Biopsychology pt 2 -Psychology

What is a fMRI- functional magnetic resonance imaging?

Detects blood oxygenation changes and flow that occur due to neural activity. Produces 3D images whilst asked to complete a task (e.g. reading/ listening) compare task blood flow to resting blood flow.

What is an EEG- electroencephalogram?

Measure electrical activity in the brain by recording brainwave patterns. Used to identify unusual patterns to indicate neurological abnormalities such as epilepsy, tumours and sleep disorders.

What is an ERP- Event-related potentials?

2nd EEG measurement in response to a stimulus.

Associated with specific neural, sensory and motor responses, by isolating this information and leave the relevant responses that relate to specific processes. What remains is an event-related potential- these brainwaves are triggered by specific events.

Steps:

1. Put EEG cap in saline solution to increase conductivity.

2. Measure diameter of the scalp

3. Place cap on head tightly

4. Adjust electrodes or add more solution. 

What is a post-mortem examinations?

Analysis of the brain after someone has died. Completed on those with rare illnesses to identify possible causes of the affliction the person suffered from, comparing the brain to an unaffected brain.

What are the strengths and weaknesses of fMRI?

S= Don’t use radiation unlike PET scans. Virtually risk free and straightforward to use. The images are high in resolution and show a great deal of detail and clear picture of localisation in the brain.

W= Expensive and only get a clear image if the person remains perfectly still. Only measure blood flow to the brain and not specific neuronal activity.- difficult to see exactly what type of brain activity is being represented on screen.

What are the strengths and weaknesses for EEG?

W= too general and not useful in pinpointing the specific source of neuronal activity- researchers can’t tell where some activities are specifically based in the brain.

S=Proven valuable in diagnosing disorders, such as epilepsy- random bursts of activity can be easily detected using this technique. Contribute to our understanding of the stages of sleep. EEG technology can detect brain activity at a resolution of a single second.

What are the strengths and weaknesses of ERP?

S= brings more specific measurement of neural processes at work. ERP information is derived from EEG information it has excellent temporal resolution- led to widespread use in looking at cognitive functions and deficits.

W= Not standardised, difficult conform findings. To get accurate reading background noise and other extraneous material need to be eliminated, which isn’t easy to do. 

What are strengths and weaknesses about a post mortem?

S= Broca and Wernicke both relied on post-mortem evidence in their research- provide medical knowledge and help generate hypotheses for further study.

W= Observed damage not linked to the actual deficit of the individual but could be caused by other traumas or brain decay. There is an issue of consent- people cannot give consent after their death. For example, HM, whose memory was damaged, couldn’t give fully informed consent, but his brain was studied anyway.

What is spatial resolution?

Accuracy of the scan in terms of pinning the activity shown to a specific area of the brain.

What is temporal resolution?

Accuracy of the scan in terms of the time that activity was detected.

How is a fMRI in investigating the brain?

SR= Good due to clear picture

TR= Poor- 5 secs lag thought between the initial neuronal firing and image being produced.

Ethical concerns= issues of claustrophobia, yet safter than PET scans- no radioactivity

Cause and effect= low due to time between neuronal activity and measurement.

How is an EEG+ERP in investigating the brain?

SR= Poor- doesn’t enable people to see where the activity is happening.

TR= Good- no lag between the activity and the recording. Recording can be in milliseconds- less interference between thought and output.

Ethical concerns= Very ethical-records brain activity passively, no injection or interference.

Cause and effect= EEG- short amount of time between neural activity and output- high cause and effect.

ERP- response to a stimulus- issues with cause and effect- can’t be sure that brain in change is in response to stimulus.

How is a post mortem in investigating the brain?

SR= n/a

TR= many years between diagnosis and death

Ethical concerns= consent is key- some patients might not have the capacity to consent- ethical limitation.

Cause and effect= lowest- very long time between diagnosis and death - treatments, life experiences which could change brain shape.

What is localisation?

Different parts of the brain perform different tasks and are involved with different parts of the body.

What and where is the Motor area?

• Back of frontal lobe (Both H)

• Voluntary movement of opposite side of the body. Damage- possible loss of fine motor movement.

