biopsych year 13 + year 12 Flashcards
what are the functions of the two hemispheres of the brain
left hemisphere- language
right hemisphere- visual motor skills
what are the 4 lobes of the brain
frontal
parietal
occipital
temporal
what is the location of the motor cortex
both hemispheres
back of the frontal lobe
what is the location of the somatosensory cortex
both hemispheres
front of parietal lobe
what are the 4 main cortex
motor
somatosensory
visual centre
auditory centre
what is the location of the visual centre
both hemispheres
occipital lobe
what is the location of the auditory centre
both hemispheres
temporal lobe
what are the two language centres
brocas area
wernickes area
what is the location of broca’s area
left hemisphere
frontal lobe
what is the location of wernickes area
left hemisphere
back of temporal lobe
what is the function of the motor cortex
involved in voluntary muscle movement
L controls R
R controls L
damage results in loss of motor movement in body
what is the function of the somatosensory cortex
receives sensory info from body
eg. temp touch pain and pressure
what is the function of the visual centre
involved in visual info
eg. shape colour movement
L eye controlled by R hemisphere
R eye controlled by L hemisphere
what is the function of the auditory centre
involved in auditory info and processes it
eg. tempo pitch and volume
L ear processed by R
R ear processed by L
what is the function of broca’s area
speech production
identified by broca
damage- speech is slow, labourous and lacking fluency
what is the function of wenickes area
lang comprehension
understanding meaning of words
can speak but meaningless speech
what is the corpus callosum
connects the left and right side of the brain + allows for communication btween two
what is localisation of function
theory that specific areas of brain associated with specific functions
what are the strengths of localisation of function
• brain scans provided evidence- petersen- wernickes area active during listening task and Broca’s area active during a reading out loud task
• Aphasia studies- damage to Brocas and Wernickes results in diff types of aphasia
expressive aphasia- Brocas- impaired ability to produce lang
receptive aphasia- Wernickes- impaired ability to extract meaning
what are the weaknesses of localisation of function
• lashley research using rats- suggested that motor and sensory are localised but higher cognitive function are not- removed areas of cortex in rats learning a maze- 10-50% - no area proven to be more important
• lashley- equpotetiality theory
in case of injury can transfer memory of function from damaged area to un damaged area
what is hemispheric lateralisation
the idea that two halves of the brain are functionally different. Each hemisphere has functional specialisations
what is the key study in hemispheric lateralisation
split brain research- sperry
what was the aim or Sperrys study
to find the extent to which the two hemispheres had diff functions- testing hemispheric lateralisation
what was the method of Sperrys research
quasi experiment
iv- split brain is pre existing
11ppts
lab experiment- highly controlled
divided field technique
word image presented for 10th of a second to ensure only processed by one visual field
what were the findings of Sperrys research
describe what you see condition :
RVF- patient easily describe what is seen ( processed by left hemisphere)
LVF- patient says there is nothing there ( processed by right hemisphere)
messages received by RH normally would be relayed to LH via corpus callosum
what was Sperrys conclusion from his research
supports hemispheric lateralisation
superiority of LH in language production
RH in visual motor tasks
what are the strengths of the method of split brain research
highly controlled lab experiment
high reliability- internal val- standardised procedures
image projected for one tenth of a second to one visual field- only one eye
what are the limitations of the of the split brain research
• method- low realism- data and task very artificial
in real life can see out both eyes and can complete everyday tasks
doesn’t allow to understand split brain patients in real world
• limited sample size- atypical sample
individual differences
don’t know when surgery was ( may have more practice)
don’t know differences in surgery
•criticism in findings - many modern neuroscientists argue not clear cut- behaviours associated with one can be performed by other
sperry may be too simplistic
JW developed capacity to speak about info presented to left or right
equipotentiality
what are the advantages of the THEORY of hemispheric lateralisation
• research to support this e.g. Sperry
• pucetti- suggested that the two hemispheres are so functionally different that they represent a form of duality in brain- split brain patients only emphasise rather than create situation
what are the disadvantages of the theory of hemispheric lateralisation?
