updated biopsychology a level aqa psychology revision

1. AQA A-Level Psychology
Revision: Biopsychology
Ella Warwick

2. Specification
• The divisions of the nervous system: central and peripheral (somatic and autonomic).
• The structure and function of sensory, relay and motor neurons. The process of synaptic
transmission, including reference to neurotransmitters, excitation and inhibition.
• The function of the endocrine system: glands and hormones.
• The fight or flight response including the role of adrenaline.
• Localisation of function in the brain and hemispheric lateralisation: motor,
somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas, split
brain research. Plasticity and functional recovery of the brain after trauma.
• Ways of studying the brain: scanning techniques, including functional magnetic
resonance imaging (fMRI); electroencephalogram (EEGs) and event-related potentials
(ERPs); post-mortem examinations.
• Biological rhythms: circadian, infradian and ultradian and the difference between these
rhythms. The effect of endogenous pacemakers and exogenous zeitgebers on the
sleep/wake cycle.

3. Nervous System
• CNS
• Made up of the brain and spinal cord.
• The spinal cord transmits messages to and from the PNS.
• Control of behaviour and regulation of physiological processes.
• PNS
• transmits messages via neurones to and from the CNS.
• Divides into somatic (conscious) and autonomic (automatic).
• Autonomic divides into sympathetic (fight & flight) and parasympathetic (rest & digest).
• Reflex arc – a stimulus is detected by organs in the PNS which convey a
message along a sensory neurone and passes into the spinal cord to a relay
neurone, the message is then passed to a motor neurone and to an
effector.

4. Neurones
• Sensory – carries impulse from PNS receptors to the CNS.
• Long dendrites, short axons, cell body branches off.
• Relay – carries impulse from sensory to the motor neurones.
• Short dendrites and short axons.
• Motor – carries impulse from CNS to effector
• Short dendrites and long axons
• Synaptic transmission – neurotransmitters are released into the synaptic cleft, they then
bind with receptor sites on the postsynaptic neurone, causing these gated channels to
open, this causes depolarisation and a new action potential is started.
• Inhibitory neurotransmitters – increases negative charge of postsynaptic neurone so
likeliness of action potential being made is lower, as the potential difference acros the
membrane may not reach the threshold. – serotonin/ GABA
• Excitatory neurotransmitters – increases the positive charge of the postsynaptic neurone,
so more likely that the threshold will be reached and the action potential started. –
adrenaline/ acetylocholine

5. Endocrine System
• Endocrine system – one of the bodies major information systems that
instructs glands to release hormones into the bloodstream towards
target organs. Endocrine glands secrete directly into the blood
without a duct.
• Pineal gland – melatonin
• Pituitary gland – growth hormone
• Thyroid gland – thyroxin
• Thymus – thymosin
• Adrenals – adrenaline
• Pancreas – insulin
• Ovaries – oestrogen
• Testes – testosterone

6. Fight or Flight
• Immediate stressors arouse the autonomic system. The sympathetic branch arouses the
animal and the parasympathetic brings it back to normal.
• The stress response was important for our ancestors.
• Adrenaline is a hormone produced by the adrenal medulla, and it is also a
neurotransmitter. The nervous system and endocrine system work together to produce
the fight or flight response
• There are two stress pathways:
• SAM – short term response
• Hypothalamus is activated  sympathetic branch is activated  adrenal medulla produces adrenaline and
noradrenaline. (increases blood pressure and breathing rate etc.)
• HPA – longer term response
• Hypothalamus is activated  pituitary gland is activated  ACTH is released into the blood stream causes
adrenal cortex to release cortisol  causes increased energy and increased healing ability.
• When we come under threat: increased hr, increased br, muscles tense, forget hunger,
dry mouth, adrenaline release, glucose release, sweat, pupils dilate, need the loo.