What and where is the Somatosensory area?

• Front of both parietal lobes. Separated from motor area by a “valley“ called central sulcus

• Sensory info from skin (touch, heat and pressure) devoted to particular body part, denotes sensitivity.

What and where is the Auditory area?

• Temporal lobes

• Analyses speech-based info. Damage-partial or extensive hearing loss

What and where is the Visual area?

• occipital lobe at the back of the brain.

• Each eye sends info from right visual field to the left visual cortex and vice versa. Damage- in left H can produce blindness in part of right visual field.

What and where is the Broca’s area?

• Left hemisphere and left frontal lob

• Responsible for speech production. Damage- Broca’s aphasia which is characterised by slow speech and lacks fluency

What and where is the Wernicke’s area?

• Left Hemisphere and left frontal lobe.

• Responsible for understanding language. Damage- Wernicke’s aphasia where patients will produce nonsense words (neologisms)

What are the strengths of localisation of function?

P= Scientific evidence from Brain scans

E= Peterson et al (1988) scanned brains to demonstrate Wernicke’s area being active during a listening task, and Broca’s area active during a reading task.

L= This means that the listening task is understanding language, activating W’s area, and the reading task is speech production, activating B’s area- supporting localisation to certain areas of the brain.

P= Evidence from case studies

E= Phineas Gage- left frontal lobe damage as a pole went through his left cheek. Became quick-tempered/ rude- change temper could suggest that the frontal lobe regulates mood- supports localisation.

H= Very small sample size of 1 person- extremely difficult to generalise localisation to everyone with brain damage. Trauma could cause the mood changes, not the biological changes.

What are the weaknesses of localisation?

P= More recent evidence suggests that the human brain is actually fairly “plastic“

E= After trauma the brain appears to correct itself with stroke patients, for example, recovering the power of speech after damage to the Broca’s or Wernicke’s area. Often different areas of the brain will take over from a damaged area (recruitment of homologous area) and start to complete the function instead.

L=This shows that various parts of the brain can take over/ adapt other functions from localised parts of the brain.

P=Research from Lashley (1950) indicates that learning processes (higher mental functions) may be holistic rather than localised

E= In his studies with rats, he discovered that when areas of the cortex were removed no areas was seen to be more important the any of the others, which indicates that all of the areas are important in learning rather than just one- equipotentiality theory (equal potential to understand)

L= Rats have significantly less neurons in the cortex than humans- shouldn’t be making these generalisations. 

What is Hemispheric Lateralisation?

Refers to the 2 halves (hemispheres) of the brain are functionally different and that some behaviours and mental processes are mainly controlled by one hemisphere.

What is lateralised functions?

Function is performed by one hemisphere rather than the other.

What is contralateral functions?

Cross wired- e.g. right H controls the left side and vice versa

What is ipsilateral functions?

Opposite and same sided- e.g. in the eye there is both same sided and opposite sided control.

What is the AO3 for Hemispheric Lateralisation?

P= Lateralisation in the “normal brain“

E= Fink et al (1966) used PET scans to find out which areas were active during a visual processing task. When ppts were asked to focus on the global image (picture of whole forest) parts of the right H were much more active. Whereas, when people focused on the finer details (individual trees) parts of the left hemisphere were more active.

L= This means that the right side is more active during a whole global image, whilst left side is responsible for finer details- easier to generalise because its on a neurotypical brain and easier to create nomothetic laws.

P=Is there a “dominant hemisphere“ within the brain?

E= Nielson et al (2013) analysed brain scans from over 1000 people aged 7-29 years and found that certain hemispheres were used for different tasks, however, there was no evidence of a dominant side in the ppts

L= Supports lateralisation- certain Hs used for different tasks (large sample). But no support for dominance- right or left side isn’t more dominant.

What was Sperry’s aim and produce into his Split-Brain research into hemispheric lateralisation?

Aim= investigate lateralisation of functions

Procedure= Special set-up in which an image projected to ppt’s RVF (processed by LH) and same, or different, image could projected to the LVF (processed by RH). "Normal“ brain, corpus callosum immediately share info between both hemispheres giving a complete picture.

