Biopsychology

Seite 1

Divisions of the nervous system

Central nervous system includes the brain and spinal chord

Peripheral nervous system includes all nerve tissue outside the CNS

Brain- maintains life and is involved in higher functions and psychological processes

Spinal chord- receives information to and from the brain

CNS- concerned with all life functions and psychological processes

Peripheral nervous system- transmits information to and from the CNS

Somatic nervous system- Transmits information to and from the senses, and to and from the CNS. Voluntary activities under conscious control and some unconscious movements such as reflexes.

Autonomic nervous system- Transmits information to and from internal organs to sustain life processes. Involuntary activities not under conscious control or reflexes.

Sympathetic nervous system- increases bodily activities. Deals with emergency situations e.g. prepares body for fight or flight.

Parasympathetic nervous system- maintains and decreases bodily activities. Controls involuntary activities not emergencies e.g. organs of the digestive system breaking down food.

Seite 2

Structure and function of nerves

Interneuron = relay neuron

Sensory neurone

Carry messages PNS snd CNS

Have long dendrites and short axons

Unipolar (only transmit information)

Relay neurone

Connects sensory neurones to motor and other relay neurones

Short dendrites and short axons

Multipolar (send and receive messages from many sources)

Motor neurone

Connects CNS to effectors in the body

Short dendrites and long axons

Multipolar

Process of synaptic transmission (process for transmitting messages from neurone to neurone)

Electrical nerve impulse travels down the neurone and is translated into a chemical signal in the form of a neurotransmitter (chemicals in the brain) at the pre-synaptic terminal

Chemical is released into the synaptic fluid where it difffuses across the synase (specialised gap between neurones through which the electrical impulse from a neurone is chemically transmitted)

Postsynaptic neurone contains receptors and they quickly take up neurotransmitters from the fluid and convert them into electrical impulses to travel down the next neurone

Excitation and inhibition

When the neurotransmitter meets the receptor an ion channel is opened in the membrane

This causes ions to flow through the membrane into the neurone and the flooding of neurones cuauses a 'potential' in the dendrites

The potential produced due to the ions entering the neurone is either excitatory or inhibitory

Excitatory neurones

Increases the chance of a neurone firing

Neurotransmitters such as noradrenaline

Inhibitory neurones

Decreases the chance of a neurone firing and the message is likely to be stopped

Generally responsible for calming the body, inducing sleep and filtering out unnecessary excitatory signals

To find the likelihood of the cell firing the excitatory and inhibitory synaptic input is added together. The sum of this then determines whether the cell fires or not (threshold it needs to reach to fire is -55 mV)

Seite 3

Endocrine system

Consists of glands which release chemicals (hormones) throughout the body via blood and other bodily fluids

Each hormone is thought to affect behaviour in different ways

Hormones travel via the bloodstream to target sites throughout the body

A given hormone usually only affects a limited number of cells known as target cells

Specific hormones e.g. testosterone must be picked up by specific receptors, cells that do not contain the receptor cannot be directly influenced by the hormone

When enough receptor sites are stimulated it results in a physiological reaction in the target cell

Thymus (below the thyroid gland and parathyroid)- helps build resistance to disease

Important glands to know about:

Pituitary gland- some of the hormones released help regulate the endocrine system. Controls other glands in the body.

Adrenal gland- Important for the fight or flight response as it helps trigger the fight or flight response

Testes- triggers the release of testosterone (male hormone)

Ovaries- triggers the release of oestrogen and progesteron

Hormones level and timings of release are critical to normal functioning. Too much or little at one time would cause dysfunction e.g. Cushings syndrome where too much cortisol (often due to taking corticosteroids) which causes weight gain, thinning skin which brusies easily and muscle or bone weakness.

Seite 4

Fight or flight

Prepares the body to fight or to flee from perceived attack, harm or threat to our survival

Primitive respone

Automatic respone

Can be useful if you are experiencing threat or danger from humans or animals such as threat from a bear, being mugged or a fire

Can be not useful in the modern day as having an adrenaline rush can cause illogical behaviour to occur and the fight or flight response in the modern day is not always a suitable response

Steps which occur in the fight or flight response:

Hypothalamus recognises there is a threat

Hypothalamus sends a message to the adrenal gland (specifically adrenal medulla)

Triggering the release of noradrenaline in the brain and adrenaline to the endocrine system

This causes changes to occur within in the body:

Increased heart rate- speeds up blood flow to vital organs and improve spread of adrenaline around the body

