KEY THEORIES

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central nervous system

central nervous system

brain and spinal cord and is the origin of all complex commands and decisions

CNS function

specialised, complex network of cells that collects, processes and responds to information in the environment and coordinates the working of different organs and cells

corpus callosum

thick collection of nerve cells that physically connects the 2 hemispheres of the brain

spinal chord function

two-way communication to and from the brain and reflex actions

brain

source of conscious awareness

cerebral cortex

outer layer of the brain - divided into 4 lobes

cerebellum

area that controls muscle movement, balance and coordination

thalamus

Relay station for sensory information

hypothalamus

controls motivational behaviours, stress response and homeostasis

lateralisation

2 hemispheres may look identical but each has different functions eg. language is lateralised to the left temporal lobe

localisation

there are certain areas in each hemisphere with specific functions eg. speech generating is localised to Broca's area

amygdala

A limbic system structure involved in memory and emotion, particularly fear and aggression.

4 lobes of the brain

frontal, parietal, occipital, temporal

frontal lobe

region at the front of the brain that controls high level cognitive functions and is involved with personality and emotional control

parietal lobe

region at the rear of the brain that processes sensory information, directions, hygiene and contains the somatosensory cortex

occipital lobe

region at the back of the brain that processes visual information and contains the visual cortex

2 language areas of the brain

Broca's and Wernicke's

broca's area

controls speech production

wernicke's area

controls language comprehension

temporal lobe

region of the brain behind the ear that processes auditory information and deals with memory and language comprehension

contralateral

the brain's control of the body is contralateral - the left h.s. controls the right side of the body and vice versa

soma cell

main part of the cell where the nucleus sits

nucleus

contains genetic material

mitochondria

site of aerobic respiration

dendrites

branches at the top of neuron that receive signals from other neurons

axon

long branch from soma that passes electrical impulses down to the end of the neuron

myelin sheath

fatty tissue that provides insulation and allows electrical impulses to be passes along

nodes of ranvier

gaps between myelin sheath

axon terminals

end of the axon that leads to the end of the neuron

terminal button

axon terminal containing synaptic vesicles

vesicles

tiny sacs in axon terminals that store neurotransmitters

motor neuron

receive CNS messages and generate movements

sensory neuron

transmit sensory information from sense to brain

relay neurons

connect sensory and motor neurons

what do biological psychologists believe?

the largest influence on our behaviour is genetics, hormones, chemicals and electrical Brian activity

parasympathetic nervous system

rest and digest

neuron

nerve cell

sympathetic nervous system

fight or flight

depolarisation

neuron at rest = negatively charged, activated neuron = positively charged, rapid switch creates an electrical impulse

synaptic transmission

diffusion of neurotransmitters from an axon terminal to a dendrite

action potential

a neural impulse - brief electrical charge that travels down an axon

Neurotransmitters

chemical messengers that diffuse across synaptic gaps between neurons

functions of neurotransmitters

have specific structures and functions - dopamine and acetylcholine

Dopamine (excitatory)

influences movement, learning, attention, and emotion

Acetylcholine (excitatory)

enables muscle action, learning, and memory

recite electrical impulse through neurone

done

recite synaptic transmission

done

what affects the voltage of an electrical impulse

type of NT and summation

excitatory NT

causes excitation of neuron making it more likely to fire

inhibitory NT

causes inhibition of the neuron making it less likely to fire

spatial summation

n.o. simultaneous signals from different neurons: more neurons that synapse = more likely to fire

temporal summation

n.o. signals from one neuron in a set time frame: repeated firing adds up voltages to reach the threshold

recreational drugs

Drugs taken by people for fun

agonist

some drugs imitate NTs - similar structure - and amplify NT activity

antagonist

some drugs block the action of an NT

downregulation

receptors decrease in number and sensitivity

cocaine facts

stimulant that blocks reuptake of dopamine by binding to dopamine transporters

heroin facts

depressant that's processed into morphine which mimics the action of endorphins and binds with the mu receptors to enhance the natural response

role of dopamine in recreational drugs

released in the reward centres of the brain that create a sense of pleasure

role of GABA

inhibits dopamine

strength of researching recreational drugs

Weinshenker and Schroeder damaged mesocorticolimbic pathway in mice brains so neurons were unable to produce dopamine - the mice were unable to administer cocaine as before therefore cocaines effects are due to dopamine

weakness of researching recreational drugs

Non-human studies to understand drug effects on human CNS transmission - human brain is more complex and process is reductionist

agression

range of behaviours that can result in both physical and psychological harm in an environment and can occur verbally, socially, mentally and physically

role of limbic system in aggression

amygdala controls fear response and perceptions - the reactivity of the amygdala can predict aggressive behaviour

role of limbic system in aggression evidence

Coccaro et al studied intermittent explosive disorder (extreme reactive agression) and scanned Ps by fMRI while they were viewing images - high amygdala activity when viewing angry faces bc angry facial expressions are an ec.v. sign of threat

role of pre-frontal cortex in aggression

PFC is the centre for moral reasoning, decision making and impulse control so if damaged, its could prevent violent impulses being stopped and negative consequences being processed

role of pre-frontal cortex in aggression evidence

Phineas Gage - iron rod destroyed large proportion of PFC and his behaviour changed from calm to highly aggressive

role of serotonin in aggression

NT that has inhibitory effects on transmission between neurons - decreased levels are associated with reduced self-control and leads to more impulsive behaviours

role of dopamine in aggression

dopamine regulates motivated behaviour - Set at al - serotonin under activity stimulates dopamine overactivity - both linked with impulsivity and aggression

strength of brain structure in aggression

Human case studies such as Phineas Gage and Charles Whitman showed that damage to frontal lobe showed an increase in agression - many psychopaths have similar cognitive functioning to patients with amygdala damage

weakness of brain structure in aggression

Reductionist - aggression depends on many interacting risk factors such as social, psychological and environmental aswell as biological in order to trigger it.

hormones

chemical messengers released from glands that can influence behaviour and thinking

evolution

changes in inherited characteristics in a biological population over successive generations

natural selection

process explaining evolution - individuals who survive and reproduce successfully, pass on genes

sexual selection

evolutionary explanation of partner preference - characteristics that are attractive to mate increases likelihood of reproduction

evolutionary explanation of aggression

gain territory and resources, deterring mates from infidelity and guarding offspring

evidence for evolutionary aggression

Buss 1988 - mate retention techniques used by males = direct guarding (restrict movements) and negative inducements (threats)

strength of evolutionary aggression

explains why males are more aggressive than females: cooperative females will have been naturally selected leading to reduced aggression, while aggressive males will have been naturally selected because they were better hunters, enhancing agression

weakness of evolutionary aggression

reductionist: reduces aggressive behaviour to only nature side of argument - we are all evolved to be aggressive and disregards any role for free will in behaviour relating to infidelity and jealousy

role of testosterone in aggression

males more aggressive than females due to more testosterone - higher levels = more aggression

evidence for role of testosterone in aggression

Dabbs et al - male criminals convicted of violent crimes has higher levels than other prisoners - same pattern with females

dual hormone theory

high cortisol levels inhibit testosterone reducing aggression

role of cortisol in aggression

manages stress levels - increased anxiety and social withdrawal reduces aggression - controlling increase of aggression associated with testosterone

evidence for role of cortisol in aggression

McBurnett et al found school boys with persistent aggression had lower cortisol levels than other school children - factor that increases aggression