Biopsychology Flashcards
The nervous system
Allows u to respond to changes in env (stimuli) and coordinate actions
Divided into central nervous system and peripheral nervous system
CNS - made up of brain and spinal cord
PNS - made up of neurons that connect cns to rest of the body - divided into autonomic nervous system and somatic nervous system
ANS controls unconscious activities like breathing split into sympathetic is flight or fight system and gets body ready for action and parasympathetic which calms body down
SNS controls conscious activities like muscle movement
The endocrine system
Controls functions in body through hormones
Glands produce hormones, pituitary gland is the master gland and controls release of other hormones from other glands
Hormones secreted in blood stream and affects cells that have specific receptor for that hormone e.g. thyroxine produced by thyroid gland which increases metabolic and so growth rates
Endocrine system works alongside ANS -
When stressor perceived, hypothalamus triggers activity in sympathetic branch which changes from its normal resting state which is parasympathetic to physiologically aroused state, hormone adrenaline released from adrenal medulla into blood stream which targets physiological changes in body e.g. increased heart rate - fight or flight response, once threat passes the parasympathetic nervous system returns body to resting state.
Structure and function of neurones
Sensory neurones have long dendrites and long dendron and cell body and short axons which transmit electrical impulse from receptors to cns
Relay neurones have short dendrites and cell body and short axons and transmit electrical impulses between sensory and motor neurones
Motor neurones - have short dendrites and cell body and long axon transmit electrical impulse from cns to effectors
Cell body has dendrites that receive info from other neurones which passes along axon in form of electrical impulse which is covered in myelin sheath to speed up nervous transmission with gaps in axons called nodes of ranvier to speed up transmission
When neuron in resting state, inside more negative than outside.
When neuron is activated, inside of cell becomes positively charged causing action potential which creates an electrical impulse that travels down axon to end of neuron
Synaptic transmission
each neuron separated by tiny gap called synapse , signals within neurons transmitted electrically but signals between neurons transmitted chemically across synapse
When electrical impulse reaches end of neuron presynaptic membrane, it triggers the release of neurotransmitter from tiny sacs called synaptic vesicles and once neurotransmitter crosses gap, its taken up by postsynaptic receptor on next neuron and the chemical msg converted back into electrical impulse and process of electric transmission begins!
Neurotransmitter fit perfectly into postsynaptic receptor site e.g. acetylcholine found where a motor neuron meets a muscle causing it to contract, serotonin - affects mood - cause of depression
Neurotransmitters have excitatory or inhibitory effects
Adrenaline is excitatory increasing positive charge of post synaptic neuron making it more likely for neuron to fire
Serotonin is inhibitory increasing negative charge of post synaptic neuron making it less likely for neuron to fire
Dopamine has both effects
Summation - excitatory and inhibitory effects summed and must reach threshold for action potential of postsynaptic neuron to be triggered - more likely to fire if net effect is excitatory
Localisation of function in the brain AO1
Holistic theory replaced by localisation
Brain divided into left and right hemispheres and lateralised so some functions controlled by certain hemisphere
Outer layer of brain is cerebral cortex - covers inner parts
Cortex of both hemispheres divided into 4 lobes: frontal, parietal, occipital and temporal.
