Localisation of function
Theory that states that different areas of the brain are responsible for different behaviours, processes or activities.
Motor area
Back of frontal lobe, involved in regulating movement.
Somatosensory area
Front of both parietal lobes, processes sensory information such as touch.
Parts of the brain: Visual area.
Occipital lobe, receives and processes visual information.
Parts of the brain: Auditory area.
Temporal lobe, analyses speech-based information.
Parts of the brain: Language areas.
Broca's area, frontal lobe in the left hemisphere = speech production.
Wernicke's area, temporal lobe in the left hemisphere = language comprehension.
Describe the case of Phineas Gage.
Aim: To explain the cause of Gage's change of personality.
While working on the railroad in 1848, 25-year-old PG was preparing to blast a section of rock with explosives to make way for a new railway line. During the process, Gage dropped his tamping iron
Provide 4 examples that can be used as evidence for biological determinism.
It is suggested that an overactive hypothalamus leads to increased aggression and causes people to experience heightened sexual feelings. Hess (1957) found by stimulating the hypothalamus in cats they behaved aggressively. Vergnes (1975) suggested stimula
Does the case of Phineas Gage support localisation theory or holistic theory? Why?
The specific changes observed in his behaviour support theories about the localisation of brain function, or the idea that certain functions are associated with specific areas of the brain. The part of the brain damaged in the accident was the area in the
Why is it difficult to draw general conclusions from the case of Gage?
It is difficult to generalise from the case of Gage as he is one individual, so all other people might not react or show the changes that he did following such an incident. He suffered an infection as a result of the injury so it could have been this whic
Brain scan evidence of localisation.
Petersen et al (1988) used brain scans to demonstrate how Wernicke's area was active during a listening task and Broca's area was active during a reading task = these areas of the brain have different functions. Tulving et al's 1994 study on LTM = semanti
Neurological evidence for localisation.
Walter Freeman developed lobotomy to control aggressive behaviour - brutal and imprecise. Neurosurgery used sparingly today for extreme cases (e.g. OCD and depression). Dougherty et al (2002): 44 OCD patients had their cingulate gyrus lesioned. Post-surgi
Describe Lashley's 1950 study on learning and rat's brains.
Removed areas in the cortex (between 10 and 15%) in rats that were learning a maze. No area was proven to be more important than any other pertaining to rats' ability to learn the maze. Process of learning appeared to require every part of the cortex, rat
Define plasticity.
Brain's tendency to change and adapt (functionally and physically) as a result of experience and new learning.
What is the law of equipotentiality?
When the brain becomes damaged and a function is compromised/lost, the rest of the brain reorganises itself in an attempt to recover the lost function. Surviving brain circuits 'chip in' so the same neurological action can be achieved.
What five things must be used to evaluate localisation of function?
Brain scan evidence, neurological evidence, case study evidence, Lashley's research and plasticity and the equipotentiality theory.
Discuss the extent to which brain functions are localised. Refer to evidence in your answer.
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Synaptic pruning.
As we age, rarely used connections are deleted and frequently used connections are strengthened.
Axonal sprouting.
Undamaged axons grow new nerve endings to reconnect neurones whose links were injured or severed.
Recruitment of homologous areas.
Regions on opposite sides of the brain take on functions of damaged areas.
Functional recovery.
Form of plasticity. Following damage through trauma, the brain's ability to redistribute/transfer functions performed by damaged areas to other, undamaged areas.
Neural plasticity.
Describes the brain's tendency to change and adapt - functionally and physically - resulting from experience and new learning.
Outline Maguire et al (2000) taxi driver study.
Studied taxi drivers' brains. Found significantly more grey matter in posterior hippocampus of taxi drivers than control group, which plays a role in human spatial memory and navigational skills. London taxi drivers must do complex test - The Knowledge -
Outline the results of Lazar et al's 2005 study.
Used MRI scans to demonstrate how experienced meditators have a thicker cortex than non-meditators.
Outline the results of Hozel et al's 2011 study.
Individuals who took part in an 8-week Mindfulness-Based Stress Reduction course showed an increase in grey matter in the left hippocampus, a part of the brain that is strongly associated with learning and memory.
Outline Drangonski et al's 2006 study on medical students.
Brain scans on medical students three months before and after their final exams. Learning-induced changes occurred in posterior hippocampus and parietal cortex presumably resulting from the exam.
What happens in the brain during recovery?
