
• Folkard studied a group of 12 people who agreed to live in a cave for 3 weeks, going to bed at 11:45 and rising at 7:45, but the clock sped up so that a normal 24 hour day was only 22 hours
• they found that only one participant was able to comfortably adjust, suggesting that the existence of a strong free running circadian rhythm cannot be easily overridden by exogenous zeitgebers

Question 29

Evaluation of circadian rythms

Answer 29

Strengths
Medical treatment
- circadian rhythms dictate processes such as heart rate, digestion, and hormone levels which rise and fall during the day and has led to the field of chronotherapeutics
-aspirin is most effective for heart attacks if taken last thing a night, as they are most likely to occur in the morning
- therefore research into circadian rhythms can help increase the effectiveness of drug treatments

Shift work
-provides an understanding of consequences if they are disrupted
- night workers experience reduced concentration at 6 in the morning, meaning mistakes and accidents are more likely
- research has shown that shift workers are 3 times more likely to develop heart disease than people who work more typical work patterns
- therefore has economic implications in terms of how best to manage worker productivity
– however, these studies investigating this use correlational methods, meaning its difficult establish cause and effect, meaning the sleep/wake cycle may not be the cause of negative effects
- Solomon concluded that high divorce rates in shift workers were due to the strain of deprived sleep and other influences such as missing out on important family events, meaning that it may not be biological factors that create the adverse consequences associated with shift work

Limitations
Individual differences
- the studies are based on very small samples and the sleep/wake cycles seem to differ widely from person to person and therefore difficult to generalize
- Czeisler found individual differences in sleep/wake cycles varying from 13 to 65 hours
- duffy revealed that some people have a natural preference for going to bed and rising early, whereas others prefer the other
- siffre observed that his own sleep/wake cycle had slowed down as he aged
- therefore its difficult to use the data to discuss anything more than averages which may be meaningless

Question 30

Describe infradian rhythms

Answer 30

the menstrual cycle
- governed by monthly changes in hormone levels which regulate ovulation
- approximately 28 days and the rising levels of estrogen cause the ovary to develop an egg and release it
- after ovulation, progesterone thicken the womb lining, if pregnancy does not occur, the womb lining comes away and leaves the body

seasonal affective disorder (SAD)
- low mood and general lack of interest in life triggered during the winter months when the number of daylight hours becomes shorter
- the pineal gland secretes melatonin until dawn where there is an increase in light, this occurs for longer in the winter due to lack of light, causing a knock on effect on the production of serotonin

Question 31

describe research into infradian rhythms

Answer 31

• stern and mcclintok studied 29 women with a history of irregular periods
• samples of pheromones were gathered from 9 of the women at different stages in their menstrual cycles via a cotton pad placed under their armpit, which were then treated with alcohol and frozen to be rubbed on the upper lip of the other participants. on day one they were given the fist day of the cycle, on day two the second, etc.
• they found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their “odor donor”

Question 32

describe ultradian rhythms

Answer 32

there are 5 stages of sleep that together last 90 minutes which are categorized by a different level of brainwave monitored using an EEG
- stages 1 and 2 - light sleep, brain waves are high frequency and short amplitude, called alpha waves, in stage 2, there are also random changes called sleep spindles
- stages 3 and 4 - deep sleep/slow wave sleep, delta waves with lower frequency and higher amplitude, difficult to wake someone
- stage 5 - body is paralyzed and brain is active, REM, theta waves and dreams are most often experienced

Question 33

Evaluation of infradian rhythms

Answer 33

Strengths
Evolutionary basis
- it may have been advantageous for women to menstruate together and become pregnant at the same time, as this would allow babies who had lost their mother during or after childbirth to have access to breast milk, improving their chances of survival, suggesting that synchronization is an adaptive strategy

Real world application
- for SAD, light therapy is able to reset the body’s internal clock
- this helps to reduce the effect of SAD in about 80% of people
- light therapy is also preferred to drugs, because it is regarded as safe
- however, light therapy can produce headaches and eyestrain and relapse rates are 46%, compared to 27% in a comparison group receiving CBT

