AMRC Bio Approach Flashcards
HM study use
- localisation
- brain imaging techniques (MRI)
HM bg info
- HM fell off his bike, leading to severe epileptic seizures
- Cognitive, longitudinal case study of HM
○ HM’s anterograde and partial
retrograde - Biological part of study:
○ Correlation between brain damage and
amnesia
HM Aim
- In 1953, Scoville performed surgery on the then 27 year old to cure him of his epileptic seizures
- Surgical procedure- only became a study
once memory damage was noted
- Surgical procedure- only became a study
HM method
- During surgery, Scoville removed brain tissues
from anterior two thirds of the hippocampus - Once extent of memory loss was realised,
Scoville and Milner wrote about this and the
results of 9 similar patients in a prominent
neurological journal, and Milner started her
cognitive studying of HM
HM results
- Seizures reduces, but HM suffered with
amnesia for the rest of his life - HM lost ability to form new memories-
anterograde amnesia - Some retrograde amnesia
- HOWEVER early childhood memories stayed
intact and his IQ remained the same.
HM conclusion
The surgery which removed part of the hippocampus resulted in total anterograde and partial retrograde amnesia.
HM strengths
- Case study
- Triangulation
○ Researcher, data method
- Triangulation
- Longitudinal study- over 50 years
- Allows for the deeper, more detailed
research compared to the amount that
would have been able to be found had it
been a shorter snapshot study
- Allows for the deeper, more detailed
- Theoretical generalisability
- Can be used as a counter to lack off
generalisability - E.g. Creating a counter:
○ HM was quite “normal” and
“healthy.” Since all humans have
hippocampus, can theorise that if all
humans had their hippocampus
removed, they would experience the
same symptoms (not being able to
transfer from short to long term
memory)
- Can be used as a counter to lack off
- Qualitative data- rich, detailed
- Ecological validity
HM limitations
- Impact of medication for epilepsy
- Possible researcher bias
- Retrospective study: Type of longitudinal case
study design in which all data are collected
after the fact (i.e. After HM’s operation)- Researchers had no knowledge of HM’s
abilities prior to operation
- Researchers had no knowledge of HM’s
- Case study –> population validity –> lowered
generalisability - Debate: localisation = reductionist
- “however not holistic” is other side of
debate - must mention both bias
- “however not holistic” is other side of
Maguire et al (2000) use
- localisation (only use as second study)
- neuroanatomy
- brain imaging techniques (MRI)
Maguire aim
To see whether the brains of London taxi drivers would be different as a result of extensive training.
Maguire method
- 16 males, all healthy - compared to 50 male
non-taxi driver scans - Quasi experiment (correlational research)
○ IV not manipulated with matched-pairs
design - Average time spent training = 2 years
- Structural MRIs used to show relationship
between brain scans and length of time
drivers were licensed
Maguire results
- Taxi drivers control subjects - larger posterior
hippocampus, smaller anterior hippocampus - Hippocampal volume positively correlated
with time spend as taxi drivers
Maguire conclusion
- Plasticity occurs in response to environmental
change - Posterior hippocampus involved in spatial
skills - Implications for brain injury victims and
rehabilitation
Maguire strengths
Quasi experiment- naturally occurring
* Strong, positive correlation between
length of time driving & grey matter in
hippocampus
○ Bidirectional ambiguity
Single-blind control - avoid researcher bias
Use of MRIs
* Provide large amount of quantitative data
for statistical analysis, reduces demand
characteristics
* Scientific
Matched pairs designs - samples matched for age, sex and handedness
Maguire weaknesses
Androcentric sample
* Gender bias –> less generalisable
* Beta bias
* HOWEVER representational
generalisability as most London cabbies
are male
Use of MRIs
* Expensive
* Time-consuming
draganski et al use (2004)
neuroanatomy
brain imaging techniques (MRI)
Draganski aim
To see whether learning a new skill - in this case, juggling - would have an effect on the brains of the participants.