The brain is rewire and reorganise itself by forming new synaptic connections close to the area damage. Secondary neural pathways that wouldn't typically be used to execute functions are activated to enable continued function, often in the same way as bef
1 AO3 point on plasticity.
Research into plasticity has had a positive impact in the field of neurorehabilitation. Gabby Giffords was shot in the head and Kameron had half of her brain removed due to her Rasmussen's syndrome. They both experienced intensive rehabilitation and survi
AO3 point on plasticity: There is research to suggest that brains that exhibit plasticity can have maladaptive behavioural consequences. (Do the rest)
Medina et al's 2007 study shows that prolonged drug use results in poorer cognitive functioning and an increased risk of dementia later in life. Moreover, 60-80% of amputees develop phantom limb syndrome - the continued experience of sensations in the mis
AO3 point on plasticity: Functional plasticity tends to reduce with age. The brain has a greater propensity for reorganisation in childhood as it is constantly adapting to new experiences and learning. (Do the rest)
That said, Ladina Bezzola et al (2012) demonstrated how 40 hours of golf training produced changes in the neural representation of movement in Ps aged 40-60. Using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared
The concept of cognitive reserve.
Evidence suggests that one's educational attainment may influence how well the brain functionally adapts after injury. A study revealed that the more time brain injury patients had spent in education - taken as an indication of their 'cognitive reserve' -
What is the central nervous system (CNS)?
Consists of brain and spinal cord; origin of all complex commands and decisions.
What is the peripheral nervous system (PNS)?
Sends info to CNS from outside world, transmitting messages from CNS to muscles and bodily glands.
Define hemispheric lateralisation.
Certain mental processes and behaviours are controlled or dominated by one hemisphere rather than the other (as in the example of language).
Corpus callosum
A band of neural fibres that connects the left and right hemispheres of the brain.
Split-brain studies.
Corpus callosum cut in patients with severe epilepsy, allowing researchers to investigate the extent to which brain function is lateralised.
Procedures.
Image/word is projected to right visual field (RVF) or left visual field (LVF).
Describing what you see.
Pictures shown to RVF could be described but not those to LVF because no language centres in left hemisphere (connected to RVF).
Recognition by touch.
Could not describe objects projected to LVF, but able to select a matching object from a selection of different objects using their left hand.
A split-brain patient is asked to focus on a dot in the centre of the screen. A single word is flashed up at a time, 'KEY' on the left, then 'RING' on the right side of the screen. Which hemisphere's visual cortex will each word be carried to?
Ring to the left; key to the right.
A split-brain patient is asked to focus on a dot in the centre of the screen. A single word is flashed up at a time, 'KEY' on the left, then 'RING' on the right side of the screen.
Why can the patient say 'RING', but not the word 'KEY'?
Language located in left hemisphere. Info taken from right visual field and registered by left hemisphere.
AO3 on split brain research.
Sperry's research produced large amount of research findings, highlighting brain lateralisation. Strong, scientific methodology. Mostly small samples/case studies, but this prompted theoretical debate and further research. But samples = issues with genera
fMRI
Measures brain activity in specific areas by detecting associated changes in blood flow.
EEG
A record of the brain wave patterns produced by millions of neurones, producing characteristic patterns.
ERPs
Isolating specific responses of neurones to specific stimuli or tasks.
Post mortem examinations
Correlating behaviours before death with brain structures after death.
How do fMRI scans work?
Detects changes in blood O2 and flow that occur resulting from neural activity in parts of the brain. Brain area more active = consumes more O2 and blood flow to active area increases to meet this demand (the haemodynamic response). fMRI produces 3D activ
How do EEG work?
Measures electrical activity within brain via electrodes that are fixed to one's scalp. Scan recording represents brainwave patterns generated from actions of millions of neurons, providing overall account of brain activity.
How do event-related potentials work? (ERPs)
Types of brainwaves are triggered by particular events. Research has found that there are many forms of ERP and how, for example, these are linked to cognitive processes like attention and perception.
Why would one do a post-mortem examination on somebody's brain?
Technique involves analysis of one's brain following their death. People have post-mortems of their brains as they are likely to have had a rare disorder /experienced unusual deficits in the mental processes/behaviour in their lifetime.
Outline the nature of functional magnetic resonance imaging (fMRI) as a way of studying the brain. (3 marks)
A method used to measure brain activity while one is performing a task that uses MRI technology (detecting radio waves from changing magnetic fields), enabling researchers to detect which brain regions are rich in oxygen and thus active.
Outline the nature of EEGs as a way of studying the brain. (3 marks.)
Measures electrical activity in brain via electrodes that are fixed to one's scalp using a skull cap. Scan created represents brainwave patterns generated from neuron activity, giving an overall view of brain activity. It is a useful diagnostic tool
Circadian rhythms.
Have cycles that generally occur once every 24hrs.
Infradian rhythms
Have cycles that occur less than once every day.
Ultradian rhythms
Have cycles that occur more than once every 24 hours.
Biological rhythm
Distinct patterns of changes in biological activity that conform to cyclical time periods.
