biopsychology Flashcards
define the nervous system
specialised network of cells and is our primary internal communication system
2 major functions of the nervous system
- to collect process and respond to information in the environment
- to coordinate the workings of different organs and cells in the body
what are the 2 subsystems the nervous system is divided into
- central nervous system
- peripheral nervous system
what is the central nervous system
consists of the brain and spinal cord
the brain is the centre of all conscious awareness
the spinal cord is an extension of the brain, responsible for reflex arc
define the peripheral nervous system
transmits messages via neurones to and from the central nervous system
subdivided into:
autnomic nervous system
somatic nervous system
define the autonomic nervous system
transits info to and from organs
the system acts involuntarily
subdivided into sympathetic and parasympathetic
define somatic nervous system
transmits info from sense organs to central nervous system,
receives info from CNS for muscles to act
define the endocrine system
works alongside the nervous system to control the vital functions of the body. Acts more slowly compared to the nervous system but has widespread effects
Instructs glands to release hormones. the hormones are then secreted into the bloodstream and are carried towards target organs in the body
the main endocrine gland is the pituitary gland located in the brain as it controls the release of all other endocrine glands in the body
biological changes in the sympathetic state 6
- increase heart rate
- increase breathing rate
- dilates pupils
- inhibits digestion
- inhibits saliva production
- contracts rectum
biological changes in the parasympathetic state 6
- decrease heart rate
- decrease breathing rate
- constricts pupils
- stimulate digestion
- stimulate saliva production
- relaxes rectum
define adrenaline
a hormone produce by adrenal glands which is part of the body immediate stress response system.
adrenaline has a strong effect on the cells in the cardiovascular system stimulating heart rate, contracting blood vessels and dilating air passages
what do the endocrine and ANS work together for
the flight or flight response
the endocrine and ANS working together
- when a stressor is perceived:
- hypothalamus triggers the activity in the sympathetic branch of the autonomic nervous system
- ANS changes from resting parasympathetic state to sympathetic state
- stress hormone adrenaline is released from the adrenal medulla into the bloodstream
- adrenaline triggers physiological change arousal for fight or flight e.g. increased heart rate
- once the stressor has passed the parasympathetic branch returns the body to resting state e.g. decrease heart rate
what are the 3 types of neurone
motor sensory and relay
define neuron
process and transmit messages through electrical and chemical signals
define sensory neurones
carry messages from the PNS to the CNS
they have long dendrites and short axons
define relay neurones
connect sensory to other relay or motor neurones
short dendrites and short axons
define motor neurones
connect CNS to the effectors
short dendrites and long axons
define the cell body of a neurone
includes a nucleus which contains genetic information of the cell.
branch-like structures dendrites protrude from the cell body
define the axon
carries an impulse away from the cell body down the length of the neurone
axon covers in a fatty layer called myelin sheath that protects the axon and speeds up electrical transmission of the impulse
define nodes of ranvier
if the myelin sheath was continuous, this would slow down the speed of transmission
so the myelin sheath is segmented by gaps, the Nodes of Ranvier which speeds up transmission by forcing them to ‘jump’
define terminal buttons
are at the end of the axon
communicate with the next neurone across a chain across a synapse
define electric transmission
when a neurone is at resting state, inside the cell is negatively charged compared to outside
when a neuron is activated by the stimulus the charge becomes positive causing an action potential
this creates an electrical impulse that travels down the axon towards the end of the neurone
define neural networks
groups of neurones where they communicate with eachother
what is each neurone separated by
a synapse
how are signals between neurone communicated
synaptic transmission
how are signals within neurone communicated
transmitted electrically
what happens when the electrical impulse reaches the end of the terminal
triggers the release of neurotransmitter from the synaptic vesicles
define neurotransmitters
chemicals that diffuse across the synapse to the next neuron in the chain, released from the synaptic vesicles
can be divided into into excitatory and inhibitory
what do neurotransmitters do
-once the neurotransmitter crosses the synapse, it Is taken up by the postsynaptic receptor sites, the dendrites of another axon
-here it is converted back into an electrical impulse
each neurotransmitter has a complementary specific shape to that of the post synaptic vesicles
-all have specific functions such as acetylcholine is found at each point where a motor neurone meets a muscle, upon its release the muscle will contract.