Limitation
- many factors may effect change to the menstrual cycle such as stress, changes in diet, exercise, etc
- these act as confounding variable which meant that any pattern found is no more than would have been expected to occur by chance, which explains why other studies have failed to replicate the findings, suggesting that these studies are flawed

Question 34

Evaluation of ultradian rhythms

Answer 34

Strength
improved understanding
- scientists have observed that slow wave sleep (SWS) reduces with age and the growth hormone is produced during this, hence this is reduced in older people
- the sleep deficit may explain issues with old age, such as reduced alertness
- to increase this sleep, relaxation and medication can be used, suggesting that this knowledge of ultradian rhythms has practical value

Limitation
individual differences
- Tucker found large differences between participants in terms of the duration of each stage of sleep, particularly in 3 and 4
- he suggested this is likely to be biologically determined, making it difficult to describe “normal sleep” in any meaningful way

Question 35

Describe endogenous pacemakers and the sleep/wake cycle

Answer 35

• the suprachiasmatic nucleus (SCN) is located in the hypothalamus in each hemisphere of the brain and one of the primary endogenous pacemakers
• it lies above the optic chiasm and receives about light directly from this structure, even when our eyes are closed, enabling the biological clock to adjust to changing patterns of daylight whilst we are asleep
• decoursey destroyed the SCN connections in the brain of 30 chipmunks who were then returned to their natural habitat and observed for 80 days
• they found that the sleep/wake cycle had disappeared and that a significant proportion had been killed by predators, as they were awake and vulnerable to attack when they were supposed to be asleep
• ralph bred mutant hamsters with a 20 hour sleep/wake cycle
• when the SCN was then transported from these hamsters to normal ones, the cycles of the second group defaulted to 20 hours

the pineal gland and melatonin
- the SCN passes on the light information that it receives to the pineal gland
- the pineal gland produces melatonin during the night, which induces sleep and is inhibited during periods of wakefulness

Question 36

Describe exogenous zeitgebers and the sleep/wake cycle

Answer 36

Light
- can reset the SCN and therefore plays a role in the maintenance of the sleep/wake cycle
- also has an indirect influence on hormone secretion and blood circulation
- Campbell and Murphy had 15 participants were woken a various times and a light pad was shined on the back of their knees
- the researchers were able to produce a deviation in their cycle of up to 3 hours, suggesting that light is a powerful zeitgeber that doesn’t rely on the eyes to exert its influence on the brain

Social cues
- babies are born with a random sleep/wake cycle, but by 16 weeks, their rhythms have been entrained by the schedules imposed by parents, including bedtimes and meal times
- adapting to local times for eating and sleeping is an effective way of entraining circadian rhythms and beating jet lag when travelling long distances

Question 37

Evaluation of endogenous pacemakers and the sleep/wake cycle

Answer 37

Limitations
beyond the master clock
- there are many circadian rhythms found in organs such as the lungs, pancreas, and skin, which are influenced by the actions of the SCN but also act independently
- Damiola found that changing feeding patterns in mice could alter the circadian rhythms of the liver cells up to 12 hours, while leaving the rhythm of the SCN unchanged
- this suggests there are other complex influences on the sleep/wake cycle

interactionist system
- total isolation studies are rare, and even then siffre used aritficial light, which could have reset his biological clock
- it is difficult to separate pacemakers and zeitgebers as they interact in real life, and makes little sense to separate the two for purpose of research
- therefore, the attempt to isolate the influence of pacemakers lowers the validity of the study

Question 38

Evaluation of exogenous zeitgebers and the sleep/wake cycle

Answer 38

Limitations
Environmental observations
- people who live in the artic circle have similar sleep patterns all year round, despite spending around 6 months in total darkness
- therefore the SW cycle is primarily controlled by endogenous pacemakers that can override environmental changes

case study evidence
- Miles recounted the study of a young man, blind from birth, who had an abnormal circadian rhythm of 24.9 hours.
- despite exposure to social cues, such as regular meal times, his SW cycle could not be adjusted
- this suggests that social cues alone are not effective in resetting the biological rhythm