Faster breathing- increases oxygen intake

Muscle tension- improve reaction time and speed

Pupil dilation- improve vision

Production of sweat- facillitate temperature regulation

Reduced function of the digestive and immune system- save energy for prioritised functions e.g. running

Adrenal glands

Adrenal cortex produces corticosteriods (a hormone)

The corticosteroids influence or regulate the body's response to stress, metabolism and immune system

Inner part of the adrenal gland is the adrenal medulla

Adrenal medulla produces catecholamines such as adrenaline (adrenaline increases heart rate and blood prssure)

Amygdala and hypothalamus role in fight or flight

The amygdala is mobilised when an individual is faced with a threat

Amygdala associates sensory signals with fight or flight emotions such as anger

Amygdala then sends signals of distress to the hypothalamus (a command centre in the brain) communicating with the rest of the body through the sympathetic nervous system

Body responds to the stressers via 2 systems, one for acute stressors (sudden) such as an attack and another for chronic (ongoing) such as stress for exams

Seite 5

Localisation of function in the brain

Brain has 2 hemispheres

The hemispheres are bridged by the corpus callosum which is a bundle of fibres

The corpus callosum enables both sides of the brain to exchange information

Phineas Gage

Localisation of function originally came from case studies

Gage was a railway workers in the USA who worked by using dynamite to blow a clear path so a railway track could be laid

Dynamite was placed into position using an iron rode (called a tamping iron) to bed the dynamite into place using sand

Rod caused a spark one day and caused the dynamite to blow up

This caused the rod to go through the chin of Phineas and out the top of his forehead

Phineas was conscious and could speak but lost sight in his left eye

Psychologically he had changed too he had gone from being calm and well-mannered to unreliable, hostile and rude

Dr Bigelow believed that there was no localisation and Phineas' recovery supported that. However Dr Harlow believed there was localisation of function within the brain as Phineas' personality had changed so it was believed the area damaged must have held the reasoning and planning of an individual. Dr Harlow was proved to be correct in that there was localisation of function within the brain

Issues with Gage as evidence

Little evidence

Reported a while after it happened

Case study- only looking at the effects on 1 person so how can you apply it to everyone?

Hemispheric (division of function between the 2 hemispheres)lateralisation

In most people the brain is contralateral (left part controls the right side of the body and the right part controls the left side of the body)

Left hemisphere

Most people, language processing is here

Focuses on detail

Right hemisphere

Recognising such as recognising emotions of others

Spatial relationships - Clarke, Assal and de Tribolet- found that a woman got lost in familiar places however if given verbal instructions she did not get lost.

Focuses on patterns

Motor cortex

Causes movement

Sends messages through the brain stem and spinal chord to the muscles

Important for complex movemeents such as running but not basic movements such as coughing

Motor cortex instructs the body on a specific outcome however the spinal chord and other areas of the body co-ordinate the body's movement in relevant areas

Areas of the brain involved in movement- spinal chord and brain (co-ordinate movement), premotor cortex (plans a movement before it is done) and the prefrontal cortex (stores sensory information before the moevement and works out the likelihood of the movement outcome

Somatosensory cortex

Makes sense of external information from our senses

2 parts to the sensory cortex- primary sensory cortex where the brain first processes information from sensory organs and the second sensory cortex which is involved in higher order processing needed for hand-held objects

Amount of neural connections needed to the somatosensory cortex in specific areas is dependent on the amount of the somatosensry cortex needed in that specific area e.g. face would need a lot however trunk of the body would need very little.

Visual centres

Primary visual cortex

In the occipital lobe

Main visual area

An area within the main visual area called Area V1 is seen to be very important for visual perception

Receives and processes sensory nerve impulses from the eyes

Those with damage in V1 are said to not have any vision including conscious vision, dreams or visual imagery while awake (Hurrovitz et al- 1999)

Visual information is transmitted along 2 pathways- 1 is components of the visual field and the other is to do with locations within a visual field

Individuals with Are V1 damage can have 'blindsight'. This is where someone appears blind as they do not have vision but they can find objects within a visual field by pointing. Shows how some processing in the visual cortex may not be conscious (Bridgeman and Staggs- 1982)

Auditory centres

Primary auditory cortex

2 primary auditory cortices, one in each hemisphere

Converts sound waves from our ears into understandable data by electric impulses

Auditory cortex in both hemispheres receives information from both ears via 2 pathways that transmit information about what a specific sound is and the location of the sound

Information from the right ear mainly goes to the left hemisphere but some is transmitted to the left primary auditory complex too (happens in the same way to the left ear)

