Biopsychology

outline the structure of the human nervous system

outline the structure of the human nervous system

divided first, into Peripheral Nervous System, and Central Nervous System.

Central Nervous system divided into brain and spinal chord

peripheral nervous system divided into somatic and autonomic nervous system

autonomic nervous system further divided into parasympathetic and sympathetic branches

what’s the role of the central nervous system (and it’s branches)

• brain - centre of all conscious awareness

• spinal chord - extension of the brain, responsible for reflex actions, passes message to and from brain - connects brain to PNS

what’s the role of the peripheral nervous system

transmits messages to and from the CNS

outline the role of the somatic nervous system

controls muscle movement, receives info from sensory receptors

outline the role of the autonomic nervous system and its branches

governs vital function

parasympathetic - ‘rest and digest’

• lowers heart rate

• lowers breathing rate

• constricts pupils

• stimulates digestion and saliva production

sympathetic - ‘fight or flight’

• raises breathing rate

• raises heart rate

• dilates pupils

• inhibits digestion and salvia production

List the major components of the endocrine system

• hypothalamus

• pituitary - ‘master gland’

• thyroid

• adrenal

• pancreas

• ovaries/testes

split into glands and hormones

works alongside the nervous system to control vital functions

define gland

organ that synthesises substances such as hormones

define hormones

chemical substances that circulate in the bloodstream affecting target organs. powerful effects and decreases quickly

Outline the steps of a fight or flight response (ANS and endocrine system working together)

• stressor perceived

• hypothalamus changes ANS from parasympathetic to sympathetic

• adrenaline is released

• adrenaline triggers physiological changes

  • creates the psychological arousal necessary for fight or flight response

• threat passes

  • parasympathetic branch of ANS takes back over

features of a sensory neuron

• long dendrite

• short axon

features of a relay neuron

• short dendrite

• short axon

features of a motor neuron

• short dendrite

• long axon

briefly outline the process of electric transmission

• when a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside

• when a neuron is activated by a stimulus, the inside of the cell becomes very quickly positively charged

• this causes action potential

• creates electrical impulse that travels down the axon toward the end of the neuron

define excitation

a neurotransmitter such as adrenaline increases the positive charge of the postsynaptic neuron - increasing the likelihood that the neuron will fire

define inhibition

a neurotransmitter such as serotonin makes the charge of the postsynaptic neuron more negative - decreasing the likelihood that the neuron will fire

name each part of the brain

A - motor area

B - somatosensory area

C - visual area

D - Wernicke’s area

E - auditory area

F - Broca’s area

motor area

frontal lobe

responsible for coordination of movement - in opposite side of body to hemisphere

somatosensory area

parietal lobe

sensory information from the skin processed - the amount of the somatosensory area devoted to the particular body part denotes its sensitivity

visual area

occipital lobe

processes visual information hemisphere opposite to eye

Wernicke’s area

temporal lobe - LH

language comprehension

those with damage/deficiency suffer from ‘Wernicke’s aphasia’

auditory area

temporal lobe

concerned with analysis of speech and sound based information

Broca’s area

frontal lobe - LH

language production

those with damage/deficiencies experience Broca’s aphasia

Give two weaknesses and one strength of localisation of function theory

• brain scan evidence - Peterson used brain scans to demonstrate how Broca’s area was active during a speaking task and Wernicke’s area was active during a listening task

• case study evidence - unique cases of neurological damage support localisation theory - Phineas Gage lost most of LFL, survived but personality completely changed, indicates that FL is potentially responsible for regulating mood

• Plasticity - law of equipotentiality - after brain injury, undamaged areas that aren’t supposed to take on certain roles can temporarily fulfill them whilst recovery occurs.

define plasticity

the brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning

define functional recovery

a form of plasticity - following damage through trauma, the brain is able to redistribute or transfer functions that are usually performed by a damaged area to other, undamaged areas

outline the procedure and findings of Maguire’s study

• studies brains of London cab drivers who knew ‘the knowledge’

• observed significantly more grey matter in the posterior hippocampus than in a matched control group

  • this was also more pronounced the longer they’d been in the job

outline the process of synaptic pruning

• during infancy, the brain experiences a rapid growth in the number of synaptic connections

