Biopsychology

A-level AQA

what are the two divisons of the nervous system

central nervous system and peripheral nervous system

What makes up the central nervous system?

brain and spinal cord

What makes up the peripheral nervous system?

somatic and autonomic nervous system

what makes up the autonomic nervous system

sympathetic and parasympathetic

what is the function of the central nervous system

to process information and form a response

what is the function of the peripheral nervous system

to relay messages from the environment and to effectors

what type of neurones are used to relay messages from the environment to the CNS

sensory neurones

what type of neurones are used to relay messages from the CNS to effecots

motor neurones

What does the autonomic nervous system do?

controls involuntary actions such as maintaining heart and breathing rate,

What does the somatic nervous system do?

controls voluntary movements - it recieves information from senses and results in effectors being stimulated by the CNS via motor neurones

What does the sympathetic nervous system do?

prepares body for fight or flight

examples of responses of the sympathetic nervous system

increase heart and breathing rate, vasoconstriction?? (narrowing of blood vessels) pupil dilation, digestion stops

what does that parasympathetic nervous system do

it is the antgonistic pair of fight or flight ---> rest and digest

examples of responses of parasympathetic nervous system

decrease heart and breathing rate, vasodilation and pupil constriction

what is the endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

what does the hypothalamus do?

controls/stimulates the pituitary gland

What does the pituitary gland do?

Secretes hormones to regulate other glands and simulates them to release other hormones. It is known as the master gland

How is the pituitary gland divided?

anterior and posterior lobes

what does the anterior lobe of the pituitary gland do

releases ACTH (adrenocortical trophic hormone) which stimulates the adrenal cortex and release of cortisol

what does the posterior lobe of the pituitary gland do?

releases oxytocin which is responsible for contractions in childbirth

what does the pineal gland do?

releases melatonin which is responsible for biological rhythms eg sleep-wake cycle

what does the thyroid gland do?

Produces thyroxine which is involved in regulating metabolism.

how is the adrenal gland divided

into 2 = adrenal medulla and adrenal cortex

what does the adrenal medulla do?

releases adrenaline and noradrenaline which play a key role in fight or flight

what does the adrenal cortex do?

releases cortisol which stimulates the release of glucose while suppressing the immune system

what does the testes do?

release androgens (male sex hormone) like testosterone which is responsible for muscle growth, and development of male sex characteristics during puberty

what does the ovaries do?

Produces oestrogen which is involved in the menstrual cycle and pregnancy

Fight or flight response

1. the body becomes aware of a stressor eg sound of a speeding car

2. through sensory receptors and neurones in the PMS, the information is sent to the hypothalmus in the brain which coordinates a response and triggers an increase in activity in the Sympathetic NS

3. adrenanline is released from the adrenal medulla and is transported to target effectors via the blood

4. results in rectum contracts saliva production inhibited increased breathing and heart rate pupils dialate digestion inhibited

5. once we are no longer threatened, the parasympathetic nervous system brings body back to rest and digest

P - other evidence to suggest fight or flight is a simplistic

E - Gray (1988) suggests that the first response to danger is not fight/flight but to avoid confrontation altogether which is known as freeze

E - this is directly contradictory evidence to fight or flight

L - suggests that fight/flight is a limited explanation and not a valid theory

P - gender bias

E - according to taylor et al (2000) women are more likely to protect their offspring (tend) and form alliances with other women (befriend) rather than fight or flee

E - suggests that fight/ flight is not generalisable to the rest of the population

HOWEVER - gender bias

ignores individual differences

P - low temporal validiy

E - modern day life rarely necessitates such an intense response and repeated fight/flight can have negative impacts on health as it can damage blood vessels etc

E - it is unethical to study, it is irrelevant today, and it is not generalisable

Sensory neurones

found in receptors such as the eyes, ears, skin and tounge, and carry impluses to spinal cord and brain.

when they reach the brain they are translated into sensations eg vision hearing taste and touch

not all reach the brain some stop at the spinal cord to allow reflex actions to occyr

Relay neurones

found between sensory input and motor output/response. found in the brain and spinal cord and allow sensory and motor neurones to communicate

motor neurons

found in CNS and control muscle movements, when motor neurones are stimulated they release neurotransmitters that bind to the receptors on muscles which triggers a reponse (movement)

What is synaptic transmission?

a method of neurons communicating with each other, relaying information to the CNS across sensory neurons and carrying out responses dictated by the brain through sending information to effectors via motor neurons.