7. Localisation of function in the brain and
hemispheric lateralisation (A2)
• Localisation suggests that there are different regions of the brain for different functions.
• Lobes : Frontal (motor), Parietal (somatosensory), Temporal (auditory), Occipetal (visual).
• Left hemisphere is the language centre.
• Area in left frontal lobe that deals with speech production (Broca’s area)
• Area in left temporal lobe that deals with speech understanding (Wernicke’s area)
• Sperry – split-brain research :patients with corpus callosum severed in cases of sever epilepsy. Could name things seen with right eye (left hemisphere) but couldn’t with
left eye, they could however point to or draw what they saw with their left hand. Shows hemispheres have different functions.
• Naturally occurring variable, so not unethical (severing corpus callosum).
• 11 patients of a minority group
• Natural experiment has lack of control over variables (individual differences).
• Limited generalisation as split brain epileptic right handed patients.
• Phineas Gage pole through left frontal lobe, personality change.
• Cannot generalise, may be one-off.
• Evidence from scan shows Wernicke's active during listening task, and Broca’s active during reading task.
• Semantic and episodic memories are in different parts of the prefrontal cortex.
• Lobotomy affecting the frontal lobe to control aggression. Post surgery for OCD 1/3 had met the criteria for successful response.
• Plasticity – ability for the brain to change throughout life.
• Maguire – taxi drivers had more grey matter in the posterior hippocampus which is linked to spatial skills. The longer they were in the job, the more the brain structure
changed.
• Unaffected areas after trauma can take over damaged areas. The brain can rewire itself with axonal sprouting, reformation of blood vessels, and using homologous
(similar) areas on the other side.
• Helps with understanding of neuro-rehabilitation.
• Brains ability to rewire can be negative – phantom limb syndrome.
• Plasticity reduces with age.
• Evidence shows females recover quicker.
• Evidence shows you recover faster if your better educated.

8. Ways of studying the brain
• Scanning:
• Functioning magnetic resonance imaging (FMRI) – detects oxygenated blood flow. This helps understanding of localisation of function.
• Doesn’t use radiation.
• High resolution.
• Clear picture of localisation.
• Expensive.
• Have to be perfectly still.
• Not specific of neuronal activity, just blood flow.
• Electroencephalogram (EEG) – electrodes record brain wave patterns (identify unusual patterns like epilepsy, tumours or sleep disorders).
• Valuable in diagnosing disorders and our understanding of sleep.
• Detect brain activity at a resolution of a millisecond.
• Isn’t useful at pinpointing (its too general).
• Event-related potentials (ERPs) – uses EEGs to establish a norm to filter out information and leave the relevant responses to a task.
• No radiation.
• More specific measurements of neural processes.
• Extraneous variables such as background noise need to be illuminated which is hard.
• Unable to see into the deeper areas of the brain.
• Other:
• Post-mortem examinations – analysis of the brain after death, areas are compared to an unaffected brain to see the damage.
• Evidence was key for our early understanding.
• Help generate hypothesis for further study.
• Damage could be caused by unknown traumas.
• Consent (HM couldn’t give fully informed consent but was studied anyway).

9. Biological Rhythms
• Biological rhythm – any change in biological activity that repeats periodically.
• Endogenous pacemakers – internal biological clocks (melatonin induces sleep, when light is detected it is inhibited, blind people
struggle to regulate a natural rhythm without drugs).
• Exogenous zeitgebers – external changes in the environment (ligt, social cues like meals).
• Circadian – occurs ever 24 hours (sleep-wake cycle).
• Shift workers are prone to poor health as there is stress on their circadian rhythm.
• Circadian rhythms coordinate hormone control, digestion, and hr. this led to drugs being advised to be taken at certain times.
• Cave study – cut off from all zeitgebers and relied on endogenous pacemaker. Siffre (6 months), he settled into the pattern of a 25 hour day
• This is a one participant study so is ungeneralizable.
• Living conditions were unusual so could have been affected by loneliness.
• Done with 12 participants where clock was reduced to 22 hours over 3 weeks, none reacted well. Evidence for strong free-running circadian rhythm.
• Similar studies have been done with rats and show similar findings.
• Study lasted a long time allowing him to settle.
• When SCN (endogenous pacemaker) of chipmunks were destroyed the sleep wake cycle disappeared. (ethics?)
• SCN does not work independently, rhythms kept in many organs and cells.
• Infradian – more than 24hrs, less than yearly (SAD- imbalance of melatonin in hypothalamus due to lack of light. Menstrual cycle).
• Found with the menstrual cycle although it is an endogenous system it can be affected by exogenous factors. Women's menstrual cycles
synchronise when samples of pheromones were rubbed on upper lip.
• Evolutionary as they could share the burden of breastfeeding and childcare.
• May have suffered from confounding variables. E.g. stress.
• Ultradian – more than once a day (eating. Stages of sleep).
• Stages of sleep measured by EEG (NREM refers to 1,2,3,4.): stage 1 = slow irregular waves, stage 2 occasional spikes of activity, stage 3&4 =
slow large waves. REM. This cycles throughout the night. (seen on slide 1)
• Found that REM stage was 90% of the time dreaming.