H= Presenting image to one H of a split-brain ppt meant info cannot be conveyed from that H to the other.

What was Sperry’s findings into his Split-Brain research into hemispheric lateralisation?

Picture shown to RVF- ppts could describe what they see. Not for LVF- “nothing there“ because, in the connected brain, messages from RH are relayed to language centres in the LH, but not possible in the split-brain.

Patients not give verbal labels to objects projected to LVF, could select matching object out of sight using left hand (linked to RH). Left hand able to select an object most closely associated with an object presented to the LVF.

Pinup picture shown to LVF- emotional reaction (e.g. giggle) but the ppts usually reported seeing nothing or just flash of light.

What was Sperry’s conclusion into his Split-Brain research into hemispheric lateralisation?

Left Hemisphere is more geared to analytic and verbal tasks whilst the right is more adept at performing spatial tasks and music. The right hemisphere can only produce rudimentary words and phrases but contributes emotional and holistic content to language.

What are the strengths for Sperry’s research?

High controlled procedure allowed Sperry to continuously replicate the findings with each ppts on many occasions.

Contributes to the debate about lateralisation and able to provide split brain patients with a better understanding of how their split brain might affect the tasks they complete, so is useful.

What are the weaknesses for Sperry’s research?

Sample size is 11 ppts which is small. Even been argued that his study is really a “case study“- all the damage was different in each ppt it would be hard to generalise even to other split-brain patients.

Low ecological validity- task focusing on a point then experiencing a word or image is not something that the patients would experience in their everyday life. They would normally see things using both visual fields- don’t see information for a tenth of a second.

What is plasticity?

the brain has an ability to change throughout life in response to the environment.

What is Maguire’s aim into plasticity?

To investigate whether changes could be detected in the brain of London taxi drivers and investigate the functions of the hippocampus in spatial memory

What is Maguire’s method into plasticity?

16 male licensed London taxi drivers compared to the control group of 60 male non-taxi drivers. Taxi D Data collected through MRI scans and non taxi D through an MRI database. Software converts information collected from the MRI into 3D image and analysis can calculate amount of grey matter in the hippocampus.

Data collected 2 ways:

Voxel-based morphometry- used to measure the density of grey matter in te brain.

Pixel counting- measuring an area by calculating number of pixels in the 3D image provided by MRI, by taking slices of the hippocampus.

The researcher who counted the pixels was unaware of the VBM results and if they were taxi drivers or non-taxi drivers.

What are the results of Maguire’s study into plasticity?

Anterior hippocampus was bigger in CG than the taxi drivers. Posterior hippocampus was bigger in taxi drivers than CG.

VBM showed significantly more grey matter in the brains of TD were as the pixel counting shows no difference in size overall but just in specific areas- anterior and posterior hippocampus deal (localisation) with different things.

Anterior= used when going through new environment layouts, more common with people who learn new locations all the time (NT)

Posterior= used previously learned environmental layouts are used (going over the knowledge in taxi-drivers)

What is functional recovery?

Following physical injury and other forms of trauma, has seen unaffected areas of the brain are able to take over and compensate for the damaged areas- another example of plasticity

What are the 4 steps during brain recovery?

1- Recruitment of homologous areas= on the opposite side of the brain to perform specific tasks- if Broca’s area was damaged on left side, the right side would then carry out the function. After recovery it would then shift back.

2- Reformation of blood vessels= increase oxygen flow around the brain.

3- Axonal sprouting= growth of new nerve endings which connect with other undamaged nerve cells to form new pathways.

3- (Same time as axonal sprouting) Neuronal unmasking= “dormant” synapses became revealed when the rate of neural input increases

What are the strengths of plasticity?

P= By understanding more about how the brain works we can better understand the recovery of patients in the field of neurorehabilitation

E= Understanding the processes of plasticity and functional recovery had led to the development of neurorehabilitation which uses motor therapy (movement) and electrical stimulation (axonal growth) of the brain to counter the negative effects and deficits in motor and cognitive functions following accidents, injuries and/or strokes.

L=It demonstrates the positive application of research in this area to help improve the cognitive functions of people suffering from injuries.