Primary auditory cortex damage does not lead to total deafness as sounds can still be heard but sounds that need complex processing such as music cannot be heard

Primary cortex also processes auditory image- when individuals watch silent films the primary auditory cortex in both hemispheres of the brain was activated e.g. if a door was shut with force as the 'bang' that would go with the closing of the door had been imagined

Disorders due to damage to this area include classical auditory agnosia (inability to process environmental sounds such as animal noises)

Language centres

Broca's area

Speech production

Not all words are equally affected if there is damage to this area of the brain- nouns and verbs seem to be unaffected in some patients with Broca's area damage and other word categories such as prepositions and conjunctions (e.g. and, if, but) are unable to be spoken e.g. cannot read out 'to be or not to be' but can read put 'two bee oar knot two bee' (Gardner and Zurif- 1975)

Louis Leborgne suffered from epilepsy and eventually was unable to speak other than to say the word tan. Following his death, Broca (a neurologist treating Leborgne before his death) found a lesion (area which has damage) on the left temporal lobe. It was the only area of the brain with visible damage so Broca concluded this was the area involved with speech production. Since then Leborgne's brain has been scanned using modern techniques and although there is more extensive damage the area of the brain Brocca found for speech production was correct

Disorders associated with damage in this area include stuttering (underactivity in the area)

Language centres

Wernicke's area

Separate area of language processing

Understanding language and assessing words

Found by Wernicke who found that those with damage in the area were unable to comprehend language and struggled to find the words they needed but could speak fluently

Case study- Phil had a stroke and was unable to speak in understandable language as the Wernick's area of the brain was damaged. He suffered from Wernicke's aphasia

Evaluation of research into localisation of function

Helps understand people's injuries when brain damage occurs

Help to find new treatments and cures for illnesses and disorders caused by damage to a specific area of the brain

Can be scientifically studied in a controlled environment

Can be studied using scientific equipment

There are few cases that can be studied to find the localisation of function

Case studies are often outdated

Lashley found that on rats' brains there was no specific area involved with memory and it seems memory is stored all over the brain. However caution should be taken when applying this to humans as there are differences physiologically

Evidence from case studies suggests there is locationalisation and lateralisation of functions. If functions were all over the brain then specific defects would not occur

Case studies only give evidence and cannot provide proof

Split brain research

To help individuals with epilepsy that cannot be controlled with drugs the area of the brain associated with the epilepsy can be removed

If there are several areas of the brain which are causing the epilepsy the corpus callosum can be cut so that the epilepsy is contained within one hemisphere. This reduces the number of epileptic fits as it stops the hemispheres rebounding from each other which can prompt seizure

This method of 'splitting the brain' can reduce epileptic fits but can affect behaviour and perception

Alien-hand syndrome

Where the 2 hemispheres are in competition between parts of the brain

The feeling that an individual has that their hand is possessed by a force outside of their control, they can feel sensation in their hand but believe the hand is not a part of their body and have no control over their movement

The right side of the brain is usually dominated by the left side of the brain, but in this case the right side refuses to be dominated by the left e.g. left hand may tie the shoelaces and right hand untie the shoe laces without an individual realising

Split brain research- Richard Sperry- 1974

Aim

To investigate the hemispheric functioning of split-brain patients

Procedure

Quasi-experiment

11 participants who all had had their corpus callosum severed

Performed tasks and the results were compared with those who had their corpus callosum intact

The tasks involved presenting information to one hemisphere by sending it to 1 visual field so they were blindfolded so only one eye recieved the information

Findings

Information shown to 1 hemisphere can only be recalled if shown to that hemisphere again

Visual information shown to the left hemisphere (right visual field) can be described in speech

Visual material shown to the right hemisphere (left visual field) will deny seeing anything but are able to pick the correct object out with their left hand

2 different figures shown to the hemispheres, the participants could draw what they had seen in the left visual field with their left hand (right hemisphere) but if asked what they had drawn they would say what they saw in their right visual field (left hemisphere)

Object placed in the right hand can be described or named (left hemisphere) but an object placed in the left hand cannot be described or named, only picked out from other objects (right hemisphere)

Objects can only be selected by the hand which they were originally placed

Left hand will ignore objects the right hand is looking for and vice versa

Conclusions

There is some lateralisation of function between the hemispheres

Evaluation of split brain research

Small sample size so cannot be generalised accurately

Small sample size is representative of the number of individuals who undergo the operation