Draganski method
- 24 volunteers between ages 20 and 24
○ 21 females and 3 males - All participants non-jugglers at start of study
- Each had MRI scan at start of study to
serve as a base rate for grey matter and
brain structure
- Each had MRI scan at start of study to
- Participants allocated one of two conditions:
jugglers and non-juggler
○ Jugglers:
§ Taught three-ball cascade juggling
routing
§ Asked to practice routing and notify
researchers when they had
mastered it - at this point, jugglers
had second MRI scan
§ After scan, told not to juggle
anymore
§ 3 months later, third and final scan
carried out
§ Non-juggling group acted as control
group for duration of study
Draganski results
- Researchers used voxel-based morphometry
(VBM) to analyse MRI scans and determine if
there was significant differences in neural
density (grey matter) in brains of jugglers vs
non jugglers - From baseline scan, no significant regional
differences found in grey matter - However, jugglers showed significantly
larger amount of grey matter in mid-
temporal area in both hemispheres - an
area associated with visual memory - Three month after participants stopped
juggling - when many were no longer
able to carry out the routine - amount of
grey matter in these parts of the brain
had increased - Non-juggling sample saw no change over
duration of study - Seems that juggling relies more on visual
memory (perception and spatial anticipation
of moving objects) than on “procedural
memory” which would more likely show
change in cerebellum or basal ganglia
Draganski conclusion
- Grey matter grows in brain in response to
environmental demands (learning) and
shrinks in the absence of stimulation (lack of
practice). - This shows that there is a cause and effect
relationship between learning and brain
structure.
Draganski strengths
- The study used a pre-test, post-test design to
show differences in neural density over time. - The study was experimental, thus helping to
argue for a cause and effect relationship. - There was a control group that didn’t juggle
that served as a control group.
Draganski weaknesses
- The sample size was very small - so it is
possible that by using averages of growth, the
data may not be reliable. - The study has potential problems with
internal validity as the participants were in
their home environments for a good part of
the study. - The study would need to be replicated to
establish its reliability
Antonova et al (2011) use
neurotransmitters
brain imaging techniques (fMRI)
Antonova aim
To determine how blocking the acetylcholine receptors with scopolamine affects spatial memory.
antonova method
- 20 healthy male adults - mean age of 28
- Double blind procedure
- All participants received training about how to
use VR set up and rules before partaking in
the task - Participants randomly allocated to two
conditions
○ Group 1: injected with scopolamine
○ Group 2: injected with a placebo - Both groups injected with their respective
substances 70-90 minutes before taking part
in the experimental tasks - Participants put into fMRI while playing the
“arena task”
○ Complex virtual reality game in which the
researchers are observing how well
participants are able to create spatial
memories
§ Goal: to navigate and reach a pole
○ After reaching pole, screen went blank
for 30 seconds - in this time participants
were told to actively rehearse their route
to the pole
○ When area reappeared, they were at a
new starting point
§ Using spatial memory, they had to
get back to the pole - Brain activity measure for 6 trials
- Participants returned 3-4 weeks later and
redid the test
○ This time, received opposite treatment
(e.g. If they got placebo the first time,
they got scopolamine this time and vice
versa)
§ Repeated measures design
Antonova results
- Participants injected with scopolamine
showed significant reduction in the activation
of the hippocampus when compared to those
injected with placebo - Appears that Ach could play a key role in the
encoding of spatial memories in humans as
well as rats
Antonova conclusion
- Although there was a higher rate of error in
the scopolamine group, not a significant
difference - Difference in activity in the hippocampus,
however, is significant. - This means that the task design may not have
been best suited for showing performance
differences
- Without the use of fMRI, there would
have been no way to know that as the
biological level there were significant
differences in the two conditions
Antonova strengths
Double blind
* Controls researcher bias
○ Non-verbal cues, opinions etc
○ Therefore increases internal validity
§ Conclusions are reliable, where the
neurotransmitter Ach does not have
a role in memory encoding
* Greatly reduces demand characteristics
Random allocation
High internal validity
* Lab experiment
○ IV and DV operationalised to establish
cause and effect
○ Control over extraneous variables
Repeated measures
* Eliminates participant variability
* counter balanced - Controlled practice effects
(order)
Use of fMRI
* Scientific and therefore:
○ Objective
○ credible
Practical applications
* The results suggest drugs targeting the Ach
system, like physostigmine, may have
application in treatment of memory disorders,
like Alzheimer’s, assuming Ach plays a role in
memory function.
antonova weaknesses
During debrief participants said they felt stressed, either as a result of the injection of an unfamiliar drug or being in fMRI (claustrophobia)
* This could affect the hippocampus
function as stress may interfere with
memory encoding
* Might decrease ecological validity
Small androcentric sample
* Beta bias - assuming that results can simply
be replicated for females
* Reduces reliability
Lab experiment
* Since setting is artificial, low external
validity
Small sample size
* Results must be replicated to determine if
reliable
Use of fMRI
* Decrease ecological validity
* Participants anxious in unfamiliar/closed
space
antonova ethical considerations
- Informed consent
- Deception
- Protection from harm (mental) - participants
said they felt claustrophobic
rogers and kesner (2003) use
neurotransmitters
rogers and kesner aim
To determine the role of acetylcholine in the formation of and retrieval from spatial memory.
rogers and kesners method
- 30 rats acclimate to a Hebb Williams maze by
placing food in one of the corners
○ Once rats were familiar - and no longer
afraid of the environment - the
experiment could begin - The rats were randomly allocated to one of
two conditions:
○ Scopolamine - blocks the acetylcholine
receptor sites and thus inhibits any
response
○ Saline solution was a placebo injection -
done to ensure that getting an injection
alone was not responsible for a change in
memory.
