Biopsychology Flashcards
(20 cards)
The Nervous System - Structure
- The Human Nervous System
- Peripheral Nervous System (PNS)
a) Somatic Nervous System (SNS)
a) Autonomous Nervous System (ANS)
b) Sympathetic Nervous System
b) Parasympathetic Nervous System - Central Nervous System
a) Brain
a) Spinal Chord
The Nervous System - Functions
- the nervous system is specialised network of cells in the human body and is our primary internal communication system, based on chemical and electrical impulses
- the two main functions of the NS are to collect, process and respond to information from the environment, and to co-ordinate the working of different organs and cells in the human body
- the CNS is made up of the brain and spinal chord, the brain is the centre of all conscious awareness, the outer-layer of the brain (cerebral cortex) is a 3mm layer that covers the entire brain like an orange peel, and is only found in mammals, the brain in humans is highly developed and sets us apart from other animals, it has two hemispheres (left and right), the spinal chord is an extension of the brain and passes messages to and from the brain and connects nerves to the PNS, it is also responsible for reflex actions
- the PNS transmits messages via millions of neurons to and from the central nervous system, it is further divided into the ANS and SNS, the ANS governs vital bodily functions like breathing and stress responses, the SNS governs muscle movements and receives information from sensory receptors
The Endocrine System - Glands and Hormones
- the endocrine system works alongside the nervous, slower but has a wide range of powerful effects
- glands around the body produce and release hormones, hormones are secreted into the bloodstream and affect and cell in the body that has a receptor for that specific hormone, most hormones affect cells in multiple organs which leads to many diverse and powerful responses
- the thyroid gland produces thyroxine which affects cells in the heart (increases heart rate) as well as affecting cells around the body increasing metabolic rates and therefore growth rates
- the key endocrine gland is the pituitary gland which is located in the brain and is often referred to as the ‘master gland’ because it controls the release of hormones from all the other glands around the body
The Endocrine System - Endocrine and Autonomous Nervous System working together
- the endocrine system and the ANS often work parallel with eachother, such as during a stressful event
- when a stressor is percieved, the hypothalamus (gland) activates the pituitary gland which triggers activity in the sympathetic branch of the ANS, the ANS changes from is parasympathetic state (resting) and sympathetic (physiologically aroused) state depending on the environment
- adrenaline is the stress hormone released into the bloodstream from the adrenal medulla (part of the adrenal gland near the kidneys), adrenaline triggers physiological changes in the body which creates physiological arousal which is necessary for the fight or flight response
- the fight or flight respond happens when a threat is detected, it is an acute response and an automatic reaction in the body
- the sympathetic state causes physiological changes including: increased heart rate, increased breathing rate, dilated pupils, inhibits digestion, inhibits saliva production, contracts rectum
- when the threat has passed the parasympathetic NS returns the body to its resting state, the actions are antagonists to the sympathetic changes, acting as a brake to the activity caused by the sympathetic changes, this is often referred to as the rest and digest response
- the parasympathetic state cause physiological changes including: decreased heart rate, decreased breathing rate, constricts pupils, stimulates digestion, stimulates saliva production, relaxes rectum
Structure and Function of Neurons (A01)
- 100 billion neurons in the human body 80% are in the brain, neurons provide the nervous system with their primary means of communication by transmitting chemical and electrical signals/impulses
- sensory neurons to relay neurons to motor neurons
- all neurons share the same basic structure; the cell body includes a nucleus which contains the genetic material of the cell and dendrites are branchlike structures that protrude from the cell body and carry nerve impulses from neighbouring neurons towards the cell body, the axon carries impulses away from the cell body and is covered by a fatty layer of myelin sheath which protects the axon and speeds up electrical transmission, if the myelin sheath was continuous it would have the reverse effect and slow down the impulse so it is therefore segmented by gaps called nodes of Ranvier which speeds up the impulse by forcing it to jump across the gaps along the axon, at the end of the axon are terminal buttons which communicate between the next neuron across a gap known as the synapse
- cell bodies may be part of the central nervous system (CNS) but they have long axons which form part of the peripheral nervous system (PNS), sensory neurons are located outside the CNS and in the PNS in clusters known as ganglia, relay neurons make up 97% of all neurons in the body and are located mostly in the brain and in the visual system
- when a neuron is resting the inside of the cell is negatively charged compared to the outside of the cell, when the neuron is activated by a stimulus it becomes positively charged for a split-second causing an action potential to occur, this creates an electrical impulse that travels down the axon towards the end of a neuron