define excitatory
when a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron
this increases the likelihood that the neurone will fire and pass on the electrical impulse
define inhibitory
when a neurotransmitter, such as serotonin, makes the large of the postsynaptic neuron more negative
this decreases the likelihood that the neurone will fire and pass on the electrical impulse
define summation
whether a postsynaptic neuron does fire
excitatory and inhibitory effects are summed; is the net effect on the postsynaptic neurone is inhibitory, the neurone will be less likely to fire
if the net effect is excitatory, the neurone will be more likely to fire and the inside of the postsynaptic neurone becomes positively charged
once the electrical impulse is created, it travels down the neurone
define the localisation of the brain
Broca and Wernicke proposed the localisation of functions
this is the idea that different parts of the brain perform different tasks and are involved in different parts of the body.
if an area of the brain becomes damaged, the function associated with that part of the brain is also damaged
the general rule of the hemispheres
the brain is divided into 2 hemispheres:
activity on the left hand side of the body is controlled by the right hemisphere
activity on the right hand side of the body is controlled by the left hemisphere
the outer layer of both the hemispheres is the cerebral cortex
the cortex appears grey due to the location of cell bodies
define the motor area
is at the back of the frontal lobe in both hemispheres
which controls the voluntary movement in the opposite side of the body
damage to this area may result in loss of control over fine movements
define the somatosensory area
is at the front of both parietal lobes
separated from the motor area by a ‘valley’ central sulcus
where sensory information from the skin is represented.
the amount of the somatosensory area devoted to a particular body part determines its sensitivity
define the visual area
is in the occipital lobe at the back of the brain
receives and processes visual information
each eye sends information from the right visual field to the left visual cortex and the left visual field to the right visual cortex
e.g. damage to the left hemisphere could cause blindness in the right visual field of both eyes
define the auditory area
is in the temporal lobes
which analyses speech-based information
damage may produce partial hearing loss
where is language limited to
language is limited to the left hemisphere
define Broca’s area
in 1880s Broca identified a small area in the left frontal lobe responsible for speech production.
Damage to Broca’s area can cause speech aphasia- slow or lack of fluidity in speech
define Wernicke’s area
in the left temporal lobe responsible for language comprehension
Discovered when Wernicke discovered patients who had no problem producing language but difficulties in understanding it
when damaged would lead to Wernicke’s aphasia where people would often produce nonsense words - Neologisms as part of their content of the speech
evaluation of localisation of function in the brain
brain scan evidence of localisation
Petersen et al 1998 used brain scans to demonstrate how the Wernickes area was active during a listening task and Broca’s area was active during a reading task, suggesting these areas have different functions
evaluation of localisation of function in the brain
neurosurgical evidence
practice of surgery in removing areas of the brain to control aspects of behaviour developed in 1950s.
early attempts such asWalter Freeman’s lobotomy were brutal and imprecise involved severing connections inn the frontal lobe to control aggressive behaviour
controversially neurosurgery is still used today in severe cases of OCD and depression.
e.g. Dougherty et al 2002 reported on 44 people with OCD who had undergone a cingulotomy- neurosurgical procedure which involves lesioning the cingulate gyrus
at post surgical follow-up, a third had met the success criteria of successful response to surgery
success of surgery suggests that symptoms and behaviours associated with mental disorders are localised
evaluation of localisation of function in the brain
case study evidence
neurological damage case studies support localisation
Phinneas Gage who was preparing to blast a section of rock to create a new railway. During this, Gage dropped his tamping iron onto the rock causing the explosive to ignite. the explosion hurtled a metre length pole into Gage’s left cheek, passing behind his left eye and exiting the skull at the top of his skull.
Gage survived but the damage to his brain had left a mark on his personality
he turned from someone who was calm and reserved to someone who was quick tempered and rude
his change in temperament suggests that the frontal lobe may be responsible for regulating mood
define fMRI
works by detecting changes in blood oxygenation and flow that occur as a result of the neural brain activity in specific parts of the brain.
when a brain area is more active it consumes more oxygen and to meet this increase demand, blood flow is directed to the active area
fMRI produces 3D images showing which parts of the brain are involved in a particular process and this has important understanding of the localisation of function
define EEG
measure the electrical activity within the brain via electrodes that are fixed onto an individuals scalp using a skull cap.