§ An injection could result in an
increase in adrenaline which would
be a confounding variable
○ Injections were made directly into the
hippocampus - 10 minutes before running the maze, the rats
were either injected with scopolamine
(experimental group) or a saline solution
(control group) - Encoding of memory assessed by average
number of errors made on the first five trials
of Day 1 compared to the last five trials of Day
1 was used to assess retrieval
rogers and kesner results
- Scopolamine group took longer and made
more mistakes in the learning maze
○ Means higher average number of
mistakes made on the last five trials on
Day 1 - However, did not appear to have an effect on
retrieval of memories that had already been
created. - Appears that acetylcholine may play an
important role in the consolidation of spatial
memories
rogers and kesner conclusion
Suggests that acetylcholine plays and important role in memory encoding, because the rats with low acetylcholine levels wandered around the maze as though lost, even though they had learned it previously
rogers and kesner strengths
- Experimental design allows for cause and
effect conclusions base on isolation of
variables in three experimental conditions - Control group allows to control for possible
confounding variables - Lab experiment - easy to replicate, control of
variables - as rodents as easy to breed.
Replication leads to reliability of theory - adds
reliability to theory of neurotransmission - Reductionist
- Scientific- can break down and identify
specific cause
- Scientific- can break down and identify
- Biological determinism
- Scientific
- Predictable
Counter argument for generalisability: rats and humans have a similar limbic system.
Practical Applications
Results suggest that drugs targeting the acetylcholine system may have applications in the treatment of memory disorders, like Alzheimer’s disease, assuming that acetylcholine plays a role in memory formation.
rogers and kesner limitations
- Difficult to generalise animals studies to
humans because results may not be wholly
applicable - Effects of neurotransmitters are difficult to
isolate, because the alteration of one
neurotransmitter may cause changes in other
neurotransmitters too. - Counter for practical applications credibility:
- Biological reductionist - therefore ignores
other potential influences
- Biological reductionist - therefore ignores
- Not free will
* Harder to suggest change or choice
kiecolt-glaser et al (1995) use
hormones
kiecolt-glaser aim
To investigate the effects of stress, caused by caring for a relative with Alzheimer’s disease, on the immune system by looking at wound healing.
kiecolt glaser method
- Participants were recruited through a
newspaper advert (volunteer samples) - Experimental group: 13 women aged 47-81
years old were carers - Control group: 13 other women were
matched with carers on basis of age and
income - matched pairs design - All participants were dressed and treated by a
nurse in the same way for every participant - Researchers also assessed biochemical
substances (such as cytokines) to regulate the
immune system - Participants were given a 10 item perceived
stress scale to assess how stressed they were
feeling.
kiecolt-glaser results
- Complete healing took on average 9 days
(24%) longer in carers than control group - Cytokine (protein) levels, which are important
for wound healing, were lower in carers than
control group - Carers reported feeling more stressed on
perceived stress scale
kiecolt-glaser conclusion
- Chronic stress (increased cortisol) suppresses
functioning of the immune system. - The behaviour is the stress response but how
it affects the immune system- E.g. Chronic stress leads to increased
corticosteroids in the blood stream –>
lowers T cells –> lowered immune system
–> takes longer to heal
- E.g. Chronic stress leads to increased
kiecolt-glaser strengths
Application:
* Research provided good evidence to medical
staff and emphasised the effects that stress
can have on recovery after surgery. It is
important to reduce stress before surgery
Experimental design
* Quasi experiment - matched pairs (can be
countered with the weakness)
kiecolt-glaser weaknesses
Matching of participants was not exact
* Participants not matched on other factors
e.g. Relationship status or smokers
* Both these variables associated with
stress levels
* Carers more likely to be married
* Social support known to lower support
* Results in sample bias which suggests
that carers should have a better
functioning immune system and so
strengthens the validity of the study
findings
kiecolt glaser ethical issues
- Protection from (physical) harm - couldn’t
guarantee that the wound wouldn’t re-open
and cause the participants any pain - Deception - could go into full informed
consent
newcomer et al (1999) use
hormones