High level of control and variables controlled so is scientific and valid

Research evidence

Low ecological validity as the research does not involves problems encountered normally so is an artificial setting

Cannot compare brains of severely epileptic people to normal people as the brain could be different due to the epilepsy or could be different due to surgery

Brain plasticity (ability of the brain to change and adapt synapses, pathways and structures after various experiences e.g. positive (e.g. learning) or negative (e.g. recovering after brain trauma)

Rosenzweig, Bennet and Diamond- 1972- role of environmental stimulation on brain plasticity

Aim

Investigate if environmental factors would affect development of neurones in the cerebal cortex

Procedure

Rats either in enriched condition (EC) or impoverished condition (IC)

EC researchers placed 10-12 rats in a cage with different stimulus objects to explore and play with and received maze training

IC researchers placed each rat into individual cages with no maze training or toys

Standard condition (SC) where rats were kept in a standard lab cage with food and water

Spent 30-60 days in the environment and then were killed to study the brain anatomy differences

Results

Anatomy of the brain was different between IC and EC

Higher thickness and weight in cortex of EC than IC

Rats in EC had greater activity in the neurones in the cerebal cortex which were involved with the transmission of acetylcholine (important neurotransmitter for learning and memory)

Just 2 hours a day in EC produced the same changes in rats that had been in the EC for a long period of time

Evaluation

Challenged the belief that brain weight cannot change

Controlled environment

Animals used so could be hard to generalise to humans

Replicated a number of times so is reliable

Ethical issues with the use of animals

Case study: Jody Miller

Aged 3 she started having frequent seizures from her right hemisphere that were nearly fatal

Had to have the right hemisphere removed

Plasticity of the brain enabled the left hemisphere to take over some of the right hemisphere functions so Jodie was now able to walk (previously she had difficulty doing this)

Neurone plasticity

Axonal sprouting- when an axon is damaged the connect between the neighbouring neurone is lost. Some cases the other axons connected to the neurone will create extra connections to the neurone to replace connections lost from the damaged axon. Occurs for about 2 weeks after damage and will only work if the damaged and compensatory axons have similar functions

Growth of new neurones (neurogenesis)- occurs in the human olfactory bulb and hippocampus. Not yet known how this helps

New behavioural strategies- Not direct recovery of function but is about using other means to have the function e.g. memory loss so writing down memories and not relying on your memory. Kaspar- 1997- recovery after brain damage is better in doctors this could be due to them having greater cognitive resources to draw on and leads them to develop better alternative starategies

Denervation supersensitivity- axons that do a similar job become more aroused so that they can compensate for axons lost. It can cause consequences such as over-sensitivity to messages such as pain

Evaluation of plasticity research

Tested on animals sometimes so is not representative

Not a large population size

Lots of different research has been done

How the brain attempts to recover

Drugs- chemicals in the brain can help control brain growth and organisation of neurones in the developing brain. Some of the chemicals it is hoped, could be used after damage to prevent the degeneration and death of neurones and increase regeneration and axon sprouting

Neuron transplant- new area. Stem cells implanted into a damaged area have the potential to grow into neurones and make functional synaptic connections to help to restore behavioural functions

Rehabilitation and brain re-organisation- practising skills can alter the brain's organisation, so practice of a skill affected by brain damage may lead to significant recovery

Evaluation

Not a large population size

Effects are seen under controlled environments not real life situations

Different researchers have studied this

Could have bias effects with medicine

Hard to know how much it has recovered as often functioning before the injury is not known

Hard to make generalisations of recovery as each individual is different and recovery varies according to the extent of damage and localisation

Factors affecting brain recovery

Perseverance- function may be lost but that could be due to the individual not properly trying and believes it is unable to be recovered

Physical exhaustion, stress and alcohol consumption- Stress and alcohol consumption can affect the ability an individual has to use a function which has been regained. When function of an individual is recovered it has to be remembered that often the function is used with lots of effort and means the person can do the task but are often fatigued by it

Age- deterioration of the brain during old age can affect the extent and speed of recovery.

Gender- research suggests women can recover better from brain injuries as their functions are not as lateralised (concentrated in 1 hemisphere). However there are mixed views on women recovering better from brain injuries so no overall conclusions can be made

Seite 6

Ways to study the brain

fMRIs (functioning magentic resonance imaging)

Operate the same way as MRIs but show activity as it occurs

Records the amount of haemoglobin as it haemoglobin reacts differently with oxygen and when an area of the brain is activated it needs more oxygen.