Synaptic Transmission (A01)
- neurons communicate with eachother in groups called neural networks, neurons are separated from the next by a tiny gap called the synapse, signals within neurons travel electrically but in order to cross the synapse they are transmitted chemically, when the electrical impulse reaches the end of a neuron (presynaptic terminal) it triggers the release of a neurotransmitter from the synaptic vesicles in the presynaptic neuron
- neurotransmitters are chemicals that diffuse across the synapse to the next neuron in the chain, after crossing the gap they are taken in by postsynaptic receptor sites on the dendrites of the next neuron, the chemical impulse is then converted back to electrical and is transmitted all over again, the direction of travel can only be one-way since the neurotransmitters are released by the presynaptic neuron terminal and received by the postsynaptic neuron receptor sites, several dozen types of neurotransmitters have been identified in the brain and some in the spinal chord and some glands, each neurotransmitter has a specific molecular structure which fits perfectly into the correct receptor sites (lock and key), each neurotransmitter has specialist functions
- neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron, such as serotonin causing inhibition which makes the neuron negatively charged and less likely to fire however adrenaline (neurotransmitter and hormone) has an excitatory effect on the neuron and makes it positively charged and more likely to fire
- whether a postsynaptic neuron fires is decided by the summation process, the excitatory and inhibitory influences are summer up - if the net effect on the postsynaptic neuron is inhibitory then the neuron is less likely to fire whereas if the net effect is excitatory then it is more likely to fire where the neuron becomes positively charged and the electrical impulse is created and travels down the neuron, therefore the action potential of the postsynaptic neuron is only triggered if the sum of the excitatory or inhibitory signals reaches the threshold
Localisation of Function in the Brain (A01)
- in the 19th century Broca and Wernicke discovered that specific areas in the brain were associated with particular physical and psychological functions when before these investigations scientists generally supported a holistic view which was that all parts of the brain were associated with the processing of thoughts and actions, Broca and Wernicke argued localisation of function which refers to different parts of the brain performing different tasks involved with different parts of the body, therefore if a certain area of the brain becomes damaged through illness or injury then the function associated with that area will also be affected
- the main part of the brain (cerebrum) is divided into the left and right hemisphere and some of our physical and psychological functions are controlled by a particular hemisphere (lateralisation), activity on the left hand side of the bod if controlled by the right hemisphere and activity on the right hand side of the body is controlled by the left hemisphere, language is also linked to the left hemisphere
- the cortex of both hemispheres is divided into four lobes: the frontal lobe, temporal lobe, parietal lobe, occipital lobe, a lobe is a part of an organ that is some way separate from the rest and each lobe is associated with a different function, at the back if the frontal lob (both hemispheres) is the motor cortex (area) which controls voluntary movement in the opposite side of the body and damage to this area may cause a loss of control of fine movements, at the front of the parietal lobe is the somatosensory cortex (area) which represents the sensory information from the skin (touch, heat, pressure etc.) which is separated from the motor cortex by a channel called the central sulcus and the more somatosensory area devoted to a particular body part measures its sensitivity, the occipital lobe is located at the back of the visual area and the left visual field sends information to the right visual cortex and vice versa meaning that damage to the left visual cortex would lead to blindness in the right eye, the temporal lobe houses the auditory area which analyses speech-based information, damage may cause partial hearing loss and damage to a specific area (eg. Wernicke’s area) of the temporal lobe may affect the ability to comprehend language
- in most people language is restricted to the left side of the brain, Broca identified a small area in the left frontal lobe that is responsible for speech production, damage to the area causes Broca’s aphasia which involves speech being slow, laborious and lacks fluency, Broca’s most famous patient was Tan as that was all he could say, people with Broca’s aphasia have problems with conjunctions and prepositions (eg. a, the, and)
- Wernicke identified an area in the left temporal lobe that is responsible for language understanding (no problem producing speech but couldn’t understand it making their speech meaningless and lack fluency), people with Wernicke’s aphasia often produces ‘nonsense’ words as part of their speech
Localisation of Function in the Brain (A03)
- a strength is evidence from neurosurgery as damage to areas of the brain have been linked to mental disorders, such as cingulate gyrus being associated with OCD, Dougherty found 44 OCD patients had undergone cingulotomies