Siffre study
Speleogist 'self-styled' cave person spent extended periods underground. Deprived of exposure to natural light and sound, but with access to adequate food and drink. Their biological rhythm settled down to one that was just beyond the usual 24 hours. Resu
Aschoff and Wever
Participants spent 4 weeks in a WWII bunker deprived of natural light. All but one of the participants displayed a circadian rhythm between 24 and 25 hours.
Folkard et al.
12 people lived in a cave. Researchers sped up the clock so a 24-hour day lasted 22 hours. No participants were able to adjust to the new regime.
The sleep/wake cycle
The fact that we feel drowsy when it's night-time and alert during the day demonstrates the affect of daylight - an important exogenous zeitgber - on our sleep/wake cycle.
Exogenous zeitgebers
External cues in the environment that entrain our endogenous rhythms.
Endogenous pacemakers
Internal body clocks that regulate many of our biological rhythms.
Describe one study that investigated a circadian rhythm. (3 marks)
Aschoff and Wever (1976) and Folkard et al (1985)
Menstrual cycle: exogenous
McClintock showed that female cycles entrained through exposure to odour donors' pheromones.
Strengths of research on circadian rhythms.
Real-world implications of sleep/wake cycles on shift workers. Practical applications in the administering drugs. With positive outcomes observed if drugs are taken at certain times in the day.
Limitations of research on circadian rhythms.
Use of case studies and individual differences - some are 'larks' and some are 'night owls'.
Menstrual cycle: endogenous
Occurs in females about every 28 days, endogenous control by the hormones oestrogen and progesterone.
Seasonal affective disorder - SAD
Depression associated with seasonal changes, usually the onset of winter and decreased darkness.
Stages of sleep
90-minute cycles during sleep brain, sleep escalator from stage 1 to 5 and REM. Brain wave activity changes.
With reference to an example, define what is meant by an ultradian rhythm .
Frequency of more than one cycle in 24 hours, such as the stages of sleep.
An example of a circadian rhythm
Circannual rhythm melatonin secreted for longer period of time due to lack of light - thought to have an effect on
What happens in stage 1 of sleep?
Light sleep; person can be easily woken. Theta waves in stage 1; person in light sleep and can easily be woken.
What happens in stage 2 of sleep?
Sleep spindles, theta waves and mixed EEG activity. Light sleep where person can be easily woken.
What waves are present in stage 3 and 4 of sleep?
Involves delta waves that are slower and greater amplitude than earlier wave patterns. This is deep sleep/slow wave sleep and it's difficult to rouse somebody at this point.
Rapid eye movement (REM sleep)
A kind of sleep that occurs at intervals during the night and is characterised by rapid eye movements, more dreaming and bodily movement, and faster pulse and breathing.
Explain what kind of rhythm the basic rest-activity cycle (BRAC) is. Justify your answer.
BRAC is characterised by a period of alertness followed by a spell of physiological fatigue. This occurs across a 90-minute cycle that then reoccurs during the course of the day. This is an example of an ultradian rhythm. These are cycles with a period of
What waves are present in stage 5 of sleep (REM sleep)?
Paralysed body yet significantly accelerated brain activity resembles awake brain. Rapid eye movement - jerky activity of eyes at this point. Research suggests that REM activity during sleep is highly correlated with experience of dreaming.
What was the aim of Stern and McClintock's 1998 study on the menstrual cycle?
Aimed to investigate how the menstrual cycle can be influenced by exogenous factors.
What was the method used in Stern and McClintock's 1998 study on the menstrual cycle?
29 women with history of irregular (unsynchronised) periods. Samples of pheromones gathered from 9 women at different stages of their menstrual cycles via cotton pad placed underneath armpit that were worn for at least 8 hours to ensure it picked up phero
What were the results of Stern and McClintock's 1998 study on the menstrual cycle?
68% of women experienced changes to their cycle which brought them closer to their odour donor.
Evolutionary basis of menstrual cycle.
Menstrual synchrony is thought to by many to have an evolutionary value. For our ancestors it may have been advantageous for females to menstruate together and therefore fall simultaneously pregnant, meaning that new-borns could be cared for collectively
Methodological limitation in synchronisation studies.
Criticisms have been made of early synchronisation studies and methods employed. Commentators argue that there are many factors that may effect change in woman's menstrual cycle like stress, changes in diet, exercise etc. that may be confounding variables
Exogenous cues for circadian rhythms.
Day light. Social cues - meal times, bed times ect.
Examples of a circadian rhythm.
Sleep/wake cycle and body temperature.
Exogenous cues for infradian rhythms.
Pheromones and light.
Evidence to support the idea of distinct stages in sleep.
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Suprachiasmatic nucleus (SCN)
.Tiny bundle of nerve cells located in the hypothalamus in each hemisphere of the brain where the optic nerves from each eye cross. The primary endogenous pacemaker in mammals. Receives info directly from this structure.