Around a 1 second time lapse in the image seen

Gives a dynamic (moving) picture

Accurate within 1-2 mm in the brain

Evaluation

Provides a moving picture of activity so can measure activity rather than just physiology

Complexity of the brain means analysis of brain scans is hard and complex

Dynamic nature of the brain is important and fMRI is useful for this

Machines are expensive to buy and operate

Often small sample sizes so is difficult to generalise

EEGs (electroencephalogram) and ERPs (event-related potentials)

EEGs

Measure electrical activity of the brain through placing electrodes on the scalp

Electrodes measure activity of cells immediately under the scalp

Brain cells communicate via electrical impulses and are active all the time so activity shows up as lines on EEG recording

ERPs

Records information in the same way as EEGs but focuses on brain acitvity in response to stimuli

Helps researchers to understand how the brain responds to specific events and can help measure the effectiveness of treatments

Costa, Braun and Birbaumer- 2003- found when young people (both sexes, aged 19-29) were asked how they felt about nude pictures men said they were generally aroused by females and females had neutral feelings for both sexes pictures. However when an ERP was done it was found they had a higher response to opposite-nude pictures than reported. More accurate than self-report studies

Evaluation

Both fairly accurate but activity close to the electrode is only measured and finer detail could be missed

Non invasive

Cheaper and more readily avaliable than fMRIs

Useful to test the reliability of self-report studies

Output must be interpreted by someone with expertise

Post-mortem examination

Examination of a dead body

See where damage has occurred in the body and brain and the behaviour shown due to this e.g. case of Leborgne (Tan)

Evaluation

No discomfort of an individual

Looks at actual brain tissue so there is no time lag

Brain could be affected by the person's death e.g. disease

Issues with function comparison before and after death

Brain activity cannot be measured

Seite 7

Biological rhythms

Circadian rhythms (biological rhythms lasting a day)

e.g. sleep/wake cycle measured by reading the time and regular events like meals.

Our body clock is regulated by internal system including the release of hormones e.g. melatonin, metabolic rate and body temperature

Siffre- 1975

Aim

Discover how natural rhythms of human life could be affected by living where there was no time

Procedure

Lived underground in isolation for 63 days

No natural light or cues at to whether it was day or night

Had an artificial light to help with navigation through the cave

He would check his pulse and do a psychological test every time he called up to the team outside the cave. The tes involved counting from 1-120 at a rate of 1 digit per second.

Findings

His psychological time had changed

His sleep/wake cycle had changed to about 25-30 hour cycle

Lost track of the days and thought he had been in the cave for a month less than he had

Conclusions

Suggests natural light is important for keeping your 24-hour cycle

Aschoff and Weber- 1962

Studied participants in a bunker with no lights or windows

Participants could turn lights on and off as they wished so the slight source fitted with their body clocks

Eventually their body clocks settled to a sleep/wake cycle of 25-27 hours

Suggests that natural light is used to adjust our pacemakers with the environment and a 24 hour clock is not inline with our natural body rhythm

Effect of endogenous pacemaker and exogenous zeitgebers on the sleep/wake cycle

Endogenous pacemaker

Rhythms from the internal body system

Can be affected by the environment specifically light

Do function without environmental clues but will vary without environmental cues

Example is of endogenous pacemakers for light:

Low light → Optic chiasm in the eye → stimulates SCN → Stimulates pineal gland → Produces melatonin → Enhances production of serotonin → Brain acitivity falls → Sleep

Superchiasmatic nucleus (SCN)- is a pacemaker of the biological clock in the sleep-wake cycle, it has it own internal biological rhythm due to protein synthesis. It is connected to the optic chiasm so receives input about the amount of light in the environment. Influences the sleep cycle as light stimulates nerve impulses that travel from the eye along the optic nerve to the brain

Pineal gland- structure contains receptors that respond to external light. It is linked to the SCN by neural pathway. Electrical simulation of SCN is transferred to pineal gland and so releases melatonin. Light and melatonin are inversely proportional so when light levels are high, melatonin levels are low.