- evidence from brain scans, Peterson showed that Wernicke’s area was active during a listening task and Tulving showed that the episodic and semantic LTM are located on opposite sides of pre-frontal cortex
- case study evidence - HM, Phineas Gage,
- language may not be localised just to Broca’s area and Wernicke’s area, Dick and Tremblay found only 2%of psychologists believe that language in the brain is controlled by these two areas, and since recent technology like fMRIs mean neural processes can be studied with more clarity and it seems language processes are mosre holistically distributed across the brain, language channels have been found elsewhere like the right hemisphere
Hemispheric Lateralisation (A01+A03)
Hemispheric Lateralisation A01
- language is lateralised (performed by one hemisphere)
- the hemispheres are not symmetrical and have different functions
- suggested that LH is the analyser and RH is the sythesiser as it adds emotional context
- vision, motor and somatosensory areas are found in both hemispheres and are not lateralised
- RH controls movement on the left side of body and vice versa
- vision is both contralateral and ipsilateral (opposite and same-side), LVF is connected to RH and vice versa which allows the visual areas to compare perspective and have deeper perception
A03
- supporting evidence, Fink et al. used PET scans to see which brain areas were active in a visual processing task, when participants looked at global elements of images the RH active and when looking at finer details the LH was active, suggests that in visual processing, hemispheric lateralisation is a feature of a normal brain
- Neilson studied brain scans from over 1000 people and found that people did use certain hemispheres for tasks but there was not a dominant side - RH being the synthesiser, no evidence of a dominant hemisphere eg. maths brain or music brain, suggests that the notions of left/right-brained people is wrong
Split-Brain Research (A01+A03)
A01
- split brain patients have severed corpus callosums in order to reduce epilepsy so hemispheres cannot communicate with eachother and seize
- Sperry (1968) conducted an experiment to see how the hemispheres worked at different task (eg. visual and speech), 11 patients, image or word was projected onto screen in RVF and same or diff. image to LVF, normal brains would be able to see complete image, when an image was shown to RVF they could describe it but not in LVF, image in LVF could be identified through touch (picking it up) but could not name it, image in LVF could be drawn but not said, right hemisphere could recognise faces left hemisphere struggled
- concluded that left hemisphere is verbal and right is silent but emotional
A03
- highly controlled experiment, highly specialised and standardised procedures, establish cause and effect by being able to control the ppt was only using one eye to look at fixation point eliminates extraneous variables, high internal validity
- methodological issue of split brain patients being rare so only 11 in study, lacks generalisability, control group of neurotypical ppt was an issue as none of them had epilepsy so large confounding variable so differences between group may be because of epilepsy rather than split brain,
Plasticity and Functional Recovery of the Brain after Trauma (A01)
- neuroplasticity is the ability for the brain to change physical structure to perform different functions due to experience of learning, occurs after trauma or damage to brain typically, in childhood the brain is highly plastic and allows children to learn new things quickly, adapt to their environment and recover from brain damage quickly, neuroplasticity reduced with age but remains, unused pathways are removed, commonly used pathways are strengthened (synaptic pruning) and new pathways can be formed
- Maguire studied london cab drivers and found higher levels of grey matter in the hippocampus compared to control group which is associated with navigational skills, learning the london roads and maps changed their brain structure and the longer they had been cabbies the more pronounced the differences were
- functional recovery is when healthy parts of the brain take over functions from damaged parts, axonal sprouting is when undamaged axons grow new nerve endings to reconnect with neurons whose links were severed to form new nerve pathways, denervation supersensitivity is when axons that do a similar job become highly aroused in order to compensate for the lost ones, homologous area adaption is when one hemisphere can take over some function of a damaged hemisphere
Plasticity and Functional Recovery of the Brain after Trauma (A03)
- supporting evidence from Maguire
- plasticity does not always reduce with age, Bezzola found that 40 hours of golf training produced changes in neural representations of movement in ppts aged 40-60, using fMRIs she observed increased motor cortex compared to a control group, suggesting more efficient neural representations after training
- real world application of functional recovery as people with brain damage can be encouraged for new therapies since we understand how axonal sprouting works such as contraint-movement therapy where affected area is trained to recover
- limitation is that level of education may influence recovery rates, Schneider revealed that the more time victim of brain damage has spent in education (higher cognitive reserve), the greater their chance of disability free recovery is, 40% of people who achieves DFR had over 16 years of education compared to 10% who had less than 12 years