Melatonin
Produced by pineal gland at night, governs sleep/wake cycle. Production inhibited during periods of wakefulness.
Light
A zeitgeber in humans that can reset the main endogenous pacemaker (SCN) and plays a role in the sleep/wake cycle.
Social cues entraining circadian rhythms.
Schedules created by others, e.g. mealtimes and bedtimes. Circadian rhythms start at 6 weeks. Most babies entrained by 16 weeks. Schedules imposed by parents are a key influence. Adapting to local eating and sleeping times is an effective way of entrainin
What was the method used by DeCoursey et al (2000)?
Removed SCNs from 30 chipmunks; returned to habitat and observed alongside 2 other groups - 24 surgical controls and 20 controls.
What was the results of DeCoursey et al's 2000 study on chipmunks?
After 80 days, significantly more of SCN-lesioned died as their sleep/wake cycles disappeared and were killed by predators.
What was the method used by Ralph et al. (1990)?
Bred 'mutant' hamsters with a 20-hour sleep/wake cycle. When SCN cells from foetal tissue of mutant hamsters were transplanted into normal hamster brains, the cycles of second group defaulted to 20 hours.
What conclusions can be drawn from DeCoursey et al's 2000 study on chipmunks?
The SCN has an important role in establishing and maintaining the sleep/wake cycle.
Zeitgebers is German for what?
Time giver.
Zeitgebers
External factors in the environment that reset our biological clocks through a process called entrainment.
Light as an exogenous zeitgeber.
One of the most dominant EZs; resets body's pacemaker through SCN. May explain why Campell and Murphy found that shining lights on knees caused a shift in circadian rhythm.
Endogenous pacemakers and exogenous zeitgeber i_______ with o__ a______. To control and m_____ bi________ r______. It is important that you discuss the two factors together.
Endogenous pacemakers and exogenous zeitgeber interact with one another. To control and manage biological rhythms. It is important that you discuss the two factors together.
Outline one evaluative point circadian rhythms (beyond the master clock).
A weakness of saying that the SCN is the only endogenous pacemaker is that it ignores other endogenous pacemakers in the body.
A weakness of saying that the SCN is the only endogenous pacemaker is that it ignores other endogenous pacemakers in the body. (Now do the evidence part.)
Research has revealed that there are numerous circadian rhythms in many organs and cells in the body, called peripheral oscillators. Although these peripheral clocks are highly influenced by the SCN, they can act independently. Damiola at al (2000) demons
Research has revealed that there are numerous circadian rhythms in many organs and cells in the body, called peripheral oscillators. Although these peripheral clocks are highly influenced by the SCN, they can act independently. Damiola at al (2000) demons
This suggests that there may be other complex influences on the sleep/wake cycle, aside the SCN, the master clock.
Point: The influence of exogenous zietgebers may be overstated. (Now do the rest of the evaluative paragraph.)
Miles et al. (1977) recount the story of a young man, blind from birth, with a circadian rhythm of 24.9 hours. Despite exposure to social cues, his sleep/wake cycle couldn't be adjusted. Consequently, he had to take sedatives at night and stimulants in th
What is the nervous system?
Specialised network of cells in the body that form the primary internal communication system, consisting of the central nervous system and the peripheral nervous system.
What is the somatic nervous system (SNS)?
Transmits information from receptor cells in the sense organs to the CNS. Also receives info from CNS that directs muscles to act.
What is the autonomic nervous system (ANS)?
Transmits info to and from receptor cells in the bodily organs. Operates involuntarily and is out of conscious control. Its 2 main divisions are sympathetic and parasympathetic.
What is the endocrine system?
One of the body's major information systems that instructs glands to release hormones directly into the bloodstream, which are carried towards target organs in the body.
What is a gland?
An organ in the body that synthesises substances like hormones.
Define the fight or flight response.
The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or flee.
What is adrenaline and where is it produced? What is its affect on the body?
A hormone produced by adrenal glands which is part of body's immediate stress response system. Raises heart rate, contracts blood vessels and dilates air passages. More blood is sent to muscles.
The endocrine system works more s----- than the nervous system but has very w--------- and po------ effects.
The endocrine system works more slowly than the nervous system but has very widespread and powerful effects.
What is the name of the 'master gland' that is located in the brain and controls the release of hormones from all other endocrine glands in the body?
Pituitary gland.
List the 6 things that the sympathetic response that is the fight or flight response cause? (i.e. What are the symptoms of the fight or flight response?)
Increases heart rate and breathing rate, dilates pupils, inhibits digestion and saliva production and contracts rectum.
Explain the process of synaptic transmission. 4 marks.
An electrical impulse reach the presynaptic terminal. This action potential then triggers release of neurotransmitters, which cross the synapse from vesicles and combine with receptors on the postsynaptic membrane. The stimulation of postsynaptic receptor