P= Research to support the concept of plasticity.

E= Maguire found that the posterior hippocampal volume of London taxi drivers’ brain was positively correlated with their time as a taxi driver and that there were significant differences between the taxi drivers’ brains and those of controls

H= Maguire’s research is biologically reductionist and only examines a single biological factor (size of 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, limiting our understanding.

L= Therefore, while Maguire’s research shows that the brain can change in response to frequent exposure to a particular task, some psychologists suggest that holistic approach to understanding complex human behaviour may be more appropriate.

What is a weakness for plasticity?

P= Sometimes the brains ability to rewire itself can have negative effects.

E= Prolonged drugs use has been seen in showing poorer cognitive ability (maladaptive) as well as an increased risk of dementia in later life. Also 60-80% of amputees have been known to develop phantom limb syndrome- the sensation that the severed limb is still there.- results in pain and unpleasant feelings.

L= Due to the brain reorganising itself (plasticity) in an incorrect or maladaptive was. Although it still not truly understood. So, plasticity is not always of benefit in every case.

What are circadian rhythms?

Cycles that occur every 24 hours, e.g. sleep/wake cycle

What is the Sleep/wake cycle?

• We feel drowsy at night and more alert during the day

• Our body has an “internal“ (SCN) clock that regulates these biological processes.

• For example, when we have been awake for a long period our body’s homeostasis is disrupted and our body will show signs of tiredness.

• Melatonin (sleep hormone) released from our pineal gland in the hypothalamus when we are ready a sleep and decreases in the morning.

• Strongest sleep drive is between 2-4am and between 1-3 in the afternoon.

What was Siffre’s cave study in circadian rhythms (1962)?

P= Siffre spent 2 months living in total isolation in a subterranean cave, without access to a clock, calendar or sun (again in 1972 for 6 months- Texas).

R= Settled into a sleep/wake cycle of 24-30 hours- usually just beyond usual 24 hrs (average 24.5).

L= Supports assumption that endogenous pacemaker (internal body clock) exert an influence an circadian rhythms because when the light (EZ) was not present Siffre still slept and woke, in a slightly longer cycle.

What was Aschoff and Wever’s study (1976) into circadian rhythms?

P= placed ppts in a bunker for 4 weeks with no natural light. Ppts were in charge of turning on and off the light. 

R= settled into a sleep/wake cycle of between 25+27 hours (apart from one which extended to 29 hours)

L= suggests endogenous pacemakers control sleep/wake cycle in the absence of light cues.

What was Folkard’s study (1985) into circadian rhythms?

Circadian rhythms cannot easily be overridden by external environment.

P= Isolated 12 ppts from natural light for 3 weeks (dark cave), manipulating the clocks so that eventually only 22 hours passed a day.

R= only one of the ppts could adjust comfortably to pace of the clock, showing strength of the circadian rhythm as a free-running cycle and questions the extent to which it can be overridden by exogenous zeitgebers.

H= Czeisler et al, individual cycles can vary from 13-65 months- difficult to generalise.

What are the strengths of circadian rhythms

P= Supporting evidence

E= Folkard et al (1985): studied 12 ppts who lived in a cave for 3 weeks, where they had to go to bed when the clock said 11:45pm and they had to get up at 7:45am. Over the course of the study, researchers gradually sped up the clock (unbeknown to ppts) so an apparent 24-hour day was reduced to 22. It was found that only one of ppts adjusted well to the new regime.

L= Suggests the existence of strong free running circadian rhythm that can’t easily be overridden by changes in the external environment.

P=Circadian rhythms co-ordinate with a number of other bodily processes.

E= E.g. heart rate, digestion and hormone levels- affects the action of drugs on the body and how well they are absorbed and distributed. Research into this had found that there are times during the day or night when drugs are most effective.

L= Led to guidelines as to when to take the drugs for a whole range of medications including anticancer and anti-epileptic drugs- known as chrono-therapeutics.

What is a weakness for circadian rhythms?