- JW had capacity to speak about information presented to left or right brain
what is brain plasticity?
The brains ability to modify its own structures as a result of an experience e.g. learning to drive a car revision or trauma
What is synaptic pruning?
plasticity reduces with age
Frequently use connections are strengthened
Rarely used connections are deleted
Fine tuning connections
why are infants more likely to have successful recovery to injury?
More plasticity around 1500 synaptic connections
Peak plasticity in childhood ability to modify to trauma
what is the key study into brain plasticity?
Maguire - taxi driver study
What were Maguires aims of the study into brain plasticity?
To examine whether structural changes could be detected in the brain of people with experience of spatial navigation
What was Maguire’s method into research into plasticity?
structural MRI scans obtained
16 right-handed male London taxi driver
All had been driving for more than 1.5 years
Scans of 50 healthy right-handed males who did not drive taxis included for comparison
Mean age did not differ between two groups
High control
what were Maguires findings in the taxi driver study?
Found increased grey matter in brains of taxi drivers compared with control in the right and left hippocampus
Also found the changes with navigation experiences and there was a correlation found between the amount of time spent as a taxi driver and the volume of Gray in posterior hippocampus
What was the conclusion of Maguire study into brain plasticity?
evidence was provided for structural differences between the hippocampus of the taxi drivers and control participants
Suggesting extensive practice with spatial navigation affects hippocampus
what is another example of research into brain plasticity?
kuhn et al - video game training
what was Kuhns research into brain plasticity?
got participants to play Super Mario for at least 30 minutes per day over two months
Compared brain development to control group not playing video games over the two month period
Found significant differences in Gray matter of video gaming participants especially in the cortex hippocampus and cerebellum( involved in coordination movement)
What is functional recovery?
an example of plasticity
The transfer of functions from a damaged area of the brain after trauma to an undamaged area
How does functional recovery take place?
Through a method called neuronal unmasking
What is neuronal unmasking?
When dormant signup says open connections and compensate for nearby damaged area of brain
Brain is able to rewire and re-organise itself forming new connections
Secondary neural pathways activate enabling function to continue
what is recruitment of homologous areas?
This is the belief that on opposite hemisphere similar areas are recruited to do specific tasks e.g. Broca area moved to right side
What are the strengths of plasticity and functional recovery?
• research to support the idea brain can modify its own structures- Maguire research- increased Gray of Taxi drivers with experience
• research from animal studies also provides evidence- compared rats in complex environment to basic cage, found that rats in the complex environment developed more neurons than basic cage, increased neurons in HIPAA campus( associated with navigation) - clear evidence of brains ability to change as a result of experience
• research into neural plasticity has contributed to field of neuron rehabilitation- understanding processes involved in plasticity- techniques including electrical stimulation to help stroke patients after stroke gain certain abilities back- contributes to development of healthcare services
what are the weaknesses of plasticity and functional recovery of the brain?