Motor area: controls voluntary movement
Somatosensory area: processes information fromskin about touch, pain
Visual area: processes info from eyes
Auditory area: processes info from ears
Brocas area: responsible for speech production (brocas aphasia - slow speech)
Wernicke’s area: understanding of language (wernickes aphasia - nonsense speech)
Localisation of function in the brain AO3
+localisation theory has brain scan evidence - petersen et al used brain scans to show activity in wernickes and brocas area during listening and reading suggesting these areas have diff functions - long term memory study by tulving et al revealed semantic and episodic memories located in diff parts of frontal cortex - many sophisticated methods now to measure brain activity - scientific evidence
+neurological evidence - surgically removing areas to control aspects of behaviour, dougherty et al reported 1/3 of ocd patients who had cingulotomy had a successful response to surgery - symptoms and behaviours associated w serious mental disorders localised too
+case studies - case of phineas gage who received serious brain damage that affected his personality and the change in temperament suggests frontal lobe responsible for regulating mood
-neural plasticity is a challenge to localisation theory - when brain damaged, rest of brain can reorganise to recover the function - lashleys law of equipotentiality - other areas of brain chip in to achieve same neurological function - several documented case studies of stroke patients that reported this
Plasticity and functional recovery of the brain AO1
Plasticity - brain can alter its structure and function in response to changes in environment - information takes pathway thru brain travelling from 1 neuron to the other via synapses but when we re presented w new info, brain forms new neural pathways and the more its used the stronger the connections between the neurons become and vice versa, constant reorganisation is how we learn and adapt to changes in environment, these changes can happen at any time
e.g. karni et al used fmri to show learning and practising finger movements over a period of 4 weeks lead to activation of larger area of motor cortex when carrying out the sequence - reorganisation took plac
Functional recovery - following trauma healthy brain areas take over functions of damaged - occurs quick then slows down and brain rewires and reorganises itself through new neural pathways
Plasticity and functional recovery of the brain AO3
+plasticity and recovery research has practical applications - understanding plasticity contributed to neurorehabilitation techniques like movement therapy and electrical stimulation of brain to counter cognitive defects after stroke - requries further intervention after plasticity
+research support for plasticity from animal studies - hubel et al sewed one eye of a kitten shut and analysed cortical responses, area of visual cortex associated with shut eye continued to process information from open eye even as inactive - loss of function leads to compensatory activity
-neural plasticity related to cognitive reserve - persons educational attainment may influence how well brain recovers - studies found that cognitive reserve increases chances of disability free recovery - cognitive reserve also crucial factor in determining how well brain recovers
-link between age and plasticity is complex - functional plasticity tends to reduce with age - brain has greater chance of reorganisation during childhood as it adapts to new experiences - BUT BEZZOLA ET AL SHOWED HOW EVEN 40 years of golf training produced changes in neural representation of movement in pps aged 40-60 - shows neural plasticity continues throughout our lifespan
Split brain research into hemispheric lateralisation AO1
Normally hemispheres connected by corpus callosum = commissurotomy cuts corpus callosum and controls epileptic seizure, sperry studied a group of epileptics who had operation
Sperry projected an image or word to patients right visual field processed by left hemisphere and another to left visual field processed by right hemisphere - corpus callosum shares info between hemispheres, in split brain, info CANT BE SHARED
Object shown to right visual field, patient easily describes what is seen, LVF patient says nothing there, cos right hemisphere lacks language centres and are normally relayed via corpus callosum to language centres in left hemisphere. They could however select a corresponding object with left hand which represented what was seen in left visual field (RIght hemisphere linked to left hand!!) as they could understand what the object was and produce a non verbal response
Split brain research into hemispheric lateralisation AO3
+shows lateralised brain functions - left hemisphere is analytical and right is adept with spatial tasks - right hemisphere produces basic words but contributes emotional content to language - but recent research shows distinction simplified and several tasks associated with one hemisphere can be done by the other
+standardised methodology - standardised procedures of presenting visual info to one hemispheric field at a time - genius - pps stared at a fixed point with one eye and an image was flashed up for 0.1 seconds so patient had no time to move their eyes over image and spread info across both sides of visual field or brain - only one hemisphere received info at a time - well controlled procedure
-differences in hemispheric functions overexaggerated - growing body of pop psychological literature that oversimplifies and overstates difference in function between hemispheres and modern neuroscientists argue these differences arent clear cut many behaviours associated with one can be performed by other hemisphere when required - conclusions drawn from sperry too simplistic doesnt account for flexibility of hemispheres