Ways of Studying the Brain - A01
- techniques for investigating the brain are often used more medical purposes when diagnosing illnesses, the purpose of scanning is often to investigate brain localisation
Functional Magnetism Resonance Imaging (fMRIs) - fMRIs work by detecting the changes in blood oxygenation and flow that occurs in specific parts of the brain as a result of neural activity, when a brain area is more active it requires more oxygen to meet its increased demand, causing the flow to increase direction to that area (known as the haemodynamic response), fMRI produces three-dimensional images which show the parts of the brain that are involved in particular mental processes, proving to be important for investigating localisation of function in the brain
Electroencephalogram (EEG) - EEGs measure electrical activity within the brain via electrodes that are fixed into an individual’s scalp using a skull cap, the scan recording represents the brainwave patterns that are generated from the action of neurons to create an account of overall brain activity, EEGs are often used by clinicians to diagnose unusual patterns of activity in the brain that may indicate neurological abnormalities like epilepsy or tumours
- EEGs have many practical and clinical applications however it is a crude, invasive and overly general measure of brain activity, within EEG data is all the neural responses associated with specific sensory, cognitive and motor events that may interest to cognitive psychologists
- researchers have therefore constructed a way of isolating these responses, by using a statistical averaging technique to filter out all extraneous brain activity (background information) from the original EEG recording and leaving only the relevant data to the research topic, such as a specific task or stimulus, these are called ERPs
Event-Related Potentials (ERPs) - ERPs are a type of brainwave that are triggered by particular events, research has revealed many ERPs and has found how they are linked to certain cognitive processes like perception or attention
Post-Mortem Exams - the analysis of a person’s brain after they have died, typically involving people who have a rare disorder or have experienced unusual deficits in mental processing or behaviour during their lives, damaged areas are examined and the causes of afflictions they experienced are determined, sometimes they are compared to a neurotypical brain to establish the extend of the difference
Ways of Studying the Brain - A03
fMRI
- One strength is that fMRIs do not use radiation when scanning, meaning the process is risk-free, non-invasive, and straightforward to use, they also produce images that have high-spatial resolution meaning that they are clear and detailed down to the millimetre providing a clear picture of the brain activity localised
- a limitation is that fMRIs have low temporal resolution because there is a 5-second long time-lag behind the image on the screen and the neuronal activity, meaning that fMRIs may not truly represent moment to moment brain activity, they are also more expensive to carry out than other neuroimaging techniques
EEG
- a strength of EEGs is that they are useful for diagnosing epilepsy, which consists of random bursts of activity in the brain and can be easily detected on the screen, they are also useful for studying stages of sleep, they have high temporal resolution, as they can detect brain activity at the resolution of a millisecond, proving them to have real life usefulness is clinical practice
- a limitation is that EEGs recieve ungeneralised information (thousands of neurons), meaning that researchers struggle to distinguish between activites originating in different locations
ERPs
- a strength is that they provide a much more specific measure of neural activity than EEGs can achieve, as they are derived from EEG measurements they also have high temporal resolution, this makes them useful for measure cognitive functions such as the allocation of attentional resources and the maintenance of the working memory model
- a limitation is that critics have pointed to a lack in standardisation in ERP methodology making it difficult to confirm findings, in order to achieve pure data the background ‘noise’ also needs to be eliminated which is often difficult to do
Post Mortems
- a strength of post-mortems is that the evidence they provided was vital in the foundation for early understanding of key processes in the brain, Broca and Wernicke both relied on post-mortems for their findings of linking language, behaviour and the brain decades before neuroimaging even became possible, they were also used to identify the damaged areas in HM’s brain, making them useful in clinical practices
- a limitation is that causation is an issue as the reason for brains to be damaged may be because of trauma or decay rather than the deficits under review, there are also ethical issues of consent from before the person died, as they may not have and are unable to give informed consent, therefore challenging the usefulness of post-mortem examinations in psychological research
Biological Rhythms: Circadian Rhythms - A01
- biological rhythms happen to all living organisms and they exert an important influence on how body systems behave
- all biological rhythms are governed by endogenous pacemakers (internal biological clocks) and exogenous zeitgebers (external changes in the environment).