• brain plasticity tends to reduce with age however some research shown evidence that contradict- maybe more complex- 40 to 60 year-old played 40 hours of golf compared to control- golfers all showed changes in motor cortex associated with golf- also stroke patients
• research has shown higher levels of education allows a better functional recovery of the brain after trauma- maybe other factors not just plasticity- degree level education is seven times more likely to be disability free a year after trauma
Cognitive factors are crucial in determining how well brain adapts after trauma
what are the 4 ways of studying the brain
EEG( electroencephalogram)
functional magnetic resonance imaging (fmri)
event related potentials (ERP)
post mortem
how do EEGs work
electrode cap on head
measures neuronal activity not blood
activity presented on EEG waves
small electrical charges detected by electrode and graphed over a period of time
4 types of EEG waves
used to detect disorders like sleep disorders and epilepsy
how do FMRIs work
measures blood flow when a person does a task (eg tap finger)
works on assumption that incr blood flow means neural activity
oxygenated blood and non have diff magnetic qualities
lights up - 3d map of brain
how do ERPs work
same as EEG- electrode cap
stimulus is presented and it looks at how you respond
stimulus is presented 100x and average is taken
still no pic of brain
how do post mortem work
physical examination of the brain
conducted after death
correlates structural abnormalities
useful for understanding disorders
eg. Tan - when alive presented an abnormality - lesion in left frontal lobe in post mortem
what is the evaluation of EEGs
high temporal resolution (1-10 milliseconds)
poor spatial resolution
( can’t pinpoint where it occurred and specific region )
non invasive - risk free no harm
can not establish cause and effect - difficult to pinpoint
cheap - widely available
larger sample sizes
what is the evaluation of fMRIs
poor temporal resolution- 1-4 second lag
high spatial resolution- 1-2mm of accuracy measures specific areas with great accuracy
non invasive- no risk no harm nothing inserted
can not establish cause and effect - correlational- measures changes in blood not neurons
expensive- not widely available - requires lots of training so not large sample sizes
what is the evaluation of ERPs
high temporal resolution- 1-10 milliseconds
poor spatial resolution- can’t pinpoint where
not invasive- risk free, no harm
can establish cause and effect- measure specific brain changes in relation to a stimuli over and over
cheap- large sample sizes
what is the evaluation of post mortem
patient is deceased- retrospective so not in real time
can allow researcher to examine deeper anatomical structures eg hypothalamus
correlational- deficit patient displays in lifetime may not be linked to deficits found in the brain after death
neural changes occurs during the process of death
need consent of either patient or family members- smaller samples
what is a circadian rhythm
a pattern or behaviour that occurs every 24 hours
which is reset by light - entrainment
eg sleep wake cycle, body temp
what is the sleep wake cycle and how does it work
dictates when you should be awake or asleep
light is an external cue for the sleep wake and provides a primary input - external zeitgeber
light is detected by ligjt sensitive cells in the eyes which send a message about the level of light to the suprachaismatic nuclei- in the hypothalamus
the SCN uses info to co ordinare the activity of the circadian system
ie- pineal gland to either inhibit or release melatonin
what are the two sleep drive “dips” in the day
between 2-4 am
between 1-3 am
what is the case study for circadian rhythms
Siffre cave study
what was siffres study
spent several extended periods underground to study the effects on biological rhythms
deprived exposure to light and sound but access to food and drink
resurfaced in sep thinking it was august
in each case his free running bio rhythm settled to 25 hours
how did siffres study support or criticise circadian rhythms
circadian rhythms is free running in the absence of an external queue EG light. Internal clock extended to around 25 hours causing him to misjudge time significantly.
Study demonstrates the importance of both
Misenlightment of internal clock shows endogenous pacemakers are crucial for maintaining
Exogenous zeitgeber are equally vital to entrain the rhythm
What is the strength of circadian rhythm research?
siffre- cave study
Application - by understanding circadian rhythms and their impacts on Health can determine when the best time to administer drug treatments- risk of heart attack drug can be taken at night, this means there is peak times for administration of variety of drugs to treat disorders such as cancer epilepsy
Support from Case study- siffre spent two months in caves terminating that his circadian rhythm remained between 24 and 25 hours- bodies internal clock is set 24 to 25 hours in the absence of external queues
What are weaknesses of study into circadian rhythms?
issues with case evidence- siffre study was only one individual, impossible to generalise these results to the whole world as maybe individual differences in research sample that makes these participants respond to changes in sleep cycle in atypical ways, age may play apart. Suggest the results cannot be generalised from the small samples.
