Biological Approach Theory Flashcards
What is Magnetic Resonance Imaging?
Non invasive technique of studying brain
Consists of large tube structure with strong magnets
Uses magnetic field & radio waves to map activity of hydrogen molecules present in brain tissues
Image viewed as slice of brain from any angle or used to create 3D image of brain
What is Localisation of Function?
Idea of localisation assumes that specific parts of the brain have specific functions that are related to specific behaviours such as memory (strict localisation)
Holism = functions of brain are the result of brain working as a whole, not specific regions
What is Neuroplasticity?
Neuroplasticity = brain’s ability to reorganise itself in response to the environment through the lifespan
2 types:
Structural = brain’s ability to change its physical structure as a result of learning
Functional = brain’s ability to move functions from damaged to undamaged area of brain
Change occurs through making/breaking of synaptic connections b/w neurons which develops neural networks in the brain due to genetic/environmental reasons e.g learning a new skill
Synaptic connections become stronger due to repeated use (long-term potentiation) which leads to longer periods of depolarisation on postsynaptic membrane thus channels are open longer allowing for stronger signal
Over time leads to protein synthesis & gene expression that are used for dendritic branching in process called neural arborization thus there are more branches, more connections & more channels
When synapse = understimulated, may go through synaptic pruning where extra synapse removed as no longer needed
What is Neurotransmission?
Process where neurons transmit info & signals to allow bodily functions to occur
Communication between neurons begins as an electrical impulse (known as action potential) travels along axon of neuron and releases NTs stored in neuron’s terminal buttons
NTs released into synaptic gap where crosses to reach receptor sites on postsynaptic neuron
Once message passed on reuptake occurs, NTs broken down by enzymes/reabsorbed by terminal buttons of presynaptic neuron
NTs can be excitatory (increase likelihood neuron will fire action potential) or inhibitory (decrease likelihood)
Agonists = chemicals that enhance action of NT
Antagonists = chemicals that counteract a NT so prevent signal being passed further e.g. scopolamine which blocks acetylcholine receptors (an excitatory neurotransmitter in memory formation) thus inhibiting any response
What are Hormones?
Chemicals secreted by glands in endocrine system directly into bloodstream which have effect on behaviour, they control most major bodily functions
Can only influence cells w/ appropriate receptors for particular hormone (called target cells)
When hormone binds to receptor, launches sequence of changes
Hormones regulate long-term ongoing processes e.g. metabolism
Adrenaline = secreted by adrenal glands, responsible for arousal & fight or flight response & key role in emotional memory formation
When stimulus threatens us, hypothalamus activates adrenal medulla which releases adrenaline & noradrenaline into bloodstream
Body preps for fight or flight, adrenaline & noradrenaline reinforce the pattern of sympathetic activation (increased heart rate, blood flow to muscles, respiration)
Evolutionary survival tactic
What are Pheromones?
Chemical substances produced and released into environment by an animal affecting behaviour/physiology of others of own species
Known to play role in signalling b/w animals of same species w/ impact on behaviours, four types found: primer, signalling, releaser and modulator, yet unclear if same in humans
Some argued could potentially affect menstrual cycles, olfactory recognition of newborn by mother & exuding different odours depending on mood
No human pheromone found yet, evidence for & against
If do exist in humans, likely play minimal role
What are Genes?
Genes = particular regions of chromosomes that control the development of a particular characteristic
We inherit genes that give rise to development of specific psychological processes that contribute to specific characteristics and behaviour
One single gene doesn’t lead to one behaviour, always a combination of genes & environment which lead to a phenotype - diathesis-stress model
Completion of the Human Genome Project allowed for study of specific genes as their location is now known
Argued that people possess genetic predispositions to disorders
5-HTT gene plays role in serotonin pathways that scientists believe are involved in controlling mood, emotions, aggression, sleep & anxiety
Caspi hypothesised those who inherit 2 short versions of 5-HTT gene (caused by mutation) = more likely to develop major depression after a stressful life event
Twin studies are also useful to investigate influence of genetics on behaviour
Twins may be monozygotic i.e. they have identical genes, so if depression is 100% genetic, if one twin has it, other will too, or dizygotic i.e. they share 50% of genes
Falconer Model - assumes phenotype is comprised of three factors: genetics, shared environment & individual environment for twins
Additionally, kinship studies look at concordance rates of a behaviour across several generations
What is Major Depressive Disorder?
MDD = disorder categorised by persistent sadness & lack of interest in previously rewarding things, low mood & lacking motivation
Significant body of evidence suggests that MDD has its causes rooted in biology
What are Evolutionary Explanations of Behaviour?
Biological psychologists argue evolutionary factors play role in how we form relationships & select partners
Evolutionary behaviours focus on process of natural selection - whereby organisms better adapted to environment survive & produce more offspring which brings about evolution
Sexual selection = type of natural selection & competition for mates, argues that to produce offspring with optimal health, perfect partner chosen
Females select while men compete as men have many opportunities to pass on genetic material but women only have 1 pregnancy a year - so women more fussy ensuring mate gives offspring best survival chance
2 types of sexual selection
Intrasexual selection = when members of same sex within a species compete for mating opportunities, involves fighting so those well adapted have better armourants
Intersexual selection = action of female selecting mate based on desirable traits e.g. possession of resources to provide for family, status, loyalty & strength
Men look for: attractiveness, signs of fertility presented in youthfulness & wide hip to narrow waist ratio & sexual faithfulness