-issues with generalisation - split brain patients are unusual sample, only 11 pps took part in all variations and had history of seizures - unique changes in the brain which influenced findings - reduces validity cos dk if findings can be generalised to normal BRAINNNN
Ways of studying the brain AO1
Medical techniques to investigate brain localisation and diagnose illness
fMRI - highlights active area of the brain - changes in blood flow that occur due to neural activity in specific areas - more active - more oxygen - more blood flow to that area - 3d image showing active parts
EEG - overall electric activity using electrodes attached on brain that represents brainwave patterns from neurons and show brain activity
ERPs - brainwaves related to particular events - leaves only the responses relating to performance of a certain tasks
Post mortem exams - anaylsis of brain following death to establish cause of a disorder suffered by a person in life and compared with neurotypical brain to establish difference
Ways of studying the brain AO3
+fMRIS are non invasive - dont rely on use of radiation and is safe - produces images with high spatial resolution showing detail by millimetre - clear picture of brain activity localisation
-FMRIs expensive - can only capture clear image if person stays still , poor temporal resolution due to lag between initial neural activity and image - may not truly represent moment to moment brain activity
+EEGs diagnose conditions like epilepsy - contributed to understanding of sleep stages, high temporal resolutiom - detects brain activity at a resolution of a single millisecond
-EEGs information received from thousands of neurons - eeg produces generalised signal from many neurons so difficult to know exact source of neural activity - cant distinguish between activity of different adjacent neurons
+ERPs are specific - achieved using raw eeg data - excellent temporal resolution - better than fmris temporal resolution
-ERPS lack of standardised methodology - difficult to confirm findings - background noise and extraneous material need to be completely removed - not easy to do
+post mortems provide foundation for understanding brain - broca and wernicke relied on post mortem studies - improves medical knoweledge - generate hypotheses for future
-post mortems causation is issue - observed damage may not be linked to disorder under review but to some other trauma, also ethical issues of consent from patient before death - patient might not be able to provide informed consent!!!!!!
Circadian Rhythms AO1
Endogenous pacemakers - internal biological clocks
Exogenous zeitgebers - external changes in env
Circadian rhythm lasts 24 hours
Exogenous zeitgebers daylight are why we feel drowsy at night and alert during the day
Endogenous pacemakers - biological clock w out influence of env
Suprachiasmatic nucleus lies part of hypothalamus acts as internal clock to keep body on a 24 hour sleep wake cycle - sensitive to light and regulates pineal gland which secretes melatonin when less light which- induces sleep
Siffre spent 6 months in a cave he had no clocks and no natural light and his sleep wake cycle extended to 25-30 hours - natural light needed to finetune our normal cycle
In some cases endogenous pacemakers completely determines a cycle - fisher et al found squirrels hibernate even when in lab conditions very diff to normal
Individual differences - wever et al found that in a group isolated from daylight, some maintained regular cycles but some had extreme cycles e.g. 29hours awake followed by 21 hours
Circadian Rhythms AO3
+practical application to drug treatments - circadian rhythms coordinate body’s basic processes - implications on pharmacokinetics how well drug acts - research shows there are times when drug more effective - guidlines developed for timing of dosages - real life medical benefits
-case studies and small samples - often involve small groups e.g. wever et al or even individual e.g. siffre - not representative of whole pop - cant be generalised, siffre observed his internal clock ticked much more slowly at 60 than when he was younger - individual differences and other factors that prevent general conclusions to be drawn so cant be generalised
-poor control in studies - pps deprived of natural light still had access to artificial light e.g. siffre had a lamp, can be like a drug that resets pps biological clock - counfounding variable that was ignored
Infradian and Ultradian Rhythms AO1
Infradian rhythms - female menstrual cycle is infradian - about 28 days - less than one cycle in 24 hours
Exogenous zeitgebers synchronise menstrual cycles - stern et al studies women with irregular periods, pheromones taken at diff stages of cycles via cotton pad under armpits which are cleaned with alcohol and later rubbed on upper lips of other pps - 68% of women cycle brought closer to the cycle of odour donor
another infradian rhythm is seasonal affective disorder - depressive, winter blues when daylight hours shorter could be caused by melatonin which induces sleep cos during winter lack of light in the morning means secretion lasts longer - results in low serotonin linked to depression
Ultradian rhythms - cycles that occur more than once in 24 hours, sleep pattern has 5 stages
1 and 2 are light sleep - brainwaves slow further as sleep becomes deeper
3 and 4 are difficult to rouse someone - deep sleep delta waves which are slower and have higher amplitude
5 is rapid eye movement sleep - body paralysed yet brain activity speeds up