- some rhythms occur multiple times throughout the day (ultradian rhythms) and some take longer than a day (infradian rhythms), some take much longer (circannual rhythms) - circadian rhythms last around 24 hours
The sleep wake cycle - daylight is an important exogenous zeitgeber in the sleep/wake cycle
- it is also governed by the suprachiasmatic nucleus (SCN), which lies just above the optic chiasm which provides information from the eye about light . exogenous zeitgebers can reset the SCU.
Siffre’s cave study - Siffre is a caveman who has spent several periods underground to study effects on his own biological rhythms while deprived of exposure to natural light and sound, but access to food and drink
- Siffre resurfaced in September 1962 after two months in the caves (Southern Alps). a decade later he performed a similar feat but stayed 6 months in a Texan cave
- in both, his biological rhythm set to 25 hours, though he remained on a pretty normal schedule sleeping and waking up
Other research - similar results were recorded by Aschoff and Wever (1976) who convinced a group of ppts to spend 4 weeks in a WW2 bunker deprived of natural light, all but one ppt (whos circadian rhythm extended to 29 hours) had a rhythm of 24/25 hours. this suggests that the natural sleep/wake cycle may be longer than 24 hours but the exogenous zeitgebers associated with our 24 hour days (eg. daylight hours, mealtimes) train it
- However, Folkard et al. (1985) studied 12 ppts who lived in a dark cave for three weeks, going to sleep at 11:45 each night and waking up at 7:45 every morning, however the researchers sped up the clock gradually so the ‘24 hours’ ended up only 22 hours, over the course of the study only one ppt managed to adapt to the new sleep schedule whilst the rest didn’t, suggesting that the strong free-running circadian rhythm cannot easily be overridden by exogenous zeitgebers
Biological Rhythms: Circadian Rhythms - A03
Biological Rhythms: Infradian Rhythms (A01+A03)
A01
- infradian rhythms last more than 24 hours
- the menstrual cycle lasts around 28 days and involves oestrogen levels rising causing ovulation, progesterone thickens the lining of he womb preparing for pregnancy and if no pregnancy occurs (egg is not fertilised) then the egg and lining is shed which is menstruation, although the menstrual cycle is an endogenous system evidence (Stern and McClintock) suggests it may be influenced by exogenous factors like other womens’ cycles, they can become synchronised as a result of other female pheromones
- SAD (seasonal affective disorder) is a depressive disorder which has a seasonal patterns of onset and is described as a mental disorder in the DSM-5, symptoms persist of low moods and lack of interest and activity, psychologists have hypothesised that the hormone melatonin is implicated in the cause of SAD
A03
- a strength of Stern and McClintock’s research into menstrual synchrony is that it can be explained by natural selection as synchronising of the female menstrual cycle us thought to have evolutionary value as it may have been an advantage for our ancestors, when females cycles synch they are more likely to get pregnant at the same time and then when the babies were born if a mother died or was unavailable other mothers would be able to breastfeed and therefore improving their chance of survival, suggesting that synchronising is an adaptive strategy
- however there are methodological problems with the study as confounding variables like diet, stress, exercise may have had an impact on the ppt’s cycles and therefore any pattern of synchrony may have just occured by chance
Biological Rhythms: Ultradian Rhythms (A01+A03)
A01
- ultradian rhythms occur multiple times within 24 hours
- one of the most researched ultradian rhythm is the sleep cycle, psychologists have identified 5 stages of sleep that span out to 90 minutes and is continuous throughout the night, each stage is measured by the brainwave activity that can be monitored using EEG, stages 1 and 2 are light sleep and the waves are high frequency and short amplitude (alpha waves), stages 3 and 4 are deep sleep where the waves have lower frequency and higher amplitude (delta waves), and stage 5 is REM sleep where the body is paralysed but the brain activity resembles as awake brain where the brain produces theta waves
A03
- improved understanding of age related changed in sleep, sleep scientists have observed that SWS (stages 3-4) reduce with age because growth hormone is usually produced during SWS, therefore the sleep deficit may explain other impairments with age such as reduced alertness, meditation and relaxation can be used to increase SWS
- a limitation is that there is significant variation between people’s ultradian rhythms, Tucker found large differences between ppts in terms of the lengths of each sleep stage and suggested that these differences are likely biologically determined, therefore making it difficult to understand or claim a ‘normal’ sleep cycle
Endogenous Pacemakers and Exogenous Zeitgebers (A01)
Endogenous Pacemakers and Exogenous Zeitgebers (A03)