the scan recording represents the brainwave patterns that are generated from the action of neurones
EEG are often used by clinicians as a diagnostic tool as unusual patterns of arrhythmic patterns of activity may indicate neurological abnormalities e.g. epilepsy
define ERP
within EEG all the neural responses associated with specific sensory, cognitive and motor areas that may be of interest. Researchers have developed a way of isolating responses
This is by using a statistical averaging response, all extraneous brain activity is filtered out leaving only the desired response
What remains are ERPs - types of brainwave that are triggered by events
define post mortems
following the analysis of a persons brain after death
individuals whose brains are subject to post mortems are likely to be those who had a rare disorder and have experienced unusual deficits in mental processes
areas are studied after death as a way of establishing the likely cause of the affliction the person experienced
may also involve comparison with a neurotypical brain to the determine the extent of the difference
strengths of fMRI
does not rely on the use of radiation
if administered correctly, it is virtually risk free and non invasive
produces images that have very high spatial resolution depicting a clear picture of how the brain is localised
weaknesses of fMRI
- is expensive compared to other methods
- can only produce a clear image if the person remains completely still
- has poor temporal resolution as there is a rough 5 second time lag behind the image on the screen to the initial firing
- only measures the blood flow in the brain, it cannot concentrate on the neurones so it can be difficult to tell what brain activity is represented on the screen
strengths of EEG
-invaluable in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can be seen on the screen
-contribted to the understanding of the stages of sleep -ultradian rhythms
unlike fMRI, EEGs have extremely high temporal -resolution, can accurately detect brain activity at the resolution of a single millisecond
weaknesses of EEG
the generalised nature of the information received.
not useful in pinpointing the exact source of neural activity
doesnt allow researchers to distinguish between the acitivites orginialy from different but adjacent regions
strengths of ERPs
much more specificity of the measurements of neural data than EEGs.
good temporal resolution which has led to their use in in the measurement of cognitive functions and deficits
researchers been able to identify many different ERPs and describe the precise role of these in cognitive functioning e.g. P300 component is thought to be involved in the allocation of attentional resources and the maintenance of working memory model
weaknesses of ERPs
lack of standardisation in ERP methodology between different research studies making it difficult to confirm findings
complete elimination of background noise and extraneous variables is not always achieved
strengths of post mortems
vital in providing the foundation of key processes in the brain. such as Paul Broca’s area and Wernicke’s area
both relied on post mortems to establish links between language brain and behaviour
improve medical knowledge and help generate hypotheses for further study
weaknesses of post mortems
causation is an issue
observed damage of the brain may not be linked to the deficits under review but to some other trauma or decay
raise ethical issues of consent, individuals may not be able to give informed consent such as HM who lost his ability to form memories and could not give consent nevertheless a post mortem was conducted on his brain.
define brain plasticity
the brain appears plastic in the sense that it has the ability to change throughout life.
during infancy the brain experiences a rapid growth in the synaptic connections
as we age, the rarely used connections are deleted and frequently used connections are strengthened - synaptic pruning
current research suggests that at any point in life existing neural connections can change or new neural connections can be formed as a result of learning or experience
what were the original thoughts of brain plasticity
changes of synaptic pruning were restricted to the developing brain through childhood, and the adult brain having moved past a critical period would remain fixed in terms of function and structure
research into plasticity
Eleanor Maguire et al 2000
studied the brains of London taxi drivers and found significantly higher volumes of grey matter in their posterior hippocampus than in a matched control group
this part of the brain is associated with the development of spatial and navigational skills.
As part of London taxi drivers must take part in a test called ‘the knowledge’ which access their recall of streets
it appears the result of this learning is to alter the structure of taxi drivers brain
positive correlation - the longer in the job the more pronounced the structural difference was
research into plasticity
Draganski et al 2006
following physical injury, or other forms of trauma such as the expeirence of a stroke unaffected areas of the brain are often able to adapt or compensate for those areas of damage
the functional recovery that may occur in the brain after trauma is another example of neural plasticity
healthy brain areas may take over the function of the damage areas
neuroscientists suggest this can take place quickly after trauma, spontaneous recovery and then slow down after a few weeks or months
at this point the individual may require rehabilitative recovery to further their recovery
what happens in the brain during recovery
the brain is able to rewire and reorganise itself by forming new synaptic connections close to the area of damage
secondary neural pathways that would not be typically sued to carry out certain functions that are activated or ‘unmasked’ to enable functioning to continue in the same way as before Doige 2007
this is supported by a number of structural changes:
axonal sprouting
reformation of blood vessels
recruitment of homologous/similar areas
define axonal sprouting
the growth of new nerve endings which connection with other undamaged nerve cells to form new neuronal pathways
define reformation of homologous/similar cells
on the opposite side of the brain to perform specific tasks. an example would be if Broca’s area was damaged on the left hand side of the brain, the right-sided equivalent would carry outfits functions
after a period of time, functionality may then shift back to the left hand side
evaluation of plasticity
practical application
understanding the processes involved in plasticity have contributed to neurorehabilitation
following illness or injury to the brain, spontaneous recovery tends to slow down after a number of weeks so forms of physical therapy may require to maintain improvements in functioning.
techniques may include movement therapy and electrical stimulation of the brain to counter the deficits in motor or cognitive functioning
process requires further intervention if its to be completely successful
evaluation of plasticity
negative plasticity
the brains ability to rewire itself can sometimes have maladaptive behavioural consequences.
prolonged drug use has been shown to result in poorer cognitive functioning as well as a greater risk of developing dementia in later life.