P= research studies in this area are either one-participant studies or studies with small samples

E= Therefore it may not be generalisable to all humans. Also Siffre’s living conditions were unusual in other ways than simply lacking time signals and other factors such as loneliness could have affected his behaviour.

H= Siffre’s study lasted a long time (2 and 6 months), allowing his rhythms to settle down into a natural pattern, so is less likely to be created by artificial, temporary factors.

How does gender affect circadian rhythms?

Adan and Natale (2002) showed men and women have different circadian rhythms with men having more of an evening preference and evidence suggests that they adapt faster to changes than women. (Shift work)

H: previous research being of men with androcentric samples- this has only recently been discovered.

If research is only completed on male samples, then when this is used to determine chrono-therapeutics it means drug timings may only be effective for men- consequence of beta bias research

What are endogenous pacemakers?

Internal body clocks that regulate many of our biological rhythms, such as the influence of SCN on the sleep/wake cycle

What is the role of SCN (suprachiasmatic nucleus)?

Small area in the hypothalamus (behind the eyes) with an in-built circadian rhythmic firing pattern, regulating melatonin in the pineal gland via an interconnecting pathway.

Another pathway links to SCN to the retina of each eye- maintains the amount of light falling on the retina- indirectly influence the release of melatonin in the pineal gland.

Describe 2 animal studies that support the role of the endogenous pacemaker and the SCN (AO3 Strengths of EP and EZ)?

• DeCoursey et al (2000) destroyed SCN connections 30 chipmunks’ brains. Returned to their natural habitats and monitored for 80 days. The sleep/wake cycle disappeared, by the end of the study a significant proportion had been killed by predators.

• Ralph et al (1990) bred “mutant“ hamsters with a 20-hour sleep/wake cycle. When foetal tissue was transferred to into the brains of normal hamsters, the cycles of the second group defaulted to 20 hours (genetic manipulation).

Both studies emphasis the role of SCN in establishing and maintaining the circadian sleep/wake cycle.

What is the role of the pineal gland on endogenous pacemakers and the SCN?

Pineal gland contains light sensitive cells, and when light is sensed, the production of melatonin is inhibited. When light decreases, melatonin is again produced which induces sleep by inhibiting the brain mechanisms that promotes wakefulness.

What are exogenous zeitgebers?

Deals with external cues such as the changing of the seasons.

Natural light is the dominant zeitgeber in human due to melatonin, affecting the SCN and certain proteins in the body that can detect changes in light.

Social cues- at 6 weeks babies’ circadian rhythms begin and by about 16 weeks, most babies are entrained (process of resetting the biological clock with exogenous zeitgebers) by schedules imposed by the parents- like set meal and bedtimes.

What are the weaknesses of EP and EZ

P= Influence of EZ could be over exaggerated 

E= Miles et al (1977) studied a young man who was blind from birth, even though he was exposed to social cues such as regular meal times he found that his cycle remained at a slightly higher than average amount of 24.9 hours

L= Suggests social cues may be exaggerated as an EZ as they did not alter the circadian rhythms in this case.

P=Ethical issues using animal studies

E= Like DeCoursey and Ralph studies, animals were subjected to harm, for example, the hamsters would have been subjected to a difficult surgical procedure.

L= Has ethical issues, but it also gives practical problems, as if the animals are in distress their behaviour may be unusual, therefore not demonstrating the effect of pacemakers in a more normal situation.

What is an Infradian Rhythm?

A cycle occurring less than once per day but more than once per year.

What is SAD (seasonal affective disorder)- infradian rhythm?

Biochemical imbalance typically during the winter months due to the lack of melatonin because in the hypothalamus there is a lack of sunlight. Diagnosis can be made after 2 or more consecutive winters of symptoms- main age of onset is 18-30, most common at the top of hemispheres.

Symptoms (only in depressive episode): worthlessness/ guilt, hard to concentrate, lack of enjoyment, fatigue and thoughts of death/ suicide (severe).

What is the menstrual cycle (infradian rhythm)?

As the ovulation process progresses both LH and FSH increase, initially at a steady rate, but then they increase sharply. They reach their peak at about half way through the cycle, just before ovulation. Then they both sharply decline and return to the levels they were at the start of the cycle.