Melatonin induces sleep as it enhances the production of seratonin causing the nervous system to slow down so brain activity falls and sleep begins

Exogenous zeitgebers

Cues from the environment which play an important role in regulating time

External cues

They are cues for endogenous pacemakers

Help regulate the body clock so it is inline with the environment

e.g. light, blue light, noise

Research to support

Campbell and Murphy- 1998

Monitored the body temperature of 15 volunteers sleeping in a lab

Were introduced to light and night with beams of light shone on the backs of their knees at intervals

Circadian rhythms were disrupted by up to 3 hours

Shows its not necessary for just light to enter the eyes for it to have a psychological effect on biological rhythms

Steel et al - 2008

Investigated effects of constant daylight on circadian rhythms by monitoring 6 participants living in isolation in Artic for 6 weeks

Constant daylight

Participants kept sleep logs

Researchers found that 5 of 6 participants developed a sleep/wake cycle longer than 24 hours

Also found sleep patterns were individual and no synchronised patterns emerged

Social cues may have a stronger effect in absence of zeitgebers

Evaluation of research into circadian rhythms

Little external validity as conditions are artificial

Sleep patterns could be caused by being monitored not the effect of the zeitgeber

Animals used in research and cannot generalise findings to animals and humans as there are physiological differences

Research can be used to find treatments

Infradian rhythms (biological rhythms lasting more than 24 hours)

e.g. menstrual cycle dictated by endocrine system and hibernation

Not purely dictated by the release of hormones

Zeitgebers such as light and odour have an effect also

McClintock and Stern- 1998

Women (1) recieved 'odourless compounds' from armpits of women (2) in the latter 1/2 of the menstrual cycle

Women (1) found their menstrual cycle shortened possibly due to the effect of the other women's pheromones as they reached the end of their cycle

Women's (2) odourless compounds from armpit in beginning of their cycle lengthened their cycle.

Menstrual cycle can be altered by pheromones

Reinberg- 1967

A woman spent 3 months in a cave with only a lamp for light

Her days lengthened to 24.9 hours and her menstrual cycle shortened to 25.7 days

Shows light can affect the menstrual cycle

After the study it took a year for the body to readjust her menstrual cycle so infradian rhythms can be affected by external zeitgebers

Evaluation

Helps to explain menstrual synchronicity could be due to pheromones

Evolutionary advantage for menstrual synchronicity as there could be synchronised pregnancies and so childcare can be shared once the baby is born

Not known what pheromones have an effect and how close and how long women have to live together to experience this

Wilson- 1992- challenged the idea of menstrual synchrony saying experimental evidence suggests it's existance is exaggerated

Ultradian rhythms (last less than 24 hours)

e.g. respiration, rapid eye movement, heart beat, sleep/wake cycle

Sleep has 5 stages through the night:

Over a course of 90 minutes an individual goes through stages 1-4 then returns to 3 and then 2 and then REM. The sleep cycle then begins again and the number of cycles depends on how long the person sleeps for.

Dement and Kleitman- 1957

Aims

Investigate brain activity change throughout night-time sleep

Procedure

7 adult males and 2 adult females

Participants reported to a lab at bedtime to have an EEG

EEG measurements taken throughout the time asleep at night

Participants told not to drink caffinated drinks before sleep was to be investigated

Findings

Everyone had REM periods during every night

High incidences of dream recall when participants woke during REM periods of sleep. If woken in other stages dreams were not reported as often. Participants were woken up during 5-15 minutes into the start of REM sleep

Brain activity of vivid dreams different to less clear dreams

Rapid eye movements of participants during REM sleep varied according to dream type and mirrored rapid eye movements when awake and completing a similar task to the task dreamt about

So they managed to identify the stage when dreams were most likely to occur

Conclusion

Sleep stages follow a typical pattern throughout the night

Dreams occur mostly during the REM stage

Evaluation

Individual differences so findings cannot be generalised

Useful as it helps to understand medical conditions and find new treatments

Small sample sizes used so cannot be generalised

Can be applied to finding out the best way to live life e.g. the best time to get to sleep or wake up etc.

Seite 8

Key definitions

Action potential

Adrenal gland

Adrenal medulla

Autonomic nervous system

Axon

Axon terminal

Brain plasticity (neuroplasticity)

Central nervous system

Circadian rhythms

Contralateral

Dendrites

Electroencephalogram (EEG)

Endocrine system

Endogenous pacemakers

Event-related potentials (ERPs)

Excitation

Exogenous zeitgebers

Functional magnetic resonance imaging (fMRI)

Glia/Gial

Hemispheric lateralisation

Hormones

Hypothalamus

Infradian rhythms

Inhibition

Ions

Limbic system

Localisation

Motor neuron

Neuron

Neurotransmitters

Parasympathetic nervous system

Peripheral nervous system

Relay neuron

Resting potential

Reticular formation

Sensory neuron

Soma

Somatic nervous system

Substantia nigra

Sympathetic nervous system

Synapses

Thalamus

Ultradian rhythms