60-80% of amputees have also been known to develop phantom limb syndrome - the continued experiences of sensations in the missing limb as if it was still there, usually unpleasant and are thought to be be due to cortical reorganisation in the somatosensory cortex
evaluation of plasticity
age and plasticity
functional plasticity tends to be reduced with age
the brain has a greater propensity for reorganisation in childhood as it is constantly adapting to new experiences and learning
Ladina Bezzola et al 2012 demonstrated how 40 hours of gold training produced changes in the neural representation of movement in participants aged 40-60.
using fMRI the researchers observed reduced motor cortex activity in novice golfers compared to the control group suggesting more neural representations after training
shows neural plasticity does continue throughout their lifespan.
define hemispheric lateralisation
the idea that the two halves (hemispheres) of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.
such as language
define split brain research
Sperrys 1968 studies involved a unique group of individuals who had undergone the same surgical procedure - a commissurotomy in which the corpus collosum and other tissues which connect the two hemispheres were cut down the middle to separate the 2 hemispheres to control frequent epileptic seizures
the procedure of hemispheric lateralisation
Sperry devised a general procedure in which an image or word could be projected to an individuals right visual field - left hemisphere and the same or different image to the left visual field - right hemisphere. In the normal brain, the corpus collosum would immediately share the information between both hemispheres giving a complete picture of the world.
However presenting the image to one hemisphere of the split brain individual meant the information could not be conveyed
findings of hemispheric lateralisation
describing what you see
when a picture or object was shown to the right visual field, they could easily describe what was seen.
if the object was shown to the left visual field, they could not describe what was seen and typically that nothing was there.
language is mostly processed in the left hemisphere thus the individuals inability to describe objects in the left visual field - right hemisphere
as there is a lack of language centres in the right hemisphere where they would normally be relayed to the left hemisphere
findings of hemispheric lateralisation
describing recognition by touch
although individuals could not attach verbal labels to objects projected in the left visual field
they were able to select a matching object from a grab-bag of different objects using their left hand- right hemisphere
the objects were placed behind a screen so not to be seen
the left hand was also able to select an object that was most closely associated with an object presented to the left visual field.
in each case the individuals could not verbally identify what they had seen but could understand what the object was using the right hemisphere and select corresponding object accordingly
findings of hemispheric lateralisation
composite words
if two words were presented simultaneously, one on either side of the visual field
the individual would select the object with their left hand and say the word
findings of hemispheric lateralisation
matching faces
right hemisphere also appeared dominant in terms of recognising faces.
when asked to match a face from a series of other faces, the picture processed by the right hemisphere - left visual field was consistently selected, whilst the picture presented to the left hemisphere was consistently ignored
when a composite picture made up of 2 different halves of a face was presented, one half to each hemisphere, the left hemisphere dominated in terms of verbal description whereas the right hemisphere dominated in terms of selecting a matching pair
evaluation of hemispheric lateralisation
demonstrated lateralised brain functions
Sperrys work on split brain research has produced impressive research findings, where the left hemisphere is more geared towards analytic and verbal tasks whilst the right is more adept at performing spatial tasks and music.
the right hemisphere can only produce rudimentary words and phrases but contributes emotional and holistic content to language
left hemisphere is the analyser and the right hemisphere is the synthesiser
evaluation of hemispheric lateralisation
strengths of the methodology
made use of highly standardised procedures.
Sperry’s method of presenting visual information to one hemispheric field at a time
the image was only quickly flashed up meaning the participants would be flashed up, meaning the split-brain individuals would not have time to move their eyes across both sides of the visual field
ensuring only one hemisphere was taking up the information
evaluation of hemispheric lateralisation
theoretical basis
promoted a theoretical and philosophical debate about the degree of communication between the two hemispheres in everyday functioning and nature of consciousness
Roland Pucetti 1977, have suggested that the 2 hemispheres are so functionally different that they represent a form of duality in the brain - that in affect we are all two minds that this is a situation that is only emphasised rather than created in the split brain person