What is an action potential?

an electrical impulse

the process of synaptic transmission

1. information is passed down the axon of the neurone as an electrical signal which is known as an action potential

2. once the action potential has reached the end of the axon, it needs to be transferred to the next neurone by crossing the synaptic gap/cleft

3. the action potential stimulates the release of neurotransmitters from the synaptic vesicles

4. neurotransmitters carry the signal across the synaptic gap. they bind to receptor sites on the post-synaptic cleft which then activate

5. once the receptors on the post-synaptic neurone has been activated they either produce excitatory or inhibitory effects on the post-synaptic cell

What is an excitatory neurotransmitter?

makes neuron more likely to fire

what is an inhibitory neurotransmitter

makes the neurone less likely to fireeg GABA

what is localisation of function

The theory that different areas of the brain are responsible for different behaviours, processes or activities.

the motor area

A region of the frontal lobe involved in regulating and controlling movement

what happens if the motor area gets damaged

inability to control voluntary fine motor movements

the auditory area

in the temporal lobe interprets/processes auditory infomation and speech

what happens if the auditory area gets damaged

hearing loss

the visual area

A part of the occipital lobe that receives and processes visual information

what happens if the visual area gets damaged

problems with vision, visual interpretation or blindness

the somatosensory area

An area of the parietal lobe that processes sensory information such as touch heat pressure etc

what happens if the somatosensory area gets damaged

loss of ability to denote sensitivity in particular areas

Wenicke's area

language comprehension, in the temporal lobe

what happens if the Wernicke's area gets damaged

wernickes aphasia which is characterised by the use of nonsensical words (syllogisms), no awareness of incorrect words, but NO ISSUE W PRONUNCIATION/INTONATION

brocas area

Controls language expression - an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech.

what happens if the brocas area gets damaged

brocas aphasia - difficulty forming and understanding sentences, failing to understand order of words and who sentences are directed to

what does the left hemisphere do

language production

P - supported by neurosurgery

E - neurosurgery is a last resort method for treating some mental disorders targeting specific areas that might be involved

E - cingulotomy is used to treat OCD and involves isolating the cingulate gyrus and were at least partly helpful

L - the success of such surgeries suggests that behaviours associated with serious mental disorders are localised

P - supported by the case study of Phineas Gage

E - phineas gage was injured by a blasting rod which tore through his prefrontal cortex on both sides

E - the damage caused a defect in his rational decision making and processing of emotion and his colleagues said he didnt seem like the same person

L - shows that some areas of the brain are for specific functions

case study HOWEVER

subjectivity of the conclusions drawn, only from one person and lack of control over confounding and extraneous variables

P - there are contradictory theories which take a more holistic approach

E - suggesting that each function requires several areas of the brain to be activated and that these functions are not restricted to these ares

E - for example, after removing 20-50% of the cortices of rats, found that no specific brain area was associated with learning to transverse through a maze

L - this suggests that intelligence is too complex to be restricted to certain area of the brain

L2 - this suggests that localisation might be a better explanation for simple functions

HOWEVER

this is based on an animal study, and humans function at a higher cognitive level than rats

What is hemispheric lateralisation?

The idea that the two halves of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.

What is the left hemisphere responsible for?

language

what side of the body does the left hemisphere control?

the right side

What is the right hemisphere responsible for?

imagination and artistic ability, left hand control, spatial relationships, insight

what side of the body does the right hemisphere control?

left

what connects hemispheres

corpus callosum which facillitates interhemispheric communication between the left and right hemisphere

Sperry and Gazzaniga participant sample and why them

11 epilieptic patients who had undergone a cerebral commissurotomy (splitting of the corpus collosum). therefore it is possible to to expose a single hemisphere to certain stimuli and thus infer the function of each hemisphere

Sperry and Gazzaniga method

An image/word is projected to the patient's left visual field (which is processed by the right hemisphere) or the right visual field (which is processed by the left hemisphere). When information is presented to one hemisphere in a split-brain patient, the information is not transferred to the other hemisphere (as the corpus callosum is cut).

Sperry and Gazzainga results - descrbe what you see

left visual field (processed by right hemisphere) - couldnt describe what was shown, and often reported that nothing was there

right visual field (processed by left hemisphere) - could describe what they saw, therefore demonstrating that the left hemisphere is dominant in language production

Sperry and Gazzaniga results - tactile

placed in left hand (processed by right hemisphere) - patient couldnt describe what they fault and could only guess byt could identify the test object by selecting it from a series of others

placed in right hand (processed by the hemisphere) - could verbally describe what they felt, could also identify the test object by selecting it from a series of others

Sperry and Gazzaniga results - drawing

the left hand would consistently draw better/more consitently drew bettr/clearer pics than the right hand even though all parties were right handed. this demonstrates that the right hemisphere is more dominant in visual motor tasks

Sperry and Gazzaniga conclusions

the left hemisphere is responsible for language and the right side is motor. supports hemispheric lateralisation and shows connectivity between the hemisphers

P - there is supporting research to sperry

E - gereon frank et al used PET scans to see what areas of the brain was active when ppts did a visual processing task

E - global features - RH, finer details - LH

L - in visual processing hemispheric lateralisation is a feature of the connected and split brain

P - more research to support Sperry

E - micheal gazing showed split brain patients perform better in some tasks than connected

E - eg identifying odd ones out as LH cognitive functions

L - left and right hemispheres are distinct

P - idea of LH as the analyser and RH as synthesiser may be incorrect

E - different functions but people do not have a dominant side that determines their personality

E - Jared Niesele et al analysed brain scans from 1000 people aged 29 and found certain tasks aligned with brain sides but no evidence of a dominance

L - right/left dominance wrong

P - causal relatonships

E - the participants of Sperry all had epilepsy