  • peaks at about 15,000 at age 2/3

• as we age, rarely used connections are deleted and frequently used connections are strengthened

list and briefly explain the three processes of functional recovery

• axonal sprouting - the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

• reformation of blood vessels

• recruitment of homologous area - on opposite side of the brain to perform specific tasks

give two strengths and weakness of the concepts of plasticity and functional recovery

• case study support - Gabby Giffords, US senator shot at point blank range, made an almost full recovery

• cognitive reserve - individual factors affect the likelihood of recovery, education and age etc

• Age and plasticity - study of golfers 40-60 years of age found that 40 hours of training could produces changes in neural representations of movement (fMRI) compared to a control group

outline Sperry’s procedure

• studied epilepsy patients who had had corpus collosum severed

• devised a set up where he could project one image/word to the right visual field and the same or a different image could be projected to the left visual field

• ‘normal brain’ would immediately share this info between hemispheres but not in these patients

outline findings for Sperry’s research

• describing what you see

  • patients could not describe an image shown to LVF

  • language centres are in the LH, so LVF (RH) can’t verbally describe

• recognition by touch

  • patients couldn’t attach labels to objects shown in LVF but could select a related object using their left hand

  • couldn’t use RH to verbally describe the object, but could gain understanding

• composite words

  • two words presented simultaneously, one on either side of the visual field (ex - key on the left and ring on the right)

  • patient writes key and says ring

• matching faces

  • face presented to LVF (RH) consistently selected and the one presented to the RVF (LH)

  • RVF(LH) dominates in visual description

  • LVF(RH) dominates in the actual matching of the face

give two strengths and one weakness of Sperry’s split brain research

• strengths of the methodology - highly specialised and standardised procedures, high internal validity

• theoretical basis - prompted a theoretical and philosophical debate within psychology

• differences in function may be overstated - pop-psychological literature oversimplifies the functional distinction

define functional magnetic resonance imaging (fMRI)

a method used to measure brain activity while a person is performing a task that uses MRI technology - detects which regions of the brain are taking up a lot of oxygen

define electroencephalogram (EEG)

scan taken by electrodes - represents brainwave patterns that are generated from actions of millions of neurons.

provides an overall account of brain activity

define event-related potential (ERP)

uses statistical technique that averages out all extraneous brain activity and leaves all those which relate to the presentation of a specific stimulus or performance of a specific task - leaving event related potentials: types of brainwaves triggered by particular events

define post-mortem examination

brain analysed after death to determine whether certain observed behaviours during the patients lifetime can be linked to abnormalities in the brain

give strengths and weaknesses of fMRI

• strengths

  • does not rely on the use of radiation

  • virtually risk free - non invasive and straightforward

  • images have v high spatial resolution

• weaknesses

  • expensive compared to other neuroimaging techniques

  • can only capture a clear image if patient stays completely still

  • poor temporal resolution

give strengths and weaknesses of EEG

• strengths

  • invaluable in diagnosis of conditions like epilepsy

  • extremely high temporal resolution

• weaknesses

  • information received is generalised - not useful for pinpointing exact source of neural activity

give strengths and weaknesses of ERPs

• strengths

  • more specificity than achieved with EEGs

  • excellent temporal resolution

• weaknesses

  • lack of standardisation in methodology = difficulty confirming results

  • not always possible to completely eliminate ‘background noise’ from EEG

give strengths and weaknesses of post-mortem examinations

• strengths

  • vital in providing an early understanding in brain functioning

  • generate hypothesis for further study

• weaknesses

  • causation difficult to identify

  • can raise ethical issues of informed consent

define biological rhythm

distinct patterns of changes in body activity that conform to cyclical time periods. Influenced by endogenous pacemakers and exogenous zeitgebers

define circadian rhythm

a type of biological rhythm subject to the 24 hour cycle, regulates a number of body processes such as sleep/wake cycle

outline procedure and findings for Siffre’s study

• spent two months, and then six months in a cave deprived of exposure to natural light and sound

• each time, his ‘free-running’ biological rhythm settled down to one that was just beyond 24 hours - around 25 hours.