What are the strengths of infradian rhythms?

P= Practical application from SAD research

E= From the research into SAD treatments such as phototherapy have been developed, this is a very strong lightbox which stimulates the effect of daylight. Fanasti (2014) showed that light therapy can effect 80% of SAD people, it is also seen as safer than taking anti-depressants.

L= Reduction of melatonin helps regulate the sleep/wake patterns and return both melatonin and serotonin to “normal“ levels so reducing symptoms of SAD.

P= Evidence to support effect of EZ on the menstrual cycle

E= Stern and McClintock (1998): 68% of 29 women with irregular periods experienced changes to their cycle which brought them closer to their “odour donor“- when half the sample rubbed the other womens’ pheromones on their upper lips.

L= Shows infradian rhythms such as the menstrual cycle can be affected by exogenous zeitgebers such as other women’s pheromones.

What are the weaknesses of infradian rhythms?

P= Explanations of SAD are reductionist

E= Biological explanations of SAD (melatonin) reduce this disorder into only biological factors and so does not take account of any other factors. For example, during the winter months, people also change their behaviour due to weather and temp; this may in turn affect how often they go out or meet friends.

L= Rather than biological factors alone, so a more holistic explanation is needed.

P= Methodological issues with research into synchronisation

E= Early studies on menstrual synchrony may have suffered from cofounding variables that may not have been considered. The changes on a woman’s menstrual cycle could be due to other factors like stress, changes in diet, exercise etc. Research only focuses on small samples of women and relies on the ppts self-reporting the onset of their own cycles.

L= All of these factors and variables could lead to a change in the menstrual cycle (DV) and therefore it is difficult to measure the effect of other pheromones alone.

What is an ultradian rhythm?

Cycle that occurs more than once per day

What is the slow-wave sleep stages?

4 stages (also called NREM sleep). The stages we pass through when we are asleep are an example of an ultradian rhythm.

What is first stage of the Slow-wave sleep?

When we first fall asleep, breathing, blood pressure and blood flow is reduced. Brain waves are slower and irregular- alpha waves. Easier to be woken up.

What is the second stage of the slow-wave sleep?

Lasts 20mins, gradually moving into deeper sleep. Large brain waves and occasional quick spikes of activity- both alpha and theta waves.

What is the third stage of the slow-wave sleep?

Beginning of deep sleep, 35 mins into sleep. Slow brain waves and quite large (delta waves)

What is the forth stage of the slow-wave sleep?

Deepest sleep occurs, lasting 40 mins. Large brain waves and difficult to wake- may suffer from “sleep drunkenness” where they may not be able to function adequately if woken during this stage.

What is REM sleep?

Rapid eye movement sleep- body is inactive, but the eyes are moving very fast which causes dreams. Tends to occur instead of going back into stage 1. In the morning, we tend to have lighter stages of sleep (REM sleep and stage 3) and dream more frequently- we remember our dreams more in the morning

What is a strength for ultradian rhythms?

P= evidence for the existence of distinct sleep stages

E= Dement and Kleitman (1957)- subjects woken during REM or Non-REM sleep in4 different ways including randomly and at the experimenters’ whim. R- regardless of how subjects are awoken, significantly more dreams were recorded in REM than NREM sleep.

L= shows a clear distinction between each sleep stage due to more dreams occurring in REM sleep

What are the weakness for ultradian rhythms?

P= It is not always the case that dreams occur in REM sleep.

E= Not all dreams occur during REM sleep. Hypnogogic dreams occur during stages 1 and 2, shortly after drifting off to sleep, and are those in which we may experience the feeling of being out of control or that we are falling. These dreams and brainwave activity during sleep are measured in sleep labs using EEGs.

L= Ppts may behave differently due to them being in a lab setting- recorded measurements could be caused by a change in state due to stress or concerns about being in a lab setting- reduces validity.

P= Issues of using self-report measurements in sleep studies

E= Rely on the information that is given to you by the ppt when they are woken up in a particular sleep stage, e.g. reporting a dream in REM.

L= This could in fact be due to socially desirability rather than a truthful response, therefore results from these studies may not give valid measurements.