Poor control in studies - in cave studies the exposure to artificial lights such as torches and phones was not controlled,v it was assumed that only natural light had an influence however research found that dim artificial lighting could adjust circadian rhythm to, means that these original studies may lack validity and impact on artificial lighting on our circadian rhythms. Also has practical applications when it comes to using iPhones a different times of the day.
What are endogenous pacemakers?
internal biological clocks
E.g. SCN
what are exogenous zeitgeber?
External cues affecting our biological rhythms
E.g. light and social queues
what did aschoff and weber study and what did they find
studied participants living in a bunker no windows only artificial light
Participants were free to turn on and off as they pleased
Found that participants settled into longer sleep wake cycles of 25 to 27 hours
Suggest that humans use natural light to regulate 24 hour circadian sleep week cycle showing importance of light
what did morgan research and what were their findings
bread hamsters so they had circadian rhythms of 20 hours rather than 24- SCN neurons from these abnormal hamsters were transplanted into brains of normal hamsters
They displayed the same abnormal rhythm of 20 hours
Suggest that the transplanted SCN had imposed its pattern onto hamster - showing significance of endogenous pacemakers and how important they are
what did duffy study and what were their findings
found that morning people prefer to rise and go to bed early - 6 am and 10 pm
Evening people prefer to wake up and go to bed later - 10 pm and 1 am
Demonstrates there may be an individual differences in circadian rhythms
This shows that research should focus on individual differences during investigations
What are infradian rhythms?
A biological rhythm that has a duration of over 24 hours
what is an example of an infradian rhythm?
Menstrual cycle
what is an ultradian rhythm?
A cycle that lasts less than 24 hours and it occurs more than once in a 24 hour period
What is an example of an ultradian rhythm?
Sleep stages 90 mins
how many stages of sleep are there and what are they?
There are five stages of sleep approximately 90 minutes long each- each level of brainwave activity is different
Stage one and stage two - light sleep brain patterns becomes slower and muscle activity slows down
Stage three and four - deep Delta waves difficult to wake up
Stage five - rapid eye movement dreaming occurs body is paralysed brain waves are desynchronised
what does Kleitmsn - basic rest activity cycle explain
how our body naturally moves through periods of high activity and rest roughly 90 minutes
Alertness and tiredness throughout the day similar to the stages of sleep
We need to rest and take a break managing energy and productivity
what are the strengths of ultradian rhythms?
Can now test or trade rhythms scientifically through the use of EEG
Research is monitored sleep patterns of nine participants in a sleep lab , found evidence for five stages
Said that REM activity correlated with the dreaming , participants woke up during dreaming and accurately recall dreams
HOWEVER
POOR EXTERNAL VALIDITY - sleep labs artificial only nine participants not generalisable
Poor internal as cannot recall how do you know if it’s accurate?
what are the weaknesses of ultradian rhythms?
There are significant individual differences in sleep stages
Variation between people that research does not take into account
Found large differences between participants, especially the duration of stages three and four
Differences are likely to be biologically determined, e.g. elderly spend less time in three and four
Difficult to define normal
Sleep
Stress, caffeine and alcohol all have an affect too
What is the menstrual cycle and how does it work?
monthly female menstrual cycle
Typical cycle takes 28 days to complete
Regulated by hormones, either promote ovulation or stimulate the uterus for fertilisation
Ovulation occurs halfway through the cycle when oestrogen levels are high
Progesterone levels increase after ovulation which helps womb lining to grow and thicken and prepare for pregnancy
what is the research into infradian rhythms?
russell et all
Found that female menstrual cycle became synchronised with other females through Odur exposure
Been one sweat samples from one group of women were rubbed onto upper lip of another group
Despite the fact the two groups were separate Changes in cycle which brought them closer to the cycle of their odour donor
Suggest can be affected by pheromones exogenous zeitgeber not just own hormones
What is the strength of infradian rhythms?
research into menstrual cycle has evolutionary value-
Maybe explained by natural selection
Synchronisation of menstrual cycle provides an evolutionary advantage
When females menstruate are pregnant at the same time it would allow babies who lost mothers during childbirth to have access to breast milk
Sink is an adaptive strategy higher chance of survival
what are the weaknesses of infradian rhythms?