• suggests that natural sleep/wake cycle is slightly longer than 24 hours but is entrained by exogenous zeitgebers

outline briefly, Aschoff and Wever’s bunker study

• group of students spent a week in an old WWII bunker

• all but one of the participants (who’s cycle extended to 29 hours) displayed a circadian rhythm of 24/25 hours

give one strength and one weakness of research into circadian rhythms

• practical applications in understanding shift work - given researchers a better understanding of adverse consequences that can occur as a result of rhythm disruption - economic implications in managing worker productivity

• use of case studies and small samples - results may not be generalisable

• poor control in studies - allowed artificial light - later studies have showed artificial light can alter circadian rhythms

define infradian rhythm

a type of biological rhythm with a frequency of less than one cycle in 24hours such as menstruation or seasonal affective disorder

define ultradian rhythm

a type of biological rhythm with a frequency of more than one cycle in 24hours - like the stages of sleep

outline Stern and McClintock’s study

• 29 women with irregular periods rubbed pheromones from other women on their upper lip for a whole cycle

• 68% of the women experienced cycle changes that brought them closer to their odour donor

outline SAD as an infradian rhythm

• depressive disorder with a seasonal pattern of onset

• hypothesised that melatonin is implicated in SAD - less light in the winter

outline briefly, the stages of sleep as an ultradian rhythm

• 5 distinct stages spanning approximately 90 minutes

  • stages 1&2 - ‘light sleep’ person may easily be woken - brainwave patterns start to become slower and more rhythmic - alpha and theta waves

  • stages 3&4 - delta waves, slower still - deep sleep

  • stage 5 - REM sleep, body is paralysed but brain activity speeds up significantly - highly correlated with experience of dreaming

evaluate research into infradian and ultradian rhythms

• methodological limitations in synchronisation studies - loads of confounding variables that can affect cycles - diet, stress, etc

• evidence supports idea of distinct stages of sleep - participants had brain scans and stages of sleep were highly observable

• practical application to SAD - 60% said phototherapy, but a placebo was also said by participants to be effective

define endogenous pacemaker

internal body clock that regulates many of our biological rhythms such as the influence of the suprachiasmatic nucleus

define exogenous zeitgeber

external cues that may affect or entrain our biological rhythms such as the influence of light on the sleep wake cycle

outline the influence of endogenous pacemakers on the sleep/wake cycle

• suprachiasmatic nucleus

  • sits in the optic chasm

  • receives info from eyes and detects light

  • sends message to pineal gland when no light

• pineal gland

  • when told no light produces melatonin

  • melatonin makes us sleep

outline procedure and findings of DeCoursey’s study

• severed SCN in 30 chipmunks

• put them back in natural habitats and observed them for 80 days

• most died as sleep/wake cycles completely evaporated and they were therefore more vulnerable to light

outline procedure and findings of Ralph’s study

• bred ‘mutant hamsters’ with a 20 hour sleep/wake cycle

• removed their SCNs and transplanted them into other hamsters

• new hamsters inherited sleep/wake cycles

• emphasises the role of the SCN in establishing and maintaining the circadian sleep/wake cycle

outline procedure and findings for Campbell and Murphy

• woke participants periodically and shone a light on the back of their knees

• managed to deviate sleep/wake cycles up to 3 hours

• light = powerful exogenous zeitgeber that need not rely on the eyes

briefly outline the role of light as an EZ for the sleep/wake cycle

• can reset body’s main EP

• Campbell and Murphy

• doesn’t need to rely on just eyes

briefly outline the role of social cues as an EZ for the sleep/wake cycle

• babies and young children are not on the same sleep/wake cycle as the rest of us

• can be suggested that the schedules imposed by parents entrain the sleep/wake cycle

  • meal times

  • bed times

give three weaknesses of research into endogenous pacemakers and exogenous zeitgebers

• methodological issues

  • generalisability and ethics in animal studies

  • potential confounding variables in Campbell and Murphy’s study

• Laughton Miles

  • recounts story of young man blind from birth with a natural sleep/wake cycle of 24.9 hours

  • despite exposure to social cues (an EZ) could not be entrained and had to take sedatives in PM and stimulants in AM

  • EZs do not always have power to change rhythms

• interactionist approach

  • more representative of real life situations

  • there are very few situations where our EP determined rhythms are truly free flowing without influence of EZs