However, validity of evolutionary perspective has been questioned- too much competition too many female cycling together would produce competition for highest quality males
Lowers the fitness for potential offspring
Issues with research into menstrual cycle synchronisation - individual differences in length of cycle length of period and day of ovulation
Factors that influence include diet exercise medication and stress
what are the two parts of the nervous system
central nervous system
peripheral nervous system
what does the CNS consist of and what are the main functions
brain- conscious awareness
-frontal, temporal, parietal, occipital
spinal cord- reflex actions
- unconscious
- delivers messages to and from brain
what is the role of the peripheral nervous system and what does it consist of
relays messages from CNS to rest of the body
consists of 2 main components :
- autonomic nervous system
- somatic nervous system
what is the role of the autonomic nervous system and what are the two components
important in role of homeostasis
consists of 2 motor pathways and has 2 components:
- sympathetic nervous system
- parasympathetic nervous system
what is the role of the autonomic nervous system and what are the two components
important in role of homeostasis
consists of 2 motor pathways and has 2 components:
- sympathetic nervous system
- parasympathetic nervous system
what is the role of the somatic nervous system
- skeletal muscle movement
- voluntary
- conscious
what is the sympathetic nervous system
fight or flight
stress response increase
heart rate increase
breathing rate increase
pupils dilate
what is the parasympathetic nervous system
rest and digest
return body back to normal
decr breathing rate
decr heart rate
what are dendrites
receive signals from other neuron cells
what does the axon do
conducts electrical impulses along cell
what does the myelin sheath do
insulate axon and speeds up transmission
what does the axon terminal do
transmits to other neuron cells
what is the function, location and distinctive features of the sensory neuron
sends signals from sense organs
receptors —> cns
myelin sheath and cell body in middle
what is the function, location and distinctive features of the relay neuron
connects neurons to other neurons
cns —> cns
no myelin sheath
what is the function, location and distinctive features of the motor neuron
sends signals to muscles to tell them to move
cns—-> effector
myelin sheath
what is the process of synaptic transmission
action potential arrives at the presinaptic neutron and causes vesicles to merge with the membrane
releases neurotransmitters into the synaptic cleft and they diffuse across synaptic cleft and are absorbed by receptors
summation- for a new action potential in post syn, electrical charge has to pass a threshold
excitatory- more likely to fire
inhibatory- less likely to fire
neurotransmitters that are not absorbed by post are reuptaken by pre
what are the 6 main features of synaptic transmission
pre + post synaptic neuron
vescicles
synaptic cleft
neurotransmitters
receptors
what is the location function and hormon of the hypothalamus
in brain
links nervous system to endocrine system with pituitary (homeostasis)
CRH
what is the location function and hormon of the pituitary gland
in brain
controls release of other hormones
ACTH
what is the location function and hormon of the thyroid gland
in front neck
modulates metabolism
thyroxine
what is the location function and hormon of the adrenal glands
top of kidneys
regulates the effects of flight or fight
adrenaline and cortisol
what is the location function and hormon of the testicle
reproductive glands - secondary sexual characteristics
hormone- testosterone
what is the location function and hormon of the ovary
reproductive glands
oestrogen
what is the location function and hormon of the pineal gland
in brain
modulates sleep pattern
melatonin
what is the fight or flight response to acute stress
hypothalamus activates autonomic NS on sympathetic branch
activated adrenal medulla
release of adrenaline and noradrenaline
body ready for fight or flight
parasympathetic to regulate back to normal
what is the nervous system
system of nerve cells that collect info, process it and then takes action via the transmission of electro chem messages
what is the endocrine system
collection of glands around the body that regulate bodily function, growth
release chemical messengers (hormones) into blood stream
